Subversion Repositories rf68000

`timescale 1ns / 1ps

// ============================================================================

//        __

//   \\__/ o\    (C) 2008-2022  Robert Finch, Waterloo

//    \  __ /    All rights reserved.

//     \/_//     robfinch@finitron.ca

//       ||

//

//      rf68000.sv

//

//

// BSD 3-Clause License

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//

// 1. Redistributions of source code must retain the above copyright notice, this

//    list of conditions and the following disclaimer.

//

// 2. Redistributions in binary form must reproduce the above copyright notice,

//    this list of conditions and the following disclaimer in the documentation

//    and/or other materials provided with the distribution.

//

// 3. Neither the name of the copyright holder nor the names of its

//    contributors may be used to endorse or promote products derived from

//    this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE

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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//

// ============================================================================

//

// Uncomment the following to optimize for performance. Increases the core size.

//`define OPT_PERF    1'b1

`define BIG_ENDIAN      1'b1

//`define SUPPORT_RETRY 1'b1

`define SUPPORT_MUL     1'b1

`define SUPPORT_DIV     1'b1

`define SUPPORT_BCD     1'b1

//`define SUPPORT_010   1'b1

`define SUPPORT_BITPAIRS 1'b1

//`define HAS_MMU 1'b1

//`define SUPPORT_TASK  1'b1

//`define SUPPORT_B24   1'b1            // To support 23-bit branch displacements

`define TRUE        1'b1

`define FALSE       1'b0

`define HIGH        1'b1

`define LOW         1'b0

`define RESET_VECTOR    32'h00000400

`define CSR_CORENO    32'hFFFFFFE0

`define CSR_TICK        32'hFFFFFFE4

`define CSR_ICNT                                32'hFFFFFFE8

`define CSR_TASK        32'hFFFFFFFC

//`define SSP_VEC       9'd000

`define RESET_VEC       9'd001

`define BUSERR_VEC      9'd002

`define ADDRERR_VEC     9'd003

`define ILLEGAL_VEC     9'd004

`define DBZ_VEC         9'd005

`define CHK_VEC         9'd006

`define TRAPV_VEC       9'd007

`define PRIV_VEC        9'd008

`define TRACE_VEC       9'd009

`define LINE10_VEC      9'd010

`define LINE15_VEC      9'd011

`define UNINITINT_VEC   9'd015

// Vectors 24-31 for IRQ's

`define SPURIOUS_VEC            9'd024

`define IRQ_VEC         9'd024

// Vectors 32-46 for TRAPQ instruction

`define TRAP_VEC        9'd032

`define DISP_VEC                                9'd063

`define USER64          9'd064

//`define NMI_TRAP        9'h1FE

`define RESET_TASK      9'h000

`define LDB             16'b0001_xxx0xx_xxxxxx

`define LDH             16'b0010_xxx0xx_xxxxxx

`define LDW             16'b0011_xxx0xx_xxxxxx

`define STB             16'b0001_xxx1xx_xxxxxx

`define STH             16'b0010_xxx1xx_xxxxxx

`define STW             16'b0011_xxx1xx_xxxxxx

// DBcc also for Scc

`define DBRA    8'h50

`define DBSR    8'h51

`define DBHI    8'h52

`define DBLS    8'h53

`define DBHS    8'h54

`define DBLO    8'h55

`define DBNE    8'h56

`define DBEQ    8'h57

`define DBVC    8'h58

`define DBVS    8'h59

`define DBPL    8'h5A

`define DBMI    8'h5B

`define DBGE    8'h5C

`define DBLT    8'h5D

`define DBGT    8'h5E

`define DBLE    8'h5F

`define BRA             8'h60

`define BSR             8'h61

`define BHI             8'h62

`define BLS             8'h63

`define BHS             8'h64

`define BLO             8'h65

`define BNE             8'h66

`define BEQ             8'h67

`define BVC             8'h68

`define BVS             8'h69

`define BPL             8'h6A

`define BMI             8'h6B

`define BGE             8'h6C

`define BLT             8'h6D

`define BGT             8'h6E

`define BLE             8'h6F

// 12000 LUTs / 80MHz

// slices

// 1600 FF's

// 2 MULTS

// 8 BRAMs

module rf68000(coreno_i, clken_i, rst_i, rst_o, clk_i, nmi_i, ipl_i, vpa_i,

        lock_o, cyc_o, stb_o, ack_i, err_i, rty_i, we_o, sel_o, fc_o,

        asid_o, mmus_o, ios_o, iops_o, adr_o, dat_i, dat_o);

