`ifdef EXECUTE
	`INSN_INCDEC16: begin
		case (cycle)
		0:	begin
				case (opcode[5:4])
				`INSN_reg16_BC:	begin
					tmp <= registers[`REG_B];
					tmp2 <= registers[`REG_C];
				end
				`INSN_reg16_DE:	begin
					tmp <= registers[`REG_D];
					tmp2 <= registers[`REG_E];
				end
				`INSN_reg16_HL:	begin
					tmp <= registers[`REG_H];
					tmp2 <= registers[`REG_L];
				end
				`INSN_reg16_SP:	begin
					tmp <= registers[`REG_SPH];
					tmp2 <= registers[`REG_SPL];
				end
				endcase
			end
		1:	begin
				`EXEC_INC_PC;
				`EXEC_NEWCYCLE;
			end
		endcase
	end
`endif

`ifdef WRITEBACK
	`INSN_INCDEC16: begin
		case (cycle)
		0:	{tmp,tmp2} <= {tmp,tmp2} +
				(opcode[3] ? 16'hFFFF : 16'h0001);
		1: begin
				case (opcode[5:4])
				`INSN_reg16_BC:	begin
					registers[`REG_B] <= tmp;
					registers[`REG_C] <= tmp2;
				end
				`INSN_reg16_DE:	begin
					registers[`REG_D] <= tmp;
					registers[`REG_E] <= tmp2;
				end
				`INSN_reg16_HL:	begin
					registers[`REG_H] <= tmp;
					registers[`REG_L] <= tmp2;
				end
				`INSN_reg16_SP:	begin
					registers[`REG_SPH] <= tmp;
					registers[`REG_SPL] <= tmp2;
				end
				endcase
			end
		endcase
	end
`endif