| 1 |
16 |
ale500 |
/*
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* Decodes an opcode
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*
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* All decoders in one module
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*
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*/
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`include "defs.v"
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module decoders(
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| 10 |
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input wire clk_in,
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| 11 |
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input wire [7:0] opcode,
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| 12 |
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input wire [7:0] postbyte0,
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input wire page2_valid, // is 1 when the postbyte0 is a valid opcode (after it was loaded)
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input wire page3_valid, // is 1 when the postbyte0 is a valid opcode (after it was loaded)
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17 |
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output reg [3:0] path_left_addr_lo,
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output reg [3:0] path_right_addr_lo,
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output reg [3:0] dest_reg_lo,
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output wire write_dest,
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output wire source_size,
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output wire result_size,
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output wire [1:0] path_left_memtype_o,
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output wire [1:0] path_right_memtype_o,
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output wire [1:0] dest_memtype_o,
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output reg [1:0] path_left_memtype_lo,
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output reg [1:0] path_right_memtype_lo,
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output reg [1:0] dest_memtype_lo,
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output wire operand_read_o, // reads 1 operand from memory
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output wire operand_write_o, // writes result to memory
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output wire [2:0] mode,
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output reg op_SYNC,
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output reg op_EXG,
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output reg op_TFR,
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output reg op_RTS,
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output reg op_RTI,
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output reg op_CWAI,
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output reg op_MUL,
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output reg op_SWI,
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output reg op_PUSH,
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output reg op_PULL,
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output reg op_LEA,
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output reg op_JMP,
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output reg op_JSR,
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output wire use_s,
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output wire [4:0] alu_opcode,
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output wire dest_flags_o
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| 50 |
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);
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reg [3:0] lr, rr, dr; // left, right and destination register addresses
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reg [1:0] lm, rm, dm; // left, right and destination memory sizes
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reg ss, sz, p2, p3; // S or *U, 16 or *8, page 2, page 3
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reg [2:0] mo; // Addressing Mode
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reg [4:0] aop; // ALU opcode
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16 |
ale500 |
assign write_dest = (dr != `RN_INV);
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assign source_size = (lr < `RN_ACCA) | sz | (rm == `MT_WORD);
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// result size is used to determine the size of the argument
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// to load, compare has no result, thus the source is used instead,
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// why do we need the result size ?... because of tfr&exg
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assign result_size = (dr == `RN_INV) ? (lr < `RN_ACCA):
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(dr < `RN_ACCA) ? 1:0;
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| 65 |
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// for registers, memory writes are handled differently
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assign operand_read_o = (lm != `MT_NONE) | (rm != `MT_NONE);
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assign operand_write_o = dm != `MT_NONE;
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assign path_left_memtype_o = lm;
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assign path_right_memtype_o = rm;
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assign dest_memtype_o = dm;
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assign dest_flags_o = (aop != `NOP) && (opcode != 8'h1a) && (opcode != 8'h1c);
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assign use_s = ss;
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| 74 |
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assign mode = mo;
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assign alu_opcode = aop;
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always @(*)
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begin
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lr = `RN_INV;
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rr = `RN_INV;
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dr = `RN_INV;
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lm = `MT_NONE;
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| 83 |
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rm = `MT_NONE;
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dm = `MT_NONE;
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mo = `NONE;
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aop = `NOP;
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ss = 1;
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| 88 |
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sz = 0;