typedef enum logic [7:0] {

        IFETCH = 8'd1,

        DECODE,

        RETSTATE,

        FETCH_BYTE,

        FETCH_WORD,

        FETCH_LWORD,

        FETCH_LWORDa,

        STORE_BYTE,

        USTORE_BYTE,

        // 10

        STORE_WORD,

        STORE_LWORD,

        STORE_LWORDa,

        LFETCH_BYTE,

        FETCH_BRDISP,

        FETCH_BRDISPa,

        FETCH_IMM16,

        FETCH_IMM16a,

        FETCH_IMM32,

        FETCH_IMM32a,

        // 20

        FETCH_IMM32b,

        JSR,

        JMP,

        DBRA,

        ADDQ,

        ADDQ2,

        ADDI,

        ADDI2,

        ADDI3,

        ADDI4,

        // 30

        ADD,

        ADD1,

        DIV1,

        DIV2,

        STORE_IN_DEST,

        SHIFT,

        SHIFT1,

        BIT,

        BIT1,

        BIT2,

        // 40

        RTD1,

        RTD2,

        RTE1,

        RTE2,

        RTE3,

        RTE4,

        RTE5,

        RTE6,

        RTE7,

        RTE8,

        // 50

        RTE9,

        RTE10,

        RTE11,

        RTS1,

        RTS2,

        LINK,

        LINK1,

        LINK2,

        UNLNK,

        UNLNK2,

        // 60

        JMP_VECTOR,

        JMP_VECTOR2,

        JMP_VECTOR3,

        NEG,

        NEGX,

        NEGX1,

        NOT,

        TAS,

        LEA,

        LEA2,

        //70

        EXG1,

        CMP,

        CMP1,

        CMPA,

        CMPM,

        CMPM1,  // defunct

        AND,

        AND1,

        EOR,

        ANDI_CCR,

        // 80

        ANDI_CCR2,

        ANDI_SR,

        ANDI_SRX,

        EORI_CCR,

        EORI_CCR2,

        EORI_SR,

        EORI_SRX,

        ORI_CCR,

        ORI_CCR2,

        ORI_SR,

        //90

        ORI_SRX,

        FETCH_NOP_BYTE,

        FETCH_NOP_WORD,

        FETCH_NOP_LWORD,

        FETCH_IMM8,

        FETCH_IMM8a,

        FETCH_D32,

        FETCH_D32a,

        FETCH_D32b,

        FETCH_D16,

        //100

        FETCH_D16a,

        FETCH_NDX,

        FETCH_NDXa,

        MOVE2CCR,

        MOVE2SR,

        MOVE2SRX,

        TRAP,

        TRAP3,

        TRAP3a,

        TRAP3b,

        //110

        TRAP4,

        TRAP5,

        TRAP6,

        TRAP7,

        TRAP7a,

        TRAP8,

        TRAP9,

        TRAP10,

        TRAP20,

        TRAP21,

        // 120

        TRAP22,

        TRAP23,

        TRAP24,

        TRAP25,

        TRAP26,

        INTA,

        RETRY,

        RETRY2,

        TST,

        MUL,

        // 130

        MUL1,

        STOP,

        STOP1,

        RESET,

        RESET2,

        RESET3,

        RESET4,

        RESET5,

        PEA1,

        PEA2,

        // 140

        PEA3,

        BCD,

        BCD0,

        BCD1,

        BCD2,

        BCD3,

        BCD4,

        OR,

        INT,

        INT2,

        INT3,

        // 150

        INT4,

        MOVEM_Xn2D,

        MOVEM_Xn2D2,

        MOVEM_Xn2D3,

        MOVEM_Xn2D4,

        MOVEM_s2Xn,

        MOVEM_s2Xn2,

        MOVEM_s2Xn3,

        TASK1,

        THREAD2,

        // 160

        TASK3,

        TASK4,

        LDT1,

        LDT2,

        LDT3,

        SDT1,

        SDT2,

        SUB,

        SUB1,

        MOVEP,

        MOVEP1,

        MOVEP2,

        MOVEP3,

        CHK,

        MOVERc2Rn,

        MOVERn2Rc,

        MOVERn2Rc2,

        MOVES,

        MOVES2,

        MOVES3,

        ADDX,

        ADDX2,

        ADDX3,

        SUBX,

        SUBX2,

        SUBX3,

        MULU1,

        MULU2,

        MULU3,

        MULS1,

        MULS2,

        MULS3,

        BIN2BCD1,

        BIN2BCD2,

        BCD2BIN1,

        BCD2BIN2,

        BCD2BIN3,

        IFETCH2,

        FSDATA2

} state_t;

