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/* Copyright (C) 2002, 2003, 2004, 2005 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_WAKE_OP 5
#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
#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
xorl %eax, %eax
LOCK
#if cond_lock == 0
cmpxchgl %esi, (%rdi)
#else
cmpxchgl %esi, cond_lock(%rdi)
#endif
jnz 1f
2: addq $cond_futex, %rdi
movq total_seq(%r8), %rcx
cmpq wakeup_seq(%r8), %rcx
jbe 4f
/* Bump the wakeup number. */
addq $1, wakeup_seq(%r8)
addl $1, (%rdi)
/* Wake up one thread. */
movl $FUTEX_WAKE_OP, %esi
movl $SYS_futex, %eax
movl $1, %edx
movl $1, %r10d
#if cond_lock != 0
addq $cond_lock, %r8
#endif
movl $FUTEX_OP_CLEAR_WAKE_IF_GT_ONE, %r9d
syscall
#if cond_lock != 0
subq $cond_lock, %r8
#endif
/* For any kind of error, we try again with WAKE.
The general test also covers running on old kernels. */
cmpq $-4095, %rax
jae 7f
xorl %eax, %eax
retq
7: movl $FUTEX_WAKE, %esi
movl $SYS_futex, %eax
/* %rdx should be 1 already from $FUTEX_WAKE_OP syscall.
movl $1, %edx */
syscall
/* 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:
movq %r8, %rdi
callq __lll_mutex_unlock_wake
jmp 6b
.size __pthread_cond_signal, .-__pthread_cond_signal
versioned_symbol (libpthread, __pthread_cond_signal, pthread_cond_signal,
GLIBC_2_3_2)
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