1 |
16 |
ale500 |
/*
|
2 |
17 |
ale500 |
* Decodes an opcode
|
3 |
16 |
ale500 |
*
|
4 |
17 |
ale500 |
* All decoders in one module
|
5 |
16 |
ale500 |
*
|
6 |
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*/
|
7 |
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`include "defs.v"
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8 |
17 |
ale500 |
|
9 |
16 |
ale500 |
module decoders(
|
10 |
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input wire clk_in,
|
11 |
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input wire [7:0] opcode,
|
12 |
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input wire [7:0] postbyte0,
|
13 |
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input wire page2_valid, // is 1 when the postbyte0 is a valid opcode (after it was loaded)
|
14 |
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input wire page3_valid, // is 1 when the postbyte0 is a valid opcode (after it was loaded)
|
15 |
17 |
ale500 |
|
16 |
16 |
ale500 |
output reg [3:0] path_left_addr_lo,
|
17 |
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output reg [3:0] path_right_addr_lo,
|
18 |
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output reg [3:0] dest_reg_lo,
|
19 |
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output wire write_dest,
|
20 |
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output wire source_size,
|
21 |
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output wire result_size,
|
22 |
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output wire [1:0] path_left_memtype_o,
|
23 |
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output wire [1:0] path_right_memtype_o,
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24 |
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output wire [1:0] dest_memtype_o,
|
25 |
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output reg [1:0] path_left_memtype_lo,
|
26 |
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output reg [1:0] path_right_memtype_lo,
|
27 |
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output reg [1:0] dest_memtype_lo,
|
28 |
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output wire operand_read_o, // reads 1 operand from memory
|
29 |
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output wire operand_write_o, // writes result to memory
|
30 |
17 |
ale500 |
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31 |
16 |
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output wire [2:0] mode,
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32 |
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output reg op_SYNC,
|
33 |
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output reg op_EXG,
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34 |
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output reg op_TFR,
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35 |
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output reg op_RTS,
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36 |
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output reg op_RTI,
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37 |
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output reg op_CWAI,
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38 |
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output reg op_MUL,
|
39 |
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output reg op_SWI,
|
40 |
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output reg op_PUSH,
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41 |
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output reg op_PULL,
|
42 |
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output reg op_LEA,
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43 |
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output reg op_JMP,
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44 |
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output reg op_JSR,
|
45 |
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output wire use_s,
|
46 |
17 |
ale500 |
|
47 |
16 |
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output wire [4:0] alu_opcode,
|
48 |
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output wire dest_flags_o
|
49 |
17 |
ale500 |
|
50 |
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|
51 |
16 |
ale500 |
);
|
52 |
17 |
ale500 |
reg [3:0] lr, rr, dr; // left, right and destination register addresses
|
53 |
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reg [1:0] lm, rm, dm; // left, right and destination memory sizes
|
54 |
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reg ss, sz, p2, p3; // S or *U, 16 or *8, page 2, page 3
|
55 |
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reg [2:0] mo; // Addressing Mode
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56 |
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reg [4:0] aop; // ALU opcode
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57 |
16 |
ale500 |
assign write_dest = (dr != `RN_INV);
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58 |