typedef enum logic [4:0] {

        FU_NONE = 5'd0,

        FU_MUL,

        FU_TST, FU_ADDX, FU_SUBX,

        FU_CMP, FU_ADD, FU_SUB, FU_LOGIC, FU_ADDQ, FU_SUBQ,

        FU_ADDI, FU_ANDI_CCR, FU_ANDI_SR, FU_EORI_CCR,

        FU_ANDI_SRX, FU_EORI_SRX, FU_ORI_SRX, FU_MOVE2SRX,

        FU_EORI_SR, FU_ORI_CCR, FU_ORI_SR, FU_MOVE2CCR,

        FU_MOVE2SR

} flag_update_t;

parameter S = 1'b0;

parameter D = 1'b1;

input [31:0] coreno_i;

input clken_i;

input rst_i;

output reg rst_o;

input clk_i;

input nmi_i;

input vpa_i;

input [2:0] ipl_i;

output lock_o;

reg lock_o;

output cyc_o;

reg cyc_o;

output stb_o;

reg stb_o;

input ack_i;

input err_i;

input rty_i;

output we_o;

reg we_o;

output [3:0] sel_o;

reg [3:0] sel_o;

output [2:0] fc_o;

reg [2:0] fc_o;

output [7:0] asid_o;

output mmus_o;

output ios_o;

output iops_o;

output [31:0] adr_o;

reg [31:0] adr_o;

input [31:0] dat_i;

output [31:0] dat_o;

reg [31:0] dat_o;

reg em;                                                 // emulation mode

reg [15:0] ir;

reg [15:0] ir2;                 // second word for ir

reg ext_ir;

reg [31:0] icnt;

state_t state;

state_t rstate;

state_t state_stk1;

state_t state_stk2;

state_t state_stk3;

state_t state_stk4;

state_t sz_state;

flag_update_t flag_update;

reg [31:0] d0 = 'd0;

reg [31:0] d1 = 'd0;

reg [31:0] d2 = 'd0;

reg [31:0] d3 = 'd0;

reg [31:0] d4 = 'd0;

reg [31:0] d5 = 'd0;

reg [31:0] d6 = 'd0;

reg [31:0] d7 = 'd0;

reg [31:0] a0 = 'd0;

reg [31:0] a1 = 'd0;

reg [31:0] a2 = 'd0;

reg [31:0] a3 = 'd0;

reg [31:0] a4 = 'd0;

reg [31:0] a5 = 'd0;

reg [31:0] a6 = 'd0;

reg [31:0] sp = 'd0;

reg [127:0] fp0 = 'd0;

reg [127:0] fp1 = 'd0;

reg [127:0] fp2 = 'd0;

reg [127:0] fp3 = 'd0;

reg [127:0] fp4 = 'd0;

reg [127:0] fp5 = 'd0;

reg [127:0] fp6 = 'd0;

reg [127:0] fp7 = 'd0;

reg [31:0] d0i;

reg [31:0] d1i;

reg [31:0] d2i;

reg [31:0] d3i;

reg [31:0] d4i;

reg [31:0] d5i;

reg [31:0] d6i;

reg [31:0] d7i;

reg [31:0] a0i;

reg [31:0] a1i;

reg [31:0] a2i;

reg [31:0] a3i;

reg [31:0] a4i;

reg [31:0] a5i;

reg [31:0] a6i;

reg [31:0] spi;

reg [31:0] flagsi;

reg [31:0] pci;

wire [31:0] d0o;

wire [31:0] d1o;

wire [31:0] d2o;

wire [31:0] d3o;

wire [31:0] d4o;

wire [31:0] d5o;

wire [31:0] d6o;

wire [31:0] d7o;

wire [31:0] a0o;

wire [31:0] a1o;

wire [31:0] a2o;

wire [31:0] a3o;

wire [31:0] a4o;

wire [31:0] a5o;

wire [31:0] a6o;

wire [31:0] spo;

wire [31:0] flagso;

wire [31:0] pco;

reg cf,vf,nf,zf,xf,sf,tf;

reg [2:0] im;

reg [2:0] ccr57;

reg [1:0] sr1112;

reg sr14;

wire [15:0] sr = {tf,sr14,sf,sr1112,im,ccr57,xf,nf,zf,vf,cf};

