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`timescale 1ns / 1ps
// ============================================================================
//        __
//   \\__/ o\    (C) 2013  Robert Finch, Stratford
//    \  __ /    All rights reserved.
//     \/_//     robfinch<remove>@opencores.org
//       ||
//
// rtf65002.v
//  - 32 bit CPU
//
// This source file is free software: you can redistribute it and/or modify 
// it under the terms of the GNU Lesser General Public License as published 
// by the Free Software Foundation, either version 3 of the License, or     
// (at your option) any later version.                                      
//                                                                          
// This source file is distributed in the hope that it will be useful,      
// but WITHOUT ANY WARRANTY; without even the implied warranty of           
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            
// GNU General Public License for more details.                             
//                                                                          
// You should have received a copy of the GNU General Public License        
// along with this program.  If not, see <http://www.gnu.org/licenses/>.    
//                                                                          
// 9000 LUT's / 850 ff's / 56 MHz
// 15 Block RAMs
// ============================================================================
//
`define TRUE            1'b1
`define FALSE           1'b0
 
`define RST_VECT        34'h3FFFFFFF8
`define NMI_VECT        34'h3FFFFFFF4
`define IRQ_VECT        34'h3FFFFFFF0
`define BRK_VECT        34'h3FFFFFFEC
`define SLP_VECT        34'h3FFFFFFE8
`define BYTE_NMI_VECT   34'h00000FFFA
`define BYTE_IRQ_VECT   34'h00000FFFE
 
`define BRK                     8'h00
`define RTI                     8'h40
`define RTS                     8'h60
`define PHP                     8'h08
`define CLC                     8'h18
`define PLP                     8'h28
`define SEC                     8'h38
`define PHA                     8'h48
`define CLI                     8'h58
`define PLA                     8'h68
`define SEI                     8'h78
`define DEY                     8'h88
`define TYA                     8'h98
`define TAY                     8'hA8
`define CLV                     8'hB8
`define INY                     8'hC8
`define CLD                     8'hD8
`define INX                     8'hE8
`define SED                     8'hF8
`define ROR_ACC         8'h6A
`define TXA                     8'h8A
`define TXS                     8'h9A
`define TAX                     8'hAA
`define TSX                     8'hBA
`define DEX                     8'hCA
`define NOP                     8'hEA
`define TXY                     8'h9B
`define TYX                     8'hBB
`define TAS                     8'h1B
`define TSA                     8'h3B
`define TRS                     8'h8B
`define TSR                     8'hAB
`define STP                     8'hDB
`define NAT                     8'hFB
`define EMM                     8'hFB
`define INA                     8'h1A
`define DEA                     8'h3A
 
`define RR                      8'h02
`define ADD_RR                  4'd0
`define SUB_RR                  4'd1
`define CMP_RR                  4'd2
`define AND_RR                  4'd3
`define EOR_RR                  4'd4
`define OR_RR                   4'd5
`define MUL_RR                  4'd8
`define MULS_RR                 4'd9
`define DIV_RR                  4'd10
`define DIVS_RR                 4'd11
`define MOD_RR                  4'd12
`define MODS_RR                 4'd13
`define LD_RR           8'h7B
 
`define ADD_IMM8        8'h65           // 8 bit operand
`define ADD_IMM16       8'h79           // 16 bit operand
`define ADD_IMM32       8'h69           // 32 bit operand
`define ADD_ZPX         8'h75           // there is no ZP mode, use R0 to syntheisze
`define ADD_IX          8'h61
`define ADD_IY          8'h71
`define ADD_ABS         8'h6D
`define ADD_ABSX        8'h7D
`define ADD_RIND        8'h72
 
`define SUB_IMM8        8'hE5
`define SUB_IMM16       8'hF9
`define SUB_IMM32       8'hE9
`define SUB_ZPX         8'hF5
`define SUB_IX          8'hE1
`define SUB_IY          8'hF1
`define SUB_ABS         8'hED
`define SUB_ABSX        8'hFD
`define SUB_RIND        8'hF2
 
// CMP = SUB r0,....
 
`define ADC_IMM         8'h69
`define ADC_ZP          8'h65
`define ADC_ZPX         8'h75
`define ADC_IX          8'h61
`define ADC_IY          8'h71
`define ADC_ABS         8'h6D
`define ADC_ABSX        8'h7D
`define ADC_ABSY        8'h79
`define ADC_I           8'h72
 
`define SBC_IMM         8'hE9
`define SBC_ZP          8'hE5
`define SBC_ZPX         8'hF5
`define SBC_IX          8'hE1
`define SBC_IY          8'hF1
`define SBC_ABS         8'hED
`define SBC_ABSX        8'hFD
`define SBC_ABSY        8'hF9
`define SBC_I           8'hF2
 
`define CMP_IMM32       8'hC9
`define CMP_IMM         8'hC9
`define CMP_ZP          8'hC5
`define CMP_ZPX         8'hD5
`define CMP_IX          8'hC1
`define CMP_IY          8'hD1
`define CMP_ABS         8'hCD
`define CMP_ABSX        8'hDD
`define CMP_ABSY        8'hD9
`define CMP_I           8'hD2
 
 
`define LDA_IMM8        8'hA5
`define LDA_IMM16       8'hB9
`define LDA_IMM32       8'hA9
 
`define AND_IMM8        8'h25
`define AND_IMM16       8'h39
`define AND_IMM32       8'h29
`define AND_IMM         8'h29
`define AND_ZP          8'h25
`define AND_ZPX         8'h35
`define AND_IX          8'h21
`define AND_IY          8'h31
`define AND_ABS         8'h2D
`define AND_ABSX        8'h3D
`define AND_ABSY        8'h39
`define AND_RIND        8'h32
`define AND_I           8'h32
 
`define OR_IMM8         8'h05
`define OR_IMM16        8'h19
`define OR_IMM32        8'h09
`define OR_ZPX          8'h15
`define OR_IX           8'h01
`define OR_IY           8'h11
`define OR_ABS          8'h0D
`define OR_ABSX         8'h1D
`define OR_RIND         8'h12
 
`define ORA_IMM         8'h09
`define ORA_ZP          8'h05
`define ORA_ZPX         8'h15
`define ORA_IX          8'h01
`define ORA_IY          8'h11
`define ORA_ABS         8'h0D
`define ORA_ABSX        8'h1D
`define ORA_ABSY        8'h19
`define ORA_I           8'h12
 
`define EOR_IMM         8'h49
`define EOR_IMM8        8'h45
`define EOR_IMM16       8'h59
`define EOR_IMM32       8'h49
`define EOR_ZP          8'h45
`define EOR_ZPX         8'h55
`define EOR_IX          8'h41
`define EOR_IY          8'h51
`define EOR_ABS         8'h4D
`define EOR_ABSX        8'h5D
`define EOR_ABSY        8'h59
`define EOR_RIND        8'h52
`define EOR_I           8'h52
 
// LD is OR rt,r0,....
 
`define ST_ZPX          8'h95
`define ST_IX           8'h81
`define ST_IY           8'h91
`define ST_ABS          8'h8D
`define ST_ABSX         8'h9D
`define ST_RIND         8'h92
 
`define ORB_ZPX         8'hB5
`define ORB_IX          8'hA1
`define ORB_IY          8'hB1
`define ORB_ABS         8'hAD
`define ORB_ABSX        8'hBD
 
`define STB_ZPX         8'h74
`define STB_ABS         8'h9C
`define STB_ABSX        8'h9E
 
 
//`define LDB_RIND      8'hB2   // Conflict with LDX #imm16
 
`define LDA_IMM         8'hA9
`define LDA_ZP          8'hA5
`define LDA_ZPX         8'hB5
`define LDA_IX          8'hA1
`define LDA_IY          8'hB1
`define LDA_ABS         8'hAD
`define LDA_ABSX        8'hBD
`define LDA_ABSY        8'hB9
`define LDA_I           8'hB2
 
`define STA_ZP          8'h85
`define STA_ZPX         8'h95
`define STA_IX          8'h81
`define STA_IY          8'h91
`define STA_ABS         8'h8D
`define STA_ABSX        8'h9D
`define STA_ABSY        8'h99
`define STA_I           8'h92
 
`define ASL_ACC         8'h0A
`define ASL_ZP          8'h06
`define ASL_RR          8'h06
`define ASL_ZPX         8'h16
`define ASL_ABS         8'h0E
`define ASL_ABSX        8'h1E
 
`define ROL_ACC         8'h2A
`define ROL_ZP          8'h26
`define ROL_RR          8'h26
`define ROL_ZPX         8'h36
`define ROL_ABS         8'h2E
`define ROL_ABSX        8'h3E
 
`define LSR_ACC         8'h4A
`define LSR_ZP          8'h46
`define LSR_RR          8'h46
`define LSR_ZPX         8'h56
`define LSR_ABS         8'h4E
`define LSR_ABSX        8'h5E
 
`define ROR_RR          8'h66
`define ROR_ZP          8'h66
`define ROR_ZPX         8'h76
`define ROR_ABS         8'h6E
`define ROR_ABSX        8'h7E
 
`define DEC_RR          8'hC6
`define DEC_ZP          8'hC6
`define DEC_ZPX         8'hD6
`define DEC_ABS         8'hCE
`define DEC_ABSX        8'hDE
`define INC_RR          8'hE6
`define INC_ZP          8'hE6
`define INC_ZPX         8'hF6
`define INC_ABS         8'hEE
`define INC_ABSX        8'hFE
 
`define BIT_IMM         8'h89
`define BIT_ZP          8'h24
`define BIT_ZPX         8'h34
`define BIT_ABS         8'h2C
`define BIT_ABSX        8'h3C
 
// CMP = SUB r0,...
// BIT = AND r0,...
`define BPL                     8'h10
`define BVC                     8'h50
`define BCC                     8'h90
`define BNE                     8'hD0
`define BMI                     8'h30
`define BVS                     8'h70
`define BCS                     8'hB0
`define BEQ                     8'hF0
`define BRL                     8'h82
 
`define JML                     8'h5C
`define JMP                     8'h4C
`define JMP_IND         8'h6C
`define JMP_INDX        8'h7C
`define JMP_RIND        8'hD2
`define JSR                     8'h20
`define JSL                     8'h22
`define JSR_INDX        8'hFC
`define JSR_RIND        8'hC2
`define RTS                     8'h60
`define RTL                     8'h6B
`define BSR                     8'h62
`define NOP                     8'hEA
 
`define BRK                     8'h00
`define PLX                     8'hFA
`define PLY                     8'h7A
`define PHX                     8'hDA
`define PHY                     8'h5A
`define BRA                     8'h80
`define WAI                     8'hCB
`define PUSH            8'h0B
`define POP                     8'h2B
 
`define LDX_IMM         8'hA2
`define LDX_ZP          8'hA6
`define LDX_ZPX         8'hB6
`define LDX_ZPY         8'hB6
`define LDX_ABS         8'hAE
`define LDX_ABSY        8'hBE
 
`define LDX_IMM32       8'hA2
`define LDX_IMM16       8'hB2
`define LDX_IMM8        8'hA6
 
`define LDY_IMM         8'hA0
`define LDY_ZP          8'hA4
`define LDY_ZPX         8'hB4
`define LDY_IMM32       8'hA0
`define LDY_ABS         8'hAC
`define LDY_ABSX        8'hBC
 
`define STX_ZP          8'h86
`define STX_ZPX         8'h96
`define STX_ZPY         8'h96
`define STX_ABS         8'h8E
 
`define STY_ZP          8'h84
`define STY_ZPX         8'h94
`define STY_ABS         8'h8C
 
`define STZ_ZP          8'h64
`define STZ_ZPX         8'h74
`define STZ_ABS         8'h9C
`define STZ_ABSX        8'h9E
 
`define CPX_IMM         8'hE0
`define CPX_IMM32       8'hE0
`define CPX_ZP          8'hE4
`define CPX_ZPX         8'hE4
`define CPX_ABS         8'hEC
`define CPY_IMM         8'hC0
`define CPY_IMM32       8'hC0
`define CPY_ZP          8'hC4
`define CPY_ZPX         8'hC4
`define CPY_ABS         8'hCC
 
`define TRB_ZP          8'h14
`define TRB_ZPX         8'h14
`define TRB_ABS         8'h1C
`define TSB_ZP          8'h04
`define TSB_ZPX         8'h04
`define TSB_ABS         8'h0C
 
`define BAZ                     8'hC1
`define BXZ                     8'hD1
`define BEQ_RR          8'hE2
 
module icachemem(wclk, wr, adr, dat, rclk, pc, insn);
input wclk;
input wr;
input [33:0] adr;
input [31:0] dat;
input rclk;
input [31:0] pc;
output reg [55:0] insn;
 
wire [63:0] insn0;
wire [63:0] insn1;
wire [31:0] pcp8 = pc + 32'd8;
reg [31:0] rpc;
 
always @(posedge rclk)
        rpc <= pc;
 
// memL and memH combined allow a 64 bit read
syncRam2kx32_1rw1r ramL0
(
        .wrst(1'b0),
        .wclk(wclk),
        .wce(~adr[2]),
        .we(wr),
        .wsel(4'hF),
        .wadr(adr[13:3]),
        .i(dat),
        .wo(),
        .rrst(1'b0),
        .rclk(rclk),
        .rce(1'b1),
        .radr(pc[13:3]),
        .o(insn0[31:0])
);
 
syncRam2kx32_1rw1r ramH0
(
        .wrst(1'b0),
        .wclk(wclk),
        .wce(adr[2]),
        .we(wr),
        .wsel(4'hF),
        .wadr(adr[13:3]),
        .i(dat),
        .wo(),
        .rrst(1'b0),
        .rclk(rclk),
        .rce(1'b1),
        .radr(pc[13:3]),
        .o(insn0[63:32])
);
 
syncRam2kx32_1rw1r ramL1
(
        .wrst(1'b0),
        .wclk(wclk),
        .wce(~adr[2]),
        .we(wr),
        .wsel(4'hF),
        .wadr(adr[13:3]),
        .i(dat),
        .wo(),
        .rrst(1'b0),
        .rclk(rclk),
        .rce(1'b1),
        .radr(pcp8[13:3]),
        .o(insn1[31:0])
);
 
syncRam2kx32_1rw1r ramH1
(
        .wrst(1'b0),
        .wclk(wclk),
        .wce(adr[2]),
        .we(wr),
        .wsel(4'hF),
        .wadr(adr[13:3]),
        .i(dat),
        .wo(),
        .rrst(1'b0),
        .rclk(rclk),
        .rce(1'b1),
        .radr(pcp8[13:3]),
        .o(insn1[63:32])
);
 
always @(rpc or insn0 or insn1)
case(rpc[2:0])
3'd0:   insn <= insn0[55:0];
3'd1:   insn <= insn0[63:8];
3'd2:   insn <= {insn1[7:0],insn0[63:16]};
3'd3:   insn <= {insn1[15:0],insn0[63:24]};
3'd4:   insn <= {insn1[23:0],insn0[63:32]};
3'd5:   insn <= {insn1[31:0],insn0[63:40]};
3'd6:   insn <= {insn1[39:0],insn0[63:48]};
3'd7:   insn <= {insn1[47:0],insn0[63:56]};
endcase
endmodule
 
module tagmem(wclk, wr, adr, rclk, pc, hit0, hit1);
input wclk;
input wr;
input [33:0] adr;
input rclk;
input [31:0] pc;
output hit0;
output hit1;
 
wire [31:0] pcp8 = pc + 32'd8;
wire [31:0] tag0;
wire [31:0] tag1;
reg [31:0] rpc;
reg [31:0] rpcp8;
 
always @(posedge rclk)
        rpc <= pc;
always @(posedge rclk)
        rpcp8 <= pcp8;
 
syncRam1kx32_1rw1r ram0 (
        .wrst(1'b0),
        .wclk(wclk),
        .wce(adr[3:2]==2'b11),
        .we(wr),
        .wsel(4'hF),
        .wadr(adr[13:4]),
        .i(adr[31:0]),
        .wo(),
 
