Add mock up LCDC
[fpgaboy.git] / insn_ldm_a.v
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1// If opcode[4], then ld A, x, else ld x, A
2// If opcode[1], then ld 16m8, else ld 8m8
3
4`ifdef EXECUTE
5 `INSN_LDM_A: begin
6 case (cycle)
7 0: begin
8 `EXEC_INC_PC
9 `EXEC_READ(`_PC + 16'h0001)
10 end
11 1: begin
12 `EXEC_INC_PC // we only hit here if 16m8
13 `EXEC_READ(`_PC + 16'h0001)
14 end
15 2: if (opcode[4]) // LD A,x
16 `EXEC_READ(({tmp, tmp2}))
17 else
18 `EXEC_WRITE(({tmp, tmp2}), `_A)
19 3: begin
20 `EXEC_NEWCYCLE
21 `EXEC_INC_PC
22 end
23 endcase
24 end
25`endif
26
27`ifdef WRITEBACK
28 `INSN_LDM_A: begin
29 case (cycle)
30 0: if (!opcode[1]) begin
31 tmp <= 8'hFF;
32 cycle <= 1; /* Skip cycle 1 */
33 end
34 1: tmp2 <= rdata;
35 2: if (opcode[1])
36 tmp2 <= rdata;
37 else
38 tmp <= rdata;
39 3: if (opcode[4]) `_A <= rdata;
40 endcase
41 end
42`endif
43
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