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| 89 |
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op_SYNC = 0;
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| 90 |
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op_EXG = 0;
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| 91 |
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op_TFR = 0;
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| 92 |
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op_RTS = 0;
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| 93 |
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op_RTI = 0;
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| 94 |
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op_CWAI = 0;
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op_MUL = 0;
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| 96 |
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op_SWI = 0;
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op_PUSH = 0;
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| 98 |
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op_PULL = 0;
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| 99 |
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op_LEA = 0;
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| 100 |
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op_JMP = 0;
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op_JSR = 0;
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| 102 |
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p2 = 0;
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| 103 |
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p3 = 0;
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case (opcode[7:4])
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4'h0:
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begin
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mo = `DIRECT;
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lm = `MT_BYTE;
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dm = `MT_BYTE;
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| 110 |
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case (opcode[3:0]) // Direct
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4'h0: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `NEG; end // NEG
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| 112 |
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4'h1: begin end
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| 113 |
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4'h2: begin end
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| 114 |
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4'h3: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `COM; end // COM
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| 115 |
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4'h4: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSR; end
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4'h5: begin end
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4'h6: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROR; end
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| 118 |
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4'h7: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ASR; end
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| 119 |
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4'h8: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSL; end
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| 120 |
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4'h9: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROL; end
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| 121 |
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4'ha: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `DEC; end
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| 122 |
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4'hb: begin end
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| 123 |
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4'hc: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `INC; end
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| 124 |
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4'hd: begin lm = `MT_BYTE; aop = `TST; end
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| 125 |
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4'he: begin op_JMP = 1; end // JMP
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| 126 |
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4'hf: begin dm = `MT_BYTE; aop = `CLR; end
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| 127 |
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endcase
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| 128 |
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end
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| 129 |
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4'h1:
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begin
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case (opcode[3:0])
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4'h0: begin p2 = 1; end
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| 133 |
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4'h1: begin p3 = 1; end
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| 134 |
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4'h2: begin end // nop
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| 135 |
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4'h3: begin op_SYNC = 1; end
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| 136 |
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4'h4: begin end
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| 137 |
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4'h5: begin end
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| 138 |
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4'h6: begin mo = `REL16; end // lbra
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| 139 |
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4'h7: begin mo = `REL16; op_JSR = 1; end
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| 140 |
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4'h8: begin end
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| 141 |
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4'h9: begin mo = `INHERENT; lr = `RN_ACCA; dr = `RN_ACCA; aop = `DAA; end
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| 142 |
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4'ha: begin mo = `IMMEDIATE; lr = `RN_CC; dr = `RN_CC; aop = `OR; end
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| 143 |
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4'hb: begin end
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| 144 |
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4'hc: begin mo = `IMMEDIATE; lr = `RN_CC; dr = `RN_CC; aop = `AND; end
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| 145 |
