diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/atomic.h | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/include/atomic.h b/include/atomic.h index 017a8455d7..9469866ebe 100644 --- a/include/atomic.h +++ b/include/atomic.h @@ -1,4 +1,5 @@ -/* Copyright (C) 2002, 2003 Free Software Foundation, Inc. +/* Internal macros for atomic operations for GNU C Library. + Copyright (C) 2002, 2003 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. @@ -25,7 +26,10 @@ #include <bits/atomic.h> -#ifndef atomic_compare_and_exchange_val_acq +/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL. + Return the old *MEM value. */ +#if !defined atomic_compare_and_exchange_val_acq \ + && defined __arch_compare_and_exchange_val_32_acq # define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \ ({ __typeof (*mem) __result; \ if (sizeof (*mem) == 1) \ @@ -48,6 +52,8 @@ #endif +/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL. + Return zero if *MEM was changed or non-zero if no exchange happened. */ #ifndef atomic_compare_and_exchange_bool_acq # ifdef __arch_compare_and_exchange_bool_32_acq # define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \ @@ -69,8 +75,10 @@ __result; }) # else # define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \ - ({ __typeof (oldval) __oldval = (oldval); \ - atomic_compare_and_exchange_val_acq (mem, newval, __oldval) != __oldval; \ + ({ /* Cannot use __oldval here, because macros later in this file might \ + call this macro with __oldval argument. */ \ + __typeof (oldval) __old = (oldval); \ + atomic_compare_and_exchange_val_acq (mem, newval, __old) != __old; \ }) # endif #endif @@ -129,9 +137,10 @@ #endif +/* Add one to *MEM and return true iff it's now nonzero. */ #ifndef atomic_increment_and_test # define atomic_increment_and_test(mem) \ - (atomic_exchange_and_add (mem, 1) == 0) + (atomic_exchange_and_add (mem, 1) != 0) #endif @@ -140,6 +149,7 @@ #endif +/* Subtract 1 from *MEM and return true iff it's now zero. */ #ifndef atomic_decrement_and_test # define atomic_decrement_and_test(mem) \ (atomic_exchange_and_add (mem, -1) == 0) @@ -150,9 +160,8 @@ #ifndef atomic_decrement_if_positive # define atomic_decrement_if_positive(mem) \ ({ __typeof (*mem) __oldval; \ - __typeof (mem) __memp; \ + __typeof (mem) __memp = (mem); \ \ - __val = *__memp; \ do \ { \ __oldval = *__memp; \ @@ -190,7 +199,7 @@ # define atomic_bit_test_set(mem, bit) \ ({ __typeof (*mem) __oldval; \ __typeof (mem) __memp = (mem); \ - __typeof (*mem) __mask = (1 << (bit)); \ + __typeof (*mem) __mask = ((__typeof (*mem)) 1 << (bit)); \ \ do \ __oldval = (*__memp); \ |