diff options
| -rw-r--r-- | include/atomic.h | 52 |
1 files changed, 47 insertions, 5 deletions
diff --git a/include/atomic.h b/include/atomic.h index 813fb80a03..517776452b 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 |