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4'hd: begin mo = `INHERENT; lr = `RN_ACCB; dr = `RN_ACCA; aop = `SEXT; end
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| 146 |
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4'he: begin op_EXG = 1; lr = postbyte0[7:4]; rr = postbyte0[3:0]; dr = postbyte0[3:0]; end
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| 147 |
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4'hf: begin op_TFR = 1; lr = postbyte0[7:4]; rr = postbyte0[3:0]; dr = postbyte0[3:0]; end
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| 148 |
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endcase
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| 149 |
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end
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| 150 |
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4'h2:
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| 151 |
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begin
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mo = `REL8;
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| 153 |
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case (opcode[3:0])
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| 154 |
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4'h0: begin end
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| 155 |
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4'h1: begin end
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| 156 |
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4'h2: begin end
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| 157 |
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4'h3: begin end
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| 158 |
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4'h4: begin end
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| 159 |
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4'h5: begin end
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| 160 |
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4'h6: begin end
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| 161 |
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4'h7: begin end
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| 162 |
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4'h8: begin end
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| 163 |
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4'h9: begin end
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| 164 |
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4'ha: begin end
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| 165 |
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4'hb: begin end
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| 166 |
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4'hc: begin end
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| 167 |
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4'hd: begin end
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| 168 |
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4'he: begin end
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| 169 |
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4'hf: begin end
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| 170 |
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endcase
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end
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| 172 |
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4'h3:
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| 173 |
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begin
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| 174 |
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case (opcode[3:0])
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| 175 |
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4'h0: begin mo = `INDEXED; op_LEA = 1; dr = `RN_IX; end
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| 176 |
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4'h1: begin mo = `INDEXED; op_LEA = 1; dr = `RN_IY; end
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| 177 |
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4'h2: begin mo = `INDEXED; op_LEA = 1; dr = `RN_S; end
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| 178 |
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4'h3: begin mo = `INDEXED; op_LEA = 1; dr = `RN_U; end
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| 179 |
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4'h4: begin op_PUSH = 1; end
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| 180 |
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4'h5: begin op_PULL = 1; end
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| 181 |
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4'h6: begin op_PUSH = 1; ss = 0; end
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| 182 |
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4'h7: begin op_PULL = 1; ss = 0; end
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| 183 |
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4'h8: begin end
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| 184 |
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4'h9: begin mo = `INHERENT; op_RTS = 1; end
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| 185 |
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4'ha: begin mo = `INHERENT; lr = `RN_ACCB; rr = `RN_IX; dr = `RN_IX; aop = `ADD; end // ABX
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| 186 |
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4'hb: begin mo = `INHERENT; op_RTI = 1; end
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| 187 |
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4'hc: begin op_CWAI = 1; end
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| 188 |
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4'hd: begin mo = `INHERENT; lr = `RN_ACCA; rr = `RN_ACCB; dr = `RN_ACCD; aop = `MUL; op_MUL = 1; end
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| 189 |
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4'he: begin end
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| 190 |
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4'hf: begin op_SWI = 1; end
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| 191 |
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endcase
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| 192 |
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end
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| 193 |
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4'h4:
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| 194 |
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begin
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| 195 |
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mo = `INHERENT;
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| 196 |
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case (opcode[3:0])
