Converting Endianess on a bit field structure

Question

I need to convert a bit-field structure from little-endian to big-endia architecture. What is the best way to do that, as there will be issues in byte boundaries, if I simply sw

Answer 1

In a project porting code from MIPS to Linux/x86 we did like this.

struct {

#ifdef __ONE_ENDIANESS__
    unsigned int    b1:1;
    unsigned int    b2:8;
    unsigned int    b3:7;
    unsigned int    b4:8;
    unsigned int    b5:7;
    unsigned int    b6:1;
#define _STRUCT_FILLED
#endif /* __ONE_ENDIANESS__ */

#ifdef __OTHER_ENDIANESS__
    unsigned int    b6:1;
    unsigned int    b5:7;
    unsigned int    b4:8;
    unsigned int    b3:7;
    unsigned int    b2:8;
    unsigned int    b1:1;
#define _STRUCT_FILLED
#endif /* __OTHER_ENDIANESS__ */

};

#ifndef _STRUCT_FILLED
#  error Endianess uncertain for struct
#else
#  undef _STRUCT_FILLED
#endif /* _STRUCT_FILLED */

The macros __ONE_ENDIANESS__ and __OTHER_ENDIANESS__ was the appropriate for the compiler we used so you might need to look into which is appropriate for you...