        .rrst(1'b0),
        .rclk(rclk),
        .rce(1'b1),
        .radr(pc[13:4]),
        .o(tag0)
);
 
syncRam1kx32_1rw1r ram1 (
        .wrst(1'b0),
        .wclk(wclk),
        .wce(adr[3:2]==2'b11),
        .we(wr),
        .wsel(4'hF),
        .wadr(adr[13:4]),
        .i(adr[31:0]),
        .wo(),
 
        .rrst(1'b0),
        .rclk(rclk),
        .rce(1'b1),
        .radr(pcp8[13:4]),
        .o(tag1)
);
 
assign hit0 = tag0[31:14]==rpc[31:14] && tag0[0];
assign hit1 = tag1[31:14]==rpcp8[31:14] && tag1[0];
 
endmodule
 
module dcachemem(wclk, wr, sel, wadr, wdat, rclk, radr, rdat);
input wclk;
input wr;
input [3:0] sel;
input [31:0] wadr;
input [31:0] wdat;
input rclk;
input [31:0] radr;
output [31:0] rdat;
 
syncRam2kx32_1rw1r ram0 (
        .wrst(1'b0),
        .wclk(wclk),
        .wce(1'b1),
        .we(wr),
        .wsel(sel),
        .wadr(wadr[10:0]),
        .i(wdat),
        .wo(),
        .rrst(1'b0),
        .rclk(rclk),
        .rce(1'b1),
        .radr(radr[10:0]),
        .o(rdat)
);
 
endmodule
 
module dtagmem(wclk, wr, wadr, rclk, radr, hit);
input wclk;
input wr;
input [31:0] wadr;
input rclk;
input [31:0] radr;
output hit;
 
reg [31:0] rradr;
wire [31:0] tag;
 
syncRam512x32_1rw1r u1
        (
                .wrst(1'b0),
                .wclk(wclk),
                .wce(wadr[1:0]==2'b11),
                .we(wr),
                .wadr(wadr[10:2]),
                .i(wadr),
                .wo(),
                .rrst(1'b0),
                .rclk(rclk),
                .rce(1'b1),
                .radr(radr[10:2]),
                .o(tag)
        );
 
 
always @(rclk)
        rradr <= radr;
 
assign hit = tag[31:11]==rradr[31:11];
 
endmodule
 
module overflow(op, a, b, s, v);
 
input op;       // 0=add,1=sub
input a;
input b;
input s;        // sum
output v;
 
// Overflow:
// Add: the signs of the inputs are the same, and the sign of the
// sum is different
// Sub: the signs of the inputs are different, and the sign of
// the sum is the same as B
assign v = (op ^ s ^ b) & (~op ^ a ^ b);
 
endmodule
 
 
module rtf65002d(rst_i, clk_i, nmi_i, irq_i, bte_o, cti_o, bl_o, lock_o, cyc_o, stb_o, ack_i, we_o, sel_o, adr_o, dat_i, dat_o);
parameter IDLE = 3'd0;
parameter LOAD_DCACHE = 3'd1;
parameter LOAD_ICACHE = 3'd2;
parameter LOAD_IBUF1 = 3'd3;
parameter LOAD_IBUF2 = 3'd4;
parameter LOAD_IBUF3 = 3'd5;
parameter RESET1 = 7'd0;
parameter IFETCH = 7'd1;
parameter JMP_IND1 = 7'd2;
parameter JMP_IND2 = 7'd3;
parameter DECODE = 7'd4;
parameter STORE1 = 7'd5;
parameter STORE2 = 7'd6;
parameter LOAD1 = 7'd7;
parameter LOAD2 = 7'd8;
parameter IRQ1 = 7'd9;
parameter IRQ2 = 7'd10;
parameter IRQ3 = 7'd11;
parameter CALC = 7'd12;
parameter JSR1 = 7'd13;
parameter JSR_INDX1 = 7'd14;
parameter JSR161 = 7'd15;
parameter RTS1 = 7'd16;
parameter RTS2 = 7'd17;
parameter IX1 = 7'd18;
parameter IX2 = 7'd19;
parameter IX3 = 7'd20;
parameter IX4 = 7'd21;
parameter IY1 = 7'd22;
parameter IY2 = 7'd23;
parameter IY3 = 7'd24;
parameter PHP1 = 7'd27;
parameter PLP1 = 7'd28;
parameter PLP2 = 7'd29;
parameter PLA1 = 7'd30;
parameter PLA2 = 7'd31;
parameter BSR1 = 7'd32;
parameter BYTE_IX1 = 7'd33;
parameter BYTE_IX2 = 7'd34;
parameter BYTE_IX3 = 7'd35;
parameter BYTE_IX4 = 7'd36;
parameter BYTE_IX5 = 7'd37;
parameter BYTE_IY1 = 7'd38;
parameter BYTE_IY2 = 7'd39;
parameter BYTE_IY3 = 7'd40;
parameter BYTE_IY4 = 7'd41;
parameter BYTE_IY5 = 7'd42;
parameter RTS3 = 7'd43;
parameter RTS4 = 7'd44;
parameter RTS5 = 7'd45;
parameter BYTE_JSR1 = 7'd46;
parameter BYTE_JSR2 = 7'd47;
parameter BYTE_JSR3 = 7'd48;
parameter BYTE_IRQ1 = 7'd49;
parameter BYTE_IRQ2 = 7'd50;
parameter BYTE_IRQ3 = 7'd51;
parameter BYTE_IRQ4 = 7'd52;
parameter BYTE_IRQ5 = 7'd53;
parameter BYTE_IRQ6 = 7'd54;
parameter BYTE_IRQ7 = 7'd55;
parameter BYTE_IRQ8 = 7'd56;
parameter BYTE_IRQ9 = 7'd57;
parameter BYTE_JMP_IND1 = 7'd58;
parameter BYTE_JMP_IND2 = 7'd59;
parameter BYTE_JMP_IND3 = 7'd60;
parameter BYTE_JMP_IND4 = 7'd61;
parameter BYTE_JSR_INDX1 = 7'd62;
parameter BYTE_JSR_INDX2 = 7'd63;
parameter BYTE_JSR_INDX3 = 7'd64;
parameter RTI1 = 7'd65;
parameter RTI2 = 7'd66;
parameter RTI3 = 7'd67;
parameter RTI4 = 7'd68;
parameter BYTE_RTS1 = 7'd69;
parameter BYTE_RTS2 = 7'd70;
parameter BYTE_RTS3 = 7'd71;
parameter BYTE_RTS4 = 7'd72;
parameter BYTE_RTS5 = 7'd73;
parameter BYTE_RTS6 = 7'd74;
parameter BYTE_RTS7 = 7'd75;
parameter BYTE_RTS8 = 7'd76;
parameter BYTE_RTS9 = 7'd77;
parameter BYTE_RTI1 = 7'd78;
parameter BYTE_RTI2 = 7'd79;
parameter BYTE_RTI3 = 7'd80;
parameter BYTE_RTI4 = 7'd81;
parameter BYTE_RTI5 = 7'd82;
parameter BYTE_RTI6 = 7'd83;
parameter BYTE_RTI7 = 7'd84;
parameter BYTE_RTI8 = 7'd85;
parameter BYTE_RTI9 = 7'd86;
parameter BYTE_RTI10 = 7'd87;
parameter BYTE_JSL1 = 7'd88;
parameter BYTE_JSL2 = 7'd89;
parameter BYTE_JSL3 = 7'd90;
parameter BYTE_JSL4 = 7'd91;
parameter BYTE_JSL5 = 7'd92;
parameter BYTE_JSL6 = 7'd93;
parameter BYTE_JSL7 = 7'd94;
parameter BYTE_PLP1 = 7'd95;
parameter BYTE_PLP2 = 7'd96;
parameter BYTE_PLA1 = 7'd97;
parameter BYTE_PLA2 = 7'd98;
parameter WAIT_DHIT = 7'd99;
parameter RESET2 = 7'd100;
parameter MULDIV1 = 7'd101;
parameter MULDIV2 = 7'd102;
 
input rst_i;
input clk_i;
input nmi_i;
input irq_i;
output reg [1:0] bte_o;
output reg [2:0] cti_o;
output reg [5:0] bl_o;
output reg lock_o;
output reg cyc_o;
output reg stb_o;
input ack_i;
output reg we_o;
output reg [3:0] sel_o;
output reg [33:0] adr_o;
input [31:0] dat_i;
output reg [31:0] dat_o;
 
reg [6:0] state;
reg [6:0] retstate;
reg [2:0] cstate;
wire [55:0] insn;
reg [55:0] ibuf;
reg [31:0] bufadr;
 
reg cf,nf,zf,vf,bf,im,df,em;
reg em1;
reg gie;
reg nmoi;       // native mode on interrupt
wire [31:0] sr = {nf,vf,em,24'b0,bf,df,im,zf,cf};
wire [7:0] sr8 = {nf,vf,1'b0,bf,df,im,zf,cf};
reg nmi1,nmi_edge;
reg wai;
reg [31:0] acc;
reg [31:0] x;
reg [31:0] y;
reg [7:0] sp;
wire [7:0] acc8 = acc[7:0];
wire [7:0] x8 = x[7:0];
wire [7:0] y8 = y[7:0];
reg [31:0] isp;          // interrupt stack pointer
wire [63:0] prod;
wire [31:0] q,r;
reg [31:0] tick;
wire [7:0] sp_dec = sp - 8'd1;
wire [7:0] sp_inc = sp + 8'd1;
wire [31:0] isp_dec = isp - 32'd1;
wire [31:0] isp_inc = isp + 32'd1;
reg [31:0] pc;
wire [31:0] pcp1 = pc + 32'd1;
wire [31:0] pcp2 = pc + 32'd2;
wire [31:0] pcp3 = pc + 32'd3;
wire [31:0] pcp4 = pc + 32'd4;
wire [31:0] pcp8 = pc + 32'd8;
reg [31:0] dp;
wire bhit=pc==bufadr;
reg [31:0] regfile [15:0];
reg [55:0] ir;
wire [3:0] Ra = ir[11:8];
wire [3:0] Rb = ir[15:12];
reg [31:0] rfoa;
reg [31:0] rfob;
always @(Ra or x or y or acc)
case(Ra)
4'h0:   rfoa <= 32'd0;
4'h1:   rfoa <= acc;
4'h2:   rfoa <= x;
4'h3:   rfoa <= y;
default:        rfoa <= regfile[Ra];
endcase
always @(Rb or x or y or acc)
case(Rb)
4'h0:   rfob <= 32'd0;
4'h1:   rfob <= acc;
4'h2:   rfob <= x;
4'h3:   rfob <= y;
default:        rfob <= regfile[Rb];
endcase
reg [3:0] Rt;
reg [33:0] ea;
reg first_ifetch;
reg [31:0] lfsr;
wire lfsr_fb;
xnor(lfsr_fb,lfsr[0],lfsr[1],lfsr[21],lfsr[31]);
reg [31:0] a, b;
reg [7:0] b8;
reg [32:0] res;
reg [8:0] res8;
wire resv8,resv32;
wire resc8 = res8[8];
wire resc32 = res[32];
wire resz8 = res8[7:0]==8'h00;
wire resz32 = res[31:0]==32'd0;
wire resn8 = res8[7];
wire resn32 = res[31];
wire resn = em ? res8[7] : res[31];
wire resz = em ? res8[7:0]==8'h00 : res[31:0]==32'd0;
wire resc = em ? res8[8] : res[32];
wire resv = em ? resv8 : resv32;
 
reg [31:0] vect;
reg [31:0] ia;                   // temporary reg to hold indirect address
wire [31:0] iapy8 = ia + y[7:0];
reg isInsnCacheLoad;
reg isDataCacheLoad;
reg isCacheReset;
wire hit0,hit1;
wire dhit;
reg write_allocate;
reg wr;
reg [3:0] wrsel;
reg [31:0] radr;
reg [1:0] radr2LSB;
wire [33:0] radr34 = {radr,radr2LSB};
wire [33:0] radr34p1 = radr34 + 34'd1;
reg [31:0] wadr;
reg [1:0] wadr2LSB;
reg [31:0] wdat;
wire [31:0] rdat;
reg imiss;
reg dmiss;
reg icacheOn,dcacheOn;
wire unCachedData = radr[31:28]==4'hD || !dcacheOn;
wire unCachedInsn =/* pc[31:28]==4'hF || */!icacheOn;
 
wire isSub = ir[7:0]==`SUB_ZPX || ir[7:0]==`SUB_IX || ir[7:0]==`SUB_IY ||
                         ir[7:0]==`SUB_ABS || ir[7:0]==`SUB_ABSX || ir[7:0]==`SUB_IMM8 || ir[7:0]==`SUB_IMM16 || ir[7:0]==`SUB_IMM32;
wire isSub8 = ir[7:0]==`SBC_ZP || ir[7:0]==`SBC_ZPX || ir[7:0]==`SBC_IX || ir[7:0]==`SBC_IY || ir[7:0]==`SBC_I ||
                         ir[7:0]==`SBC_ABS || ir[7:0]==`SBC_ABSX || ir[7:0]==`SBC_ABSY || ir[7:0]==`SBC_IMM;
wire isCmp = ir[7:0]==`CPX_ZPX || ir[7:0]==`CPX_ABS || ir[7:0]==`CPX_IMM32 ||
                         ir[7:0]==`CPY_ZPX || ir[7:0]==`CPY_ABS || ir[7:0]==`CPY_IMM32;
wire isRMW32 =
                         ir[7:0]==`ASL_ZPX || ir[7:0]==`ROL_ZPX || ir[7:0]==`LSR_ZPX || ir[7:0]==`ROR_ZPX || ir[7:0]==`INC_ZPX || ir[7:0]==`DEC_ZPX ||
                         ir[7:0]==`ASL_ABS || ir[7:0]==`ROL_ABS || ir[7:0]==`LSR_ABS || ir[7:0]==`ROR_ABS || ir[7:0]==`INC_ABS || ir[7:0]==`DEC_ABS ||
                         ir[7:0]==`ASL_ABSX || ir[7:0]==`ROL_ABSX || ir[7:0]==`LSR_ABSX || ir[7:0]==`ROR_ABSX || ir[7:0]==`INC_ABSX || ir[7:0]==`DEC_ABSX ||
                         ir[7:0]==`TRB_ZP || ir[7:0]==`TRB_ZPX || ir[7:0]==`TRB_ABS || ir[7:0]==`TSB_ZP || ir[7:0]==`TSB_ZPX || ir[7:0]==`TSB_ABS;
                         ;
wire isRMW8 =
                         ir[7:0]==`ASL_ZP || ir[7:0]==`ROL_ZP || ir[7:0]==`LSR_ZP || ir[7:0]==`ROR_ZP || ir[7:0]==`INC_ZP || ir[7:0]==`DEC_ZP ||
                         ir[7:0]==`ASL_ZPX || ir[7:0]==`ROL_ZPX || ir[7:0]==`LSR_ZPX || ir[7:0]==`ROR_ZPX || ir[7:0]==`INC_ZPX || ir[7:0]==`DEC_ZPX ||
                         ir[7:0]==`ASL_ABS || ir[7:0]==`ROL_ABS || ir[7:0]==`LSR_ABS || ir[7:0]==`ROR_ABS || ir[7:0]==`INC_ABS || ir[7:0]==`DEC_ABS ||
                         ir[7:0]==`ASL_ABSX || ir[7:0]==`ROL_ABSX || ir[7:0]==`LSR_ABSX || ir[7:0]==`ROR_ABSX || ir[7:0]==`INC_ABSX || ir[7:0]==`DEC_ABSX ||
                         ir[7:0]==`TRB_ZP || ir[7:0]==`TRB_ZPX || ir[7:0]==`TRB_ABS || ir[7:0]==`TSB_ZP || ir[7:0]==`TSB_ZPX || ir[7:0]==`TSB_ABS;
                         ;
wire isRMW = em ? isRMW8 : isRMW32;
wire isOrb = ir[7:0]==`ORB_ZPX || ir[7:0]==`ORB_IX || ir[7:0]==`ORB_IY || ir[7:0]==`ORB_ABS || ir[7:0]==`ORB_ABSX;
wire isStb = ir[7:0]==`STB_ZPX || ir[7:0]==`STB_ABS || ir[7:0]==`STB_ABSX;
 