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| 197 |
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4'h0: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `NEG; end // NEG
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| 198 |
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4'h1: begin end
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| 199 |
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4'h2: begin end
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| 200 |
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4'h3: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `COM; end // COM
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| 201 |
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4'h4: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `LSR; end
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| 202 |
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4'h5: begin end
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| 203 |
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4'h6: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ROR; end
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| 204 |
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4'h7: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ASR; end
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| 205 |
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4'h8: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `LSL; end
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| 206 |
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4'h9: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ROL; end
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| 207 |
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4'ha: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `DEC; end
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| 208 |
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4'hb: begin end
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| 209 |
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4'hc: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `INC; end
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| 210 |
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4'hd: begin lr = `RN_ACCA; aop = `TST; end
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| 211 |
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4'he: begin end
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| 212 |
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4'hf: begin dr = `RN_ACCA; aop = `CLR; end
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| 213 |
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endcase
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| 214 |
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end
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| 215 |
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4'h5:
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| 216 |
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begin
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| 217 |
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mo = `INHERENT;
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| 218 |
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case (opcode[3:0])
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| 219 |
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4'h0: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `NEG; end // NEG
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| 220 |
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4'h1: begin end
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| 221 |
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4'h2: begin end
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| 222 |
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4'h3: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `COM; end // COM
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| 223 |
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4'h4: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `LSR; end
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| 224 |
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4'h5: begin end
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| 225 |
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4'h6: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ROR; end
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| 226 |
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4'h7: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ASR; end
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| 227 |
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4'h8: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `LSL; end
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| 228 |
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4'h9: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ROL; end
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| 229 |
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4'ha: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `DEC; end
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| 230 |
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4'hb: begin end
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| 231 |
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4'hc: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `INC; end
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| 232 |
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4'hd: begin lr = `RN_ACCB; aop = `TST; end
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| 233 |
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4'he: begin end
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| 234 |
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4'hf: begin dr = `RN_ACCB; aop = `CLR; end
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| 235 |
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endcase
|
| 236 |
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end
|
| 237 |
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4'h6:
|
| 238 |
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begin
|
| 239 |
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mo = `INDEXED;
|
| 240 |
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case (opcode[3:0])
|
| 241 |
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4'h0: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `NEG; end // NEG
|
| 242 |
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4'h1: begin end
|
| 243 |
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4'h2: begin end
|
| 244 |
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4'h3: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `COM; end // COM
|
| 245 |
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4'h4: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSR; end
|
| 246 |
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4'h5: begin end
|
| 247 |
