diff options
Diffstat (limited to 'libraries/ghc-prim/cbits/atomic.c')
| -rw-r--r-- | libraries/ghc-prim/cbits/atomic.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/libraries/ghc-prim/cbits/atomic.c b/libraries/ghc-prim/cbits/atomic.c index b091d22b58..2ded465fcd 100644 --- a/libraries/ghc-prim/cbits/atomic.c +++ b/libraries/ghc-prim/cbits/atomic.c @@ -264,33 +264,53 @@ hs_cmpxchg64(StgWord x, StgWord64 old, StgWord64 new) // __ATOMIC_SEQ_CST: Full barrier in both directions (hoisting and sinking // of code) and synchronizes with acquire loads and release stores in // all threads. +// +// When we lack C11 atomics support we emulate these using the old GCC __sync +// primitives which the GCC documentation claims "usually" implies a full +// barrier. extern StgWord hs_atomicread8(StgWord x); StgWord hs_atomicread8(StgWord x) { +#if HAVE_C11_ATOMICS return __atomic_load_n((StgWord8 *) x, __ATOMIC_SEQ_CST); +#else + return __sync_add_and_fetch((StgWord8 *) x, 0); +#endif } extern StgWord hs_atomicread16(StgWord x); StgWord hs_atomicread16(StgWord x) { +#if HAVE_C11_ATOMICS return __atomic_load_n((StgWord16 *) x, __ATOMIC_SEQ_CST); +#else + return __sync_add_and_fetch((StgWord16 *) x, 0); +#endif } extern StgWord hs_atomicread32(StgWord x); StgWord hs_atomicread32(StgWord x) { +#if HAVE_C11_ATOMICS return __atomic_load_n((StgWord32 *) x, __ATOMIC_SEQ_CST); +#else + return __sync_add_and_fetch((StgWord32 *) x, 0); +#endif } extern StgWord64 hs_atomicread64(StgWord x); StgWord64 hs_atomicread64(StgWord x) { +#if HAVE_C11_ATOMICS return __atomic_load_n((StgWord64 *) x, __ATOMIC_SEQ_CST); +#else + return __sync_add_and_fetch((StgWord64 *) x, 0); +#endif } // AtomicWriteByteArrayOp_Int @@ -301,26 +321,42 @@ extern void hs_atomicwrite8(StgWord x, StgWord val); void hs_atomicwrite8(StgWord x, StgWord val) { +#if HAVE_C11_ATOMICS __atomic_store_n((StgWord8 *) x, (StgWord8) val, __ATOMIC_SEQ_CST); +#else + while (!__sync_bool_compare_and_swap((StgWord8 *) x, *(StgWord8 *) x, (StgWord8) val)); +#endif } extern void hs_atomicwrite16(StgWord x, StgWord val); void hs_atomicwrite16(StgWord x, StgWord val) { +#if HAVE_C11_ATOMICS __atomic_store_n((StgWord16 *) x, (StgWord16) val, __ATOMIC_SEQ_CST); +#else + while (!__sync_bool_compare_and_swap((StgWord16 *) x, *(StgWord16 *) x, (StgWord16) val)); +#endif } extern void hs_atomicwrite32(StgWord x, StgWord val); void hs_atomicwrite32(StgWord x, StgWord val) { +#if HAVE_C11_ATOMICS __atomic_store_n((StgWord32 *) x, (StgWord32) val, __ATOMIC_SEQ_CST); +#else + while (!__sync_bool_compare_and_swap((StgWord32 *) x, *(StgWord32 *) x, (StgWord32) val)); +#endif } extern void hs_atomicwrite64(StgWord x, StgWord64 val); void hs_atomicwrite64(StgWord x, StgWord64 val) { +#if HAVE_C11_ATOMICS __atomic_store_n((StgWord64 *) x, (StgWord64) val, __ATOMIC_SEQ_CST); +#else + while (!__sync_bool_compare_and_swap((StgWord64 *) x, *(StgWord64 *) x, (StgWord64) val)); +#endif } |