adtools/clib2

#if defined(USE_64_BIT_INTS)

#if defined(__PPC__) && defined(__GNUC__)

asm("    .text\n\
    .align 2\n\
    .globl bswap64\n\
    .type    bswap64, @function\n\
bswap64:\n\
    rlwinm    %r5,%r3,8,8,31\n\
    rlwimi    %r5,%r3,24,0,7\n\
    rlwimi    %r5,%r3,24,16,23\n\
    rlwinm    %r3,%r4,8,8,31\n\
    rlwimi    %r3,%r4,24,0,7\n\
    rlwimi    %r3,%r4,24,16,23\n\
    or            %r4,%r5,%r5\n\
    blr\n\
");

#else

#include <stdint.h>

uint64_t bswap64(uint64_t u64)
{
union {
    uint64_t ll;
    uint32_t l[2];
} v={.ll=u64};
uint32_t tmp;
tmp=v.l[0];
v.l[0]=((v.l[1]&0xff)<<24)|
        ((v.l[1]&0xff00)<<8)|
        ((v.l[1]&0xff0000)>>8)|
        ((v.l[1]&0xff000000)>>24);
v.l[1]=((tmp&0xff)<<24)|
        ((tmp&0xff00)<<8)|
        ((tmp&0xff0000)>>8)|
        ((tmp&0xff000000)>>24);
return(v.ll);
}

#endif

#endif