+/*****************************************************************************
+ * bytes_swap.h: fast routines to swap bytes order.
+ *****************************************************************************
+ * Copyright (C) 1998, 1999, 2000 VideoLAN
+ * $Id: bytes_swap.h,v 1.1 2001/11/25 22:52:21 gbazin Exp $
+ *
+ * Authors: This code was borrowed from the GNU C Library.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
+ *****************************************************************************/
+
+/* Swap bytes in 16 bit value. */
+#define __bswap_constant_16(x) \
+ ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
+
+#if defined __GNUC__ && __GNUC__ >= 2
+# define __bswap_16(x) \
+ (__extension__ \
+ ({ register unsigned short int __v; \
+ if (__builtin_constant_p (x)) \
+ __v = __bswap_constant_16 (x); \
+ else \
+ __asm__ __volatile__ ("rorw $8, %w0" \
+ : "=r" (__v) \
+ : "0" ((unsigned short int) (x)) \
+ : "cc"); \
+ __v; }))
+#else
+/* This is better than nothing. */
+# define __bswap_16(x) __bswap_constant_16 (x)
+#endif
+
+
+/* Swap bytes in 32 bit value. */
+#define __bswap_constant_32(x) \
+ ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \
+ (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
+
+#if defined __GNUC__ && __GNUC__ >= 2
+/* To swap the bytes in a word the i486 processors and up provide the
+ `bswap' opcode. On i386 we have to use three instructions. */
+# if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__
+# define __bswap_32(x) \
+ (__extension__ \
+ ({ register unsigned int __v; \
+ if (__builtin_constant_p (x)) \
+ __v = __bswap_constant_32 (x); \
+ else \
+ __asm__ __volatile__ ("rorw $8, %w0;" \
+ "rorl $16, %0;" \
+ "rorw $8, %w0" \
+ : "=r" (__v) \
+ : "0" ((unsigned int) (x)) \
+ : "cc"); \
+ __v; }))
+# else
+# define __bswap_32(x) \
+ (__extension__ \
+ ({ register unsigned int __v; \
+ if (__builtin_constant_p (x)) \
+ __v = __bswap_constant_32 (x); \
+ else \
+ __asm__ __volatile__ ("bswap %0" \
+ : "=r" (__v) \
+ : "0" ((unsigned int) (x))); \
+ __v; }))
+# endif
+#else
+# define __bswap_32(x) __bswap_constant_32 (x)
+#endif
+
+
+#if defined __GNUC__ && __GNUC__ >= 2
+/* Swap bytes in 64 bit value. */
+#define __bswap_constant_64(x) \
+ ((((x) & 0xff00000000000000ull) >> 56) \
+ | (((x) & 0x00ff000000000000ull) >> 40) \
+ | (((x) & 0x0000ff0000000000ull) >> 24) \
+ | (((x) & 0x000000ff00000000ull) >> 8) \
+ | (((x) & 0x00000000ff000000ull) << 8) \
+ | (((x) & 0x0000000000ff0000ull) << 24) \
+ | (((x) & 0x000000000000ff00ull) << 40) \
+ | (((x) & 0x00000000000000ffull) << 56))
+
+# define __bswap_64(x) \
+ (__extension__ \
+ ({ union { __extension__ unsigned long long int __ll; \
+ unsigned long int __l[2]; } __w, __r; \
+ if (__builtin_constant_p (x)) \
+ __r.__ll = __bswap_constant_64 (x); \
+ else \
+ { \
+ __w.__ll = (x); \
+ __r.__l[0] = __bswap_32 (__w.__l[1]); \
+ __r.__l[1] = __bswap_32 (__w.__l[0]); \
+ } \
+ __r.__ll; }))
+#endif