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4'h6: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROR; end
|
| 248 |
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4'h7: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ASR; end
|
| 249 |
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4'h8: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSL; end
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| 250 |
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4'h9: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROL; end
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| 251 |
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4'ha: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `DEC; end
|
| 252 |
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4'hb: begin end
|
| 253 |
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4'hc: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `INC; end
|
| 254 |
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4'hd: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `AND; end// TST FIXME
|
| 255 |
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4'he: begin op_JMP = 1; end // JMP
|
| 256 |
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4'hf: begin dm = `MT_BYTE; aop = `CLR; end // CLR FIXME
|
| 257 |
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endcase
|
| 258 |
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end
|
| 259 |
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4'h7:
|
| 260 |
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begin
|
| 261 |
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mo = `EXTENDED;
|
| 262 |
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case (opcode[3:0])
|
| 263 |
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4'h0: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `NEG; end // NEG
|
| 264 |
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4'h1: begin end
|
| 265 |
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4'h2: begin end
|
| 266 |
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4'h3: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `COM; end // COM
|
| 267 |
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4'h4: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSR; end
|
| 268 |
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4'h5: begin end
|
| 269 |
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4'h6: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROR; end
|
| 270 |
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4'h7: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ASR; end
|
| 271 |
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4'h8: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSL; end
|
| 272 |
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4'h9: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROL; end
|
| 273 |
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4'ha: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `DEC; end
|
| 274 |
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4'hb: begin end
|
| 275 |
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4'hc: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `INC; end
|
| 276 |
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4'hd: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `AND; end // TST FIXME
|
| 277 |
|
|
4'he: begin op_JMP = 1; end // JMP
|
| 278 |
|
|
4'hf: begin dm = `MT_BYTE; aop = `CLR; end // CLR FIXME
|
| 279 |
|
|
endcase
|
| 280 |
|
|
end
|
| 281 |
|
|
4'h8:
|
| 282 |
|
|
begin
|
| 283 |
|
|
mo = `IMMEDIATE; // right path filled in the right-path mux
|
| 284 |
|
|
case (opcode[3:0])
|
| 285 |
|
|
4'h0: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `SUB; end
|
| 286 |
|
|
4'h1: begin lr = `RN_ACCA; aop = `SUB; end // cmpa
|
| 287 |
|
|
4'h2: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `SBC; end
|
| 288 |
|
|
4'h3: begin lr = `RN_ACCD; dr = `RN_ACCD; aop = `SUB; end
|
| 289 |
|
|
4'h4: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `AND; end
|
| 290 |
|
|
4'h5: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `AND; end
|
| 291 |
|
|
4'h6: begin dr = `RN_ACCA; aop = `LD; end
|
| 292 |
|
|
4'h7: begin end
|
| 293 |
|
|
4'h8: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `EOR; end
|
| 294 |
|
|
4'h9: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ADC; end
|
| 295 |
|
|
4'ha: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `OR; end
|
| 296 |
|
|
4'hb: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ADD; end
|
| 297 |
|
|
4'hc: begin lr = `RN_IX; aop = `SUB; end // cmpx
|
| 298 |
|
|
4'hd: begin mo = `REL8; op_JSR = 1; end
|
| 299 |
|
|
4'he: begin dr = `RN_IX; aop = `LD; end
|
| 300 |
|
|
4'hf: begin end
|
| 301 |
|
|
endcase
|
| 302 |
|
|
end
|
| 303 |
|
|
4'h9:
|
| 304 |
|
|
begin
|
| 305 |
|
|
mo = `DIRECT;
|
| 306 |
|
|
case (opcode[3:0])
|
| 307 |
|
|
4'h0: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `SUB; end
|
| 308 |
|
|
4'h1: begin lr = `RN_ACCA; rm = `MT_BYTE; aop = `SUB; end // cmpa
|
| 309 |
|
|
4'h2: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `SBC; end
|
| 310 |
|
|
4'h3: begin lr = `RN_ACCD; rm = `MT_BYTE; dr = `RN_ACCD; aop = `SUB; end
|
| 311 |
|
|
4'h4: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `AND; end
|
| 312 |
|
|
4'h5: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `AND; end
|
| 313 |
|
|
4'h6: begin rm = `MT_BYTE; dr = `RN_ACCA; aop = `LD; end
|
| 314 |
|
|
4'h7: begin lr = `RN_ACCA; dm = `MT_BYTE; aop = `ST; end
|
| 315 |
|
|
4'h8: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `EOR; end
|
| 316 |
|
|
4'h9: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `ADC; end
|
| 317 |
|
|
4'ha: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `OR; end
|
| 318 |
|
|
4'hb: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `ADD; end
|
| 319 |
|
|
4'hc: begin lr = `RN_IX; rm = `MT_WORD; aop = `SUB; end // cmpx
|
| 320 |
|
|
4'hd: begin op_JSR = 1; end
|
| 321 |
|
|
4'he: begin rm = `MT_WORD; dr = `RN_IX; aop = `LD; end
|
| 322 |
|
|
4'hf: begin lr = `RN_IX; dm = `MT_WORD; aop = `ST; end
|
| 323 |
|
|
endcase
|
| 324 |
|
|
end
|
| 325 |
|
|
4'ha:
|
| 326 |
|
|
begin
|
| 327 |
|
|
mo = `INDEXED;
|
| 328 |
|
|
case (opcode[3:0])
|
| 329 |
|
|
4'h0: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `SUB; end
|
| 330 |
|
|
4'h1: begin lr = `RN_ACCA; rm = `MT_BYTE; aop = `SUB; end // cmpa
|
| 331 |
|
|
4'h2: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `SBC; end
|
| 332 |
|
|
4'h3: begin lr = `RN_ACCD; rm = `MT_BYTE; dr = `RN_ACCD; aop = `SUB; end
|
| 333 |
|
|
4'h4: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `AND; end
|
| 334 |
|
|
4'h5: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `AND; end
|
| 335 |
|
|
4'h6: begin rm = `MT_BYTE; dr = `RN_ACCA; aop = `LD; end
|
| 336 |
|
|
4'h7: begin lr = `RN_ACCA; dm = `MT_BYTE; aop = `ST; end
|
| 337 |
|
|
4'h8: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `EOR; end
|
| 338 |
|
|
4'h9: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `ADC; end
|
| 339 |
|
|
