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#ifndef _BITS_BYTESWAP_H
#define _BITS_BYTESWAP_H
/** @file
*
* Byte-order swapping functions
*
*/
#include <stdint.h>
FILE_LICENCE ( GPL2_OR_LATER );
static inline __attribute__ (( always_inline, const )) uint16_t
__bswap_variable_16 ( uint16_t x ) {
__asm__ ( "xchgb %b0,%h0" : "=q" ( x ) : "0" ( x ) );
return x;
}
static inline __attribute__ (( always_inline )) void
__bswap_16s ( uint16_t *x ) {
__asm__ ( "rorw $8, %0" : "+m" ( *x ) );
}
static inline __attribute__ (( always_inline, const )) uint32_t
__bswap_variable_32 ( uint32_t x ) {
__asm__ ( "bswapl %0" : "=r" ( x ) : "0" ( x ) );
return x;
}
static inline __attribute__ (( always_inline )) void
__bswap_32s ( uint32_t *x ) {
__asm__ ( "bswapl %0" : "=r" ( *x ) : "0" ( *x ) );
}
static inline __attribute__ (( always_inline, const )) uint64_t
__bswap_variable_64 ( uint64_t x ) {
uint32_t in_high = ( x >> 32 );
uint32_t in_low = ( x & 0xffffffffUL );
uint32_t out_high;
uint32_t out_low;
__asm__ ( "bswapl %0\n\t"
"bswapl %1\n\t"
"xchgl %0,%1\n\t"
: "=r" ( out_high ), "=r" ( out_low )
: "0" ( in_high ), "1" ( in_low ) );
return ( ( ( ( uint64_t ) out_high ) << 32 ) |
( ( uint64_t ) out_low ) );
}
static inline __attribute__ (( always_inline )) void
__bswap_64s ( uint64_t *x ) {
struct {
uint32_t __attribute__ (( may_alias )) low;
uint32_t __attribute__ (( may_alias )) high;
} __attribute__ (( may_alias )) *dwords = ( ( void * ) x );
uint32_t discard;
__asm__ ( "movl %0,%2\n\t"
"bswapl %2\n\t"
"xchgl %2,%1\n\t"
"bswapl %2\n\t"
"movl %2,%0\n\t"
: "+m" ( dwords->low ), "+m" ( dwords->high ),
"=r" ( discard ) );
}
#endif /* _BITS_BYTESWAP_H */
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