`ifdef EXECUTE
- `INSN_ALU8: begin
- if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 0)) begin
- // fffffffff fuck your shit, read from (HL) :(
- rd <= 1;
- address <= {registers[`REG_H], registers[`REG_L]};
- end else begin
- `EXEC_NEWCYCLE;
- `EXEC_INC_PC;
+ `INSN_ALU8,`INSN_ALU8IMM: begin
+ if ((opcode[7:6] == 2'b11) && (cycle == 0)) begin // alu8imm
+ `EXEC_INC_PC
+ `EXEC_READ(`_PC + 1)
+ end else if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 0))
+ `EXEC_READ(`_HL)
+ else begin
+ `EXEC_NEWCYCLE
+ `EXEC_INC_PC
case (opcode[2:0])
- `INSN_reg_A: tmp <= registers[`REG_A];
- `INSN_reg_B: tmp <= registers[`REG_B];
- `INSN_reg_C: tmp <= registers[`REG_C];
- `INSN_reg_D: tmp <= registers[`REG_D];
- `INSN_reg_E: tmp <= registers[`REG_E];
- `INSN_reg_H: tmp <= registers[`REG_H];
- `INSN_reg_L: tmp <= registers[`REG_L];
+ `INSN_reg_A: tmp <= `_A;
+ `INSN_reg_B: tmp <= `_B;
+ `INSN_reg_C: tmp <= `_C;
+ `INSN_reg_D: tmp <= `_D;
+ `INSN_reg_E: tmp <= `_E;
+ `INSN_reg_H: tmp <= `_H;
+ `INSN_reg_L: tmp <= `_L;
`INSN_reg_dHL: tmp <= rdata;
endcase
end
`endif
`ifdef WRITEBACK
- `INSN_ALU8: begin
- if ((opcode[2:0] == `INSN_reg_dHL) && (cycle == 0)) begin
+ `INSN_ALU8,`INSN_ALU8IMM: begin
+ if (((opcode[2:0] == `INSN_reg_dHL) || (opcode[7:6] == 2'b11)) && (cycle == 0)) begin
/* Sit on our asses. */
end else begin /* Actually do the computation! */
case (opcode[5:3])
`INSN_alu_ADD: begin
- registers[`REG_A] <=
- registers[`REG_A] + tmp;
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] + tmp) == 0) ? 1'b1 : 1'b0,
+ `_A <= `_A + tmp;
+ `_F <= { /* Z */ ((`_A + tmp) == 8'b0) ? 1'b1 : 1'b0,
/* N */ 1'b0,
- /* H */ (({1'b0,registers[`REG_A][3:0]} + {1'b0,tmp[3:0]}) >> 4 == 1) ? 1'b1 : 1'b0,
- /* C */ (({1'b0,registers[`REG_A]} + {1'b0,tmp}) >> 8 == 1) ? 1'b1 : 1'b0,
- registers[`REG_F][3:0]
+ /* H */ (({1'b0,`_A[3:0]} + {1'b0,tmp[3:0]}) >> 4 == 1) ? 1'b1 : 1'b0,
+ /* C */ (({1'b0,`_A} + {1'b0,tmp}) >> 8 == 1) ? 1'b1 : 1'b0,
+ `_F[3:0]
};
end
`INSN_alu_ADC: begin
- registers[`REG_A] <=
- registers[`REG_A] + tmp + {7'b0,registers[`REG_F][4]};
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] + tmp + {7'b0,registers[`REG_F][4]}) == 0) ? 1'b1 : 1'b0,
+ `_A <= `_A + tmp + {7'b0,`_F[4]};
+ `_F <= { /* Z */ ((`_A + tmp + {7'b0,`_F[4]}) == 8'b0) ? 1'b1 : 1'b0,
/* N */ 1'b0,
- /* H */ (({1'b0,registers[`REG_A][3:0]} + {1'b0,tmp[3:0]} + {4'b0,registers[`REG_F][4]}) >> 4 == 1) ? 1'b1 : 1'b0,
- /* C */ (({1'b0,registers[`REG_A]} + {1'b0,tmp} + {8'b0,registers[`REG_F][4]}) >> 8 == 1) ? 1'b1 : 1'b0,
- registers[`REG_F][3:0]
+ /* H */ (({1'b0,`_A[3:0]} + {1'b0,tmp[3:0]} + {4'b0,`_F[4]}) >> 4 == 1) ? 1'b1 : 1'b0,