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assign source_size = (lr < `RN_ACCA) | sz | (rm == `MT_WORD);
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59 |
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// result size is used to determine the size of the argument
|
60 |
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// to load, compare has no result, thus the source is used instead,
|
61 |
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// why do we need the result size ?... because of tfr&exg
|
62 |
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assign result_size = (dr == `RN_INV) ? (lr < `RN_ACCA):
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63 |
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(dr < `RN_ACCA) ? 1:0;
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64 |
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|
65 |
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// for registers, memory writes are handled differently
|
66 |
17 |
ale500 |
|
67 |
16 |
ale500 |
assign operand_read_o = (lm != `MT_NONE) | (rm != `MT_NONE);
|
68 |
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assign operand_write_o = dm != `MT_NONE;
|
69 |
|
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assign path_left_memtype_o = lm;
|
70 |
|
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assign path_right_memtype_o = rm;
|
71 |
|
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assign dest_memtype_o = dm;
|
72 |
|
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assign dest_flags_o = (aop != `NOP) && (opcode != 8'h1a) && (opcode != 8'h1c);
|
73 |
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assign use_s = ss;
|
74 |
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assign mode = mo;
|
75 |
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assign alu_opcode = aop;
|
76 |
17 |
ale500 |
|
77 |
16 |
ale500 |
always @(*)
|
78 |
|
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begin
|
79 |
|
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lr = `RN_INV;
|
80 |
|
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rr = `RN_INV;
|
81 |
|
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dr = `RN_INV;
|
82 |
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lm = `MT_NONE;
|
83 |
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rm = `MT_NONE;
|
84 |
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dm = `MT_NONE;
|
85 |
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mo = `NONE;
|
86 |
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aop = `NOP;
|
87 |
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ss = 1;
|
88 |
|
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sz = 0;
|
89 |
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op_SYNC = 0;
|
90 |
|
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op_EXG = 0;
|
91 |
|
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op_TFR = 0;
|
92 |
|
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op_RTS = 0;
|
93 |
|
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op_RTI = 0;
|
94 |
|
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op_CWAI = 0;
|
95 |
|
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op_MUL = 0;
|
96 |
|
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op_SWI = 0;
|
97 |
|
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op_PUSH = 0;
|
98 |
|
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op_PULL = 0;
|
99 |
|
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op_LEA = 0;
|
100 |
|
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op_JMP = 0;
|
101 |
|
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op_JSR = 0;
|
102 |
|
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p2 = 0;
|
103 |
|
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p3 = 0;
|
104 |
|
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case (opcode[7:4])
|
105 |
|
|
4'h0:
|
106 |
|
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begin
|
107 |
|
|
mo = `DIRECT;
|
108 |
|
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lm = `MT_BYTE;
|
109 |
|
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dm = `MT_BYTE;
|
110 |
|
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case (opcode[3:0]) // Direct
|
111 |
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4'h0: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `NEG; end // NEG
|
112 |
|
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4'h1: begin end
|
113 |
|
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4'h2: begin end
|
114 |
|
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4'h3: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `COM; end // COM
|
115 |
|
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4'h4: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSR; end
|
116 |
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4'h5: begin end
|
117 |
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4'h6: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROR; end
|
118 |
