diff --git a/system/decoder.v b/system/decoder.v
index faef720..0094364 100644
--- a/system/decoder.v
+++ b/system/decoder.v
@@ -100,15 +100,10 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
 				reg_read_port2_addr={Wbit,3'b000};
 				reg_write_addr={Wbit,3'b000};
 				ALU_1OP=`ALU_OP_ADD;
-				case({Sbit,Wbit})
-					2'b00,2'b11:
-						next_state=`PROC_DE_LOAD_8_PARAM;
-					2'b01:
-						next_state=`PROC_DE_LOAD_16_PARAM;
-					default:begin
-						`invalid_instruction
-					end
-				endcase
+				if(Wbit)
+					next_state=`PROC_DE_LOAD_16_PARAM;
+				else
+					next_state=`PROC_DE_LOAD_8_PARAM;
 			end
 			11'b1000_00xx_101, /* SUB */
 				11'b1000_00xx_000 : /* ADD */ begin