Fix some flag bugs in INC and DEC

[fpgaboy.git] / core / insn_add_hl.v

`define INSN_ADD_HL		9'b000xx1001

`ifdef EXECUTE
	`INSN_ADD_HL: begin
		case (cycle)
		0:	case (opcode[5:4])
			`INSN_reg16_BC:	{tmp,tmp2} <= `_BC;
			`INSN_reg16_DE:	{tmp,tmp2} <= `_DE;
			`INSN_reg16_HL:	{tmp,tmp2} <= `_HL;
			`INSN_reg16_SP:	{tmp,tmp2} <= `_SP;
			endcase
		1:	begin
				`EXEC_INC_PC
				`EXEC_NEWCYCLE
			end
		endcase
	end
`endif

`ifdef WRITEBACK
	`INSN_ADD_HL: begin
		case (cycle)
		1:	begin
				`_F <=	{ /* Z */ `_F[7],
					  /* N */ 1'b0,
					  /* H */ (({`_HL} + {tmp,tmp2}) & 16'h1000) ? 1'b1 : 1'b0,
					  /* C */ (({1'b0,`_HL} + {1'b0,tmp,tmp2}) & 17'h10000) ? 1'b1 : 1'b0,
					  `_F[3:0]
					};
				`_HL <= `_HL + {tmp, tmp2};
			end
		endcase
	end
`endif