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4'h7: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ASR; end
|
119 |
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4'h8: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSL; end
|
120 |
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4'h9: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROL; end
|
121 |
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4'ha: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `DEC; end
|
122 |
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4'hb: begin end
|
123 |
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4'hc: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `INC; end
|
124 |
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4'hd: begin lm = `MT_BYTE; aop = `TST; end
|
125 |
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4'he: begin op_JMP = 1; end // JMP
|
126 |
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4'hf: begin dm = `MT_BYTE; aop = `CLR; end
|
127 |
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endcase
|
128 |
|
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end
|
129 |
|
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4'h1:
|
130 |
|
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begin
|
131 |
|
|
case (opcode[3:0])
|
132 |
|
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4'h0: begin p2 = 1; end
|
133 |
|
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4'h1: begin p3 = 1; end
|
134 |
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4'h2: begin end // nop
|
135 |
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4'h3: begin op_SYNC = 1; end
|
136 |
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4'h4: begin end
|
137 |
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4'h5: begin end
|
138 |
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4'h6: begin mo = `REL16; end // lbra
|
139 |
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4'h7: begin mo = `REL16; op_JSR = 1; end
|
140 |
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4'h8: begin end
|
141 |
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4'h9: begin mo = `INHERENT; lr = `RN_ACCA; dr = `RN_ACCA; aop = `DAA; end
|
142 |
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4'ha: begin mo = `IMMEDIATE; lr = `RN_CC; dr = `RN_CC; aop = `OR; end
|
143 |
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4'hb: begin end
|
144 |
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4'hc: begin mo = `IMMEDIATE; lr = `RN_CC; dr = `RN_CC; aop = `AND; end
|
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
|
147 |
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4'hf: begin op_TFR = 1; lr = postbyte0[7:4]; rr = postbyte0[3:0]; dr = postbyte0[3:0]; end
|
148 |
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endcase
|
149 |
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end
|
150 |
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4'h2:
|
151 |
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begin
|
152 |
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mo = `REL8;
|
153 |
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case (opcode[3:0])
|
154 |
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4'h0: begin end
|
155 |
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4'h1: begin end
|
156 |
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4'h2: begin end
|
157 |
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4'h3: begin end
|
158 |
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4'h4: begin end
|
159 |
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4'h5: begin end
|
160 |
|
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4'h6: begin end
|
161 |
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4'h7: begin end
|
162 |
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4'h8: begin end
|
163 |
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4'h9: begin end
|
164 |
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4'ha: begin end
|
165 |
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4'hb: begin end
|
166 |
|
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4'hc: begin end
|
167 |
|
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4'hd: begin end
|
168 |
|
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4'he: begin end
|
169 |
|
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4'hf: begin end
|
170 |
|
|
endcase
|
171 |
|
|
end
|
172 |
|
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4'h3:
|
173 |
|
|
begin
|
174 |
|
|
case (opcode[3:0])
|
175 |
|
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4'h0: begin mo = `INDEXED; op_LEA = 1; dr = `RN_IX; end
|
176 |
|
|
4'h1: begin mo = `INDEXED; op_LEA = 1; dr = `RN_IY; end
|
177 |
|
|
4'h2: begin mo = `INDEXED; op_LEA = 1; dr = `RN_S; end
|
178 |
|
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4'h3: begin mo = `INDEXED; op_LEA = 1; dr = `RN_U; end
|
179 |
|
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4'h4: begin op_PUSH = 1; end
|
180 |
|
|
4'h5: begin op_PULL = 1; end
|
181 |
|