wire ld_muldiv = state==DECODE && ir[7:0]==`RR;
wire md_done;
wire clk;
 
mult_div umd1
(
        .rst(rst),
        .clk(clk),
        .ld(ld_muldiv),
        .op(ir[23:20]),
        .a(rfoa),
        .b(rfob),
        .p(prod),
        .q(q),
        .r(r),
        .done(md_done)
);
 
icachemem icm0 (
        .wclk(clk),
        .wr(ack_i & isInsnCacheLoad),
        .adr(adr_o),
        .dat(dat_i),
        .rclk(~clk_i),
        .pc(pc),
        .insn(insn)
);
 
tagmem tgm0 (
        .wclk(clk),
        .wr((ack_i & isInsnCacheLoad)|isCacheReset),
        .adr({adr_o[31:1],!isCacheReset}),
        .rclk(~clk_i),
        .pc(pc),
        .hit0(hit0),
        .hit1(hit1)
);
 
wire ihit = (hit0 & hit1);//(pc[2:0] > 3'd1 ? hit1 : 1'b1));
 
dcachemem dcm0 (
        .wclk(clk),
        .wr(wr | (ack_i & isDataCacheLoad)),
        .sel(wr ? wrsel : sel_o),
        .wadr(wr ? wadr : adr_o[33:2]),
        .wdat(wr ? wdat : dat_i),
        .rclk(~clk_i),
        .radr(radr),
        .rdat(rdat)
);
 
dtagmem dtm0 (
        .wclk(clk),
        .wr(wr | (ack_i & isDataCacheLoad)),
        .wadr(wr ? wadr : adr_o[33:2]),
        .rclk(~clk_i),
        .radr(radr),
        .hit(dhit)
);
 
overflow uovr1 (
        .op(isSub),
        .a(a[31]),
        .b(b[31]),
        .s(res[31]),
        .v(resv32)
);
 
overflow uovr2 (
        .op(isSub8),
        .a(acc8[7]),
        .b(b8[7]),
        .s(res8[7]),
        .v(resv8)
);
 
wire [7:0] bcaio;
wire [7:0] bcao;
wire [7:0] bcsio;
wire [7:0] bcso;
wire bcaico,bcaco,bcsico,bcsco;
 
BCDAdd ubcdai1 (.ci(cf),.a(acc8),.b(ir[15:8]),.o(bcaio),.c(bcaico));
BCDAdd ubcda2 (.ci(cf),.a(acc8),.b(b8),.o(bcao),.c(bcaco));
BCDSub ubcdsi1 (.ci(cf),.a(acc8),.b(ir[15:8]),.o(bcsio),.c(bcsico));
BCDSub ubcds2 (.ci(cf),.a(acc8),.b(b8),.o(bcso),.c(bcsco));
 
reg [7:0] dati;
always @(radr2LSB or dat_i)
case(radr2LSB)
2'd0:   dati <= dat_i[7:0];
2'd1:   dati <= dat_i[15:8];
2'd2:   dati <= dat_i[23:16];
2'd3:   dati <= dat_i[31:24];
endcase
reg [7:0] rdat8;
always @(radr2LSB or rdat)
case(radr2LSB)
2'd0:   rdat8 <= rdat[7:0];
2'd1:   rdat8 <= rdat[15:8];
2'd2:   rdat8 <= rdat[23:16];
2'd3:   rdat8 <= rdat[31:24];
endcase
 
reg takb;
always @(ir or cf or vf or nf or zf)
case(ir[7:0])
`BEQ:   takb <= zf;
`BNE:   takb <= !zf;
`BPL:   takb <= !nf;
`BMI:   takb <= nf;
`BCS:   takb <= cf;
`BCC:   takb <= !cf;
`BVS:   takb <= vf;
`BVC:   takb <= !vf;
`BRA:   takb <= 1'b1;
`BRL:   takb <= 1'b1;
//`BAZ: takb <= acc8==8'h00;
//`BXZ: takb <= x8==8'h00;
default:        takb <= 1'b0;
endcase
 
wire [31:0] zpx_address = dp + ir[15:8] + x8;
wire [31:0] zpy_address = dp + ir[15:8] + y8;
wire [31:0] zp_address = dp + ir[15:8];
wire [31:0] abs_address = {16'h0,ir[23:8]};
wire [31:0] absx_address = {16'h0,ir[23:8] + {8'h0,x8}};
wire [31:0] absy_address = {16'h0,ir[23:8] + {8'h0,y8}};
wire [31:0] zpx32xy_address = dp + ir[23:12] + rfoa;
wire [31:0] absx32xy_address = ir[47:16] + rfob;
wire [31:0] zpx32_address = dp + ir[31:20] + rfob;
wire [31:0] absx32_address = ir[55:24] + rfob;
 
//-----------------------------------------------------------------------------
// Clock control
// - reset or NMI reenables the clock
// - this circuit must be under the clk_i domain
//-----------------------------------------------------------------------------
//
reg cpu_clk_en;
reg clk_en;
BUFGCE u20 (.CE(cpu_clk_en), .I(clk_i), .O(clk) );
 
always @(posedge clk_i)
if (rst_i) begin
        cpu_clk_en <= 1'b1;
        nmi1 <= 1'b0;
end
else begin
        nmi1 <= nmi_i;
        if (nmi_i)
                cpu_clk_en <= 1'b1;
        else
                cpu_clk_en <= clk_en;
end
 