4'ha: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `OR; end
|
| 340 |
|
|
4'hb: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `ADD; end
|
| 341 |
|
|
4'hc: begin lr = `RN_IX; rm = `MT_WORD; aop = `SUB; end // cmpx
|
| 342 |
|
|
4'hd: begin op_JSR = 1; end
|
| 343 |
|
|
4'he: begin rm = `MT_WORD; dr = `RN_IX; aop = `LD; end
|
| 344 |
|
|
4'hf: begin lr = `RN_IX; dm = `MT_WORD; aop = `ST; end
|
| 345 |
|
|
endcase
|
| 346 |
|
|
end
|
| 347 |
|
|
4'hb:
|
| 348 |
|
|
begin
|
| 349 |
|
|
mo = `EXTENDED;
|
| 350 |
|
|
case (opcode[3:0])
|
| 351 |
|
|
4'h0: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `SUB; end
|
| 352 |
|
|
4'h1: begin lr = `RN_ACCA; rm = `MT_BYTE; aop = `SUB; end // cmpa
|
| 353 |
|
|
4'h2: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `SBC; end
|
| 354 |
|
|
4'h3: begin lr = `RN_ACCD; rm = `MT_BYTE; dr = `RN_ACCD; aop = `SUB; end
|
| 355 |
|
|
4'h4: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `AND; end
|
| 356 |
|
|
4'h5: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `AND; end
|
| 357 |
|
|
4'h6: begin rm = `MT_BYTE; dr = `RN_ACCA; aop = `LD; end
|
| 358 |
|
|
4'h7: begin lr = `RN_ACCA; dm = `MT_BYTE; aop = `ST; end
|
| 359 |
|
|
4'h8: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `EOR; end
|
| 360 |
|
|
4'h9: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `ADC; end
|
| 361 |
|
|
4'ha: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `OR; end
|
| 362 |
|
|
4'hb: begin lr = `RN_ACCA; rm = `MT_BYTE; dr = `RN_ACCA; aop = `ADD; end
|
| 363 |
|
|
4'hc: begin lr = `RN_IX; rm = `MT_WORD; aop = `SUB; end // cmpx
|
| 364 |
|
|
4'hd: begin op_JSR = 1; end
|
| 365 |
|
|
4'he: begin rm = `MT_WORD; dr = `RN_IX; aop = `LD; end
|
| 366 |
|
|
4'hf: begin lr = `RN_IX; dm = `MT_WORD; aop = `ST; end
|
| 367 |
|
|
endcase
|
| 368 |
|
|
end
|
| 369 |
|
|
4'hc:
|
| 370 |
|
|
begin
|
| 371 |
|
|
mo = `IMMEDIATE; // right path filled in the right-path mux
|
| 372 |
|
|
case (opcode[3:0])
|
| 373 |
|
|
4'h0: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `SUB; end
|
| 374 |
|
|
4'h1: begin lr = `RN_ACCB; aop = `SUB; end // cmp
|
| 375 |
|
|
4'h2: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `SBC; end
|
| 376 |
|
|
4'h3: begin sz = 1; lr = `RN_ACCD; dr = `RN_ACCD; aop = `ADD; end
|
| 377 |
|
|
4'h4: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `AND; end
|
| 378 |
|
|
4'h5: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `AND; end // bit
|
| 379 |
|
|
4'h6: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `LD; end
|
| 380 |
|
|
4'h7: begin end
|
| 381 |
|
|
4'h8: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `EOR; end
|
| 382 |
|
|
4'h9: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ADC; end
|
| 383 |
|
|
4'ha: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `OR; end
|
| 384 |
|
|
4'hb: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ADD; end
|
| 385 |
|
|
4'hc: begin sz = 1; dr = `RN_ACCD; aop = `LD; end
|
| 386 |
|
|
4'hd: begin end
|
| 387 |
|
|
4'he: begin sz = 1; dr = `RN_U; aop = `LD; end
|
| 388 |
|
|
4'hf: begin end
|
| 389 |
|
|
endcase
|
| 390 |
|
|
end
|
| 391 |
|
|
4'hd:
|
| 392 |
|
|
begin
|
| 393 |
|
|
mo = `DIRECT;
|
| 394 |
|
|
case (opcode[3:0])
|
| 395 |
|
|
4'h0: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `SUB; end
|
| 396 |
|
|
4'h1: begin lr = `RN_ACCB; rm = `MT_BYTE; aop = `SUB; end // cmp
|
| 397 |
|
|
4'h2: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `SBC; end
|
| 398 |
|
|
4'h3: begin lr = `RN_ACCD; rm = `MT_BYTE; dr = `RN_ACCD; aop = `ADD; end
|
| 399 |
|
|
4'h4: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `AND; end
|
| 400 |
|
|
4'h5: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `AND; end // bit
|
| 401 |
|
|
4'h6: begin rm = `MT_BYTE; dr = `RN_ACCB; aop = `LD; end
|
| 402 |
|
|
4'h7: begin lr = `RN_ACCB; dm = `MT_BYTE; aop = `ST; end
|
| 403 |
|
|
4'h8: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `EOR; end
|
| 404 |
|
|
4'h9: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `ADC; end
|
| 405 |
|
|
4'ha: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `OR; end
|
| 406 |
|
|
4'hb: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `ADD; end
|
| 407 |
|
|
4'hc: begin rm = `MT_WORD; dr = `RN_ACCD; aop = `LD; end
|
| 408 |
|
|
4'hd: begin lr = `RN_ACCD; dm = `MT_WORD; aop = `ST; end
|
| 409 |
|
|
4'he: begin rm = `MT_WORD; dr = `RN_U; aop = `LD; end
|
| 410 |
|
|
4'hf: begin lr = `RN_U; dm = `MT_WORD; aop = `ST; end
|
| 411 |
|
|
endcase
|
| 412 |
17 |
ale500 |
|
| 413 |
16 |
ale500 |
end
|
| 414 |
|
|
4'he:
|
| 415 |
|
|
begin
|
| 416 |
|
|
mo = `INDEXED;
|
| 417 |
|
|
case (opcode[3:0])
|
| 418 |
|
|
4'h0: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `SUB; end
|
| 419 |
|
|
4'h1: begin lr = `RN_ACCB; rm = `MT_BYTE; aop = `SUB; end // cmp
|
| 420 |
|
|
4'h2: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `SBC; end
|
| 421 |
|
|
4'h3: begin lr = `RN_ACCD; rm = `MT_BYTE; dr = `RN_ACCD; aop = `ADD; end
|
| 422 |
|
|
4'h4: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `AND; end
|
| 423 |
|
|
4'h5: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `AND; end // bit
|
| 424 |
|
|
4'h6: begin rm = `MT_BYTE; dr = `RN_ACCB; aop = `LD; end
|
| 425 |
|
|
4'h7: begin lr = `RN_ACCB; dm = `MT_BYTE; aop = `ST; end
|
| 426 |
|
|
4'h8: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `EOR; end
|
| 427 |
|
|
4'h9: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `ADC; end
|
| 428 |
|
|
4'ha: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `OR; end
|
| 429 |
|
|
4'hb: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `ADD; end
|
| 430 |
|
|
4'hc: begin rm = `MT_WORD; dr = `RN_ACCD; aop = `LD; end
|
| 431 |
|
|
4'hd: begin lr = `RN_ACCD; dm = `MT_WORD; aop = `ST; end
|
| 432 |
|
|
4'he: begin rm = `MT_WORD; dr = `RN_U; aop = `LD; end
|
| 433 |
|
|
4'hf: begin lr = `RN_U; dm = `MT_WORD; aop = `ST; end
|
| 434 |
|
|
endcase
|
| 435 |
17 |
ale500 |
|
| 436 |
16 |
ale500 |
end
|
| 437 |
|
|
4'hf:
|
| 438 |
|
|
begin
|
| 439 |
|
|
mo = `EXTENDED;
|
| 440 |
|
|
case (opcode[3:0])
|
| 441 |
|
|
4'h0: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `SUB; end
|
| 442 |
|
|
4'h1: begin lr = `RN_ACCB; rm = `MT_BYTE; aop = `SUB; end // cmp
|
| 443 |
|
|
4'h2: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `SBC; end
|
| 444 |
|
|
4'h3: begin lr = `RN_ACCD; rm = `MT_BYTE; dr = `RN_ACCD; aop = `ADD; end
|
| 445 |
|
|
4'h4: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `AND; end
|
| 446 |
|
|
4'h5: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `AND; end // bit
|
| 447 |
|
|
4'h6: begin rm = `MT_BYTE; dr = `RN_ACCB; aop = `LD; end
|
| 448 |
|
|
4'h7: begin lr = `RN_ACCB; dm = `MT_BYTE; aop = `ST; end
|
| 449 |
|
|
4'h8: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `EOR; end
|
| 450 |
|
|
4'h9: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `ADC; end
|
| 451 |
|
|
4'ha: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `OR; end
|
| 452 |
|
|
4'hb: begin lr = `RN_ACCB; rm = `MT_BYTE; dr = `RN_ACCB; aop = `ADD; end
|
| 453 |
|
|
4'hc: begin rm = `MT_WORD; dr = `RN_ACCD; aop = `LD; end
|
| 454 |
|
|
4'hd: begin lr = `RN_ACCD; dm = `MT_WORD; aop = `ST; end