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4'h6: begin op_PUSH = 1; ss = 0; end
|
182 |
|
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4'h7: begin op_PULL = 1; ss = 0; end
|
183 |
|
|
4'h8: begin end
|
184 |
|
|
4'h9: begin mo = `INHERENT; op_RTS = 1; end
|
185 |
|
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4'ha: begin mo = `INHERENT; lr = `RN_ACCB; rr = `RN_IX; dr = `RN_IX; aop = `ADD; end // ABX
|
186 |
|
|
4'hb: begin mo = `INHERENT; op_RTI = 1; end
|
187 |
|
|
4'hc: begin op_CWAI = 1; end
|
188 |
|
|
4'hd: begin mo = `INHERENT; lr = `RN_ACCA; rr = `RN_ACCB; dr = `RN_ACCD; aop = `MUL; op_MUL = 1; end
|
189 |
|
|
4'he: begin end
|
190 |
|
|
4'hf: begin op_SWI = 1; end
|
191 |
|
|
endcase
|
192 |
|
|
end
|
193 |
|
|
4'h4:
|
194 |
|
|
begin
|
195 |
|
|
mo = `INHERENT;
|
196 |
|
|
case (opcode[3:0])
|
197 |
|
|
4'h0: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `NEG; end // NEG
|
198 |
|
|
4'h1: begin end
|
199 |
|
|
4'h2: begin end
|
200 |
|
|
4'h3: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `COM; end // COM
|
201 |
|
|
4'h4: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `LSR; end
|
202 |
|
|
4'h5: begin end
|
203 |
|
|
4'h6: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ROR; end
|
204 |
|
|
4'h7: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ASR; end
|
205 |
|
|
4'h8: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `LSL; end
|
206 |
|
|
4'h9: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `ROL; end
|
207 |
|
|
4'ha: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `DEC; end
|
208 |
|
|
4'hb: begin end
|
209 |
|
|
4'hc: begin lr = `RN_ACCA; dr = `RN_ACCA; aop = `INC; end
|
210 |
|
|
4'hd: begin lr = `RN_ACCA; aop = `TST; end
|
211 |
|
|
4'he: begin end
|
212 |
|
|
4'hf: begin dr = `RN_ACCA; aop = `CLR; end
|
213 |
|
|
endcase
|
214 |
|
|
end
|
215 |
|
|
4'h5:
|
216 |
|
|
begin
|
217 |
|
|
mo = `INHERENT;
|
218 |
|
|
case (opcode[3:0])
|
219 |
|
|
4'h0: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `NEG; end // NEG
|
220 |
|
|
4'h1: begin end
|
221 |
|
|
4'h2: begin end
|
222 |
|
|
4'h3: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `COM; end // COM
|
223 |
|
|
4'h4: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `LSR; end
|
224 |
|
|
4'h5: begin end
|
225 |
|
|
4'h6: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ROR; end
|
226 |
|
|
4'h7: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ASR; end
|
227 |
|
|
4'h8: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `LSL; end
|
228 |
|
|
4'h9: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `ROL; end
|
229 |
|
|
4'ha: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `DEC; end
|
230 |
|
|
4'hb: begin end
|
231 |
|
|
4'hc: begin lr = `RN_ACCB; dr = `RN_ACCB; aop = `INC; end
|
232 |
|
|
4'hd: begin lr = `RN_ACCB; aop = `TST; end
|
233 |
|
|
4'he: begin end
|
234 |
|
|
4'hf: begin dr = `RN_ACCB; aop = `CLR; end
|
235 |
|
|
endcase
|
236 |
|
|
end
|
237 |
|
|
4'h6:
|
238 |
|
|
begin
|
239 |
|
|
mo = `INDEXED;
|
240 |
|
|
case (opcode[3:0])
|
241 |
|
|
4'h0: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `NEG; end // NEG
|
242 |
|
|
4'h1: begin end
|
243 |
|
|
4'h2: begin end
|
244 |
|
|
4'h3: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `COM; end // COM
|
245 |
|
|
4'h4: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSR; end
|
246 |
|
|
4'h5: begin end
|
247 |
|
|
4'h6: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROR; end
|
248 |
|
|
4'h7: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ASR; end
|
249 |
|
|
4'h8: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSL; end
|
250 |
|
|
4'h9: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROL; end
|
251 |
|
|
4'ha: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `DEC; end
|
252 |
|
|
4'hb: begin end
|
253 |
|
|
4'hc: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `INC; end
|
254 |
|
|
4'hd: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `AND; end// TST FIXME
|
255 |
|
|
4'he: begin op_JMP = 1; end // JMP
|
256 |
|
|
4'hf: begin dm = `MT_BYTE; aop = `CLR; end // CLR FIXME
|
257 |
|
|
endcase
|
258 |
|
|
end
|
259 |
|
|
4'h7:
|
260 |
|
|
begin
|
261 |
|
|
mo = `EXTENDED;
|
262 |
|
|
case (opcode[3:0])
|
263 |
|
|
4'h0: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `NEG; end // NEG
|
264 |
|
|
4'h1: begin end
|
265 |
|
|
4'h2: begin end
|
266 |
|
|
4'h3: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `COM; end // COM
|
267 |
|
|
4'h4: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSR; end
|
268 |
|
|
4'h5: begin end
|
269 |
|
|
4'h6: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROR; end
|
270 |
|
|
4'h7: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ASR; end
|
271 |
|
|
4'h8: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `LSL; end
|
272 |
|
|
4'h9: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `ROL; end
|
273 |
|
|
4'ha: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `DEC; end
|
274 |
|
|
4'hb: begin end
|
275 |
|
|
4'hc: begin lm = `MT_BYTE; dm = `MT_BYTE; aop = `INC; end
|
276 |
|
|
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
|