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-rw-r--r--libc/sysdeps/linux/common/bits/atomic.h43
1 files changed, 43 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/common/bits/atomic.h b/libc/sysdeps/linux/common/bits/atomic.h
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+++ b/libc/sysdeps/linux/common/bits/atomic.h
@@ -0,0 +1,43 @@
+/* Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _BITS_ATOMIC_H
+#define _BITS_ATOMIC_H 1
+
+/* We have by default no support for atomic operations. So define
+ them non-atomic. If this is a problem somebody will have to come
+ up with real definitions. */
+
+/* The only basic operation needed is compare and exchange. */
+#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
+ ({ __typeof (mem) __gmemp = (mem); \
+ __typeof (*mem) __gret = *__gmemp; \
+ __typeof (*mem) __gnewval = (newval); \
+ \
+ if (__gret == (oldval)) \
+ *__gmemp = __gnewval; \
+ __gret; })
+
+#define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
+ ({ __typeof (mem) __gmemp = (mem); \
+ __typeof (*mem) __gnewval = (newval); \
+ \
+ *__gmemp == (oldval) ? (*__gmemp = __gnewval, 0) : 1; })
+
+#endif /* bits/atomic.h */