[thirdparty/glibc.git] / nptl / sysdeps / unix / sysv / linux / x86_64 / pthread_rwlock_rdlock.S

/* 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 <lowlevelrwlock.h>
#include <pthread-errnos.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_rdlock
	.type	__pthread_rwlock_rdlock,@function
	.align	16
__pthread_rwlock_rdlock:
	xorq	%r10, %r10

	/* 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:	movl	WRITER(%rdi), %eax
	testl	%eax, %eax
	jne	14f
	cmpl	$0, WRITERS_QUEUED(%rdi)
	je	5f
	cmpl	$0, FLAGS(%rdi)
	je	5f

3:	incl	READERS_QUEUED(%rdi)
	je	4f

	movl	READERS_WAKEUP(%rdi), %edx

	LOCK
#if MUTEX == 0
	decl	(%rdi)
#else
	decl	MUTEX(%rdi)
#endif
	jne	10f

11:	addq	$READERS_WAKEUP, %rdi
	movq	%r10, %rsi	/* movq $FUTEX_WAIT, %rsi */
	movq	$SYS_futex, %rax
	syscall

	subq	$READERS_WAKEUP, %rdi

	/* Reget the lock.  */
	movl	$1, %esi
	xorl	%eax, %eax
	LOCK
#if MUTEX == 0
	cmpxchgl %esi, (%rdi)
#else
	cmpxchgl %esi, MUTEX(%rdi)
#endif
	jnz	12f

13:	decl	READERS_QUEUED(%rdi)
	jmp	2b

5:	xorq	%rdx, %rdx
	incl	NR_READERS(%rdi)
	je	8f
9:	LOCK
#if MUTEX == 0
	decl	(%rdi)
#else
	decl	MUTEX(%rdi)
#endif
	jne	6f
7:

	movq	%rdx, %rax
	retq

1:
#if MUTEX != 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_mutex_lock_wait
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	2b

14:	cmpl	%fs:TID, %eax
	jne	3b
	/* Deadlock detected.  */
	movq	$EDEADLK, %rdx
	jmp	9b

6:
#if MUTEX != 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_mutex_unlock_wake
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	7b

	/* Overflow.  */
8:	decl	NR_READERS(%rdi)
	movq	$EAGAIN, %rdx
	jmp	9b

	/* Overflow.  */
4:	decl	READERS_QUEUED(%rdi)
	movq	$EAGAIN, %rdx
	jmp	9b

10:
#if MUTEX != 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_mutex_unlock_wake
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	11b

