linux _InterlockedCompareExchange128的实现

#include <stdint.h>

namespace types
{
struct uint128_t
{
uint64_t lo ;
uint64_t hi ;
}
__attribute__ (( __aligned__ ( 16 ) ));
}

template < class T > inline bool cas ( volatile T * src , T cmp , T with );

template <> inline bool cas ( volatile types :: uint128_t * src , types :: uint128_t cmp , types :: uint128_t with )
{
bool result ;
__asm__ __volatile__
(
"lock cmpxchg16b  %1\n\t"
"setz %0"
: "=q" ( result )
, "+m" ( * src )
, "+d" ( cmp . hi )
, "+a" ( cmp . lo )
: "c" ( with . hi )
, "b" ( with . lo )
: "cc"
);
return result ;
}

int main ()
{
using namespace types ;
uint128_t test = { 0xdecafbad , 0xfeedbeef };
uint128_t cmp = test ;
uint128_t with = { 0x55555555 , 0xaaaaaaaa };
return ! cas ( & test , cmp , with );
}