wire [31:0] srx = {sr};

reg [31:0] isr;

reg [3:0] ifmt;

reg [31:0] pc;

reg [31:0] opc;                 // pc for branch references

reg [31:0] ssp,usp;

reg [31:0] disp;

reg [31:0] s,d,dd,imm,immx;

reg [31:0] bit2test;

reg wl;

reg ds;

reg [5:0] cnt;                          // shift count

reg [31:0] ea;                          // effective address

reg [31:0] vector;

reg [7:0] vecno;

reg [3:0] Rt;

wire [1:0] sz = ir[7:6];

reg dsix;

reg [2:0] mmm,mmmx,mmm_save='d0;

reg [2:0] rrr,rrrx;

reg [3:0] rrrr;

wire [2:0] MMM = ir[8:6];

wire [2:0] RRR = ir[11:9];

wire [2:0] QQQ = ir[11:9];

wire [2:0] DDD = ir[11:9];

wire [2:0] AAA = ir[11:9];

reg MMMRRR;

wire Anabit;

wire [31:0] sp_dec = sp - 32'd2;

reg [31:0] rfoAn;

always_comb

case(rrr)

3'd0: rfoAn <= a0;

3'd1: rfoAn <= a1;

3'd2: rfoAn <= a2;

3'd3: rfoAn <= a3;

3'd4: rfoAn <= a4;

3'd5: rfoAn <= a5;

3'd6: rfoAn <= a6;

3'd7: rfoAn <= sp;

endcase

reg [31:0] rfoAna;

always_comb

case(AAA)

3'd0: rfoAna <= a0;

3'd1: rfoAna <= a1;

3'd2: rfoAna <= a2;

3'd3: rfoAna <= a3;

3'd4: rfoAna <= a4;

3'd5: rfoAna <= a5;

3'd6: rfoAna <= a6;

3'd7: rfoAna <= sp;

endcase

//wire [31:0] rfoAn =   rrr==3'b111 ? sp : regfile[{1'b1,rrr}];

reg [31:0] rfoDn;

always_comb

case(DDD)

3'd0:   rfoDn <= d0;

3'd1:   rfoDn <= d1;

3'd2:   rfoDn <= d2;

3'd3:   rfoDn <= d3;

3'd4:   rfoDn <= d4;

3'd5:   rfoDn <= d5;

3'd6:   rfoDn <= d6;

3'd7:   rfoDn <= d7;

endcase

reg [31:0] rfoDnn;

always_comb

case(rrr)

3'd0:   rfoDnn <= d0;

3'd1:   rfoDnn <= d1;

3'd2:   rfoDnn <= d2;

3'd3:   rfoDnn <= d3;

3'd4:   rfoDnn <= d4;

3'd5:   rfoDnn <= d5;

3'd6:   rfoDnn <= d6;

3'd7:   rfoDnn <= d7;

endcase

reg [31:0] rfob;

always_comb

case({mmm[0],rrr})

4'd0:   rfob <= d0;

4'd1:   rfob <= d1;

4'd2:   rfob <= d2;

4'd3:   rfob <= d3;

4'd4:   rfob <= d4;

4'd5:   rfob <= d5;

4'd6:   rfob <= d6;

4'd7:   rfob <= d7;

4'd8:   rfob <= a0;

4'd9:   rfob <= a1;

4'd10:  rfob <= a2;

4'd11:  rfob <= a3;

4'd12:  rfob <= a4;

4'd13:  rfob <= a5;

4'd14:  rfob <= a6;

4'd15:  rfob <= sp;

endcase

reg [31:0] rfoRnn;

always_comb

case(rrrr)

4'd0:   rfoRnn <= d0;

4'd1:   rfoRnn <= d1;

4'd2:   rfoRnn <= d2;

4'd3:   rfoRnn <= d3;

4'd4:   rfoRnn <= d4;

4'd5:   rfoRnn <= d5;

4'd6:   rfoRnn <= d6;

4'd7:   rfoRnn <= d7;

4'd8:   rfoRnn <= a0;

4'd9:   rfoRnn <= a1;

4'd10:  rfoRnn <= a2;

4'd11:  rfoRnn <= a3;

4'd12:  rfoRnn <= a4;

4'd13:  rfoRnn <= a5;

4'd14:  rfoRnn <= a6;

4'd15:  rfoRnn <= sp;

endcase

//wire [31:0] rfoDn = regfile[{1'b0,DDD}];