always @(posedge clk)
if (rst_i) begin
        bte_o <= 2'b00;
        cti_o <= 3'b000;
        bl_o <= 6'd0;
        cyc_o <= 1'b0;
        stb_o <= 1'b0;
        we_o <= 1'b0;
        sel_o <= 4'h0;
        adr_o <= 34'd0;
        dat_o <= 32'd0;
        nmi_edge <= 1'b0;
        wai <= 1'b0;
        first_ifetch <= `TRUE;
        wr <= 1'b0;
        em <= 1'b0;
        cf <= 1'b0;
        ir <= 56'hEAEAEAEAEAEAEA;
        imiss <= `FALSE;
        dmiss <= `FALSE;
        dcacheOn <= 1'b0;
        icacheOn <= 1'b1;
        write_allocate <= 1'b0;
        nmoi <= 1'b1;
        state <= RESET1;
        cstate <= IDLE;
        vect <= `RST_VECT;
        pc <= 32'hFFFFFFF0;
        bufadr <= 32'd0;
        dp <= 32'd0;
        clk_en <= 1'b1;
        isCacheReset <= `TRUE;
        gie <= 1'b0;
        tick <= 32'd0;
end
else begin
tick <= tick + 32'd1;
wr <= 1'b0;
if (nmi_i & !nmi1)
        nmi_edge <= 1'b1;
if (nmi_i|nmi1)
        clk_en <= 1'b1;
case(state)
RESET1:
        begin
                adr_o <= adr_o + 32'd4;
                if (adr_o[13:4]==10'h3FF) begin
                        state <= RESET2;
                        isCacheReset <= `FALSE;
                end
        end
RESET2:
        begin
                vect <= `RST_VECT;
                radr <= vect[31:2];
                state <= JMP_IND1;
        end
IFETCH:
        begin
                if (nmi_edge & !imiss & gie) begin      // imiss indicates cache controller is active and this state is in a waiting loop
                        nmi_edge <= 1'b0;
                        wai <= 1'b0;
                        bf <= 1'b0;
                        if (em & !nmoi) begin
                                radr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr <= {24'h1,sp[7:2]};
                                wadr2LSB <= sp[1:0];
                                wdat <= {4{pc[31:24]}};
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{pc[31:24]}};
                                sp <= sp_dec;
                                vect <= `BYTE_NMI_VECT;
                                state <= BYTE_IRQ1;
                        end
                        else begin
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= pc;
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                sel_o <= 4'hF;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= pc;
                                vect <= `NMI_VECT;
                                state <= IRQ1;
                        end
                end
                else if (irq_i && !imiss & gie) begin
                        if (im) begin
                                wai <= 1'b0;
                                if (unCachedInsn) begin
                                        if (bhit) begin
                                                ir <= ibuf;
                                                state <= DECODE;
                                        end
                                        else
                                                imiss <= `TRUE;
                                end
                                else begin
                                        if (ihit) begin
                                                ir <= insn;
                                                state <= DECODE;
                                        end
                                        else
                                                imiss <= `TRUE;
                                end
                        end
                        else begin
                                bf <= 1'b0;
                                wai <= 1'b0;
                                if (em & !nmoi) begin
                                        radr <= {24'h1,sp[7:2]};
                                        radr2LSB <= sp[1:0];
                                        wadr <= {24'h1,sp[7:2]};
                                        wadr2LSB <= sp[1:0];
                                        wdat <= {4{pc[31:24]}};
                                        cyc_o <= 1'b1;
                                        stb_o <= 1'b1;
                                        we_o <= 1'b1;
                                        case(sp[1:0])
                                        2'd0:   sel_o <= 4'b0001;
                                        2'd1:   sel_o <= 4'b0010;
                                        2'd2:   sel_o <= 4'b0100;
                                        2'd3:   sel_o <= 4'b1000;
                                        endcase
                                        adr_o <= {24'h1,sp[7:2],2'b00};
                                        dat_o <= {4{pc[31:24]}};
                                        sp <= sp_dec;
                                        vect <= `BYTE_IRQ_VECT;
                                        state <= BYTE_IRQ1;
                                end
                                else begin
                                        radr <= isp_dec;
                                        wadr <= isp_dec;
                                        wdat <= pc;
                                        cyc_o <= 1'b1;
                                        stb_o <= 1'b1;
                                        we_o <= 1'b1;
                                        sel_o <= 4'hF;
                                        adr_o <= {isp_dec,2'b00};
                                        dat_o <= pc;
                                        vect <= `IRQ_VECT;
                                        state <= IRQ1;
                                end
                        end
                end
                else if (!wai) begin
                        if (unCachedInsn) begin
                                if (bhit) begin
                                        ir <= ibuf;
                                        state <= DECODE;
                                end
                                else
                                        imiss <= `TRUE;
                        end
                        else begin
                                if (ihit) begin
                                        ir <= insn;
                                        state <= DECODE;
                                end
                                else
                                        imiss <= `TRUE;
                        end
                end
                if (first_ifetch) begin
                        first_ifetch <= `FALSE;
                        if (em) begin
                                case(ir[7:0])
                                `NAT:   em <= 1'b0;
                                `TAY,`TXY,`DEY,`INY:    begin y[7:0] <= res8; nf <= resn8; zf <= resz8; end
                                `TAX,`TYX,`TSX,`DEX,`INX:       begin x[7:0] <= res8; nf <= resn8; zf <= resz8; end
                                `TSA,`TYA,`TXA,`INA,`DEA:       begin acc[7:0] <= res8; nf <= resn8; zf <= resz8; end
                                `TAS,`TXS: begin sp <= res8[7:0]; end
                                `ADC_IMM:
                                        begin
                                                acc[7:0] <= df ? bcaio : res8;
                                                cf <= df ? bcaico : resc8;
                                                vf <= resv;
                                                nf <= df ? bcaio[7] : resn8;
                                                zf <= df ? bcaio==8'h00 : resz8;
                                        end
                                `ADC_ZP,`ADC_ZPX,`ADC_IX,`ADC_IY,`ADC_ABS,`ADC_ABSX,`ADC_ABSY,`ADC_I:
                                        begin
                                                acc[7:0] <= df ? bcao : res8;
                                                cf <= df ? bcaco : resc8;
                                                vf <= resv;
                                                nf <= df ? bcao[7] : resn8;
                                                zf <= df ? bcao==8'h00 : resz8;
                                        end
                                `SBC_IMM:
                                        begin
                                                acc[7:0] <= df ? bcsio : res8;
                                                cf <= ~(df ? bcsico : resc8);
                                                vf <= resv;
                                                nf <= df ? bcsio[7] : resn8;
                                                zf <= df ? bcsio==8'h00 : resz8;
                                        end
                                `SBC_ZP,`SBC_ZPX,`SBC_IX,`SBC_IY,`SBC_ABS,`SBC_ABSX,`SBC_ABSY,`SBC_I:
                                        begin
                                                acc[7:0] <= df ? bcso : res8;
                                                vf <= resv;
                                                cf <= ~(df ? bcsco : resc8);
                                                nf <= df ? bcso[7] : resn8;
                                                zf <= df ? bcso==8'h00 : resz8;
                                        end
                                `CMP_IMM,`CMP_ZP,`CMP_ZPX,`CMP_IX,`CMP_IY,`CMP_ABS,`CMP_ABSX,`CMP_ABSY,`CMP_I,
                                `CPX_IMM,`CPX_ZP,`CPX_ABS,
                                `CPY_IMM,`CPY_ZP,`CPY_ABS:
                                                begin cf <= ~resc8; nf <= resn8; zf <= resz8; end
                                `BIT_ZP,`BIT_ABS:
                                                begin nf <= resn8; vf <= res8[6]; zf <= resz8; end
                                `TRB_ZP,`TRB_ABS,`TSB_ZP,`TSB_ABS:
                                        begin zf <= resz8; end
                                `LDA_IMM,`LDA_ZP,`LDA_ZPX,`LDA_IX,`LDA_IY,`LDA_ABS,`LDA_ABSX,`LDA_ABSY,`LDA_I,
                                `AND_IMM,`AND_ZP,`AND_ZPX,`AND_IX,`AND_IY,`AND_ABS,`AND_ABSX,`AND_ABSY,`AND_I,
                                `ORA_IMM,`ORA_ZP,`ORA_ZPX,`ORA_IX,`ORA_IY,`ORA_ABS,`ORA_ABSX,`ORA_ABSY,`ORA_I,
                                `EOR_IMM,`EOR_ZP,`EOR_ZPX,`EOR_IX,`EOR_IY,`EOR_ABS,`EOR_ABSX,`EOR_ABSY,`EOR_I:
                                        begin acc[7:0] <= res8; nf <= resn8; zf <= resz8; end
                                `ASL_ACC:       begin acc[7:0] <= res8; cf <= resc8; nf <= resn8; zf <= resz8; end
                                `ROL_ACC:       begin acc[7:0] <= res8; cf <= resc8; nf <= resn8; zf <= resz8; end
                                `LSR_ACC:       begin acc[7:0] <= res8; cf <= resc8; nf <= resn8; zf <= resz8; end
                                `ROR_ACC:       begin acc[7:0] <= res8; cf <= resc8; nf <= resn8; zf <= resz8; end
                                `ASL_ZP,`ASL_ZPX,`ASL_ABS,`ASL_ABSX: begin cf <= resc8; nf <= resn8; zf <= resz8; end
                                `ROL_ZP,`ROL_ZPX,`ROL_ABS,`ROL_ABSX: begin cf <= resc8; nf <= resn8; zf <= resz8; end
                                `LSR_ZP,`LSR_ZPX,`LSR_ABS,`LSR_ABSX: begin cf <= resc8; nf <= resn8; zf <= resz8; end
                                `ROR_ZP,`ROR_ZPX,`ROR_ABS,`ROR_ABSX: begin cf <= resc8; nf <= resn8; zf <= resz8; end
                                `INC_ZP,`INC_ZPX,`INC_ABS,`INC_ABSX: begin nf <= resn8; zf <= resz8; end
                                `DEC_ZP,`DEC_ZPX,`DEC_ABS,`DEC_ABSX: begin nf <= resn8; zf <= resz8; end
                                `PLA:   begin acc[7:0] <= res8; zf <= resz8; nf <= resn8; end
                                `PLX:   begin x[7:0] <= res8; zf <= resz8; nf <= resn8; end
                                `PLY:   begin y[7:0] <= res8; zf <= resz8; nf <= resn8; end
                                `LDX_IMM,`LDX_ZP,`LDX_ZPY,`LDX_ABS,`LDX_ABSY:   begin x[7:0] <= res8; nf <= resn8; zf <= resz8; end
                                `LDY_IMM,`LDY_ZP,`LDY_ZPX,`LDY_ABS,`LDY_ABSX:   begin y[7:0] <= res8; nf <= resn8; zf <= resz8; end
                                endcase
                        end
                        else begin
                                regfile[Rt] <= res;
                                case(Rt)
                                4'h1:   acc <= res;
                                4'h2:   x <= res;
                                4'h3:   y <= res;
                                default:        ;
                                endcase
                                case(ir[7:0])
//                              `XCE:           begin cf <= em; em <= cf; end
                                `EMM:   em <= 1'b1;
                                `TAY,`TXY,`DEY,`INY:    begin y <= res; nf <= resn32; zf <= resz32; end
                                `TAX,`TYX,`TSX,`DEX,`INX:       begin x <= res; nf <= resn32; zf <= resz32; end
                                `TAS,`TXS:      begin isp <= res; gie <= 1'b1; end
                                `TSA,`TYA,`TXA,`INA,`DEA:       begin acc <= res; nf <= resn32; zf <= resz32; end
                                `TRS:
                                        begin
                                                case(ir[15:12])
                                                4'h0:   begin
                                                                $display("res=%h",res);
                                                                icacheOn <= res[0];
                                                                dcacheOn <= res[1];
                                                                write_allocate <= res[2];
                                                                end
                                                4'h1:   dp <= res;
                                                4'h5:   lfsr <= res;
                                                4'hE:   begin sp <= res[7:0]; end
                                                4'hF:   begin isp <= res; gie <= 1'b1; end
                                                endcase
                                        end
                                `RR:
                                        case(ir[23:20])
                                        `ADD_RR:        begin vf <= resv32; cf <= resc32; nf <= resn32; zf <= resz32; end
                                        `SUB_RR:
                                                        if (Rt==4'h0)   // CMP doesn't set overflow
                                                                begin cf <= ~resc32; nf <= resn32; zf <= resz32; end
                                                        else
                                                                begin vf <= resv32; cf <= ~resc32; nf <= resn32; zf <= resz32; end
                                        `AND_RR:
                                                if (Rt==4'h0)   // BIT sets overflow
                                                        begin nf <= resn32; vf <= res[30]; zf <= resz32; end
                                                else
                                                        begin nf <= resn32; zf <= resz32; end
                                        `OR_RR: begin nf <= resn32; zf <= resz32; end
                                        `EOR_RR:        begin nf <= resn32; zf <= resz32; end
                                        `MUL_RR:        begin nf <= resn32; zf <= resz32; end
                                        `MULS_RR:       begin nf <= resn32; zf <= resz32; end
                                        `DIV_RR:        begin nf <= resn32; zf <= resz32; end
                                        `DIVS_RR:       begin nf <= resn32; zf <= resz32; end
                                        `MOD_RR:        begin nf <= resn32; zf <= resz32; end
                                        `MODS_RR:       begin nf <= resn32; zf <= resz32; end
                                        endcase
                                `LD_RR: begin zf <= resz32; nf <= resn32; end
                                `DEC_RR,`INC_RR: begin zf <= resz32; nf <= resn32; end
                                `ASL_RR,`ROL_RR,`LSR_RR,`ROR_RR: begin cf <= resc32; nf <= resn32; zf <= resz32; end
                                `ADD_IMM8,`ADD_IMM16,`ADD_IMM32,`ADD_ZPX,`ADD_IX,`ADD_IY,`ADD_ABS,`ADD_ABSX,`ADD_RIND:
                                        begin vf <= resv32; cf <= resc32; nf <= resn32; zf <= resz32; end
                                `SUB_IMM8,`SUB_IMM16,`SUB_IMM32,`SUB_ZPX,`SUB_IX,`SUB_IY,`SUB_ABS,`SUB_ABSX,`SUB_RIND:
                                        if (Rt==4'h0)   // CMP doesn't set overflow
                                                begin cf <= ~resc32; nf <= resn32; zf <= resz32; end
                                        else
                                                begin vf <= resv32; cf <= ~resc32; nf <= resn32; zf <= resz32; end
                                `AND_IMM8,`AND_IMM16,`AND_IMM32,`AND_ZPX,`AND_IX,`AND_IY,`AND_ABS,`AND_ABSX,`AND_RIND:
                                        if (Rt==4'h0)   // BIT sets overflow
                                                begin nf <= resn32; vf <= res[30]; zf <= resz32; end
                                        else
                                                begin nf <= resn32; zf <= resz32; end
                                `ORB_ZPX,`ORB_ABS,`ORB_ABSX,
                                `OR_IMM8,`OR_IMM16,`OR_IMM32,`OR_ZPX,`OR_IX,`OR_IY,`OR_ABS,`OR_ABSX,`OR_RIND,
                                `EOR_IMM8,`EOR_IMM16,`EOR_IMM32,`EOR_ZPX,`EOR_IX,`EOR_IY,`EOR_ABS,`EOR_ABSX,`EOR_RIND:
                                        begin nf <= resn32; zf <= resz32; end
                                `ASL_ACC:       begin acc <= res; cf <= resc32; nf <= resn32; zf <= resz32; end
                                `ROL_ACC:       begin acc <= res; cf <= resc32; nf <= resn32; zf <= resz32; end
                                `LSR_ACC:       begin acc <= res; cf <= resc32; nf <= resn32; zf <= resz32; end
                                `ROR_ACC:       begin acc <= res; cf <= resc32; nf <= resn32; zf <= resz32; end
                                `ASL_ZPX,`ASL_ABS,`ASL_ABSX: begin cf <= resc32; nf <= resn32; zf <= resz32; end
                                `ROL_ZPX,`ROL_ABS,`ROL_ABSX: begin cf <= resc32; nf <= resn32; zf <= resz32; end
                                `LSR_ZPX,`LSR_ABS,`LSR_ABSX: begin cf <= resc32; nf <= resn32; zf <= resz32; end
                                `ROR_ZPX,`ROR_ABS,`ROR_ABSX: begin cf <= resc32; nf <= resn32; zf <= resz32; end
                                `INC_ZPX,`INC_ABS,`INC_ABSX: begin nf <= resn32; zf <= resz32; end
                                `DEC_ZPX,`DEC_ABS,`DEC_ABSX: begin nf <= resn32; zf <= resz32; end
                                `PLA:   begin acc <= res; zf <= resz32; nf <= resn32; end
                                `PLX:   begin x <= res; zf <= resz32; nf <= resn32; end
                                `PLY:   begin y <= res; zf <= resz32; nf <= resn32; end
                                `LDX_IMM32,`LDX_IMM16,`LDX_IMM8,`LDX_ZPY,`LDX_ABS,`LDX_ABSY:    begin x <= res; nf <= resn32; zf <= resz32; end
                                `LDY_IMM32,`LDY_ZPX,`LDY_ABS,`LDY_ABSX: begin y <= res; nf <= resn32; zf <= resz32; end
                                `CPX_IMM32,`CPX_ZPX,`CPX_ABS:   begin cf <= ~resc; nf <= resn32; zf <= resz32; end
                                `CPY_IMM32,`CPY_ZPX,`CPY_ABS:   begin cf <= ~resc; nf <= resn32; zf <= resz32; end
                                `LDA_IMM32,`LDA_IMM16,`LDA_IMM8:        begin acc <= res; nf <= resn32; zf <= resz32; end
                                endcase
                        end
                end
        end
DECODE:
        begin
        first_ifetch <= `TRUE;
        Rt <= 4'h0;             // Default
        if (em) begin
                state <= IFETCH;
                case(ir[7:0])
                `STP:   begin clk_en <= 1'b0; pc <= pc + 32'd1; end
                `NAT:   pc <= pc + 32'd1;
                `NOP:   pc <= pc + 32'd1;
                `CLC:   begin cf <= 1'b0; pc <= pc + 32'd1; end
                `SEC:   begin cf <= 1'b1; pc <= pc + 32'd1; end
                `CLV:   begin vf <= 1'b0; pc <= pc + 32'd1; end
                `CLI:   begin im <= 1'b0; pc <= pc + 32'd1; end
                `SEI:   begin im <= 1'b1; pc <= pc + 32'd1; end
                `CLD:   begin df <= 1'b0; pc <= pc + 32'd1; end
                `SED:   begin df <= 1'b1; pc <= pc + 32'd1; end
                `WAI:   begin wai <= 1'b1; pc <= pc + 32'd1; end
                `DEX:   begin res8 <= x[7:0] - 8'd1; pc <= pc + 32'd1; end
                `INX:   begin res8 <= x[7:0] + 8'd1; pc <= pc + 32'd1; end
                `DEY:   begin res8 <= y[7:0] - 8'd1; pc <= pc + 32'd1; end
                `INY:   begin res8 <= y[7:0] + 8'd1; pc <= pc + 32'd1; end
                `DEA:   begin res8 <= acc[7:0] - 8'd1; pc <= pc + 32'd1; end
                `INA:   begin res8 <= acc[7:0] + 8'd1; pc <= pc + 32'd1; end
                `TSX,`TSA:      begin res8 <= sp[7:0]; pc <= pc + 32'd1; end
                `TXS,`TXA,`TXY: begin res8 <= x[7:0]; pc <= pc + 32'd1; end
                `TAX,`TAY,`TAS: begin res8 <= acc[7:0]; pc <= pc + 32'd1; end
                `TYA,`TYX:      begin res8 <= y[7:0]; pc <= pc + 32'd1; end
                `ASL_ACC:       begin res8 <= {acc8,1'b0}; pc <= pc + 32'd1; end
                `ROL_ACC:       begin res8 <= {acc8,cf}; pc <= pc + 32'd1; end
                `LSR_ACC:       begin res8 <= {acc8[0],1'b0,acc8[7:1]}; pc <= pc + 32'd1; end
                `ROR_ACC:       begin res8 <= {acc8[0],cf,acc8[7:1]}; pc <= pc + 32'd1; end
                // Handle # mode
                `LDA_IMM,`LDX_IMM,`LDY_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= ir[15:8];
                                state <= IFETCH;
                        end
                `ADC_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= acc8 + ir[15:8] + {7'b0,cf};
                                b8 <= ir[15:8];         // for overflow calc
                                state <= IFETCH;
                        end
                `SBC_IMM:
                        begin
                                pc <= pc + 32'd2;
//                              res8 <= acc8 - ir[15:8] - ~cf;
                                res8 <= acc8 - ir[15:8] - {7'b0,~cf};
                                $display("sbc: %h= %h-%h-%h", acc8 - ir[15:8] - {7'b0,~cf},acc8,ir[15:8],~cf);
                                b8 <= ir[15:8];         // for overflow calc
                                state <= IFETCH;
                        end
                `AND_IMM,`BIT_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= acc8 & ir[15:8];
                                state <= IFETCH;
                        end
                `ORA_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= acc8 | ir[15:8];
                                state <= IFETCH;
                        end
                `EOR_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= acc8 ^ ir[15:8];
                                state <= IFETCH;
                        end
                `CMP_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= acc8 - ir[15:8];
                                state <= IFETCH;
                        end
                `CPX_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= x8 - ir[15:8];
                                state <= IFETCH;
                        end
                `CPY_IMM:
                        begin
                                pc <= pc + 32'd2;
                                res8 <= y8 - ir[15:8];
                                state <= IFETCH;
                        end
                // Handle zp mode
                `ADC_ZP,`SBC_ZP,`AND_ZP,`ORA_ZP,`EOR_ZP,`CMP_ZP,`LDA_ZP,
                `LDX_ZP,`LDY_ZP,`BIT_ZP,`CPX_ZP,`CPY_ZP,
                `ASL_ZP,`ROL_ZP,`LSR_ZP,`ROR_ZP,`INC_ZP,`DEC_ZP,`TRB_ZP,`TSB_ZP:
                        begin
                                pc <= pc + 32'd2;
                                radr <= zp_address[31:2];
                                radr2LSB <= zp_address[1:0];
                                state <= LOAD1;
                        end
                `STA_ZP:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zp_address[31:2];
                                wadr2LSB <= zp_address[1:0];
                                wdat <= {4{acc8}};
                                state <= STORE1;
                        end
                `STX_ZP:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zp_address[31:2];
                                wadr2LSB <= zp_address[1:0];
                                wdat <= {4{x8}};
                                state <= STORE1;
                        end
                `STY_ZP:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zp_address[31:2];
                                wadr2LSB <= zp_address[1:0];
                                wdat <= {4{y8}};
                                state <= STORE1;
                        end
                `STZ_ZP:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zp_address[31:2];
                                wadr2LSB <= zp_address[1:0];
                                wdat <= {4{8'h00}};
                                state <= STORE1;
                        end
                // Handle zp,x mode
                `ADC_ZPX,`SBC_ZPX,`AND_ZPX,`ORA_ZPX,`EOR_ZPX,`CMP_ZPX,`LDA_ZPX,
                `LDY_ZPX,`BIT_ZPX,
                `ASL_ZPX,`ROL_ZPX,`LSR_ZPX,`ROR_ZPX,`INC_ZPX,`DEC_ZPX:
                        begin
                                pc <= pc + 32'd2;
                                radr <= zpx_address[31:2];
                                radr2LSB <= zpx_address[1:0];
                                state <= LOAD1;
                        end
                `STA_ZPX:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zpx_address[31:2];
                                wadr2LSB <= zpx_address[1:0];
                                wdat <= {4{acc8}};
                                state <= STORE1;
                        end
                `STY_ZPX:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zpx_address[31:2];
                                wadr2LSB <= zpx_address[1:0];
                                wdat <= {4{y8}};
                                state <= STORE1;
                        end
                `STZ_ZPX:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zpx_address[31:2];
                                wadr2LSB <= zpx_address[1:0];
                                wdat <= {4{8'h00}};
                                state <= STORE1;
                        end
                // Handle zp,y
                `LDX_ZPY:
                        begin
                                pc <= pc + 32'd2;
                                radr <= zpy_address[31:2];
                                radr2LSB <= zpy_address[1:0];
                                state <= LOAD1;
                        end
                `STX_ZPY:
                        begin
                                pc <= pc + 32'd2;
                                wadr <= zpy_address[31:2];
                                wadr2LSB <= zpy_address[1:0];
                                wdat <= {4{x8}};
                                state <= STORE1;
                        end
                // Handle (zp,x)
                `ADC_IX,`SBC_IX,`AND_IX,`ORA_IX,`EOR_IX,`CMP_IX,`LDA_IX,`STA_IX:
                        begin
                                pc <= pc + 32'd2;
                                radr <= zpx_address[31:2];
                                radr2LSB <= zpx_address[1:0];
                                state <= BYTE_IX1;
                        end
                // Handle (zp),y
                `ADC_IY,`SBC_IY,`AND_IY,`ORA_IY,`EOR_IY,`CMP_IY,`LDA_IY,`STA_IY:
                        begin
                                pc <= pc + 32'd2;
                                radr <= zp_address[31:2];
                                radr2LSB <= zp_address[1:0];
                                state <= BYTE_IY1;
                        end
                // Handle abs
                `ADC_ABS,`SBC_ABS,`AND_ABS,`ORA_ABS,`EOR_ABS,`CMP_ABS,`LDA_ABS,
                `ASL_ABS,`ROL_ABS,`LSR_ABS,`ROR_ABS,`INC_ABS,`DEC_ABS,`TRB_ABS,`TSB_ABS,
                `LDX_ABS,`LDY_ABS,
                `CPX_ABS,`CPY_ABS,
                `BIT_ABS:
                        begin
                                pc <= pc + 32'd3;
                                radr <= abs_address[31:2];
                                radr2LSB <= abs_address[1:0];
                                state <= LOAD1;
                        end
                `STA_ABS:
                        begin
                                pc <= pc + 32'd3;
                                wadr <= abs_address[31:2];
                                wadr2LSB <= abs_address[1:0];
                                wdat <= {4{acc8}};
                                state <= STORE1;
                        end
                `STX_ABS:
                        begin
                                pc <= pc + 32'd3;
                                wadr <= abs_address[31:2];
                                wadr2LSB <= abs_address[1:0];
                                wdat <= {4{x8}};
                                state <= STORE1;
                        end             // Handle abs,x
                `STY_ABS:
                        begin
                                pc <= pc + 32'd3;
                                wadr <= abs_address[31:2];
                                wadr2LSB <= abs_address[1:0];
                                wdat <= {4{y8}};
                                state <= STORE1;
                        end
                `STZ_ABS:
                        begin
                                pc <= pc + 32'd3;
                                wadr <= abs_address[31:2];
                                wadr2LSB <= abs_address[1:0];
                                wdat <= {4{8'h00}};
                                state <= STORE1;
                        end
                `ADC_ABSX,`SBC_ABSX,`AND_ABSX,`ORA_ABSX,`EOR_ABSX,`CMP_ABSX,`LDA_ABSX,
                `ASL_ABSX,`ROL_ABSX,`LSR_ABSX,`ROR_ABSX,`INC_ABSX,`DEC_ABSX,`BIT_ABSX,
                `LDY_ABSX:
                        begin
                                pc <= pc + 32'd3;
                                radr <= absx_address[31:2];
                                radr2LSB <= absx_address[1:0];
                                state <= LOAD1;
                        end
                `STA_ABSX:
                        begin
                                pc <= pc + 32'd3;
                                wadr <= absx_address[31:2];
                                wadr2LSB <= absx_address[1:0];
                                wdat <= {4{acc8}};
                                state <= STORE1;
                        end
                `STZ_ABSX:
                        begin
                                pc <= pc + 32'd3;
                                wadr <= absx_address[31:2];
                                wadr2LSB <= absx_address[1:0];
                                wdat <= {4{8'h00}};
                                state <= STORE1;
                        end
                // Handle abs,y
                `ADC_ABSY,`SBC_ABSY,`AND_ABSY,`ORA_ABSY,`EOR_ABSY,`CMP_ABSY,`LDA_ABSY,
                `LDX_ABSY:
                        begin
                                pc <= pc + 32'd3;
                                radr <= absy_address[31:2];
                                radr2LSB <= absy_address[1:0];
                                state <= LOAD1;
                        end
                `STA_ABSY:
                        begin
                                pc <= pc + 32'd3;
                                wadr <= absy_address[31:2];
                                wadr2LSB <= absy_address[1:0];
                                wdat <= {4{acc8}};
                                state <= STORE1;
                        end
                // Handle (zp)
                `ADC_I,`SBC_I,`AND_I,`ORA_I,`EOR_I,`CMP_I,`LDA_I,`STA_I:
                        begin
                                pc <= pc + 32'd2;
                                radr <= zp_address[31:2];
                                radr2LSB <= zp_address[1:0];
                                state <= BYTE_IX1;
                        end
                `BRK:
                        begin
                                radr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr <= {24'h1,sp[7:2]};
                                wadr2LSB <= sp[1:0];
                                wdat <= {4{pcp1[31:24]}};
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{pcp1[31:24]}};
                                sp <= sp_dec;
                                vect <= `BYTE_IRQ_VECT;
                                state <= BYTE_IRQ1;
                                bf <= 1'b1;
                        end
                `JMP:
                        begin
                                pc[15:0] <= abs_address[15:0];
                                state <= IFETCH;
                        end
                `JML:
                        begin
                                pc <= ir[39:8];
                                state <= IFETCH;
                        end
                `JMP_IND:
                        begin
                                radr <= abs_address[31:2];
                                radr2LSB <= abs_address[1:0];
                                state <= BYTE_JMP_IND1;
                        end
                `JMP_INDX:
                        begin
                                radr <= absx_address[31:2];
                                radr2LSB <= absx_address[1:0];
                                state <= BYTE_JMP_IND1;
                        end
                `JSR:
                        begin
                                radr <= {24'h1,sp[7:2]};
                                wadr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr2LSB <= sp[1:0];
                                wdat <= {4{pcp2[15:8]}};
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{pcp2[15:8]}};
                                sp <= sp_dec;
                                state <= BYTE_JSR1;
                        end
                `JSL:
                        begin
                                radr <= {24'h1,sp[7:2]};
                                wadr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr2LSB <= sp[1:0];
                                wdat <= {4{pcp4[31:24]}};
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{pcp4[31:24]}};
                                sp <= sp_dec;
                                state <= BYTE_JSL1;
                        end
                `JSR_INDX:
                        begin
                                radr <= {24'h1,sp[7:2]};
                                wadr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr2LSB <= sp[1:0];
                                wdat <= {4{pcp2[15:8]}};
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                case(sp_dec[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{pcp2[15:8]}};
                                sp <= sp_dec;
                                state <= BYTE_JSR_INDX1;
                        end
                `RTS,`RTL:
                        begin
                                radr <= {24'h1,sp_inc[7:2]};
                                radr2LSB <= sp_inc[1:0];
                                sp <= sp_inc;
                                state <= BYTE_RTS1;
                        end
                `RTI:   begin
                                radr <= {24'h1,sp_inc[7:2]};
                                radr2LSB <= sp_inc[1:0];
                                sp <= sp_inc;
                                state <= BYTE_RTI9;
                                end
                `BEQ,`BNE,`BPL,`BMI,`BCC,`BCS,`BVC,`BVS,`BRA:
                        begin
                                state <= IFETCH;
//                              if (ir[15:8]==8'hFE) begin
//                                      radr <= {24'h1,sp[7:2]};
//                                      radr2LSB <= sp[1:0];
//                                      wadr <= {24'h1,sp[7:2]};
//                                      wadr2LSB <= sp[1:0];
//                                      case(sp[1:0])
//                                      2'd0:   sel_o <= 4'b0001;
//                                      2'd1:   sel_o <= 4'b0010;
//                                      2'd2:   sel_o <= 4'b0100;
//                                      2'd3:   sel_o <= 4'b1000;
//                                      endcase
//                                      wdat <= {4{pcp2[31:24]}};
//                                      cyc_o <= 1'b1;
//                                      stb_o <= 1'b1;
//                                      we_o <= 1'b1;
//                                      adr_o <= {24'h1,sp[7:2],2'b00};
//                                      dat_o <= {4{pcp2[31:24]}};
//                                      vect <= `SLP_VECT;
//                                      state <= BYTE_IRQ1;
//                              end
//                              else
                                if (ir[15:8]==8'hFF) begin
                                        if (takb)
                                                pc <= pc + {{16{ir[31]}},ir[31:16]};
                                        else
                                                pc <= pc + 32'd4;
                                end
                                else begin
                                        if (takb)
                                                pc <= pc + {{24{ir[15]}},ir[15:8]} + 32'd2;
                                        else
                                                pc <= pc + 32'd2;
                                end
                        end
                `PHP:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                radr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr <= {24'h1,sp[7:2]};
                                wadr2LSB <= sp[1:0];
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{sr8}};
                                wdat <= {4{sr8}};
                                sp <= sp_dec;
                                state <= PHP1;
                        end
                `PHA:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                radr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr <= {24'h1,sp[7:2]};
                                wadr2LSB <= sp[1:0];
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{acc8}};
                                wdat <= {4{acc8}};
                                sp <= sp_dec;
                                state <= PHP1;
                        end
                `PHX:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                radr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr <= {24'h1,sp[7:2]};
                                wadr2LSB <= sp[1:0];
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{x8}};
                                wdat <= {4{x8}};
                                sp <= sp_dec;
                                state <= PHP1;
                        end
                `PHY:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                radr <= {24'h1,sp[7:2]};
                                radr2LSB <= sp[1:0];
                                wadr <= {24'h1,sp[7:2]};
                                wadr2LSB <= sp[1:0];
                                case(sp[1:0])
                                2'd0:   sel_o <= 4'b0001;
                                2'd1:   sel_o <= 4'b0010;
                                2'd2:   sel_o <= 4'b0100;
                                2'd3:   sel_o <= 4'b1000;
                                endcase
                                adr_o <= {24'h1,sp[7:2],2'b00};
                                dat_o <= {4{y8}};
                                wdat <= {4{y8}};
                                sp <= sp_dec;
                                state <= PHP1;
                        end
                `PLP:
                        begin
                                radr <= {24'h1,sp_inc[7:2]};
                                radr2LSB <= sp_inc[1:0];
                                sp <= sp_inc;
                                state <= BYTE_PLP1;
                                pc <= pc + 32'd1;
                        end
                `PLA,`PLX,`PLY:
                        begin
                                radr <= {24'h1,sp_inc[7:2]};
                                radr2LSB <= sp_inc[1:0];
                                sp <= sp_inc;
                                state <= PLA1;
                                pc <= pc + 32'd1;
                        end
                default:        // unimplemented opcode
                        pc <= pc + 32'd1;
                endcase
        end
        else begin
                state <= IFETCH;
                case(ir[7:0])
                `STP:   begin clk_en <= 1'b0; pc <= pc + 32'd1; end
                `NOP:   begin pc <= pc + 32'd1; end
                `CLC:   begin cf <= 1'b0; pc <= pc + 32'd1; end
                `SEC:   begin cf <= 1'b1; pc <= pc + 32'd1; end
                `CLV:   begin vf <= 1'b0; pc <= pc + 32'd1; end
                `CLI:   begin im <= 1'b0; pc <= pc + 32'd1; end
                `CLD:   begin df <= 1'b0; pc <= pc + 32'd1; end
                `SED:   begin df <= 1'b1; pc <= pc + 32'd1; end
                `SEI:   begin im <= 1'b1; pc <= pc + 32'd1; end
                `WAI:   begin wai <= 1'b1; pc <= pc + 32'd1; end
                `EMM:   begin pc <= pc + 32'd1; end
                `DEX:   begin res <= x - 32'd1; pc <= pc + 32'd1; end
                `INX:   begin res <= x + 32'd1; pc <= pc + 32'd1; end
                `DEY:   begin res <= y - 32'd1; pc <= pc + 32'd1; end
                `INY:   begin res <= y + 32'd1; pc <= pc + 32'd1; end
                `DEA:   begin res <= acc - 32'd1; pc <= pc + 32'd1; end
                `INA:   begin res <= acc + 32'd1; pc <= pc + 32'd1; end
                `TSX:   begin res <= isp; pc <= pc + 32'd1; end
                `TXS,`TXA,`TXY: begin res <= x; pc <= pc + 32'd1; end
                `TAX,`TAY,`TAS: begin res <= acc; pc <= pc + 32'd1; end
                `TYA,`TYX:      begin res <= y; pc <= pc + 32'd1; end
                `TRS:           begin
                                                res <= rfoa; pc <= pc + 32'd2; end
                `TSR:           begin
                                                Rt <= ir[15:12];
                                                case(ir[11:8])
                                                4'h0:   res <= {write_allocate,dcacheOn,icacheOn};
                                                4'h1:   res <= dp;
                                                4'h2:   res <= prod[31:0];
                                                4'h3:   res <= prod[63:32];
                                                4'h4:   res <= tick;
                                                4'h5:   begin res <= lfsr; lfsr <= {lfsr[30:0],lfsr_fb}; end
                                                4'hE:   res <= sp;
                                                4'hF:   res <= isp;
                                                endcase
                                                pc <= pc + 32'd2;
                                        end
                `ASL_ACC:       begin res <= {acc,1'b0}; pc <= pc + 32'd1; end
                `ROL_ACC:       begin res <= {acc,cf}; pc <= pc + 32'd1; end
                `LSR_ACC:       begin res <= {acc[0],1'b0,acc[31:1]}; pc <= pc + 32'd1; end
                `ROR_ACC:       begin res <= {acc[0],cf,acc[31:1]}; pc <= pc + 32'd1; end
 