12:
#if MUTEX == 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_mutex_lock_wait
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	13b
	.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
Commit	Line	Data
a334319f	1	/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
da49194d UD	2	This file is part of the GNU C Library.
	3	Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
	16	License along with the GNU C Library; if not, write to the Free
	17	Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
	18	02111-1307 USA. */
	19
	20	#include <sysdep.h>
	21	#include <lowlevelrwlock.h>
326132db	22	#include <pthread-errnos.h>
da49194d UD	23
	24
	25	#define SYS_futex 202
	26	#define FUTEX_WAIT 0
	27	#define FUTEX_WAKE 1
	28
da49194d UD	29	#ifndef UP
	30	# define LOCK lock
	31	#else
	32	# define LOCK
	33	#endif
	34
	35
	36	.text
	37
	38	.globl __pthread_rwlock_rdlock
	39	.type __pthread_rwlock_rdlock,@function
	40	.align 16
	41	__pthread_rwlock_rdlock:
	42	xorq %r10, %r10
	43
	44	/* Get the lock. */
	45	movl $1, %esi
3a226d33	46	xorl %eax, %eax
da49194d UD	47	LOCK
da49194d UD	48	#if MUTEX == 0
3a226d33	49	cmpxchgl %esi, (%rdi)
da49194d	50	#else
3a226d33	51	cmpxchgl %esi, MUTEX(%rdi)
da49194d	52	#endif
3a226d33	53	jnz 1f
da49194d	54
4ad0bbf4 UD	55	2: movl WRITER(%rdi), %eax
4ad0bbf4 UD	56	testl %eax, %eax
da49194d UD	57	jne 14f
	58	cmpl $0, WRITERS_QUEUED(%rdi)
	59	je 5f
	60	cmpl $0, FLAGS(%rdi)
	61	je 5f
	62
	63	3: incl READERS_QUEUED(%rdi)
	64	je 4f
	65
	66	movl READERS_WAKEUP(%rdi), %edx
	67
	68	LOCK
	69	#if MUTEX == 0
46a32546	70	decl (%rdi)
da49194d	71	#else
46a32546	72	decl MUTEX(%rdi)
da49194d UD	73	#endif
	74	jne 10f
	75
46a32546	76	11: addq $READERS_WAKEUP, %rdi
a334319f UD	77	movq %r10, %rsi /* movq $FUTEX_WAIT, %rsi */
a334319f UD	78	movq $SYS_futex, %rax
da49194d UD	79	syscall
da49194d UD	80
46a32546	81	subq $READERS_WAKEUP, %rdi
da49194d UD	82
	83	/* Reget the lock. */
	84	movl $1, %esi
3a226d33	85	xorl %eax, %eax
da49194d UD	86	LOCK
da49194d UD	87	#if MUTEX == 0
3a226d33	88	cmpxchgl %esi, (%rdi)
da49194d	89	#else
3a226d33	90	cmpxchgl %esi, MUTEX(%rdi)
da49194d	91	#endif
3a226d33	92	jnz 12f
da49194d UD	93
	94	13: decl READERS_QUEUED(%rdi)
	95	jmp 2b
	96
a334319f	97	5: xorq %rdx, %rdx
da49194d UD	98	incl NR_READERS(%rdi)
	99	je 8f
	100	9: LOCK
	101	#if MUTEX == 0
	102	decl (%rdi)
	103	#else
	104	decl MUTEX(%rdi)
	105	#endif
	106	jne 6f
	107	7:
	108
92ed3daf	109	movq %rdx, %rax
da49194d UD	110	retq
	111
	112	1:
	113	#if MUTEX != 0
	114	addq $MUTEX, %rdi
	115	#endif
92ed3daf	116	callq __lll_mutex_lock_wait
da49194d UD	117	#if MUTEX != 0
	118	subq $MUTEX, %rdi
	119	#endif
	120	jmp 2b
	121
4ad0bbf4	122	14: cmpl %fs:TID, %eax
da49194d UD	123	jne 3b
da49194d UD	124	/* Deadlock detected. */
a334319f	125	movq $EDEADLK, %rdx
da49194d UD	126	jmp 9b
	127
	128	6:
	129	#if MUTEX != 0
	130	addq $MUTEX, %rdi
	131	#endif
92ed3daf	132	callq __lll_mutex_unlock_wake
da49194d UD	133	#if MUTEX != 0
	134	subq $MUTEX, %rdi
	135	#endif
	136	jmp 7b
	137
	138	/* Overflow. */
	139	8: decl NR_READERS(%rdi)
a334319f	140	movq $EAGAIN, %rdx
da49194d UD	141	jmp 9b
	142
	143	/* Overflow. */
	144	4: decl READERS_QUEUED(%rdi)
a334319f	145	movq $EAGAIN, %rdx
da49194d UD	146	jmp 9b
	147
	148	10:
	149	#if MUTEX != 0
	150	addq $MUTEX, %rdi
	151	#endif
92ed3daf	152	callq __lll_mutex_unlock_wake
da49194d UD	153	#if MUTEX != 0
	154	subq $MUTEX, %rdi
	155	#endif
	156	jmp 11b
	157
	158	12:
	159	#if MUTEX == 0
	160	addq $MUTEX, %rdi
	161	#endif
92ed3daf	162	callq __lll_mutex_lock_wait
da49194d UD	163	#if MUTEX != 0
	164	subq $MUTEX, %rdi
	165	#endif
	166	jmp 13b
	167	.size __pthread_rwlock_rdlock,.-__pthread_rwlock_rdlock
	168
	169	.globl pthread_rwlock_rdlock
	170	pthread_rwlock_rdlock = __pthread_rwlock_rdlock
	171
	172	.globl __pthread_rwlock_rdlock_internal
	173	__pthread_rwlock_rdlock_internal = __pthread_rwlock_rdlock