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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 202
#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:
/* Get internal lock. */
movq %rdi, %r8
movl $1, %esi
LOCK
#if cond_lock == 0
xaddl %esi, (%rdi)
#else
xaddl %esi, cond_lock(%rdi)
#endif
testl %esi, %esi
jne 1f
2: addq $wakeup_seq, %rdi
movq total_seq(%r8), %rcx
cmpq (%rdi), %rcx
jbe 4f
/* Bump the wakeup number. */
addq $1, (%rdi)
/* Wake up one thread. */
movq $FUTEX_REQUEUE, %rsi
movq $SYS_futex, %rax
xorq %rdx, %rdx
movq $1, %r10
syscall
#ifndef __ASSUME_FUTEX_REQUEUE
cmpq $-EINVAL, %rax
je 7f
#endif
/* If we moved a thread we in any case have to make the syscall. */
testq %rax, %rax
jne 5f
/* Unlock. */
4: LOCK
#if cond_lock == 0
decl (%r8)
#else
decl cond_lock(%r8)
#endif
jne 5f
6: xorl %eax, %eax
retq
/* Initial locking failed. */
1:
#if cond_lock != 0
addq $cond_lock, %rdi
#endif
callq __lll_mutex_lock_wait
#if cond_lock != 0
subq $cond_lock, %rdi
#endif
jmp 2b
/* Unlock in loop requires wakeup. */
5:
#if cond_lock != 0
addq $cond_lock-wakeup_seq, %rdi
#else
movq %r8, %rdi
#endif
callq __lll_mutex_unlock_wake
jmp 6b
#ifndef __ASSUME_FUTEX_REQUEUE
7: /* The futex requeue functionality is not available. */
movq $1, %rdx
movq $FUTEX_WAKE, %rsi
movq $SYS_futex, %rax
syscall
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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