                `RR:
                        begin
                                state <= IFETCH;
                                case(ir[23:20])
                                `ADD_RR:        res <= rfoa + rfob;
                                `SUB_RR:        res <= rfoa - rfob;
                                `AND_RR:        res <= rfoa & rfob;
                                `OR_RR:         res <= rfoa | rfob;
                                `EOR_RR:        res <= rfoa ^ rfob;
                                `MUL_RR:        begin state <= MULDIV1; end
                                `MULS_RR:       begin state <= MULDIV1; end
                                `DIV_RR:        begin state <= MULDIV1; end
                                `DIVS_RR:       begin state <= MULDIV1; end
                                `MOD_RR:        begin state <= MULDIV1; end
                                `MODS_RR:       begin state <= MULDIV1; end
                                endcase
                                Rt <= ir[19:16];
                                pc <= pc + 32'd3;
                        end
                `LD_RR:         begin res <= rfoa; Rt <= ir[15:12]; pc <= pc + 32'd2; end
                `ASL_RR:        begin res <= {rfoa,1'b0}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
                `ROL_RR:        begin res <= {rfoa,cf}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
                `LSR_RR:        begin res <= {rfoa[0],1'b0,rfoa[31:1]}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
                `ROR_RR:        begin res <= {rfoa[0],cf,rfoa[31:1]}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
                `DEC_RR:        begin res <= rfoa - 32'd1; pc <= pc + 32'd2; Rt <= ir[15:12]; end
                `INC_RR:        begin res <= rfoa + 32'd1; pc <= pc + 32'd2; Rt <= ir[15:12]; end
 