+ /* C */ (({1'b0,`_A} + {1'b0,tmp} + {8'b0,`_F[4]}) >> 8 == 1) ? 1'b1 : 1'b0,
+ `_F[3:0]
};
end
`INSN_alu_SUB: begin
- registers[`REG_A] <=
- registers[`REG_A] - tmp;
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] - tmp) == 0) ? 1'b1 : 1'b0,
+ `_A <= `_A - tmp;
+ `_F <= { /* Z */ (`_A == tmp) ? 1'b1 : 1'b0,
/* N */ 1'b1,
- /* H */ (({1'b0,registers[`REG_A][3:0]} - {1'b0,tmp[3:0]}) >> 4 == 1) ? 1'b1 : 1'b0,
- /* C */ (({1'b0,registers[`REG_A]} - {1'b0,tmp}) >> 8 == 1) ? 1'b1 : 1'b0,
- registers[`REG_F][3:0]
+ /* H */ (tmp[3:0] > `_A[3:0]) ? 1'b1 : 1'b0,
+ /* C */ (tmp > `_A) ? 1'b1 : 1'b0,
+ `_F[3:0]
};
end
`INSN_alu_SBC: begin
- registers[`REG_A] <=
- registers[`REG_A] - (tmp + {7'b0,registers[`REG_F][4]});
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] - (tmp + {7'b0,registers[`REG_F][4]})) == 0) ? 1'b1 : 1'b0,
+ `_A <= `_A - (tmp + {7'b0,`_F[4]});
+ `_F <= { /* Z */ ((`_A - (tmp + {7'b0,`_F[4]})) == 8'b0) ? 1'b1 : 1'b0,
/* N */ 1'b1,
- /* H */ (({1'b0,registers[`REG_A][3:0]} - ({1'b0,tmp[3:0]} + {4'b0,registers[`REG_F][4]})) >> 4 == 1) ? 1'b1 : 1'b0,
- /* C */ (({1'b0,registers[`REG_A]} - ({1'b0,tmp} + {8'b0,registers[`REG_F][4]})) >> 8 == 1) ? 1'b1 : 1'b0,
- registers[`REG_F][3:0]
+ /* H */ (({1'b0,tmp[3:0]} + {4'b0,`_F[4]}) > {1'b0,`_A[3:0]}) ? 1'b1 : 1'b0,
+ /* C */ (({1'b0,tmp} + {8'b0,`_F[4]}) > {1'b0,`_A[7:0]}) ? 1'b1 : 1'b0,
+ `_F[3:0]
};
end
`INSN_alu_AND: begin
- registers[`REG_A] <=
- registers[`REG_A] & tmp;
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] & tmp) == 0) ? 1'b1 : 1'b0,
+ `_A <= `_A & tmp;
+ `_F <= { /* Z */ ((`_A & tmp) == 0) ? 1'b1 : 1'b0,
3'b010,
- registers[`REG_F][3:0]
+ `_F[3:0]
};
end
`INSN_alu_OR: begin
- registers[`REG_A] <=
- registers[`REG_A] | tmp;
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] | tmp) == 0) ? 1'b1 : 1'b0,
+ `_A <= `_A | tmp;
+ `_F <= { /* Z */ ((`_A | tmp) == 0) ? 1'b1 : 1'b0,
3'b000,
- registers[`REG_F][3:0]
+ `_F[3:0]
};
end
`INSN_alu_XOR: begin
- registers[`REG_A] <=
- registers[`REG_A] ^ tmp;
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] ^ tmp) == 0) ? 1'b1 : 1'b0,
+ `_A <= `_A ^ tmp;
+ `_F <= { /* Z */ ((`_A ^ tmp) == 0) ? 1'b1 : 1'b0,
3'b000,
- registers[`REG_F][3:0]
+ `_F[3:0]
};
end
`INSN_alu_CP: begin
- registers[`REG_F] <=
- { /* Z */ ((registers[`REG_A] - tmp) == 0) ? 1'b1 : 1'b0,
+ `_F <= { /* Z */ (`_A == tmp) ? 1'b1 : 1'b0,
/* N */ 1'b1,
- /* H */ (({1'b0,registers[`REG_A][3:0]} - {1'b0,tmp[3:0]}) >> 4 == 1) ? 1'b1 : 1'b0,
- /* C */ (({1'b0,registers[`REG_A]} - {1'b0,tmp}) >> 8 == 1) ? 1'b1 : 1'b0,
- registers[`REG_F][3:0]
+ /* H */ (tmp[3:0] > `_A[3:0]) ? 1'b1 : 1'b0,
+ /* C */ (tmp > `_A) ? 1'b1 : 1'b0,
+ `_F[3:0]
};
end
default:
git.joshuawise.com / fpgaboy.git / blobdiff