| /* |
| Copyright (c) 2013 mingw-w64 project |
| Copyright (c) 2015 Intel Corporation |
| |
| Permission is hereby granted, free of charge, to any person obtaining a |
| copy of this software and associated documentation files (the "Software"), |
| to deal in the Software without restriction, including without limitation |
| the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| and/or sell copies of the Software, and to permit persons to whom the |
| Software is furnished to do so, subject to the following conditions: |
| |
| The above copyright notice and this permission notice shall be included in |
| all copies or substantial portions of the Software. |
| |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
| DEALINGS IN THE SOFTWARE. |
| */ |
| |
| #include "pthread.h" |
| |
| #define likely(cond) __builtin_expect((cond) != 0, 1) |
| #define unlikely(cond) __builtin_expect((cond) != 0, 0) |
| |
| /* We use the pthread_spinlock_t itself as a lock: |
| -1 is free, 0 is locked. |
| (This is dictated by PTHREAD_SPINLOCK_INITIALIZER, which we can't change |
| without breaking binary compatibility.) */ |
| typedef intptr_t spinlock_word_t; |
| |
| int |
| pthread_spin_init (pthread_spinlock_t *lock, int pshared) |
| { |
| spinlock_word_t *lk = (spinlock_word_t *)lock; |
| *lk = -1; |
| return 0; |
| } |
| |
| |
| int |
| pthread_spin_destroy (pthread_spinlock_t *lock) |
| { |
| return 0; |
| } |
| |
| int |
| pthread_spin_lock (pthread_spinlock_t *lock) |
| { |
| volatile spinlock_word_t *lk = (volatile spinlock_word_t *)lock; |
| while (unlikely(__sync_lock_test_and_set(lk, 0) == 0)) |
| do { |
| asm("pause" ::: "memory"); |
| } while (*lk == 0); |
| return 0; |
| } |
| |
| int |
| pthread_spin_trylock (pthread_spinlock_t *lock) |
| { |
| spinlock_word_t *lk = (spinlock_word_t *)lock; |
| return __sync_lock_test_and_set(lk, 0) == 0 ? EBUSY : 0; |
| } |
| |
| |
| int |
| pthread_spin_unlock (pthread_spinlock_t *lock) |
| { |
| volatile spinlock_word_t *lk = (volatile spinlock_word_t *)lock; |
| *lk = -1; |
| return 0; |
| } |