|
| 455 |
|
|
4'he: begin rm = `MT_WORD; dr = `RN_U; aop = `LD; end
|
| 456 |
|
|
4'hf: begin lr = `RN_U; dm = `MT_WORD; aop = `ST; end
|
| 457 |
|
|
endcase
|
| 458 |
|
|
end
|
| 459 |
|
|
endcase
|
| 460 |
|
|
if (p2)
|
| 461 |
|
|
case (postbyte0[7:4])
|
| 462 |
|
|
4'h0, 4'h1, 4'h4, 4'h5, 4'h6, 4'h7: begin end
|
| 463 |
|
|
4'h2: mo = `REL16;
|
| 464 |
|
|
4'h3: if (postbyte0[3:0] == 4'hf) op_SWI = 1;
|
| 465 |
|
|
4'h8:
|
| 466 |
|
|
begin
|
| 467 |
|
|
case (postbyte0[3:0])
|
| 468 |
|
|
4'h0: begin end
|
| 469 |
|
|
4'h1: begin end
|
| 470 |
|
|
4'h2: begin end
|
| 471 |
|
|
4'h3: begin mo = `IMMEDIATE; sz = 1; lr = `RN_ACCD; aop = `SUB; end // cmpd
|
| 472 |
|
|
4'h4: begin end
|
| 473 |
|
|
4'h5: begin end
|
| 474 |
|
|
4'h6: begin end
|
| 475 |
|
|
4'h7: begin end
|
| 476 |
|
|
4'h8: begin end
|
| 477 |
|
|
4'h9: begin end
|
| 478 |
|
|
4'ha: begin end
|
| 479 |
|
|
4'hb: begin end
|
| 480 |
|
|
4'hc: begin mo = `IMMEDIATE; sz = 1; lr = `RN_IY; aop = `SUB; end
|
| 481 |
|
|
4'hd: begin end
|
| 482 |
|
|
4'he: begin mo = `IMMEDIATE; sz = 1; dr = `RN_IY; aop = `LD; end
|
| 483 |
|
|
4'hf: begin end
|
| 484 |
|
|
endcase
|
| 485 |
|
|
end
|
| 486 |
|
|
4'h9:
|
| 487 |
|
|
begin
|
| 488 |
|
|
case (postbyte0[3:0])
|
| 489 |
|
|
4'h0: begin end
|
| 490 |
|
|
4'h1: begin end
|
| 491 |
|
|
4'h2: begin end
|
| 492 |
|
|
4'h3: begin mo = `DIRECT; lr = `RN_ACCD; rm = `MT_WORD; aop = `SUB; end // cmpd
|
| 493 |
|
|
4'h4: begin end
|
| 494 |
|
|
4'h5: begin end
|
| 495 |
|
|
4'h6: begin end
|
| 496 |
|
|
4'h7: begin end
|
| 497 |
|
|
4'h8: begin end
|
| 498 |
|
|
4'h9: begin end
|
| 499 |
|
|
4'ha: begin end
|
| 500 |
|
|
4'hb: begin end
|
| 501 |
|
|
4'hc: begin mo = `DIRECT; lr = `RN_IY; rm = `MT_WORD; aop = `SUB; end
|
| 502 |
|
|
4'hd: begin end
|
| 503 |
|
|
4'he: begin mo = `DIRECT; rm = `MT_WORD; dr = `RN_IY; aop = `LD; end
|
| 504 |
|
|
4'hf: begin mo = `DIRECT; lr = `RN_IY; dm = `MT_WORD; aop = `ST; end
|
| 505 |
|
|
endcase
|
| 506 |
|
|
end
|
| 507 |
|
|
4'ha:
|
| 508 |
|
|
begin
|
| 509 |
|
|
case (postbyte0[3:0])
|
| 510 |
|
|
4'h0: begin end
|
| 511 |
|
|
4'h1: begin end
|
| 512 |
|
|
4'h2: begin end
|
| 513 |
|
|
4'h3: begin mo = `INDEXED; lr = `RN_ACCD; rm = `MT_WORD; aop = `SUB; end // cmpd
|
| 514 |
|
|
4'h4: begin end
|
| 515 |
|
|
4'h5: begin end
|
| 516 |
|
|
4'h6: begin end
|
| 517 |
|
|
4'h7: begin end
|
| 518 |
|
|
4'h8: begin end
|
| 519 |
|
|
4'h9: begin end
|
| 520 |
|
|
4'ha: begin end
|
| 521 |
|
|
4'hb: begin end
|
| 522 |
|
|
4'hc: begin mo = `INDEXED; lr = `RN_IY; rm = `MT_WORD; aop = `SUB; end
|
| 523 |
|
|
4'hd: begin end
|
| 524 |
|
|
4'he: begin mo = `INDEXED; rm = `MT_WORD; dr = `RN_IY; aop = `LD; end
|
| 525 |
|
|
4'hf: begin mo = `INDEXED; lr = `RN_IY; dm = `MT_WORD; aop = `ST; end
|
| 526 |
|
|
endcase
|
| 527 |
|
|
end
|
| 528 |
|
|
4'hb:
|
| 529 |
|
|
begin
|
| 530 |
|
|
case (postbyte0[3:0])
|
| 531 |
|
|
4'h0: begin end
|
| 532 |
|
|
4'h1: begin end
|
| 533 |
|
|
4'h2: begin end
|
| 534 |
|
|
4'h3: begin mo = `EXTENDED; lr = `RN_ACCD; rm = `MT_WORD; aop = `SUB; end // cmpd
|
| 535 |
|
|
4'h4: begin end
|
| 536 |
|
|
4'h5: begin end
|
| 537 |
|
|
4'h6: begin end
|
| 538 |
|
|
4'h7: begin end
|
| 539 |
|
|
4'h8: begin end
|
| 540 |
|
|
4'h9: begin end
|
| 541 |
|
|
4'ha: begin end
|
| 542 |
|
|
4'hb: begin end
|
| 543 |
|
|
4'hc: begin mo = `EXTENDED; lr = `RN_IY; rm = `MT_WORD; aop = `SUB; end
|
| 544 |
|
|
4'hd: begin end
|
| 545 |
|
|
4'he: begin mo = `EXTENDED; rm = `MT_WORD; dr = `RN_IY; aop = `LD; end
|
| 546 |
|
|
4'hf: begin mo = `EXTENDED; lr = `RN_IY; dm = `MT_WORD; aop = `ST; end
|
| 547 |
|
|
endcase
|
| 548 |
|
|
end
|
| 549 |
|
|
4'hc:
|
| 550 |
|
|
begin
|
| 551 |
|
|
case (postbyte0[3:0])
|
| 552 |
|
|
4'h0: begin end
|
| 553 |
|
|
4'h1: begin end
|
| 554 |
|
|
4'h2: begin end
|
| 555 |
|
|
4'h3: begin end
|
| 556 |
|
|
4'h4: begin end
|
| 557 |
|
|
4'h5: begin end
|
| 558 |
|
|
4'h6: begin end
|
| 559 |
|
|
4'h7: begin end
|
| 560 |
|
|
4'h8: begin end
|
| 561 |
|
|
4'h9: begin end
|
| 562 |
|
|
4'ha: begin end
|
| 563 |
|
|
4'hb: begin end
|
| 564 |
|
|
4'hc: begin end
|
| 565 |
|
|
4'hd: begin end
|
| 566 |
|
|
4'he: begin mo = `IMMEDIATE; sz = 1; dr = `RN_S; aop = `LD; end
|
| 567 |
|
|
4'hf: begin end
|
| 568 |
|
|
endcase
|
| 569 |
|
|
end
|
| 570 |
|
|
4'hd:
|
| 571 |
|
|
begin
|
| 572 |
|
|
case (postbyte0[3:0])
|
| 573 |
|
|
4'h0: begin end
|
| 574 |
|
|
4'h1: begin end
|
| 575 |
|
|
4'h2: begin end
|
| 576 |
|
|
4'h3: begin end
|
| 577 |
|
|
4'h4: begin end
|
| 578 |
|
|
4'h5: begin end
|
| 579 |
|
|
4'h6: begin end
|
| 580 |
|
|
4'h7: begin end
|
| 581 |
|
|
4'h8: begin end
|
| 582 |
|
|
4'h9: begin end
|
| 583 |
|
|
4'ha: begin end
|
| 584 |
|
|
4'hb: begin end
|
| 585 |
|
|
4'hc: begin end
|
| 586 |
|
|
4'hd: begin end
|
| 587 |
|
|
4'he: begin mo = `DIRECT; rm = `MT_WORD; dr = `RN_S; aop = `LD; end
|
| 588 |
|
|
4'hf: begin mo = `DIRECT; lr = `RN_S; dm = `MT_WORD; aop = `ST; end
|
| 589 |
|
|
endcase
|
| 590 |
|
|
end
|
| 591 |
|
|
4'he:
|
| 592 |
|
|
begin
|
| 593 |
|
|
case (postbyte0[3:0])
|
| 594 |
|
|
4'h0: begin end
|
| 595 |
|
|
4'h1: begin end
|
| 596 |
|
|
4'h2: begin end
|
| 597 |
|
|
4'h3: begin end
|
| 598 |
|
|
4'h4: begin end
|
| 599 |
|
|
4'h5: begin end
|
| 600 |
|
|
4'h6: begin end
|
| 601 |
|
|
4'h7: begin end
|
| 602 |
|
|
4'h8: begin end
|
| 603 |
|
|
4'h9: begin end
|
| 604 |
|
|
4'ha: begin end
|
| 605 |
|
|
4'hb: begin end
|
| 606 |
|
|
4'hc: begin end
|
| 607 |
|
|
4'hd: begin end
|
| 608 |
|
|
4'he: begin mo = `INDEXED; rm = `MT_WORD; dr = `RN_S; aop = `LD; end
|
| 609 |
|
|
4'hf: begin mo = `INDEXED; lr = `RN_S; dm = `MT_WORD; aop = `ST; end
|
| 610 |
|
|
endcase
|
| 611 |
|
|
end
|
| 612 |
|
|
4'hf:
|
| 613 |
|
|
begin
|
| 614 |
|
|
case (postbyte0[3:0])
|
| 615 |
|
|
4'h0: begin end
|
| 616 |
|
|
4'h1: begin end
|
| 617 |
|
|
4'h2: begin end
|
| 618 |
|
|
4'h3: begin end // cmpd
|
| 619 |
|
|
4'h4: begin end
|
| 620 |
|
|
4'h5: begin end
|
| 621 |
|
|
4'h6: begin end
|
| 622 |
|
|
4'h7: begin end
|
| 623 |
|
|
4'h8: begin end
|
| 624 |
|
|
4'h9: begin end
|
| 625 |
|
|
4'ha: begin end
|
| 626 |
|
|
4'hb: begin end
|
| 627 |
|
|
4'hc: begin end
|
| 628 |
|
|
4'hd: begin end
|
| 629 |
|
|
4'he: begin mo = `EXTENDED; rm = `MT_WORD; dr = `RN_S; aop = `LD; end
|
| 630 |
|
|
4'hf: begin mo = `EXTENDED; lr = `RN_S; dm = `MT_WORD; aop = `ST; end
|
| 631 |
|
|
endcase
|
| 632 |
|
|
end
|
| 633 |
|
|
endcase
|
| 634 |
|
|
if (p3)
|
| 635 |
|
|
case (postbyte0[7:4])
|
| 636 |
|
|
4'h0, 4'h1, 4'h4, 4'h5, 4'h6, 4'h7,
|
| 637 |
|
|
4'hc, 4'hd, 4'he, 4'hf: begin end
|
| 638 |
|
|
4'h3: if (postbyte0[3:0] == 4'hf) op_SWI = 1;
|
| 639 |
|
|
4'h8:
|
| 640 |
|
|
begin
|
| 641 |
|
|
case (postbyte0[3:0])
|
| 642 |
|
|
4'h0: begin end
|
| 643 |
|
|
4'h1: begin end
|
| 644 |
|
|
4'h2: begin end
|
| 645 |
|
|
4'h3: begin mo = `IMMEDIATE; sz = 1; lr = `RN_U; aop = `SUB; end // cmpd
|
| 646 |
|
|
4'h4: begin end
|
| 647 |
|
|
4'h5: begin end
|
| 648 |
|
|
4'h6: begin end
|
| 649 |
|
|
4'h7: begin end
|
| 650 |
|
|
4'h8: begin end
|
| 651 |
|
|
4'h9: begin end
|
| 652 |
|
|
4'ha: begin end
