ObjFW  Check-in [96a128f954]

Overview
Comment:atomic.h: Improve memory barrier

Replace of_memory_read_barrier() and of_memory_write_barrier() - which
are quite unspecific - with of_memory_enter_barrier() and
of_memory_leave_barrier().

Also add an assembly implementation for ARM and ARM64.

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SHA3-256: 96a128f95416d10874cdc3525cf46411862ed745f529a8a291e97f00d9698e46
User & Date: js on 2016-07-30 21:18:37
Other Links: manifest | tags
Context
2016-07-30
21:22
of_spinlock_(un)lock: Add memory barrier check-in: 8e7c6ddf8c user: js tags: trunk
21:18
atomic.h: Improve memory barrier check-in: 96a128f954 user: js tags: trunk
17:09
runtime/exception.m: Small fix for SjLj and SEH check-in: 3c71107e06 user: js tags: trunk
Changes
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Modified src/atomic.h from [17afd94567] to [c6a5af4a20].

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#endif
}

static OF_INLINE void
of_memory_barrier(void)
{
#if !defined(OF_HAVE_THREADS)
	/* nop */
#elif defined(OF_X86_64_ASM) || defined(OF_X86_ASM)
	__asm__ __volatile__ (
	    "mfence"
	    "mfence" ::: "memory"
	);
#elif defined(OF_POWERPC_ASM)
	__asm__ __volatile__ (
	    "sync"
	    "sync" ::: "memory"
	);
#elif defined(OF_ARMV7_ASM) || defined(OF_ARM64_ASM)
	__asm__ __volatile__ (
	    "dmb" ::: "memory"
	);
#elif defined(OF_HAVE_GCC_ATOMIC_OPS)
	__sync_synchronize();
#elif defined(OF_HAVE_OSATOMIC)
	OSMemoryBarrier();
#else
# error of_memory_barrier not implemented!
#endif
}

static OF_INLINE void
of_memory_read_barrier(void)
of_memory_enter_barrier(void)
{
#if !defined(OF_HAVE_THREADS)
#elif defined(OF_X86_64_ASM) || defined(OF_X86_ASM)
	__asm__ __volatile__ (
	    "lfence"
	);
#else
	of_memory_barrier();
#endif
}

static OF_INLINE void
of_memory_write_barrier(void)
of_memory_leave_barrier(void)
{
#if !defined(OF_HAVE_THREADS)
#elif defined(OF_X86_64_ASM) || defined(OF_X86_ASM)
	__asm__ __volatile__ (
	    "sfence"
	);
#else
	of_memory_barrier();
#endif
}

OF_ASSUME_NONNULL_END