//wire [31:0] rfoAna = AAA==3'b111 ? sp : regfile[{1'b1,AAA}];

//wire [31:0] rfob = {mmm[0],rrr}==4'b1111 ? sp : regfile[{mmm[0],rrr}];

//wire [31:0] rfoDnn = regfile[{1'b0,rrr}];

//wire [31:0] rfoRnn = rrrr==4'b1111 ? sp : regfile[rrrr];

wire clk_g;

reg rfwrL,rfwrB,rfwrW;

reg rfwrFp;

reg takb;

reg [8:0] resB;

reg [16:0] resW;

reg [32:0] resL;

(* USE_DSP = "no" *)

reg [32:0] resL1,resL2;

reg [32:0] resMS1,resMS2,resMU1,resMU2;

reg [31:0] st_data;

wire [11:0] bcdaddo,bcdsubo,bcdnego;

wire bcdaddoc,bcdsuboc,bcdnegoc;

reg [31:0] bad_addr;

reg [15:0] mac_cycle_type;

reg prev_nmi;

reg pe_nmi;

reg is_nmi;

reg is_irq, is_trace, is_priv, is_illegal;

reg is_adr_err;

reg is_rst;

reg is_bus_err;

reg use_dfc, use_sfc;

reg [4:0] rst_cnt;

reg [2:0] shift_op;

reg rtr;

reg bsr;

reg lea;

reg bcdsub, bcdneg;

reg [31:0] dati_buf;    // input data from bus error

reg [31:0] dato_buf;

// CSR's

reg [31:0] tick;        // FF0

reg [7:0] asid;         // 003

assign asid_o = asid;

reg [31:0] vbr;         // 801

reg [31:0] sfc;         // 000

reg [31:0] dfc;         // 001

reg [31:0] apc;

reg [7:0] cpl;

reg [31:0] tr;

reg [31:0] tcba;

reg [31:0] mmus, ios, iops;

assign mmus_o = adr_o[31:20] == mmus[31:20];

assign iops_o = adr_o[31:16] == iops[31:16];

assign ios_o  = adr_o[31:20] == ios [31:20];

wire [16:0] lfsr_o;

lfsr17 ulfsr1

(

        .rst(rst_i),

        .clk(clk_g),

        .ce(1'b1),

        .cyc(1'b0),

        .o(lfsr_o)

);

/*

reg [31:0] cache_tag [0:7];

reg [15:0] cache_dat [0:7];

task tPushCache;

input [31:0] adr;

input [15:0] dat;

integer n;

begin

        for (n = 1; n < 8; n = n + 1) begin

                cache_tag[n] <= cache_tag[n-1];

                cache_dat[n] <= cache_dat[n-1];

        end

        cache_tag[0] <= adr;

        cache_dat[0] <= dat;

end

endtask

function fnInCache;

input [31:0] adr;

integer n;

begin

        fnInCache = 1'b0;

        for (n = 0; n < 8; n = n + 1) begin

                if (cache_tag[n]==adr) begin

                        fnInCache = 1'b1;

        end

end

endfunction

task tFindInCache;

input [31:0] adr;

output [15:0] dat;

integer n;

begin

        dat = 16'h4E71; // NOP

        for (n = 0; n < 8; n = n + 1) begin

                if (cache_tag[n]==adr) begin

                        dat = cache_dat[n];

                end

        end

end

endtask

*/

function [31:0] rbo;

input [31:0] w;

rbo = {w[7:0],w[15:8],w[23:16],w[31:24]};

endfunction

wire [7:0] dbin, sbin;

reg [9:0] bcdres;

wire dd_done;

wire [11:0] bcdreso;

BCDToBin ub2b1 (clk_g, d, dbin);

BCDToBin ub2b2 (clk_g, s, sbin);

DDBinToBCD #(.WID(10)) udd1

(

        .rst(rst_i),

        .clk(clk_g),

        .ld(state==BCD3),

        .bin(bcdres),

        .bcd(bcdreso),

        .done(dd_done)

);

reg [31:0] dd32in;

wire [39:0] dd32out;

wire dd32done;

DDBinToBCD #(.WID(32)) udd2

(

        .rst(rst_i),

        .clk(clk_g),

        .ld(state==BIN2BCD1),

        .bin(dd32in),

        .bcd(dd32out),

        .done(dd32done)

);

/*

BCDAdd u1

(

        .ci(xf),

        .a(s[7:0]),

        .b(d[7:0]),

        .o(bcdaddo),

        .c(bcdaddoc)

);

BCDSub u2

(

        .ci(xf),

        .a(d[7:0]),

        .b(s[7:0]),

        .o(bcdsubo),

        .c(bcdsuboc)

);

BCDSub u3

(

        .ci(xf),

        .a(8'h00),

        .b(d[7:0]),

        .o(bcdnego),

        .c(bcdnegoc)

);

*/

// These functions take the MSBs of the operands and results and return an

// overflow status.

