root/usr/src/grub/grub-0.97/netboot/i386_byteswap.h
#ifndef ETHERBOOT_BITS_BYTESWAP_H
#define ETHERBOOT_BITS_BYTESWAP_H

#include "types.h"
static inline uint16_t __i386_bswap_16(uint16_t x)
{
        __asm__("xchgb %b0,%h0\n\t"
                : "=q" (x)
                : "0" (x));
        return x;
}

static inline uint32_t __i386_bswap_32(uint32_t x)
{
        __asm__("xchgb %b0,%h0\n\t"
                "rorl $16,%0\n\t"
                "xchgb %b0,%h0"
                : "=q" (x)
                : "0" (x));
        return x;
}


#define __bswap_constant_16(x) \
        ((uint16_t)((((uint16_t)(x) & 0x00ff) << 8) | \
                (((uint16_t)(x) & 0xff00) >> 8)))

#define __bswap_constant_32(x) \
        ((uint32_t)((((uint32_t)(x) & 0x000000ffU) << 24) | \
                (((uint32_t)(x) & 0x0000ff00U) <<  8) | \
                (((uint32_t)(x) & 0x00ff0000U) >>  8) | \
                (((uint32_t)(x) & 0xff000000U) >> 24)))

#define __bswap_16(x) \
        (__builtin_constant_p(x) ? \
        __bswap_constant_16(x) : \
        __i386_bswap_16(x))


#define __bswap_32(x) \
        (__builtin_constant_p(x) ? \
        __bswap_constant_32(x) : \
        __i386_bswap_32(x))


#endif /* ETHERBOOT_BITS_BYTESWAP_H */