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author | Ulrich Drepper <drepper@redhat.com> | 2000-05-25 06:15:25 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 2000-05-25 06:15:25 +0000 |
commit | 0f5504179a2e37a20e409c48dcc8d640393cd16d (patch) | |
tree | 5e61a218eacec17393a6688dab8bb0e59943592b /linuxthreads/sysdeps/alpha | |
parent | db33f7d4aef7422140d5e19c440bb5e084fbe186 (diff) | |
download | glibc-0f5504179a2e37a20e409c48dcc8d640393cd16d.tar.gz glibc-0f5504179a2e37a20e409c48dcc8d640393cd16d.tar.xz glibc-0f5504179a2e37a20e409c48dcc8d640393cd16d.zip |
Update.
2000-05-23 Jakub Jelinek <jakub@redhat.com> * sysdeps/i386/fpu/bits/mathinline.h (__sincos, __sincosf, __sincosl): Guard with __USE_GNU.
Diffstat (limited to 'linuxthreads/sysdeps/alpha')
-rw-r--r-- | linuxthreads/sysdeps/alpha/pspinlock.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/linuxthreads/sysdeps/alpha/pspinlock.c b/linuxthreads/sysdeps/alpha/pspinlock.c new file mode 100644 index 0000000000..0d871b4174 --- /dev/null +++ b/linuxthreads/sysdeps/alpha/pspinlock.c @@ -0,0 +1,109 @@ +/* POSIX spinlock implementation. Alpha version. + Copyright (C) 2000 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <errno.h> +#include <pthread.h> + + +/* This implementation is similar to the one used in the Linux kernel. + But the kernel is byte instructions for the memory access. This is + faster but unusable here. The problem is that only 128 + threads/processes could use the spinlock at the same time. If (by + a design error in the program) a thread/process would hold the + spinlock for a time long enough to accumulate 128 waiting + processes, the next one will find a positive value in the spinlock + and assume it is unlocked. We cannot accept that. */ + +int +__pthread_spin_lock (pthread_spinlock_t *lock) +{ + unsigned int tmp; + asm volatile + ("1: ldl_l %0,%1\n" + " blbs %0,2f\n" + " or %0,1,%0\n" + " stl_c %0,%1\n" + " beq %0,2f\n" + " mb\n" + ".subsection 2\n" + "2: ldl %0,%1\n" + " blbs %0,2b\n" + " br 1b\n" + ".previous" + : "=r" (tmp), "=m" (lock) + : "m" (lock)); + return 0; +} +weak_alias (__pthread_spin_lock, pthread_spin_lock) + + +int +__pthread_spin_trylock (pthread_spinlock_t *lock) +{ + unsigned long int oldval; + unsigned long int temp; + + asm volatile + ("1: ldl_l %0,%1\n" + " and %0,%3,%2\n" + " bne %2,2f\n" + " xor %0,%3,%0\n" + " stl_c %0,%1\n" + " beq %0,3f\n" + " mb\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : "=&r" (temp), "=m" (*lock), "=&r" (oldval) + : "Ir" (1UL), "m" (*lock)); + + return oldval == 0 ? 0 : EBUSY; +} +weak_alias (__pthread_spin_trylock, pthread_spin_trylock) + + +int +__pthread_spin_unlock (pthread_spinlock_t *lock) +{ + asm volatile ("mb"); + return *lock = 0; +} +weak_alias (__pthread_spin_unlock, pthread_spin_unlock) + + +int +__pthread_spin_init (pthread_spinlock_t *lock, int pshared) +{ + /* We can ignore the `pshared' parameter. Since we are busy-waiting + all processes which can access the memory location `lock' points + to can use the spinlock. */ + *lock = 0; + return 0; +} +weak_alias (__pthread_spin_init, pthread_spin_init) + + +int +__pthread_spin_destroy (pthread_spinlock_t *lock) +{ + /* Nothing to do. */ + return 0; +} +weak_alias (__pthread_spin_destroy, pthread_spin_destroy) |