#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#define _SWAP16(b) ((((unsigned char *)&(b))[0] & 0xff) | (((unsigned char *)&(b))[1] & 0xff) << 8)
-#define _SWAP32(b) ((((unsigned char *)&(b))[0] & 0xff) | ((((unsigned char *)&(b))[1] & 0xff) << 8) | ((((unsigned char *)&(b))[2] & 0xff) << 16) | (((unsigned char *)&(b))[3] << 24))
-
-#define SWAP16(v) ((((v) & 0xff00) >> 8) +(((v) & 0xff) << 8))
-#define SWAP32(v) ((((v) & 0xff000000ul) >> 24) + (((v) & 0xff0000ul) >> 8) + (((v) & 0xff00ul)<<8) +(((v) & 0xfful) << 24))
+#define SWAP16(v) __builtin_bswap16(v)
+#define SWAP32(v) __builtin_bswap32(v)
#define SWAPu32(v) SWAP32((u32)(v))
#define SWAPs32(v) SWAP32((s32)(v))