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authorUlrich Drepper <drepper@redhat.com>2003-03-20 10:11:43 +0000
committerUlrich Drepper <drepper@redhat.com>2003-03-20 10:11:43 +0000
commit5132931e18d50a1caf7399aa46dafd0142a7c7ae (patch)
treebaaf5dcc710962d18de5bc51b0695948f560e5c7 /include/atomic.h
parent100a7100a77029d3e56174c4a9124779c40a5d72 (diff)
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Define atomic_exchange and atomic_decrement_if_positive if not already defined. Add some __builtin_expect.
Diffstat (limited to 'include/atomic.h')
-rw-r--r--include/atomic.h52
1 files changed, 47 insertions, 5 deletions
diff --git a/include/atomic.h b/include/atomic.h
index 813fb80..5177764 100644
--- a/include/atomic.h
+++ b/include/atomic.h
@@ -49,6 +49,24 @@
#endif
+/* Store NEWVALUE in *MEM and return the old value. */
+#ifndef atomic_exchange
+# define atomic_exchange(mem, newvalue) \
+ ({ __typeof (*mem) __oldval; \
+ __typeof (mem) __memp = (mem); \
+ __typeof (*mem) __value = (newvalue); \
+ \
+ do \
+ __oldval = (*__memp); \
+ while (__builtin_expect (atomic_compare_and_exchange_acq (__memp, \
+ __value, \
+ __oldval), 0));\
+ \
+ __oldval; })
+#endif
+
+
+/* Add VALUE to *MEM and return the old value of *MEM. */
#ifndef atomic_exchange_and_add
# define atomic_exchange_and_add(mem, value) \
({ __typeof (*mem) __oldval; \
@@ -57,10 +75,12 @@
\
do \
__oldval = (*__memp); \
- while (atomic_compare_and_exchange_acq (__memp, __oldval + __value, \
- __oldval)); \
+ while (__builtin_expect (atomic_compare_and_exchange_acq (__memp, \
+ __oldval \
+ + __value, \
+ __oldval), 0));\
\
- __oldval + __value; })
+ __oldval; })
#endif
@@ -91,6 +111,26 @@
#endif
+/* Decrement *MEM if it is > 0, and return the old value. */
+#ifndef atomic_decrement_if_positive(mem) \
+ ({ __typeof (*mem) __val; \
+ __typeof (*mem) __oldval; \
+ __typeof (mem) __memp; \
+ \
+ __val = *__memp; \
+ do \
+ { \
+ if (__builtin_expect (__val <= 0, 0)) \
+ break; \
+ __oldval = __val; \
+ __val = atomic_compare_and_exchange_acq (__memp, __oldval - 1, \
+ __oldval); \
+ } \
+ while (__builtin_expect (__val != __oldval, 0)); \
+ __val; })
+#endif
+
+
#ifndef atomic_add_negative
# define atomic_add_negative(mem, value) \
(atomic_exchange_and_add (mem, value) < 0)
@@ -117,8 +157,10 @@
\
do \
__oldval = (*__memp); \
- while (atomic_compare_and_exchange_acq (__memp, \
- __oldval | __mask, __oldval)); \
+ while (__builtin_expect (atomic_compare_and_exchange_acq (__memp, \
+ __oldval \
+ | __mask, \
+ __oldval), 0));\
\
__oldval & __mask; })
#endif