2003-03-22 Roland McGrath <roland@redhat.com>
authorroland <roland>
Sat, 22 Mar 2003 23:00:22 +0000 (23:00 +0000)
committerroland <roland>
Sat, 22 Mar 2003 23:00:22 +0000 (23:00 +0000)
* include/atomic.h (atomic_increment_and_test): Invert sense of test.
Add comment.
(atomic_decrement_and_test): Add comment.
2003-03-22  Jakub Jelinek  <jakub@redhat.com>

* include/atomic.h (atomic_compare_and_exchange_val_acq): Add comment.
Don't define if __arch_compare_and_exchange_val_32_acq is not defined.
(atomic_compare_and_exchange_bool_acq): Add comment.  Don't use
__oldval variable in the macro, since it might be macro argument.
(atomic_decrement_if_positive): Initialize __memp, remove setting
of non-existent variable.
(atomic_bit_test_set): Cast 1 to __typeof (*mem) before shifting.
* sysdeps/ia64/bits/atomic.h (atomic_exchange_and_add): Implement
using atomic_compare_and_exchange_val_acq.
(atomic_decrement_if_positive, atomic_bit_test_set): Define.
* sysdeps/s390/bits/atomic.h (__arch_compare_and_exchange_val_8_acq):
Renamed from...
(__arch_compare_and_exchange_bool_8_acq): ... this.
(__arch_compare_and_exchange_val_16_acq): Renamed from...
(__arch_compare_and_exchange_bool_16_acq): ... this.
(__arch_compare_and_exchange_val_32_acq): Return old value.  Renamed
from...
(__arch_compare_and_exchange_bool_32_acq): ... this.
(__arch_compare_and_exchange_val_64_acq): Return old value.  Renamed
from...
(__arch_compare_and_exchange_bool_64_acq): ... this.
(__arch_compare_and_exchange_val_32_acq): Use __typeof for local
variables types instead of assuming int.
Change prefix of local variables to __arch.
* sysdeps/generic/bits/atomic.h (arch_compare_and_exchange_acq):
Remove.
(atomic_compare_and_exchange_val_acq,
atomic_compare_and_exchange_bool_acq): Define.

include/atomic.h

index 017a845..9469866 100644 (file)
@@ -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.
 
 #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) \
      __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
 #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
 
 
 #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)
 #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;                                                  \
 # 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);                                                 \