                `ADD_IMM8:      begin res <= rfoa + {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; end
                `SUB_IMM8:      begin res <= rfoa - {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; end
                `OR_IMM8:       begin res <= rfoa | {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; end
                `AND_IMM8:      begin res <= rfoa & {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; end
                `EOR_IMM8:      begin res <= rfoa ^ {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; end
 
                `ADD_IMM16:     begin res <= rfoa + {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; end
                `SUB_IMM16:     begin res <= rfoa - {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; end
                `OR_IMM16:      begin res <= rfoa | {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; end
                `AND_IMM16:     begin res <= rfoa & {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; end
                `EOR_IMM16:     begin res <= rfoa ^ {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; end
 
                `ADD_IMM32:     begin res <= rfoa + ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; end
                `SUB_IMM32:     begin res <= rfoa - ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; end
                `OR_IMM32:      begin res <= rfoa | ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; end
                `AND_IMM32:     begin res <= rfoa & ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; end
                `EOR_IMM32:     begin res <= rfoa ^ ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; end
 
                `LDX_IMM32,`LDY_IMM32,`LDA_IMM32:       begin res <= ir[39:8]; pc <= pc + 32'd5; end
                `LDX_IMM16,`LDA_IMM16:  begin res <= {{16{ir[23]}},ir[23:8]}; pc <= pc + 32'd3; end
                `LDX_IMM8,`LDA_IMM8: begin res <= {{24{ir[15]}},ir[15:8]}; pc <= pc + 32'd2; end
 
                `LDX_ZPX,`LDY_ZPX:
                        begin
                                radr <= zpx32xy_address;
                                pc <= pc + 32'd3;
                                state <= LOAD1;
                        end
                `ORB_ZPX:
                        begin
                                a <= rfoa;
                                Rt <= ir[19:16];
                                radr <= zpx32_address[31:2];
                                radr2LSB <= zpx32_address[1:0];
                                pc <= pc + 32'd4;
                                state <= LOAD1;
                        end
                `LDX_ABS,`LDY_ABS:
                        begin
                                radr <= ir[39:8];
                                pc <= pc + 32'd5;
                                state <= LOAD1;
                        end
                `ORB_ABS:
                        begin
                                a <= rfoa;
                                Rt <= ir[15:12];
                                radr <= ir[47:18];
                                radr2LSB <= ir[17:16];
                                pc <= pc + 32'd6;
                                state <= LOAD1;
                        end
                `LDX_ABSY,`LDY_ABSX:
                        begin
                                radr <= absx32xy_address;
                                pc <= pc + 32'd6;
                                state <= LOAD1;
                        end
                `ORB_ABSX:
                        begin
                                a <= rfoa;
                                Rt <= ir[19:16];
                                radr <= absx32_address[31:2];
                                radr2LSB <= absx32_address[1:0];
                                pc <= pc + 32'd7;
                                state <= LOAD1;
                        end
                `ST_ZPX:
                        begin
                                wadr <= zpx32_address;
                                wdat <= rfoa;
                                pc <= pc + 32'd4;
                                state <= STORE1;
                        end
                `STB_ZPX:
                        begin
                                wadr <= zpx32_address[31:2];
                                wadr2LSB <= zpx32_address[1:0];
                                pc <= pc + 32'd4;
                                state <= STORE1;
                        end
                `ST_ABS:
                        begin
                                wadr <= ir[47:16];
                                wdat <= rfoa;
                                pc <= pc + 32'd6;
                                state <= STORE1;
                        end
                `STB_ABS:
                        begin
                                wadr <= ir[47:18];
                                wadr2LSB <= ir[17:16];
                                wdat <= {4{rfoa[7:0]}};
                                pc <= pc + 32'd6;
                                state <= STORE1;
                        end
                `ST_ABSX:
                        begin
                                wadr <= absx32_address;
                                wdat <= rfoa;
                                pc <= pc + 32'd7;
                                state <= STORE1;
                        end
                `STB_ABSX:
                        begin
                                wadr <= absx32_address[31:2];
                                wadr2LSB <= absx32_address[1:0];
                                wdat <= {4{rfoa[7:0]}};
                                pc <= pc + 32'd7;
                                state <= STORE1;
                        end
                `STX_ZPX:
                        begin
                                wadr <= dp + ir[23:12] + rfoa;
                                wdat <= x;
                                pc <= pc + 32'd3;
                                state <= STORE1;
                        end
                `STX_ABS:
                        begin
                                wadr <= ir[39:8];
                                wdat <= x;
                                pc <= pc + 32'd5;
                                state <= STORE1;
                        end
                `STY_ZPX:
                        begin
                                wadr <= dp + ir[23:12] + rfoa;
                                wdat <= y;
                                pc <= pc + 32'd3;
                                state <= STORE1;
                        end
                `STY_ABS:
                        begin
                                wadr <= ir[39:8];
                                wdat <= y;
                                pc <= pc + 32'd5;
                                state <= STORE1;
                        end
                `ADD_ZPX,`SUB_ZPX,`OR_ZPX,`AND_ZPX,`EOR_ZPX:
                        begin
                                a <= rfoa;
                                Rt <= ir[19:16];
                                radr <= zpx32_address;
                                pc <= pc + 32'd4;
                                state <= LOAD1;
                        end
                `ASL_ZPX,`ROL_ZPX,`LSR_ZPX,`ROR_ZPX,`INC_ZPX,`DEC_ZPX:
                        begin
                                radr <= dp + rfoa + ir[23:12];
                                pc <= pc + 32'd3;
                                state <= LOAD1;
                        end
                `ADD_IX,`SUB_IX,`OR_IX,`AND_IX,`EOR_IX,`ST_IX:
                        begin
                                a <= rfoa;
                                if (ir[7:0]==`ST_IX)
                                        res <= rfoa;            // for ST_IX, Rt=0
                                else
                                        Rt <= ir[19:16];
                                pc <= pc + 32'd4;
                                radr <= dp + ir[31:20] + rfob;
                                state <= IX1;
                        end
                `ADD_RIND,`SUB_RIND,`OR_RIND,`AND_RIND,`EOR_RIND,`ST_RIND:
                        begin
                                radr <= rfob;
                                wadr <= rfob;           // for store
                                wdat <= rfoa;
                                a <= rfoa;
                                if (ir[7:0]==`ST_RIND) begin
                                        res <= rfoa;            // for ST_IX, Rt=0
                                        pc <= pc + 32'd2;
                                        state <= STORE1;
                                end
                                else begin
                                        Rt <= ir[19:16];
                                        pc <= pc + 32'd3;
                                        state <= LOAD1;
                                end
                        end
                `ADD_IY,`SUB_IY,`OR_IY,`AND_IY,`EOR_IY,`ST_IY:
                        begin
                                a <= rfoa;
                                if (ir[7:0]==`ST_IY)
                                        res <= rfoa;            // for ST_IY, Rt=0
                                else
                                        Rt <= ir[19:16];
                                pc <= pc + 32'd4;
                                radr <= dp + ir[31:20];
                                state <= IY1;
                        end
                `ADD_ABS,`SUB_ABS,`OR_ABS,`AND_ABS,`EOR_ABS:
                        begin
                                a <= rfoa;
                                radr <= ir[47:16];
                                Rt <= ir[15:12];
                                pc <= pc + 32'd6;
                                state <= LOAD1;
                        end
                `ASL_ABS,`ROL_ABS,`LSR_ABS,`ROR_ABS,`INC_ABS,`DEC_ABS:
                        begin
                                radr <= ir[39:8];
                                pc <= pc + 32'd5;
                                state <= LOAD1;
                        end
                `ADD_ABSX,`SUB_ABSX,`OR_ABSX,`AND_ABSX,`EOR_ABSX:
                        begin
                                a <= rfoa;
                                radr <= ir[55:24] + rfob;
                                Rt <= ir[19:16];
                                pc <= pc + 32'd7;
                                state <= LOAD1;
                        end
                `ASL_ABSX,`ROL_ABSX,`LSR_ABSX,`ROR_ABSX,`INC_ABSX,`DEC_ABSX:
                        begin
                                radr <= ir[47:16] + rfob;
                                pc <= pc + 32'd6;
                                state <= LOAD1;
                        end
                `CPX_IMM32:
                        begin
                                res <= x - ir[39:8];
                                pc <= pc + 32'd5;
                                state <= IFETCH;
                        end
                `CPY_IMM32:
                        begin
                                res <= y - ir[39:8];
                                pc <= pc + 32'd5;
                                state <= IFETCH;
                        end
                `CPX_ZPX:
                        begin
                                radr <= dp + ir[23:12] + rfoa;
                                pc <= pc + 32'd3;
                                state <= LOAD1;
                        end
                `CPY_ZPX:
                        begin
                                radr <= dp + ir[23:12] + rfoa;
                                pc <= pc + 32'd3;
                                state <= LOAD1;
                        end
                `CPX_ABS:
                        begin
                                radr <= ir[39:8];
                                pc <= pc + 32'd5;
                                state <= LOAD1;
                        end
                `CPY_ABS:
                        begin
                                radr <= ir[39:8];
                                pc <= pc + 32'd5;
                                state <= LOAD1;
                        end
                `BRK:
                        begin
                                bf <= 1'b1;
                                radr <= isp - 32'd1;
                                wadr <= isp - 32'd1;
                                wdat <= pc + 32'd1;
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                sel_o <= 4'hF;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= pc + 32'd1;
                                vect <= `BRK_VECT;
                                state <= IRQ1;
                        end
                `JMP:
                        begin
                                pc[15:0] <= ir[23:8];
                                state <= IFETCH;
                        end
                `JML:
                        begin
                                pc <= ir[39:8];
                                state <= IFETCH;
                        end
                `JMP_IND:
                        begin
                                radr <= ir[39:8];
                                state <= JMP_IND1;
                        end
                `JMP_INDX:
                        begin
                                radr <= ir[39:8] + x;
                                state <= JMP_IND1;
                        end
                `JMP_RIND:
                        begin
                                pc <= rfoa;
                                res <= pc + 32'd2;
                                Rt <= ir[15:12];
                                state <= IFETCH;
                        end
                `JSR:
                        begin
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= pc + 32'd3;
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                sel_o <= 4'hF;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= pc + 32'd3;
                                vect <= {pc[31:16],ir[23:8]};
                                state <= JSR1;
                        end
                `JSR_RIND:
                        begin
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= pc + 32'd2;
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                sel_o <= 4'hF;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= pc + 32'd2;
                                vect <= rfoa;
                                state <= JSR1;
                                $stop;
                        end
                `JSL:
                        begin
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= pc + 32'd5;
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                sel_o <= 4'hF;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= pc + 32'd5;
                                vect <= ir[39:8];
                                state <= JSR1;
                        end
                `BSR:
                        begin
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= pc + 32'd3;
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                sel_o <= 4'hF;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= pc + 32'd3;
                                vect <= pc + {{16{ir[23]}},ir[23:8]};
                                state <= JSR1;
                        end
                `JSR_INDX:
                        begin
                                radr <= isp - 32'd1;
                                wadr <= isp - 32'd1;
                                wdat <= pc + 32'd5;
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                we_o <= 1'b1;
                                sel_o <= 4'hF;
                                adr_o <= {isp-32'd1,2'b00};
                                dat_o <= pc + 32'd5;
                                state <= JSR_INDX1;
                        end
//              `JSR16:
//                      begin
//                              radr <= isp - 32'd1;
//                              wadr <= isp - 32'd1;
//                              wdat <= pc + 32'd3;
//                              cyc_o <= 1'b1;
//                              stb_o <= 1'b1;
//                              we_o <= 1'b1;
//                              sel_o <= 4'hF;
//                              adr_o <= {isp-32'd1,2'b00};
//                              dat_o <= pc + 32'd3;
//                              state <= JSR161;
//                      end
                `RTS,`RTL:
                                begin
                                radr <= isp;
                                state <= RTS1;
                                end
                `RTI:   begin
                                radr <= isp;
                                state <= RTI1;
                                end
                `BEQ,`BNE,`BPL,`BMI,`BCC,`BCS,`BVC,`BVS,`BRA:
                        begin
                                state <= IFETCH;
                                if (ir[15:8]==8'h00) begin
                                        radr <= isp_dec;
                                        wadr <= isp_dec;
                                        wdat <= pc + 32'd2;
                                        cyc_o <= 1'b1;
                                        stb_o <= 1'b1;
                                        we_o <= 1'b1;
                                        sel_o <= 4'hF;
                                        adr_o <= {isp_dec,2'b00};
                                        dat_o <= pc + 32'd2;
                                        vect <= `SLP_VECT;
                                        state <= IRQ1;
                                end
                                else if (ir[15:8]==8'h1) begin
                                        if (takb)
                                                pc <= pc + {{16{ir[31]}},ir[31:16]};
                                        else
                                                pc <= pc + 32'd4;
                                end
                                else begin
                                        if (takb)
                                                pc <= pc + {{24{ir[15]}},ir[15:8]};
                                        else
                                                pc <= pc + 32'd2;
                                end
                        end
/*              `BEQ_RR:
                        begin
                                state <= IFETCH;
                                if (ir[23:16]==8'h00) begin
                                        radr <= isp_dec;
                                        wadr <= isp_dec;
                                        wdat <= pc + 32'd2;
                                        cyc_o <= 1'b1;
                                        stb_o <= 1'b1;
                                        we_o <= 1'b1;
                                        sel_o <= 4'hF;
                                        adr_o <= {isp_dec,2'b00};
                                        dat_o <= pc + 32'd2;
                                        vect <= `SLP_VECT;
                                        state <= IRQ1;
                                end
                                else if (ir[23:16]==8'h1) begin
                                        if (rfoa==rfob)
                                                pc <= pc + {{16{ir[39]}},ir[39:24]};
                                        else
                                                pc <= pc + 32'd5;
                                end
                                else begin
                                        if (takb)
                                                pc <= pc + {{24{ir[23]}},ir[23:16]};
                                        else
                                                pc <= pc + 32'd3;
                                end
                        end*/
                `BRL:
                        begin
                                if (ir[23:8]==16'h0000) begin
                                        radr <= isp_dec;
                                        wadr <= isp_dec;
                                        wdat <= pc + 32'd3;
                                        cyc_o <= 1'b1;
                                        stb_o <= 1'b1;
                                        we_o <= 1'b1;
                                        sel_o <= 4'hF;
                                        adr_o <= {isp_dec,2'b00};
                                        dat_o <= pc + 32'd3;
                                        vect <= `SLP_VECT;
                                        state <= IRQ1;
                                end
                                else begin
                                        pc <= pc + {{16{ir[23]}},ir[23:8]};
                                        state <= IFETCH;
                                end
                        end
                `PHP:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                sel_o <= 4'hF;
                                we_o <= 1'b1;
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= sr;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= sr;
                                isp <= isp_dec;
                                state <= PHP1;
                        end
                `PHA:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                sel_o <= 4'hF;
                                we_o <= 1'b1;
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= acc;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= acc;
                                isp <= isp_dec;
                                state <= PHP1;
                        end
                `PHX:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                sel_o <= 4'hF;
                                we_o <= 1'b1;
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= x;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= x;
                                isp <= isp_dec;
                                state <= PHP1;
                        end
                `PHY:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                sel_o <= 4'hF;
                                we_o <= 1'b1;
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= y;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= y;
                                isp <= isp_dec;
                                state <= PHP1;
                        end
                `PUSH:
                        begin
                                cyc_o <= 1'b1;
                                stb_o <= 1'b1;
                                sel_o <= 4'hF;
                                we_o <= 1'b1;
                                radr <= isp_dec;
                                wadr <= isp_dec;
                                wdat <= rfoa;
                                adr_o <= {isp_dec,2'b00};
                                dat_o <= rfoa;
                                state <= PHP1;
                                isp <= isp_dec;
                                pc <= pc + 32'd1;
                        end
                `PLP:
                        begin
                                radr <= isp;
                                state <= PLP1;
                                pc <= pc + 32'd1;
                        end
                `PLA,`PLX,`PLY:
                        begin
                                radr <= isp;
                                isp <= isp_inc;
                                state <= PLA1;
                                pc <= pc + 32'd1;
                        end
                `POP:
                        begin
                                Rt <= ir[15:12];
                                radr <= isp;
                                isp <= isp_inc;
                                state <= PLA1;
                                pc <= pc + 32'd2;
                        end
                default:        // unimplemented opcode
                        pc <= pc + 32'd1;
                endcase
                end
        end
 
