Atomic: Add support for atomic operations since gcc 4.4 (e4ff22ec) · Commits · 戴 / Bird

aclocal.m4

+24 −0

Original line number	Diff line number	Diff line
		@@ -20,6 +20,30 @@ AC_DEFUN([BIRD_CHECK_THREAD_LOCAL],
		)
		])

		AC_DEFUN([BIRD_CHECK_OLD_SYNC],
		[
		AC_CACHE_CHECK(
		[whether GCC old-style __sync_* calls are available],
		[bird_cv_old_sync],
		[
		AC_COMPILE_IFELSE([
		AC_LANG_PROGRAM([
		#include <stdint.h>
		], [
		uint64_t value = 0;
		__sync_fetch_and_add(&value, 64);
		__sync_fetch_and_sub(&value, 42);
		uint64_t old = __sync_val_compare_and_swap(&value, 22, 64);
		])
		],
		[bird_cv_old_sync=yes],
		[bird_cv_old_sync=no],
		)
		]
		)
		])


		AC_DEFUN([BIRD_CHECK_PTHREADS],
		[
		bird_tmp_cflags="$CFLAGS"

+11 −0

Original line number	Diff line number	Diff line
		@@ -120,6 +120,17 @@ if test "$bird_cv_thread_local" = yes ; then
		AC_DEFINE([HAVE_THREAD_LOCAL], [1], [Define to 1 if _Thread_local is available])
		fi

		AC_CHECK_HEADER([stdatomic.h],
		[AC_DEFINE([HAVE_ATOMIC], [1], [Define to 1 if stdatomic.h is present])],
		[
		BIRD_CHECK_OLD_SYNC
		if test "$bird_cv_old_sync" = no ; then
		AC_MSG_ERROR([No atomic operations available.])
		fi
		],
		[]
		)

		if test "$enable_pthreads" != no ; then
		BIRD_CHECK_PTHREADS

0 → 100644

+36 −0

Original line number	Diff line number	Diff line
		#ifndef _BIRD_ATOMIC_H_
		#define _BIRD_ATOMIC_H_

		#if HAVE_ATOMIC
		#include <stdatomic.h>
		#else

		#define _Atomic

		#define atomic_load(ptr) __sync_val_compare_and_swap(ptr, 0, 0)
		#define atomic_load_explicit(ptr, mem) atomic_load(ptr)
		#define atomic_store(ptr, val) __sync_lock_test_and_set(ptr, val)

		#define atomic_fetch_add(ptr, val) __sync_fetch_and_add((ptr), (val))
		#define atomic_fetch_add_explicit(ptr, val, memory) __sync_fetch_and_add((ptr), (val))
		#define atomic_fetch_sub(ptr, val) __sync_fetch_and_sub((ptr), (val))
		#define atomic_fetch_sub_explicit(ptr, val, memory) __sync_fetch_and_sub((ptr), (val))

		#define atomic_compare_exchange_weak(ptr, desired, wanted) ({ \
		typeof(desired) _desptr = desired; /* save the pointer */ \
		typeof(_desptr) _old = __sync_val_compare_and_swap(ptr, _desptr, wanted); /* do the exchange */ \
		int result = _old == _desptr; / get the return value */ \
		_desptr = _old; / store the old value */ \
		result; /* and return */ })

		#define atomic_compare_exchange_strong(ptr, desired, wanted) \
		atomic_compare_exchange_weak(ptr, desired, wanted)

		#define atomic_compare_exchange_weak_explicit(ptr, desired, wanted, success, failure) \
		atomic_compare_exchange_weak(ptr, desired, wanted)

		#define atomic_compare_exchange_strong_explicit(ptr, desired, wanted, success, failure) \
		atomic_compare_exchange_weak(ptr, desired, wanted)

		#endif
		#endif