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[i386] Fix building on older versions of gcc 

Fix a strict-aliasing error on certain versions of gcc.

Reported-by: Marko Myllynen <myllynen@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown 2012-03-04 21:09:40 +00:00
parent 76f5939736
commit e187de7239
1 changed files with 7 additions and 3 deletions
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10
src/arch/i386/include/bits/byteswap.h
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@ -52,7 +52,10 @@ __bswap_variable_64 ( uint64_t x ) {
static inline __attribute__ (( always_inline )) void
__bswap_64s ( uint64_t *x ) {
uint32_t __attribute__ (( may_alias )) *dwords = ( ( void * ) x );
struct {
uint32_t low;
uint32_t high;
} __attribute__ (( may_alias )) *dwords = ( ( void * ) x );
uint32_t discard;
__asm__ ( "movl %0,%2\n\t"
@ -60,8 +63,9 @@ __bswap_64s ( uint64_t *x ) {
"xchgl %2,%1\n\t"
"bswapl %2\n\t"
"movl %2,%0\n\t"
: "=g" ( dwords[0] ), "=g" ( dwords[1] ), "=r" ( discard )
: "0" ( dwords[0] ), "1" ( dwords[1] ) );
: "=g" ( dwords->low ), "=g" ( dwords->high ),
"=r" ( discard )
: "0" ( dwords->low ), "1" ( dwords->high ) );
}
#endif /* _BITS_BYTESWAP_H */