bswap.h

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/*
 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file bswap.h
 * byte swap.
 */

#ifndef __BSWAP_H__
#define __BSWAP_H__

#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#else

#undef ROCKBOX
#ifdef ROCKBOX

/* rockbox' optimised inline functions */
#define bswap_16(x) swap16(x)
#define bswap_32(x) swap32(x)

static inline uint64_t ByteSwap64(uint64_t x)
{
    union { 
        uint64_t ll;
        struct {
           uint32_t l,h;
        } l;
    } r;
    r.l.l = bswap_32 (x);
    r.l.h = bswap_32 (x>>32);
    return r.ll;
}
#define bswap_64(x) ByteSwap64(x)

#elif defined(ARCH_X86)
static inline unsigned short ByteSwap16(unsigned short x)
{
  __asm("xchgb %b0,%h0" :
        "=q" (x)    :
        "0" (x));
    return x;
}
#define bswap_16(x) ByteSwap16(x)

static inline unsigned int ByteSwap32(unsigned int x)
{
#if __CPU__ > 386
 __asm("bswap   %0":
      "=r" (x)     :
#else
 __asm("xchgb   %b0,%h0\n"
      " rorl    $16,%0\n"
      " xchgb   %b0,%h0":
      "=q" (x)      :
#endif
      "0" (x));
  return x;
}
#define bswap_32(x) ByteSwap32(x)

static inline unsigned long long int ByteSwap64(unsigned long long int x)
{
  register union { __extension__ uint64_t __ll;
          uint32_t __l[2]; } __x;
  asm("xchgl    %0,%1":
      "=r"(__x.__l[0]),"=r"(__x.__l[1]):
      "0"(bswap_32((unsigned long)x)),"1"(bswap_32((unsigned long)(x>>32))));
  return __x.__ll;
}
#define bswap_64(x) ByteSwap64(x)

#elif defined(ARCH_SH4)

static inline uint16_t ByteSwap16(uint16_t x) {
    __asm__("swap.b %0,%0":"=r"(x):"0"(x));
    return x;
}

static inline uint32_t ByteSwap32(uint32_t x) {
    __asm__(
    "swap.b %0,%0\n"
    "swap.w %0,%0\n"
    "swap.b %0,%0\n"
    :"=r"(x):"0"(x));
    return x;
}

#define bswap_16(x) ByteSwap16(x)
#define bswap_32(x) ByteSwap32(x)

static inline uint64_t ByteSwap64(uint64_t x)
{
    union { 
        uint64_t ll;
        struct {
           uint32_t l,h;
        } l;
    } r;
    r.l.l = bswap_32 (x);
    r.l.h = bswap_32 (x>>32);
    return r.ll;
}
#define bswap_64(x) ByteSwap64(x)

#else

#define bswap_16(x) (((x) & 0x00ff) << 8 | ((x) & 0xff00) >> 8)

// code from bits/byteswap.h (C) 1997, 1998 Free Software Foundation, Inc.
#define bswap_32(x) \
     ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >>  8) | \
      (((x) & 0x0000ff00) <<  8) | (((x) & 0x000000ff) << 24))

static inline uint64_t ByteSwap64(uint64_t x)
{
    union { 
        uint64_t ll;
        uint32_t l[2]; 
    } w, r;
    w.ll = x;
    r.l[0] = bswap_32 (w.l[1]);
    r.l[1] = bswap_32 (w.l[0]);
    return r.ll;
}
#define bswap_64(x) ByteSwap64(x)

#endif  /* !ARCH_X86 */

#endif  /* !HAVE_BYTESWAP_H */

// be2me ... BigEndian to MachineEndian
// le2me ... LittleEndian to MachineEndian

#ifdef WORDS_BIGENDIAN
#define be2me_16(x) (x)
#define be2me_32(x) (x)
#define be2me_64(x) (x)
#define le2me_16(x) bswap_16(x)
#define le2me_32(x) bswap_32(x)
#define le2me_64(x) bswap_64(x)
#else
#define be2me_16(x) bswap_16(x)
#define be2me_32(x) bswap_32(x)
#define be2me_64(x) bswap_64(x)
#define le2me_16(x) (x)
#define le2me_32(x) (x)
#define le2me_64(x) (x)
#endif

#endif /* __BSWAP_H__ */