Implement atomic operations for x86/x64.

Add inline assembly implementations of atomic_{add,sub}_uint{32,64}()
for x86/x64, in order to support compilers that are missing the relevant
gcc intrinsics.
This commit is contained in:
Jason Evans 2011-03-24 16:48:11 -07:00
parent 9f949f9d82
commit 3e292475ee

View File

@ -40,6 +40,7 @@ uint32_t atomic_sub_uint32(uint32_t *p, uint32_t x);
#endif
#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_ATOMIC_C_))
/******************************************************************************/
/* 64-bit operations. */
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
JEMALLOC_INLINE uint64_t
@ -69,12 +70,40 @@ atomic_sub_uint64(uint64_t *p, uint64_t x)
return (OSAtomicAdd64(-((int64_t)x), (int64_t *)p));
}
#elif (defined(__amd64_) || defined(__x86_64__))
JEMALLOC_INLINE uint64_t
atomic_add_uint64(uint64_t *p, uint64_t x)
{
asm volatile (
"lock; xaddq %0, %1;"
: "+r" (x), "=m" (*p) /* Outputs. */
: "m" (*p) /* Inputs. */
);
return (x);
}
JEMALLOC_INLINE uint64_t
atomic_sub_uint64(uint64_t *p, uint64_t x)
{
x = (uint64_t)(-(int64_t)x);
asm volatile (
"lock; xaddq %0, %1;"
: "+r" (x), "=m" (*p) /* Outputs. */
: "m" (*p) /* Inputs. */
);
return (x);
}
#else
# if (LG_SIZEOF_PTR == 3)
# error "Missing implementation for 64-bit atomic operations"
# endif
#endif
/******************************************************************************/
/* 32-bit operations. */
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
JEMALLOC_INLINE uint32_t
@ -104,6 +133,33 @@ atomic_sub_uint32(uint32_t *p, uint32_t x)
return (OSAtomicAdd32(-((int32_t)x), (int32_t *)p));
}
#elif (defined(__i386__) || defined(__amd64_) || defined(__x86_64__))
JEMALLOC_INLINE uint32_t
atomic_add_uint32(uint32_t *p, uint32_t x)
{
asm volatile (
"lock; xaddl %0, %1;"
: "+r" (x), "=m" (*p) /* Outputs. */
: "m" (*p) /* Inputs. */
);
return (x);
}
JEMALLOC_INLINE uint32_t
atomic_sub_uint32(uint32_t *p, uint32_t x)
{
x = (uint32_t)(-(int32_t)x);
asm volatile (
"lock; xaddl %0, %1;"
: "+r" (x), "=m" (*p) /* Outputs. */
: "m" (*p) /* Inputs. */
);
return (x);
}
#else
# error "Missing implementation for 32-bit atomic operations"
#endif