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FFmpeg/libavutil/bswap.h

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/**
* @file bswap.h
* byte swap.
*/
#ifndef __BSWAP_H__
#define __BSWAP_H__
#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#else
#ifdef ARCH_X86_64
# define LEGACY_REGS "=Q"
#else
# define LEGACY_REGS "=q"
#endif
#if defined(ARCH_X86) || defined(ARCH_X86_64)
static always_inline uint16_t bswap_16(uint16_t x)
{
__asm("rorw $8, %0" :
LEGACY_REGS (x) :
"0" (x));
return x;
}
static always_inline uint32_t bswap_32(uint32_t x)
{
#if __CPU__ > 386
__asm("bswap %0":
"=r" (x) :
#else
__asm("xchgb %b0,%h0\n"
" rorl $16,%0\n"
" xchgb %b0,%h0":
LEGACY_REGS (x) :
#endif
"0" (x));
return x;
}
static inline uint64_t bswap_64(uint64_t x)
{
#ifdef ARCH_X86_64
__asm("bswap %0":
"=r" (x) :
"0" (x));
return x;
#else
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;
#endif
}
#elif defined(ARCH_SH4)
static always_inline uint16_t bswap_16(uint16_t x) {
__asm__("swap.b %0,%0":"=r"(x):"0"(x));
return x;
}
static always_inline uint32_t bswap_32(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;
}
static inline uint64_t bswap_64(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;
}
#else
static always_inline uint16_t bswap_16(uint16_t x){
return (x>>8) | (x<<8);
}
#ifdef ARCH_ARM
static always_inline uint32_t bswap_32(uint32_t x){
uint32_t t;
__asm__ (
"eor %1, %0, %0, ror #16 \n\t"
"bic %1, %1, #0xFF0000 \n\t"
"mov %0, %0, ror #8 \n\t"
"eor %0, %0, %1, lsr #8 \n\t"
: "+r"(x), "+r"(t));
return x;
}
#else
static always_inline uint32_t bswap_32(uint32_t x){
x= ((x<<8)&0xFF00FF00) | ((x>>8)&0x00FF00FF);
return (x>>16) | (x<<16);
}
#endif
static inline uint64_t bswap_64(uint64_t x)
{
#if 0
x= ((x<< 8)&0xFF00FF00FF00FF00ULL) | ((x>> 8)&0x00FF00FF00FF00FFULL);
x= ((x<<16)&0xFFFF0000FFFF0000ULL) | ((x>>16)&0x0000FFFF0000FFFFULL);
return (x>>32) | (x<<32);
#else
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;
#endif
}
#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__ */