// Stores always write through to memory, then optionally update the cache if
// there was a write hit.
STORE1:
        begin
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                we_o <= 1'b1;
                if (em || isStb)
                        case(wadr2LSB)
                        2'd0:   sel_o <= 4'b0001;
                        2'd1:   sel_o <= 4'b0010;
                        2'd2:   sel_o <= 4'b0100;
                        2'd3:   sel_o <= 4'b1000;
                        endcase
                else
                        sel_o <= 4'hf;
                adr_o <= {wadr,2'b00};
                dat_o <= wdat;
                radr <= wadr;           // Do a cache read to test the hit
                state <= STORE2;
        end
 
// Terminal state for stores. Update the data cache if there was a cache hit.
// Clear any previously set lock status
STORE2:
        if (ack_i) begin
                state <= IFETCH;
                lock_o <= 1'b0;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'h0;
                dat_o <= 32'h0;
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        dmiss <= `TRUE;
                        state <= WAIT_DHIT;
                        retstate <= IFETCH;
                end
        end
WAIT_DHIT:
        if (dhit)
                state <= retstate;
 
`include "byte_ix.v"
`include "byte_iy.v"
 
// Indirect and indirect X addressing mode eg. LDA ($12,x) : (zp)
IX1:
        if (unCachedData) begin
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                sel_o <= 4'hf;
                adr_o <= {radr,2'b00};
                state <= IX2;
        end
        else if (dhit) begin
                radr <= rdat;
                state <= IX3;
        end
        else
                dmiss <= `TRUE;
IX2:
        if (ack_i) begin
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'h0;
                radr <= dat_i;
                state <= IX3;
        end
IX3:
        if (ir[7:0]==`ST_IX || ir[7:0]==`ST_RIND) begin
                wadr <= radr;
                wdat <= rfoa;
                state <= STORE1;
        end
        else if (unCachedData) begin
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                sel_o <= 4'hf;
                adr_o <= {radr,2'b00};
                state <= IX4;
        end
        else if (dhit) begin
                b <= rdat;
                state <= CALC;
        end
        else
                dmiss <= `TRUE;
IX4:
        if (ack_i) begin
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'h0;
                b <= dat_i;
                state <= CALC;
        end
 
 
// Indirect Y addressing mode eg. LDA ($12),y
IY1:
        if (unCachedData) begin
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                sel_o <= 4'hf;
                adr_o <= {radr,2'b00};
                state <= IY2;
        end
        else if (dhit) begin
                radr <= rdat;
                state <= IY3;
        end
        else
                dmiss <= `TRUE;
IY2:
        if (ack_i) begin
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'h0;
                radr <= dat_i;
                state <= IY3;
        end
IY3:
        begin
                radr <= radr + y;
                wadr <= radr + y;
                wdat <= rfoa;
                if (ir==`ST_IY)
                        state <= STORE1;
                else
                        state <= LOAD1;
        end
 
// Performs the data fetch for both eight bit and 32 bit modes
// Handle the following address modes: zp : zp,Rn : abs : abs,Rn
LOAD1:
        if (unCachedData) begin
                if (isRMW)
                        lock_o <= 1'b1;
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                sel_o <= 4'hf;
                adr_o <= {radr,2'b00};
                state <= LOAD2;
        end
        else if (dhit) begin
                b8 <= rdat8;
                b <= rdat;
                state <= CALC;
        end
        else
                dmiss <= `TRUE;
LOAD2:
        if (ack_i) begin
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'd0;
                b8 <= dati;
                b <= dat_i;
                state <= CALC;
        end
 
`include "calc.v"
 
JSR1:
        if (ack_i) begin
                state <= IFETCH;
                retstate <= IFETCH;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'd0;
                dat_o <= 32'd0;
                pc <= vect;
                isp <= isp_dec;
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        state <= WAIT_DHIT;
                        dmiss <= `TRUE;
                end
        end
 
`include "byte_jsr.v"
`include "byte_jsl.v"
 
JSR_INDX1:
        if (ack_i) begin
                state <= JMP_IND1;
                retstate <= JMP_IND1;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'd0;
                dat_o <= 32'd0;
                radr <= ir[39:8] + x;
                isp <= isp_dec;
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        dmiss <= `TRUE;
                        state <= WAIT_DHIT;
                end
        end
BYTE_JSR_INDX1:
        if (ack_i) begin
                state <= BYTE_JSR_INDX2;
                retstate <= BYTE_JSR_INDX2;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        state <= WAIT_DHIT;
                        dmiss <= `TRUE;
                end
        end
BYTE_JSR_INDX2:
        begin
                radr <= {24'h1,sp[7:2]};
                wadr <= {24'h1,sp[7:2]};
                radr2LSB <= sp[1:0];
                wadr2LSB <= sp[1:0];
                wdat <= {4{pcp2[7:0]}};
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                we_o <= 1'b1;
                case(sp[1:0])
                2'd0:   sel_o <= 4'b0001;
                2'd1:   sel_o <= 4'b0010;
                2'd2:   sel_o <= 4'b0100;
                2'd3:   sel_o <= 4'b1000;
                endcase
                adr_o <= {24'h1,sp[7:2],2'b00};
                dat_o <= {4{pcp2[7:0]}};
                sp <= sp_dec;
                state <= BYTE_JSR_INDX3;
        end
BYTE_JSR_INDX3:
        if (ack_i) begin
                state <= BYTE_JMP_IND1;
                retstate <= BYTE_JMP_IND1;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'd0;
                dat_o <= 32'd0;
                radr <= absx_address[15:2];
                radr2LSB <= absx_address[1:0];
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        state <= WAIT_DHIT;
                        dmiss <= `TRUE;
                end
        end
JSR161:
        if (ack_i) begin
                state <= IFETCH;
                retstate <= IFETCH;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                pc <= {{16{ir[23]}},ir[23:8]};
                isp <= isp_dec;
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        state <= WAIT_DHIT;
                        dmiss <= `TRUE;
                end
        end
 
`include "byte_plp.v"
`include "byte_rts.v"
`include "byte_rti.v"
`include "rti.v"
`include "rts.v"
 
PHP1:
        if (ack_i) begin
                state <= IFETCH;
                retstate <= IFETCH;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'd0;
                dat_o <= 32'd0;
                pc <= pc + 32'd1;
                if (dhit) begin
                        wr <= 1'b1;
                        wrsel <= sel_o;
                end
                else if (write_allocate) begin
                        state <= WAIT_DHIT;
                        dmiss <= `TRUE;
                end
        end
`include "plp.v"
`include "pla.v"
 
`include "byte_irq.v"
`include "byte_jmp_ind.v"
 
IRQ1:
        if (ack_i) begin
                state <= IRQ2;
                retstate <= IRQ2;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                isp <= isp_dec;
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        state <= WAIT_DHIT;
                        dmiss <= `TRUE;
                end
        end
IRQ2:
        begin
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                we_o <= 1'b1;
                sel_o <= 4'hF;
                radr <= isp_dec;
                wadr <= isp_dec;
                wdat <= sr;
                adr_o <= {isp_dec,2'b00};
                dat_o <= sr;
                state <= IRQ3;
        end
IRQ3:
        if (ack_i) begin
                state <= JMP_IND1;
                retstate <= JMP_IND1;
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                we_o <= 1'b0;
                sel_o <= 4'h0;
                isp <= isp_dec;
                if (dhit) begin
                        wrsel <= sel_o;
                        wr <= 1'b1;
                end
                else if (write_allocate) begin
                        dmiss <= `TRUE;
                        state <= WAIT_DHIT;
                end
                radr <= vect[31:2];
                if (!bf)
                        im <= 1'b1;
                em <= 1'b0;                     // make sure we process in native mode; we might have been called up during emulation mode
        end
JMP_IND1:
        if (unCachedData) begin
                cyc_o <= 1'b1;
                stb_o <= 1'b1;
                sel_o <= 4'hF;
                adr_o <= {radr,2'b00};
                state <= JMP_IND2;
        end
        else if (dhit) begin
                pc <= rdat;
                state <= IFETCH;
        end
        else
                dmiss <= `TRUE;
JMP_IND2:
        if (ack_i) begin
                cyc_o <= 1'b0;
                stb_o <= 1'b0;
                sel_o <= 4'h0;
                adr_o <= 34'd0;
                pc <= dat_i;
                state <= IFETCH;
        end
MULDIV1:
        state <= MULDIV2;
MULDIV2:
        if (md_done) begin
                state <= IFETCH;
                case(ir[23:20])
                `MUL_RR:        begin res <= prod[31:0]; end
                `MULS_RR:       begin res <= prod[31:0]; end
                `DIV_RR:        begin res <= q; end
                `DIVS_RR:       begin res <= q; end
                `MOD_RR:        begin res <= r; end
                `MODS_RR:       begin res <= r; end
                endcase
        end
 
endcase
 
`include "cache_controller.v"
 
