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/* Copyright (C) 2003 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 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>
#include <tcb-offsets.h>
#include <pthread-errnos.h>
#include "lowlevel-atomic.h"
#define SYS_futex 240
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
.text
.globl __pthread_rwlock_rdlock
.type __pthread_rwlock_rdlock,@function
.align 5
__pthread_rwlock_rdlock:
mov.l r12, @-r15
mov.l r8, @-r15
sts.l pr, @-r15
mov r4, r8
/* Get the lock. */
mov #1, r3
#if MUTEX == 0
XADD (r3, @r4, r2)
#else
XADD (r3, @(MUTEX,r4), r2)
#endif
tst r2, r2
bf 1f
2:
mov.l @(WRITER,r8), r0
tst r0, r0
bf 14f
mov.l @(WRITERS_QUEUED,r8), r0
tst r0, r0
bt 5f
mov.l @(FLAGS,r8), r0
tst r0, r0
bt 5f
3:
mov.l @(READERS_QUEUED,r8), r0
add #1, r0
mov.l r0, @(READERS_QUEUED,r8)
tst r0, r0
bt 4f
#if MUTEX == 0
DEC (@r8, r2)
#else
DEC (@(MUTEX,r8), r2)
#endif
tst r2, r2
bf 10f
11:
mov r8, r4
add #READERS_WAKEUP, r4
mov #FUTEX_WAIT, r5
mov.l @(READERS_WAKEUP,r8), r6
mov #0, r7
mov #SYS_futex, r3
extu.b r3, r3
trapa #0x14
SYSCALL_INST_PAD
/* Reget the lock. */
mov #1, r3
#if MUTEX == 0
XADD (r3, @r4, r2)
#else
XADD (r3, @(MUTEX,r4), r2)
#endif
tst r2, r2
bf 12f
13:
mov.l @(READERS_QUEUED,r8), r0
add #-1, r0
bra 2b
mov.l r0, @(READERS_QUEUED,r8)
5:
mov #0, r3
mov.l @(NR_READERS,r8), r0
add #1, r0
mov.l r0, @(NR_READERS,r8)
tst r0, r0
bt 8f
9:
#if MUTEX == 0
DEC (@r8, r2)
#else
DEC (@(MUTEX,r8), r2)
#endif
tst r2, r2
bf 6f
7:
lds.l @r15+, pr
mov.l @r15+, r8
mov.l @r15+, r12
rts
mov r3, r0
1:
mov r8, r5
#if MUTEX != 0
add #MUTEX, r5
#endif
mov r2, r4
mov.l .Lwait0, r1
bsrf r1
nop
.Lwait0b:
bra 2b
nop
14:
stc gbr, r1
mov.w .Ltcboff,r2
sub r2,r1
cmp/eq r1, r0
bf 3b
/* Deadlock detected. */
bra 9b
mov #EDEADLK, r3
6:
mov r8, r4
#if MUTEX != 0
add #MUTEX, r4
#endif
mov.l .Lwake0, r1
bsrf r1
nop
.Lwake0b:
bra 7b
mov #0, r3
8:
/* Overflow. */
mov.l @(NR_READERS,r8), r1
add #-1, r1
mov.l r1, @(NR_READERS,r8)
bra 9b
mov #EAGAIN, r3
4:
/* Overflow. */
mov.l @(READERS_QUEUED,r8), r1
add #-1, r1
mov.l r1, @(READERS_QUEUED,r8)
bra 9b
mov #EAGAIN, r3
10:
mov r8, r4
#if MUTEX != 0
add #MUTEX, r4
#endif
mov.l .Lwake1, r1
bsrf r1
nop
.Lwake1b:
bra 11b
nop
12:
mov r8, r5
#if MUTEX != 0
add #MUTEX, r5
#endif
mov r2, r4
mov.l .Lwait1, r1
bsrf r1
nop
.Lwait1b:
bra 13b
nop
.Ltcboff:
.word TLS_PRE_TCB_SIZE
.align 2
.Lwait0:
.long __lll_mutex_lock_wait-.Lwait0b
.Lwake0:
.long __lll_mutex_unlock_wake-.Lwake0b
.Lwait1:
.long __lll_mutex_lock_wait-.Lwait1b
.Lwake1:
.long __lll_mutex_unlock_wake-.Lwake1b
.size __pthread_rwlock_rdlock,.-__pthread_rwlock_rdlock
.globl pthread_rwlock_rdlock
pthread_rwlock_rdlock = __pthread_rwlock_rdlock
.globl __pthread_rwlock_rdlock_internal
__pthread_rwlock_rdlock_internal = __pthread_rwlock_rdlock
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