| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | /* POSIX spinlock implementation. SH version. |
| 2 | Copyright (C) 2000, 2001 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public License as |
| 7 | published by the Free Software Foundation; either version 2.1 of the |
| 8 | License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; see the file COPYING.LIB. If not, |
| 17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 18 | Boston, MA 02111-1307, USA. */ |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include <pthread.h> |
| 22 | #include "internals.h" |
| 23 | |
| 24 | int |
| 25 | __pthread_spin_lock (pthread_spinlock_t *lock) |
| 26 | { |
| 27 | unsigned int val; |
| 28 | |
| 29 | do |
| 30 | __asm__ __volatile__ ("tas.b @%1; movt %0" |
| 31 | : "=r" (val) |
| 32 | : "r" (lock) |
| 33 | : "memory"); |
| 34 | while (val == 0); |
| 35 | |
| 36 | return 0; |
| 37 | } |
| 38 | weak_alias (__pthread_spin_lock, pthread_spin_lock) |
| 39 | |
| 40 | |
| 41 | int |
| 42 | __pthread_spin_trylock (pthread_spinlock_t *lock) |
| 43 | { |
| 44 | unsigned int val; |
| 45 | |
| 46 | __asm__ __volatile__ ("tas.b @%1; movt %0" |
| 47 | : "=r" (val) |
| 48 | : "r" (lock) |
| 49 | : "memory"); |
| 50 | return val ? 0 : EBUSY; |
| 51 | } |
| 52 | weak_alias (__pthread_spin_trylock, pthread_spin_trylock) |
| 53 | |
| 54 | |
| 55 | int |
| 56 | __pthread_spin_unlock (pthread_spinlock_t *lock) |
| 57 | { |
| 58 | return *lock = 0; |
| 59 | } |
| 60 | weak_alias (__pthread_spin_unlock, pthread_spin_unlock) |
| 61 | |
| 62 | |
| 63 | int |
| 64 | __pthread_spin_init (pthread_spinlock_t *lock, int pshared) |
| 65 | { |
| 66 | /* We can ignore the `pshared' parameter. Since we are busy-waiting |
| 67 | all processes which can access the memory location `lock' points |
| 68 | to can use the spinlock. */ |
| 69 | return *lock = 0; |
| 70 | } |
| 71 | weak_alias (__pthread_spin_init, pthread_spin_init) |
| 72 | |
| 73 | |
| 74 | int |
| 75 | __pthread_spin_destroy (pthread_spinlock_t *lock) |
| 76 | { |
| 77 | /* Nothing to do. */ |
| 78 | return 0; |
| 79 | } |
| 80 | weak_alias (__pthread_spin_destroy, pthread_spin_destroy) |