|
| 653 |
|
|
4'hb: begin end
|
| 654 |
|
|
4'hc: begin mo = `IMMEDIATE; sz = 1; lr = `RN_S; aop = `SUB; end
|
| 655 |
|
|
4'hd: begin end
|
| 656 |
|
|
4'he: begin end
|
| 657 |
|
|
4'hf: begin end
|
| 658 |
|
|
endcase
|
| 659 |
|
|
end
|
| 660 |
|
|
4'h9:
|
| 661 |
|
|
begin
|
| 662 |
|
|
case (postbyte0[3:0])
|
| 663 |
|
|
4'h0: begin end
|
| 664 |
|
|
4'h1: begin end
|
| 665 |
|
|
4'h2: begin end
|
| 666 |
|
|
4'h3: begin mo = `DIRECT; lr = `RN_U; rm = `MT_WORD; aop = `SUB; end // cmpd
|
| 667 |
|
|
4'h4: begin end
|
| 668 |
|
|
4'h5: begin end
|
| 669 |
|
|
4'h6: begin end
|
| 670 |
|
|
4'h7: begin end
|
| 671 |
|
|
4'h8: begin end
|
| 672 |
|
|
4'h9: begin end
|
| 673 |
|
|
4'ha: begin end
|
| 674 |
|
|
4'hb: begin end
|
| 675 |
|
|
4'hc: begin mo = `DIRECT; lr = `RN_S; rm = `MT_WORD; aop = `SUB; end
|
| 676 |
|
|
4'hd: begin end
|
| 677 |
|
|
4'he: begin end
|
| 678 |
|
|
4'hf: begin end
|
| 679 |
|
|
endcase
|
| 680 |
|
|
end
|
| 681 |
|
|
4'ha:
|
| 682 |
|
|
begin
|
| 683 |
|
|
case (postbyte0[3:0])
|
| 684 |
|
|
4'h0: begin end
|
| 685 |
|
|
4'h1: begin end
|
| 686 |
|
|
4'h2: begin end
|
| 687 |
|
|
4'h3: begin mo = `INDEXED; lr = `RN_U; rm = `MT_WORD; aop = `SUB; end // cmpd
|
| 688 |
|
|
4'h4: begin end
|
| 689 |
|
|
4'h5: begin end
|
| 690 |
|
|
4'h6: begin end
|
| 691 |
|
|
4'h7: begin end
|
| 692 |
|
|
4'h8: begin end
|
| 693 |
|
|
4'h9: begin end
|
| 694 |
|
|
4'ha: begin end
|
| 695 |
|
|
4'hb: begin end
|
| 696 |
|
|
4'hc: begin mo = `INDEXED; lr = `RN_S; rm = `MT_WORD; aop = `SUB; end
|
| 697 |
|
|
4'hd: begin end
|
| 698 |
|
|
4'he: begin end
|
| 699 |
|
|
4'hf: begin end
|
| 700 |
|
|
endcase
|
| 701 |
|
|
end
|
| 702 |
|
|
4'hb:
|
| 703 |
|
|
begin
|
| 704 |
|
|
case (postbyte0[3:0])
|
| 705 |
|
|
4'h0: begin end
|
| 706 |
|
|
4'h1: begin end
|
| 707 |
|
|
4'h2: begin end
|
| 708 |
|
|
4'h3: begin mo = `EXTENDED; lr = `RN_U; rm = `MT_WORD; aop = `SUB; end // cmpd
|
| 709 |
|
|
4'h4: begin end
|
| 710 |
|
|
4'h5: begin end
|
| 711 |
|
|
4'h6: begin end
|
| 712 |
|
|
4'h7: begin end
|
| 713 |
|
|
4'h8: begin end
|
| 714 |
|
|
4'h9: begin end
|
| 715 |
|
|
4'ha: begin end
|
| 716 |
|
|
4'hb: begin end
|
| 717 |
|
|
4'hc: begin mo = `EXTENDED; lr = `RN_S; rm = `MT_WORD; aop = `SUB; end
|
| 718 |
|
|
4'hd: begin end
|
| 719 |
|
|
4'he: begin end
|
| 720 |
|
|
4'hf: begin end
|
| 721 |
|
|
endcase
|
| 722 |
|
|
end
|
| 723 |
|
|
endcase
|
| 724 |
17 |
ale500 |
|
| 725 |
16 |
ale500 |
end
|
| 726 |
|
|
always @(posedge clk_in)
|
| 727 |
|
|
begin
|
| 728 |
|
|
path_right_addr_lo <= rr;
|
| 729 |
|
|
path_left_addr_lo <= lr;
|
| 730 |
|
|
dest_reg_lo <= dr;
|
| 731 |
|
|
path_right_memtype_lo <= rm;
|
| 732 |
|
|
path_left_memtype_lo <= lm;
|
| 733 |
|
|
dest_memtype_lo <= dm;
|
| 734 |
|
|
end
|
| 735 |
17 |
ale500 |
|
| 736 |
16 |
ale500 |
endmodule
|
| 737 |
17 |
ale500 |
|
| 738 |
16 |
ale500 |
module decode_ea(
|
| 739 |
|
|
input wire [7:0] eapostbyte,
|
| 740 |
|
|
output reg [3:0] eabase_o, // base register
|
| 741 |
|
|
output reg [3:0] eaindex_o, // index register
|
| 742 |
|
|
output reg ea_ofs5_o,
|
| 743 |
|
|
output reg ea_ofs8_o,
|
| 744 |
|
|
output reg ea_ofs16_o,
|
| 745 |
|
|
output wire ea_is_indirect_o,
|
| 746 |
|
|
output reg ea_write_back_o
|
| 747 |
|
|
);
|
| 748 |
17 |
ale500 |
|
| 749 |
16 |
ale500 |
assign ea_is_indirect_o = eapostbyte[7] & eapostbyte[4];
|
| 750 |
17 |
ale500 |
|
| 751 |
16 |
ale500 |
always @(*)
|
| 752 |
|
|
begin
|
| 753 |
|
|
eabase_o = `RN_PC;
|
| 754 |
|
|
if (eapostbyte[7] & eapostbyte[3] & eapostbyte[2] & (!eapostbyte[1]))
|
| 755 |
|
|
eabase_o = `RN_PC;
|
| 756 |
|
|
else
|
| 757 |
|
|
casex (eapostbyte)
|
| 758 |
|
|
8'bx00_x_xxxx: eabase_o = `RN_IX;
|
| 759 |
|
|
8'bx01_x_xxxx: eabase_o = `RN_IY;
|
| 760 |
|
|
8'bx10_x_xxxx: eabase_o = `RN_U;
|
| 761 |
|
|
8'bx11_x_xxxx: eabase_o = `RN_S;
|
| 762 |
|
|
endcase
|
| 763 |
|
|
end
|
| 764 |
17 |
ale500 |
|
| 765 |
16 |
ale500 |
always @(*)
|
| 766 |
|
|
begin
|
| 767 |
|
|
ea_ofs5_o = 1'b0;
|
| 768 |
|
|
ea_ofs8_o = 1'b0;
|
| 769 |
|
|
ea_ofs16_o = 1'b0;
|
| 770 |
|
|
ea_write_back_o = 1'b0;
|
| 771 |
18 |
ale500 |
eaindex_o = `RN_ACCA;
|
| 772 |
16 |
ale500 |
casex (eapostbyte)
|
| 773 |
|
|
8'b0xx0xxxx: // base + 5 bit signed offset +
|
| 774 |
|
|
ea_ofs5_o = 1'b1;
|
| 775 |
|
|
8'b0xx1xxxx: // 5 bit signed offset -
|
| 776 |
|
|
ea_ofs5_o = 1'b1;
|
| 777 |
|
|
8'b1xx_x_0000, // post increment, increment occurs at a later stage
|
| 778 |
|
|
8'b1xx_x_0001: ea_write_back_o = 1'b1;
|
| 779 |
|
|
8'b1xx_x_0100: begin end
|
| 780 |
|
|
8'b1xx_x_0010, // pre decrement
|
| 781 |
|
|
8'b1xx_x_0011: ea_write_back_o = 1'b1;
|
| 782 |
|
|
8'b1xx_x_0101: // B,R
|
| 783 |
|
|
eaindex_o = `RN_ACCB;
|
| 784 |
|
|
8'b1xx_x_0110: // A,R
|
| 785 |
|
|
eaindex_o = `RN_ACCA;
|
| 786 |
|
|
8'b1xx_x_1011: // D,R
|
| 787 |
|
|
eaindex_o = `RN_ACCD;
|
| 788 |
|
|
8'b1xx_x_1000: // n,R 8 bit offset
|
| 789 |
|
|
ea_ofs8_o = 1'b1;
|
| 790 |
|
|
8'b1xx_x_1001: // n,R // 16 bit offset
|
| 791 |
|
|
ea_ofs16_o = 1'b1;
|
| 792 |
|
|
8'b1xx_x_1100: // n,PC
|
| 793 |
|
|
ea_ofs8_o = 1'b1;
|
| 794 |
|
|
8'b1xx_x_1101: // n,PC
|
| 795 |
|
|
ea_ofs16_o = 1'b1;
|
| 796 |
|
|
endcase
|
| 797 |
|
|
end
|
| 798 |
|
|
endmodule
|
| 799 |
17 |
ale500 |
|
| 800 |
|
|
|
| 801 |
16 |
ale500 |
/* decodes the condition and checks the flags to see if it is met */
|
| 802 |
|
|
module test_condition(
|
| 803 |
|
|
input wire [7:0] opcode,
|
| 804 |
|
|
input wire [7:0] postbyte0,
|
| 805 |
|
|
input wire page2_valid,
|
| 806 |
|
|
input wire [7:0] CCR,
|
| 807 |
|
|
output reg cond_taken
|
| 808 |
9 |
ale500 |
);
|
| 809 |
17 |
ale500 |
|
| 810 |
16 |
ale500 |
wire [7:0] op = page2_valid ? postbyte0:opcode;
|
| 811 |
17 |
ale500 |
|
| 812 |
16 |
ale500 |
always @(*)
|
| 813 |
9 |
ale500 |
begin
|
| 814 |
16 |
ale500 |
cond_taken = 1'b0;
|
| 815 |
17 |
ale500 |
if ((opcode == 8'h16) || (opcode == 8'h17) || (opcode == 8'h8D) ||
|
| 816 |
|
|
(opcode == 8'h0e) || (opcode == 8'h6e) || (opcode == 8'h7e)) // jmp
|
| 817 |
16 |
ale500 |
cond_taken = 1'b1; // LBRA/LBSR, BSR
|
| 818 |
|
|
if (op[7:4] == 4'h2)
|
| 819 |
|
|
case (op[3:0])
|
| 820 |
|
|
4'h0: cond_taken = 1'b1; // BRA
|
| 821 |
|
|
4'h1: cond_taken = 0; // BRN
|
| 822 |
|
|
4'h2: cond_taken = !(`DFLAGC & `DFLAGZ); // BHI
|
| 823 |
|
|
4'h3: cond_taken = `DFLAGC | `DFLAGZ; // BLS
|
| 824 |
|
|
4'h4: cond_taken = !`DFLAGC; // BCC, BHS
|
| 825 |
|
|
4'h5: cond_taken = `DFLAGC; // BCS, BLO
|
| 826 |
|
|
4'h6: cond_taken = !`DFLAGZ; // BNE
|
| 827 |
|
|
4'h7: cond_taken = `DFLAGZ; // BEQ
|
| 828 |
|
|
4'h8: cond_taken = !`DFLAGV; // BVC
|
| 829 |
|
|
4'h9: cond_taken = `DFLAGV; // BVS
|
| 830 |
|
|
4'ha: cond_taken = !`DFLAGN; // BPL
|
| 831 |
|
|
4'hb: cond_taken = `DFLAGN; // BMI
|
| 832 |
|
|
4'hc: cond_taken = `DFLAGN == `DFLAGV; // BGE
|
| 833 |
|
|
4'hd: cond_taken = `DFLAGN != `DFLAGV; // BLT
|
| 834 |
|
|
4'he: cond_taken = (`DFLAGN == `DFLAGV) & (!`DFLAGZ); // BGT
|
| 835 |
|
|
4'hf: cond_taken = (`DFLAGN != `DFLAGV) | (`DFLAGZ); // BLE
|
| 836 |
|
|
endcase
|
| 837 |
|
|
end
|
| 838 |
17 |
ale500 |
|
| 839 |
2 |
ale500 |
endmodule
|
