Hi, I get a curious result when compiling such a following code :
typedef union { unsigned char cCtrlFullByte; struct { unsigned char bEnable : 1; unsigned char cUnused : 7; } cCtrlStruct; } CtrlUnion; void main (void) { unsigned char dummy = 0x55; CtrlUnion xdata bitUnion; bitUnion.cCtrlStruct.bEnable = dummy & 0x40; return; }
MOV A,#0x55 ANL A,#0x00 MOV R7,A MOV DPTR, #0x0000 MOVX A,@DPTR ANL A,#0xFE ORL A,R7 MOVX @DPTR, A
You're right. It does exactly what it should when the destination is a Keil "bit" type. If the type of the destination is a 1-bit wide field in a bit-field structure, the result will be different. For me, that should not happen. Regards Arnaud