`ifdef EXECUTE `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 <= `_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 end `endif `ifdef WRITEBACK `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 `_A <= `_A + tmp; `_F <= { /* Z */ ((`_A + tmp) == 0) ? 1'b1 : 1'b0, /* N */ 1'b0, /* 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 `_A <= `_A + tmp + {7'b0,`_F[4]}; `_F <= { /* Z */ ((`_A + tmp + {7'b0,`_F[4]}) == 0) ? 1'b1 : 1'b0, /* N */ 1'b0, /* 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 `_A <= `_A - tmp; `_F <= { /* Z */ (`_A == tmp) ? 1'b1 : 1'b0, /* N */ 1'b1, /* 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 `_A <= `_A - (tmp + {7'b0,`_F[4]}); `_F <= { /* Z */ ((`_A - (tmp + {7'b0,`_F[4]})) == 0) ? 1'b1 : 1'b0, /* N */ 1'b1, /* 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 `_A <= `_A & tmp; `_F <= { /* Z */ ((`_A & tmp) == 0) ? 1'b1 : 1'b0, 3'b010, `_F[3:0] }; end `INSN_alu_OR: begin `_A <= `_A | tmp; `_F <= { /* Z */ ((`_A | tmp) == 0) ? 1'b1 : 1'b0, 3'b000, `_F[3:0] }; end `INSN_alu_XOR: begin `_A <= `_A ^ tmp; `_F <= { /* Z */ ((`_A ^ tmp) == 0) ? 1'b1 : 1'b0, 3'b000, `_F[3:0] }; end `INSN_alu_CP: begin `_F <= { /* Z */ (`_A == tmp) ? 1'b1 : 1'b0, /* N */ 1'b1, /* H */ (tmp[3:0] > `_A[3:0]) ? 1'b1 : 1'b0, /* C */ (tmp > `_A) ? 1'b1 : 1'b0, `_F[3:0] }; end default: $stop; endcase end end `endif