// If the signs of the operands are the same, and the sign of the result does

// not match the operands sign.

function fnAddOverflow;

input r;

input a;

input b;

        fnAddOverflow = (r ^ b) & (1'b1 ^ a ^ b);

endfunction

// If the signs of the operands are different and sign of the result does not

// match the first operand.

function fnSubOverflow;

input r;

input a;

input b;

        fnSubOverflow = (r ^ a) & (a ^ b);

endfunction

reg divs;

wire dvdone;

wire dvByZr;

wire dvovf;

wire [31:0] divq;

wire [31:0] divr;

rf68000_divider udiv1

(

        .rst(rst_i),

        .clk(clk_g),

        .ld(state==DIV1),

        .abort(1'b0),

        .sgn(divs),

        .sgnus(1'b0),

        .a(d),

        .b(divs? {{16{s[15]}},s[15:0]}:{16'd0,s[15:0]}),

        .qo(divq),

        .ro(divr),

        .dvByZr(dvByZr),

        .ovf(dvovf),

        .done(dvdone),

        .idle()

);

always_comb

case(ir[15:8])

`BRA:   takb = 1'b1;

`BSR:   takb = 1'b0;

`BHI:   takb = !cf & !zf;

`BLS:   takb = cf | zf;

`BHS:   takb = !cf;

`BLO:   takb =  cf;

`BNE:   takb = !zf;

`BEQ:   takb =  zf;

`BVC:   takb = !vf;

`BVS:   takb =  vf;

`BPL:   takb = !nf;

`BMI:   takb =  nf;

`BGE:   takb = (nf & vf)|(!nf & !vf);

`BLT:   takb = (nf & !vf)|(!nf & vf);

`BGT:   takb = (nf & vf & !zf)|(!nf & !vf & zf);

`BLE:   takb = zf | (nf & !vf) | (!nf & vf);

`DBRA:  takb = 1'b1;

`DBSR:  takb = 1'b0;

`DBHI:  takb = !cf & !zf;

`DBLS:  takb = cf | zf;

`DBHS:  takb = !cf;

`DBLO:  takb =  cf;

`DBNE:  takb = !zf;

`DBEQ:  takb =  zf;

`DBVC:  takb = !vf;

`DBVS:  takb =  vf;

`DBPL:  takb = !nf;

`DBMI:  takb =  nf;

`DBGE:  takb = ((nf & vf)|(!nf & !vf));

`DBLT:  takb = ((nf & !vf)|(!nf & vf));

`DBGT:  takb = ((nf & vf & !zf)|(!nf & !vf & zf));

`DBLE:  takb = (zf | (nf & !vf) | (!nf & vf));

default:        takb = 1'b1;

endcase

`ifdef BIG_ENDIAN

wire [15:0] iri = pc[1] ? {dat_i[23:16],dat_i[31:24]} : {dat_i[7:0],dat_i[15:8]};

`else

wire [15:0] iri = pc[1] ? dat_i[31:16] : dat_i[15:0];

`endif

assign clk_g = clk_i;

always_ff @(posedge clk_g)

if (rst_i) begin

        em <= 1'b0;

        lock_o <= 1'b0;

        cyc_o <= 1'b0;

        stb_o <= 1'b0;

        we_o <= 1'b0;

        sel_o <= 4'b0000;

        fc_o <= 3'b000;

        adr_o <= 32'd0;

        dat_o <= 32'd0;

        rfwrB <= 1'b0;

        rfwrW <= 1'b0;

        rfwrL <= 1'b0;

        zf <= 1'b0;

        nf <= 1'b0;

        cf <= 1'b0;

        vf <= 1'b0;

        xf <= 1'b0;

        im <= 3'b111;

        sf <= 1'b1;

        tf <= 1'b0;

        goto (RESET);

        rstate <= RESET;

        prev_nmi <= 1'b0;

        pe_nmi <= 1'b0;

  tick <= 32'd0;

  rst_cnt <= 5'd10;

  rst_o <= 1'b1;

  is_rst <= 1'b1;