ARP responder
[fpgaboy.git] / core / insn_alu_ext.v
1 `define INSN_ALU_EXT            9'b100xxxxxx
2
3 `ifdef LOCALWIRES
4         wire [7:0] rlc,rrc,rl,rr,sla,sra,swap,srl;
5         wire [3:0] rlcf,rrcf,rlf,rrf,slaf,sraf,swapf,srlf;
6         wire [7:0] alu_res;
7         wire [3:0] f_res;
8
9         assign rlc   = {tmp[6:0],tmp[7]};
10         assign rlcf  = {(tmp == 0 ? 1'b1 : 1'b0)
11                         ,2'b0,
12                         tmp[7]};
13
14         assign rrc   = {tmp[0],tmp[7:1]};
15         assign rrcf  = {(tmp == 0 ? 1'b1 : 1'b0),
16                         2'b0,
17                         tmp[0]};
18
19         assign rl    = {tmp[6:0],`_F[4]};
20         assign rlf   = {({tmp[6:0],`_F[4]} == 0 ? 1'b1 : 1'b0),
21                         2'b0,
22                         tmp[7]};
23
24         assign rr    = {`_F[4],tmp[7:1]};
25         assign rrf   = {({`_F[4],tmp[7:1]} == 0 ? 1'b1 : 1'b0),
26                         2'b0,
27                         tmp[0]};
28
29         assign sla   = {tmp[6:0],1'b0};
30         assign slaf  = {(tmp[6:0] == 0 ? 1'b1 : 1'b0),
31                         2'b0,
32                         tmp[7]};
33
34         assign sra   = {tmp[7],tmp[7:1]};
35 //      assign sraf  = {(tmp[7:1] == 0 ? 1'b1 : 1'b0),2'b0,tmp[0]};   now in assign srlf =
36
37         assign swap  = {tmp[3:0],tmp[7:4]};
38         assign swapf = {(tmp == 1'b0 ? 1'b1 : 1'b0),
39                         3'b0};
40
41         assign srl   = {1'b0,tmp[7:1]};
42         assign srlf  = {(tmp[7:1] == 0 ? 1'b1 : 1'b0),
43                         2'b0,
44                         tmp[0]};
45         assign sraf  = srlf;
46
47         /*  Y U Q  */
48         assign {alu_res,f_res} =
49                 opcode[5] ? (
50                         opcode[4] ? (
51                                 opcode[3] ? {srl,srlf} : {swap,swapf}
52                         ) : (
53                                 opcode[3] ? {sra,sraf} : {sla,slaf}
54                         )
55                 ) : (
56                         opcode[4] ? (
57                                 opcode[3] ? {rr,rrf} : {rl,rlf}
58                         ) : (
59                                 opcode[3] ? {rrc,rrcf} : {rlc,rlcf}
60                         )
61                 );
62 `endif
63
64 `ifdef EXECUTE
65         `INSN_ALU_EXT: begin
66                 if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 0))
67                         `EXEC_READ(`_HL)
68                 else begin
69                         `EXEC_INC_PC
70                         case (opcode[2:0])
71                         `INSN_reg_A:    tmp <= `_A;
72                         `INSN_reg_B:    tmp <= `_B;
73                         `INSN_reg_C:    tmp <= `_C;
74                         `INSN_reg_D:    tmp <= `_D;
75                         `INSN_reg_E:    tmp <= `_E;
76                         `INSN_reg_H:    tmp <= `_H;
77                         `INSN_reg_L:    tmp <= `_L;
78                         `INSN_reg_dHL:  tmp <= rdata;
79                         endcase
80                 end
81         end
82 `endif
83
84 `ifdef WRITEBACK
85         `INSN_ALU_EXT: begin
86                 if (opcode[2:0] == `INSN_reg_dHL) begin
87                         if(cycle == 0) begin end
88                         else if(cycle == 1) begin
89                                 `EXEC_WRITE(`_HL, alu_res)
90                                 `_F <= {f_res,`_F[3:0]};
91                         end else begin
92                                 `EXEC_NEWCYCLE
93                         end
94                 end else begin
95                         case(opcode[2:0])
96                         `INSN_reg_B: `_B <= alu_res;
97                         `INSN_reg_C: `_C <= alu_res;
98                         `INSN_reg_D: `_D <= alu_res;
99                         `INSN_reg_E: `_E <= alu_res;
100                         `INSN_reg_H: `_H <= alu_res;
101                         `INSN_reg_L: `_L <= alu_res;
102                         `INSN_reg_A: `_A <= alu_res;
103                         `INSN_reg_dHL: begin end /* eat dicks */
104                         endcase
105                         `_F <= {f_res,`_F[3:0]};
106                         `EXEC_NEWCYCLE
107                 end
108         end
109 `endif
This page took 0.023814 seconds and 4 git commands to generate.