end
endmodule
Line No.	Rev	Author	Line
1	10	robfinch	`timescale 1ns / 1ps
2			`// ============================================================================`
3			`// __`
4			`// \\__/ o\ (C) 2013 Robert Finch, Stratford`
5			`// \ __ / All rights reserved.`
6			`// \/_// robfinch<remove>@opencores.org`
7			`// \|\|`
8			`//`
9			`// rtf65002.v`
10			`// - 32 bit CPU`
11			`//`
12			`// This source file is free software: you can redistribute it and/or modify`
13			`// it under the terms of the GNU Lesser General Public License as published`
14			`// by the Free Software Foundation, either version 3 of the License, or`
15			`// (at your option) any later version.`
16			`//`
17			`// This source file is distributed in the hope that it will be useful,`
18			`// but WITHOUT ANY WARRANTY; without even the implied warranty of`
19			`// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the`
20			`// GNU General Public License for more details.`
21			`//`
22			`// You should have received a copy of the GNU General Public License`
23			`// along with this program. If not, see <http://www.gnu.org/licenses/>.`
24			`//`
25			`// 9000 LUT's / 850 ff's / 56 MHz`
26			`// 15 Block RAMs`
27			`// ============================================================================`
28			`//`
29	5	robfinch	`define TRUE 1'b1
30			`define FALSE 1'b0
31
32			`define RST_VECT 34'h3FFFFFFF8
33			`define NMI_VECT 34'h3FFFFFFF4
34			`define IRQ_VECT 34'h3FFFFFFF0
35			`define BRK_VECT 34'h3FFFFFFEC
36			`define SLP_VECT 34'h3FFFFFFE8
37			`define BYTE_NMI_VECT 34'h00000FFFA
38			`define BYTE_IRQ_VECT 34'h00000FFFE
39
40			`define BRK 8'h00
41			`define RTI 8'h40
42			`define RTS 8'h60
43			`define PHP 8'h08
44			`define CLC 8'h18
45			`define PLP 8'h28
46			`define SEC 8'h38
47			`define PHA 8'h48
48			`define CLI 8'h58
49			`define PLA 8'h68
50			`define SEI 8'h78
51			`define DEY 8'h88
52			`define TYA 8'h98
53			`define TAY 8'hA8
54			`define CLV 8'hB8
55			`define INY 8'hC8
56			`define CLD 8'hD8
57			`define INX 8'hE8
58			`define SED 8'hF8
59			`define ROR_ACC 8'h6A
60			`define TXA 8'h8A
61			`define TXS 8'h9A
62			`define TAX 8'hAA
63			`define TSX 8'hBA
64			`define DEX 8'hCA
65			`define NOP 8'hEA
66			`define TXY 8'h9B
67			`define TYX 8'hBB
68			`define TAS 8'h1B
69			`define TSA 8'h3B
70			`define TRS 8'h8B
71			`define TSR 8'hAB
72			`define STP 8'hDB
73			`define NAT 8'hFB
74			`define EMM 8'hFB
75			`define INA 8'h1A
76			`define DEA 8'h3A
77
78			`define RR 8'h02
79	12	robfinch	`define ADD_RR 4'd0
80			`define SUB_RR 4'd1
81			`define CMP_RR 4'd2
82			`define AND_RR 4'd3
83			`define EOR_RR 4'd4
84			`define OR_RR 4'd5
85			`define MUL_RR 4'd8
86			`define MULS_RR 4'd9
87			`define DIV_RR 4'd10
88			`define DIVS_RR 4'd11
89			`define MOD_RR 4'd12
90			`define MODS_RR 4'd13
91			`define LD_RR 8'h7B
92	5	robfinch
93			`define ADD_IMM8 8'h65 // 8 bit operand
94			`define ADD_IMM16 8'h79 // 16 bit operand
95			`define ADD_IMM32 8'h69 // 32 bit operand
96			`define ADD_ZPX 8'h75 // there is no ZP mode, use R0 to syntheisze
97			`define ADD_IX 8'h61
98			`define ADD_IY 8'h71
99			`define ADD_ABS 8'h6D
100			`define ADD_ABSX 8'h7D
101			`define ADD_RIND 8'h72
102
103			`define SUB_IMM8 8'hE5
104			`define SUB_IMM16 8'hF9
105			`define SUB_IMM32 8'hE9
106			`define SUB_ZPX 8'hF5
107			`define SUB_IX 8'hE1
108			`define SUB_IY 8'hF1
109			`define SUB_ABS 8'hED
110			`define SUB_ABSX 8'hFD
111			`define SUB_RIND 8'hF2
112
113			`// CMP = SUB r0,....`
114
115			`define ADC_IMM 8'h69
116			`define ADC_ZP 8'h65
117			`define ADC_ZPX 8'h75
118			`define ADC_IX 8'h61
119			`define ADC_IY 8'h71
120			`define ADC_ABS 8'h6D
121			`define ADC_ABSX 8'h7D
122			`define ADC_ABSY 8'h79
123			`define ADC_I 8'h72
124
125			`define SBC_IMM 8'hE9
126			`define SBC_ZP 8'hE5
127			`define SBC_ZPX 8'hF5
128			`define SBC_IX 8'hE1
129			`define SBC_IY 8'hF1
130			`define SBC_ABS 8'hED
131			`define SBC_ABSX 8'hFD
132			`define SBC_ABSY 8'hF9
133			`define SBC_I 8'hF2
134
135			`define CMP_IMM32 8'hC9
136			`define CMP_IMM 8'hC9
137			`define CMP_ZP 8'hC5
138			`define CMP_ZPX 8'hD5
139			`define CMP_IX 8'hC1
140			`define CMP_IY 8'hD1
141			`define CMP_ABS 8'hCD
142			`define CMP_ABSX 8'hDD
143			`define CMP_ABSY 8'hD9
144			`define CMP_I 8'hD2
145
146
147			`define LDA_IMM8 8'hA5
148			`define LDA_IMM16 8'hB9
149			`define LDA_IMM32 8'hA9
150
151			`define AND_IMM8 8'h25
152			`define AND_IMM16 8'h39
153			`define AND_IMM32 8'h29
154			`define AND_IMM 8'h29
155			`define AND_ZP 8'h25
156			`define AND_ZPX 8'h35
157			`define AND_IX 8'h21
158			`define AND_IY 8'h31
159			`define AND_ABS 8'h2D
160			`define AND_ABSX 8'h3D
161			`define AND_ABSY 8'h39
162			`define AND_RIND 8'h32
163			`define AND_I 8'h32
164
165			`define OR_IMM8 8'h05
166			`define OR_IMM16 8'h19
167			`define OR_IMM32 8'h09
168			`define OR_ZPX 8'h15
169			`define OR_IX 8'h01
170			`define OR_IY 8'h11
171			`define OR_ABS 8'h0D
172			`define OR_ABSX 8'h1D
173			`define OR_RIND 8'h12
174
175			`define ORA_IMM 8'h09
176			`define ORA_ZP 8'h05
177			`define ORA_ZPX 8'h15
178			`define ORA_IX 8'h01
179			`define ORA_IY 8'h11
180			`define ORA_ABS 8'h0D
181			`define ORA_ABSX 8'h1D
182			`define ORA_ABSY 8'h19
183			`define ORA_I 8'h12
184
185			`define EOR_IMM 8'h49
186			`define EOR_IMM8 8'h45
187			`define EOR_IMM16 8'h59
188			`define EOR_IMM32 8'h49
189			`define EOR_ZP 8'h45
190			`define EOR_ZPX 8'h55
191			`define EOR_IX 8'h41
192			`define EOR_IY 8'h51
193			`define EOR_ABS 8'h4D
194			`define EOR_ABSX 8'h5D
195			`define EOR_ABSY 8'h59
196			`define EOR_RIND 8'h52
197			`define EOR_I 8'h52
198
199			`// LD is OR rt,r0,....`
200
201			`define ST_ZPX 8'h95
202			`define ST_IX 8'h81
203			`define ST_IY 8'h91
204			`define ST_ABS 8'h8D
205			`define ST_ABSX 8'h9D
206			`define ST_RIND 8'h92
207
208			`define ORB_ZPX 8'hB5
209			`define ORB_IX 8'hA1
210			`define ORB_IY 8'hB1
211			`define ORB_ABS 8'hAD
212			`define ORB_ABSX 8'hBD
213
214			`define STB_ZPX 8'h74
215			`define STB_ABS 8'h9C
216			`define STB_ABSX 8'h9E
217
218
219			//`define LDB_RIND 8'hB2 // Conflict with LDX #imm16
220
221			`define LDA_IMM 8'hA9
222			`define LDA_ZP 8'hA5
223			`define LDA_ZPX 8'hB5
224			`define LDA_IX 8'hA1
225			`define LDA_IY 8'hB1
226			`define LDA_ABS 8'hAD
227			`define LDA_ABSX 8'hBD
228			`define LDA_ABSY 8'hB9
229			`define LDA_I 8'hB2
230
231			`define STA_ZP 8'h85
232			`define STA_ZPX 8'h95
233			`define STA_IX 8'h81
234			`define STA_IY 8'h91
235			`define STA_ABS 8'h8D
236			`define STA_ABSX 8'h9D
237			`define STA_ABSY 8'h99
238			`define STA_I 8'h92
239
240			`define ASL_ACC 8'h0A
241			`define ASL_ZP 8'h06
242			`define ASL_RR 8'h06
243			`define ASL_ZPX 8'h16
244			`define ASL_ABS 8'h0E
245			`define ASL_ABSX 8'h1E
246
247			`define ROL_ACC 8'h2A
248			`define ROL_ZP 8'h26
249			`define ROL_RR 8'h26
250			`define ROL_ZPX 8'h36
251			`define ROL_ABS 8'h2E
252			`define ROL_ABSX 8'h3E
253
254			`define LSR_ACC 8'h4A
255			`define LSR_ZP 8'h46
256			`define LSR_RR 8'h46
257			`define LSR_ZPX 8'h56
258			`define LSR_ABS 8'h4E
259			`define LSR_ABSX 8'h5E
260
261			`define ROR_RR 8'h66
262			`define ROR_ZP 8'h66
263			`define ROR_ZPX 8'h76
264			`define ROR_ABS 8'h6E
265			`define ROR_ABSX 8'h7E
266
267	12	robfinch	`define DEC_RR 8'hC6
268	5	robfinch	`define DEC_ZP 8'hC6
269			`define DEC_ZPX 8'hD6
270			`define DEC_ABS 8'hCE
271			`define DEC_ABSX 8'hDE
272	12	robfinch	`define INC_RR 8'hE6
273	5	robfinch	`define INC_ZP 8'hE6
274			`define INC_ZPX 8'hF6
275			`define INC_ABS 8'hEE
276			`define INC_ABSX 8'hFE
277
278			`define BIT_IMM 8'h89
279			`define BIT_ZP 8'h24
280			`define BIT_ZPX 8'h34
281			`define BIT_ABS 8'h2C
282			`define BIT_ABSX 8'h3C
283
284			`// CMP = SUB r0,...`
285			`// BIT = AND r0,...`
286			`define BPL 8'h10
287			`define BVC 8'h50
288			`define BCC 8'h90
289			`define BNE 8'hD0
290			`define BMI 8'h30
291			`define BVS 8'h70
292			`define BCS 8'hB0
293			`define BEQ 8'hF0
294			`define BRL 8'h82
295
296			`define JML 8'h5C
297			`define JMP 8'h4C
298			`define JMP_IND 8'h6C
299			`define JMP_INDX 8'h7C
300			`define JMP_RIND 8'hD2
301			`define JSR 8'h20
302			`define JSL 8'h22
303			`define JSR_INDX 8'hFC
304			`define JSR_RIND 8'hC2
305			`define RTS 8'h60
306			`define RTL 8'h6B
307			`define BSR 8'h62
308			`define NOP 8'hEA
309
310			`define BRK 8'h00
311			`define PLX 8'hFA
312			`define PLY 8'h7A
313			`define PHX 8'hDA
314			`define PHY 8'h5A
315			`define BRA 8'h80
316			`define WAI 8'hCB
317			`define PUSH 8'h0B
318			`define POP 8'h2B
319
320			`define LDX_IMM 8'hA2
321			`define LDX_ZP 8'hA6
322			`define LDX_ZPX 8'hB6
323			`define LDX_ZPY 8'hB6
324			`define LDX_ABS 8'hAE
325			`define LDX_ABSY 8'hBE
326
327			`define LDX_IMM32 8'hA2
328			`define LDX_IMM16 8'hB2
329			`define LDX_IMM8 8'hA6
330
331			`define LDY_IMM 8'hA0
332			`define LDY_ZP 8'hA4
333			`define LDY_ZPX 8'hB4
334			`define LDY_IMM32 8'hA0
335			`define LDY_ABS 8'hAC
336			`define LDY_ABSX 8'hBC
337
338			`define STX_ZP 8'h86
339			`define STX_ZPX 8'h96
340			`define STX_ZPY 8'h96
341			`define STX_ABS 8'h8E
342
343			`define STY_ZP 8'h84
344			`define STY_ZPX 8'h94
345			`define STY_ABS 8'h8C
346
347			`define STZ_ZP 8'h64
348			`define STZ_ZPX 8'h74
349			`define STZ_ABS 8'h9C
350			`define STZ_ABSX 8'h9E
351
352			`define CPX_IMM 8'hE0
353			`define CPX_IMM32 8'hE0
354			`define CPX_ZP 8'hE4
355			`define CPX_ZPX 8'hE4
356			`define CPX_ABS 8'hEC
357			`define CPY_IMM 8'hC0
358			`define CPY_IMM32 8'hC0
359			`define CPY_ZP 8'hC4
360			`define CPY_ZPX 8'hC4
361			`define CPY_ABS 8'hCC
362
363			`define TRB_ZP 8'h14
364			`define TRB_ZPX 8'h14
365			`define TRB_ABS 8'h1C
366			`define TSB_ZP 8'h04
367			`define TSB_ZPX 8'h04
368			`define TSB_ABS 8'h0C
369
370	10	robfinch	`define BAZ 8'hC1
371			`define BXZ 8'hD1
372			`define BEQ_RR 8'hE2
373
374	5	robfinch	`module icachemem(wclk, wr, adr, dat, rclk, pc, insn);`
375			`input wclk;`
376			`input wr;`
377			`input [33:0] adr;`
378			`input [31:0] dat;`
379			`input rclk;`
380			`input [31:0] pc;`
381			`output reg [55:0] insn;`
382
383			`wire [63:0] insn0;`
384			`wire [63:0] insn1;`
385			`wire [31:0] pcp8 = pc + 32'd8;`
386			`reg [31:0] rpc;`
387
388			`always @(posedge rclk)`
389			`rpc <= pc;`
390
391			`// memL and memH combined allow a 64 bit read`
392	10	robfinch	`syncRam2kx32_1rw1r ramL0`
393	5	robfinch	`(`
394			`.wrst(1'b0),`
395			`.wclk(wclk),`
396			`.wce(~adr[2]),`
397			`.we(wr),`
398			`.wsel(4'hF),`
399	10	robfinch	`.wadr(adr[13:3]),`
400	5	robfinch	`.i(dat),`
401			`.wo(),`
402			`.rrst(1'b0),`
403			`.rclk(rclk),`
404			`.rce(1'b1),`
405	10	robfinch	`.radr(pc[13:3]),`
406	5	robfinch	`.o(insn0[31:0])`
407			`);`
408
409	10	robfinch	`syncRam2kx32_1rw1r ramH0`
410	5	robfinch	`(`
411			`.wrst(1'b0),`
412			`.wclk(wclk),`
413			`.wce(adr[2]),`
414			`.we(wr),`
415			`.wsel(4'hF),`
416	10	robfinch	`.wadr(adr[13:3]),`
417	5	robfinch	`.i(dat),`
418			`.wo(),`
419			`.rrst(1'b0),`
420			`.rclk(rclk),`
421			`.rce(1'b1),`
422	10	robfinch	`.radr(pc[13:3]),`
423	5	robfinch	`.o(insn0[63:32])`
424			`);`
425
426	10	robfinch	`syncRam2kx32_1rw1r ramL1`
427	5	robfinch	`(`
428			`.wrst(1'b0),`
429			`.wclk(wclk),`
430			`.wce(~adr[2]),`
431			`.we(wr),`
432			`.wsel(4'hF),`
433	10	robfinch	`.wadr(adr[13:3]),`
434	5	robfinch	`.i(dat),`
435			`.wo(),`
436			`.rrst(1'b0),`
437			`.rclk(rclk),`
438			`.rce(1'b1),`
439	10	robfinch	`.radr(pcp8[13:3]),`
440	5	robfinch	`.o(insn1[31:0])`
441			`);`
442
443	10	robfinch	`syncRam2kx32_1rw1r ramH1`
444	5	robfinch	`(`
445			`.wrst(1'b0),`
446			`.wclk(wclk),`
447			`.wce(adr[2]),`
448			`.we(wr),`
449			`.wsel(4'hF),`
450	10	robfinch	`.wadr(adr[13:3]),`
451	5	robfinch	`.i(dat),`
452			`.wo(),`
453			`.rrst(1'b0),`
454			`.rclk(rclk),`
455			`.rce(1'b1),`
456	10	robfinch	`.radr(pcp8[13:3]),`
457	5	robfinch	`.o(insn1[63:32])`
458			`);`
459
460			`always @(rpc or insn0 or insn1)`
461			`case(rpc[2:0])`
462			`3'd0: insn <= insn0[55:0];`
463			`3'd1: insn <= insn0[63:8];`
464			`3'd2: insn <= {insn1[7:0],insn0[63:16]};`
465			`3'd3: insn <= {insn1[15:0],insn0[63:24]};`
466			`3'd4: insn <= {insn1[23:0],insn0[63:32]};`
467			`3'd5: insn <= {insn1[31:0],insn0[63:40]};`
468			`3'd6: insn <= {insn1[39:0],insn0[63:48]};`
469			`3'd7: insn <= {insn1[47:0],insn0[63:56]};`
470			`endcase`
471			`endmodule`
472
473			`module tagmem(wclk, wr, adr, rclk, pc, hit0, hit1);`
474			`input wclk;`
475			`input wr;`
476			`input [33:0] adr;`
477			`input rclk;`
478			`input [31:0] pc;`
479			`output hit0;`
480			`output hit1;`
481
482			`wire [31:0] pcp8 = pc + 32'd8;`
483			`wire [31:0] tag0;`
484			`wire [31:0] tag1;`
485			`reg [31:0] rpc;`
486			`reg [31:0] rpcp8;`
487
488			`always @(posedge rclk)`
489			`rpc <= pc;`
490			`always @(posedge rclk)`
491			`rpcp8 <= pcp8;`
492
493	10	robfinch	`syncRam1kx32_1rw1r ram0 (`
494	5	robfinch	`.wrst(1'b0),`
495			`.wclk(wclk),`
496			`.wce(adr[3:2]==2'b11),`
497			`.we(wr),`
498	10	robfinch	`.wsel(4'hF),`
499			`.wadr(adr[13:4]),`
500	5	robfinch	`.i(adr[31:0]),`
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[/] [rtf65002/] [trunk/] [rtl/] [verilog/] [rtf65002d.v] - Blame information for rev 12

Line No.	Rev	Author	Line
1	10	robfinch	`timescale 1ns / 1ps
2			`// ============================================================================`
3			`// __`
4			`// \\__/ o\ (C) 2013 Robert Finch, Stratford`
5			`// \ __ / All rights reserved.`
6			`// \/_// robfinch<remove>@opencores.org`
7			`// \|\|`
8			`//`
9			`// rtf65002.v`
10			`// - 32 bit CPU`
11			`//`
12			`// This source file is free software: you can redistribute it and/or modify`
13			`// it under the terms of the GNU Lesser General Public License as published`
14			`// by the Free Software Foundation, either version 3 of the License, or`
15			`// (at your option) any later version.`
16			`//`
17			`// This source file is distributed in the hope that it will be useful,`
18			`// but WITHOUT ANY WARRANTY; without even the implied warranty of`
19			`// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the`
20			`// GNU General Public License for more details.`
21			`//`
22			`// You should have received a copy of the GNU General Public License`
23			`// along with this program. If not, see <http://www.gnu.org/licenses/>.`
24			`//`
25			`// 9000 LUT's / 850 ff's / 56 MHz`
26			`// 15 Block RAMs`
27			`// ============================================================================`
28			`//`
29	5	robfinch	`define TRUE 1'b1
30			`define FALSE 1'b0
31
32			`define RST_VECT 34'h3FFFFFFF8
33			`define NMI_VECT 34'h3FFFFFFF4
34			`define IRQ_VECT 34'h3FFFFFFF0
35			`define BRK_VECT 34'h3FFFFFFEC
36			`define SLP_VECT 34'h3FFFFFFE8
37			`define BYTE_NMI_VECT 34'h00000FFFA
38			`define BYTE_IRQ_VECT 34'h00000FFFE
39
40			`define BRK 8'h00