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/* 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.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include <shlib-compat.h>
#include <lowlevelcond.h>
#include <kernel-features.h>
#ifdef UP
# define LOCK
#else
# define LOCK lock
#endif
#define SYS_futex 240
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
#define FUTEX_REQUEUE 3
#define EINVAL 22
.text
/* int pthread_cond_signal (pthread_cond_t *cond) */
.globl __pthread_cond_signal
.type __pthread_cond_signal, @function
.align 16
__pthread_cond_signal:
pushl %ebx
pushl %esi
pushl %edi
movl 16(%esp), %edi
/* Get internal lock. */
movl $1, %eax
LOCK
#if cond_lock == 0
xaddl %eax, (%edi)
#else
xaddl %eax, cond_lock(%edi)
#endif
testl %eax, %eax
jne 1f
2: leal wakeup_seq(%edi), %ebx
movl total_seq+4(%edi), %eax
movl total_seq(%edi), %ecx
cmpl 4(%ebx), %eax
ja 3f
jb 4f
cmpl (%ebx), %ecx
jbe 4f
/* Bump the wakeup number. */
3: addl $1, (%ebx)
adcl $0, 4(%ebx)
/* Wake up one thread by moving it to the internal lock futex. */
movl $FUTEX_REQUEUE, %ecx
movl $SYS_futex, %eax
xorl %edx, %edx
movl $1, %esi
ENTER_KERNEL
#ifndef __ASSUME_FUTEX_REQUEUE
cmpl $-EINVAL, %eax
je 7f
#endif
/* If we moved a thread we in any case have to make the syscall. */
testl %eax, %eax
jne 5f
/* Unlock. */
4: LOCK
subl $1, (%edi)
jne 5f
6: xorl %eax, %eax
popl %edi
popl %esi
popl %ebx
ret
/* Initial locking failed. */
1:
#if cond_lock == 0
movl %ebx, %ecx
#else
leal cond_lock(%ebx), %ecx
#endif
call __lll_mutex_lock_wait
jmp 2b
/* Unlock in loop requires wakeup. */
5:
#if cond_lock == 0
movl %edi, %eax
#else
leal cond_lock(%edi), %eax
#endif
call __lll_mutex_unlock_wake
jmp 6b
#ifndef __ASSUME_FUTEX_REQUEUE
7: /* The futex requeue functionality is not available. */
movl $1, %edx
movl $FUTEX_WAKE, %ecx
movl $SYS_futex, %eax
ENTER_KERNEL
jmp 4b
#endif
.size __pthread_cond_signal, .-__pthread_cond_signal
versioned_symbol (libpthread, __pthread_cond_signal, pthread_cond_signal,
GLIBC_2_3_2)
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