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/* Copyright (C) 2002, 2003, 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 <lowlevelrwlock.h>
#define SYS_futex 202
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
#ifndef UP
# define LOCK lock
#else
# define LOCK
#endif
.text
.globl __pthread_rwlock_unlock
.type __pthread_rwlock_unlock,@function
.align 16
__pthread_rwlock_unlock:
/* Get the lock. */
movl $1, %esi
xorl %eax, %eax
LOCK
#if MUTEX == 0
cmpxchgl %esi, (%rdi)
#else
cmpxchgl %esi, MUTEX(%rdi)
#endif
jnz 1f
2: cmpl $0, WRITER(%rdi)
jne 5f
decl NR_READERS(%rdi)
jnz 6f
5: movl $0, WRITER(%rdi)
movl $1, %esi
leaq WRITERS_WAKEUP(%rdi), %r10
movq %rsi, %rdx
cmpl $0, WRITERS_QUEUED(%rdi)
jne 0f
/* If also no readers waiting nothing to do. */
cmpl $0, READERS_QUEUED(%rdi)
je 6f
movl $0x7fffffff, %edx
leaq READERS_WAKEUP(%rdi), %r10
0: incl (%r10)
LOCK
#if MUTEX == 0
decl (%rdi)
#else
decl MUTEX(%rdi)
#endif
jne 7f
8: movl $SYS_futex, %eax
movq %r10, %rdi
syscall
xorl %eax, %eax
retq
.align 16
6: LOCK
#if MUTEX == 0
decl (%rdi)
#else
decl MUTEX(%rdi)
#endif
jne 3f
4: xorl %eax, %eax
retq
1:
#if MUTEX != 0
addq $MUTEX, %rdi
#endif
callq __lll_mutex_lock_wait
#if MUTEX != 0
subq $MUTEX, %rdi
#endif
jmp 2b
3:
#if MUTEX != 0
addq $MUTEX, %rdi
#endif
callq __lll_mutex_unlock_wake
jmp 4b
7:
#if MUTEX != 0
addq $MUTEX, %rdi
#endif
callq __lll_mutex_unlock_wake
jmp 8b
.size __pthread_rwlock_unlock,.-__pthread_rwlock_unlock
.globl pthread_rwlock_unlock
pthread_rwlock_unlock = __pthread_rwlock_unlock
.globl __pthread_rwlock_unlock_internal
__pthread_rwlock_unlock_internal = __pthread_rwlock_unlock
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