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

/* Copyright (C) 2002-2015 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, see
   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>
#include <lowlevellock.h>
#include <lowlevelbarrier.h>


	.text

	.globl	pthread_barrier_wait
	.type	pthread_barrier_wait,@function
	.align	16
pthread_barrier_wait:
	/* Get the mutex.  */
	xorl	%eax, %eax
	movl	$1, %esi
	LOCK
	cmpxchgl %esi, MUTEX(%rdi)
	jnz	1f

	/* One less waiter.  If this was the last one needed wake
	   everybody.  */
2:	decl	LEFT(%rdi)
	je	3f

	/* There are more threads to come.  */
#if CURR_EVENT == 0
	movl	(%rdi), %edx
#else
	movl	CURR_EVENT(%rdi), %edx
#endif

	/* Release the mutex.  */
	LOCK
	decl	MUTEX(%rdi)
	jne	6f

	/* Wait for the remaining threads.  The call will return immediately
	   if the CURR_EVENT memory has meanwhile been changed.  */
7:
#if FUTEX_WAIT == 0
	movl	PRIVATE(%rdi), %esi
#else
	movl	$FUTEX_WAIT, %esi
	orl	PRIVATE(%rdi), %esi
#endif
	xorq	%r10, %r10
8:	movl	$SYS_futex, %eax
	syscall

	/* Don't return on spurious wakeups.  The syscall does not change
	   any register except %eax so there is no need to reload any of
	   them.  */
#if CURR_EVENT == 0
	cmpl	%edx, (%rdi)
#else
	cmpl	%edx, CURR_EVENT(%rdi)
#endif
	je	8b

	/* Increment LEFT.  If this brings the count back to the
	   initial count unlock the object.  */
	movl	$1, %edx
	movl	INIT_COUNT(%rdi), %eax
	LOCK
	xaddl	%edx, LEFT(%rdi)
	subl	$1, %eax
	cmpl	%eax, %edx
	jne,pt	10f

	/* Release the mutex.  We cannot release the lock before
	   waking the waiting threads since otherwise a new thread might
	   arrive and gets waken up, too.  */
	LOCK
	decl	MUTEX(%rdi)
	jne	9f

10:	xorl	%eax, %eax		/* != PTHREAD_BARRIER_SERIAL_THREAD */

	retq

	/* The necessary number of threads arrived.  */
3:
#if CURR_EVENT == 0
	incl	(%rdi)
#else
	incl	CURR_EVENT(%rdi)
#endif

	/* Wake up all waiters.  The count is a signed number in the kernel
	   so 0x7fffffff is the highest value.  */
	movl	$0x7fffffff, %edx
	movl	$FUTEX_WAKE, %esi
	orl	PRIVATE(%rdi), %esi
	movl	$SYS_futex, %eax
	syscall

	/* Increment LEFT.  If this brings the count back to the
	   initial count unlock the object.  */
	movl	$1, %edx
	movl	INIT_COUNT(%rdi), %eax
	LOCK
	xaddl	%edx, LEFT(%rdi)
	subl	$1, %eax
	cmpl	%eax, %edx
	jne,pt	5f

	/* Release the mutex.  We cannot release the lock before
	   waking the waiting threads since otherwise a new thread might
	   arrive and gets waken up, too.  */
	LOCK
	decl	MUTEX(%rdi)
	jne	4f

5:	orl	$-1, %eax		/* == PTHREAD_BARRIER_SERIAL_THREAD */

	retq

1:	movl	PRIVATE(%rdi), %esi
	addq	$MUTEX, %rdi
	xorl	$LLL_SHARED, %esi
	callq	__lll_lock_wait
	subq	$MUTEX, %rdi
	jmp	2b

4:	movl	PRIVATE(%rdi), %esi
	addq	$MUTEX, %rdi
	xorl	$LLL_SHARED, %esi
	callq	__lll_unlock_wake
	jmp	5b

6:	movl	PRIVATE(%rdi), %esi
	addq	$MUTEX, %rdi
	xorl	$LLL_SHARED, %esi
	callq	__lll_unlock_wake
	subq	$MUTEX, %rdi
	jmp	7b

9:	movl	PRIVATE(%rdi), %esi
	addq	$MUTEX, %rdi
	xorl	$LLL_SHARED, %esi
	callq	__lll_unlock_wake
	jmp	10b
	.size	pthread_barrier_wait,.-pthread_barrier_wait
Commit	Line	Data
b168057a	1	/* Copyright (C) 2002-2015 Free Software Foundation, Inc.
6a4263e3 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
59ba27a6 PE	16	License along with the GNU C Library; if not, see
59ba27a6 PE	17	<http://www.gnu.org/licenses/>. */
6a4263e3 UD	18
6a4263e3 UD	19	#include <sysdep.h>
e51deae7	20	#include <lowlevellock.h>
6a4263e3 UD	21	#include <lowlevelbarrier.h>
6a4263e3 UD	22
6a4263e3 UD	23
	24	.text
	25
	26	.globl pthread_barrier_wait
	27	.type pthread_barrier_wait,@function
	28	.align 16
	29	pthread_barrier_wait:
	30	/* Get the mutex. */
3a226d33 UD	31	xorl %eax, %eax
3a226d33 UD	32	movl $1, %esi
6a4263e3	33	LOCK
3a226d33 UD	34	cmpxchgl %esi, MUTEX(%rdi)
3a226d33 UD	35	jnz 1f
6a4263e3 UD	36
	37	/* One less waiter. If this was the last one needed wake
	38	everybody. */
	39	2: decl LEFT(%rdi)
	40	je 3f
	41
	42	/* There are more threads to come. */
	43	#if CURR_EVENT == 0
	44	movl (%rdi), %edx
	45	#else
	46	movl CURR_EVENT(%rdi), %edx
	47	#endif
	48
	49	/* Release the mutex. */
	50	LOCK
3a226d33 UD	51	decl MUTEX(%rdi)
3a226d33 UD	52	jne 6f
6a4263e3 UD	53
	54	/* Wait for the remaining threads. The call will return immediately
	55	if the CURR_EVENT memory has meanwhile been changed. */
ee618985 UD	56	7:
ee618985 UD	57	#if FUTEX_WAIT == 0
d8ff3792	58	movl PRIVATE(%rdi), %esi
ee618985 UD	59	#else
ee618985 UD	60	movl $FUTEX_WAIT, %esi
d8ff3792	61	orl PRIVATE(%rdi), %esi
ee618985	62	#endif
6a4263e3	63	xorq %r10, %r10
ee618985	64	8: movl $SYS_futex, %eax
6a4263e3 UD	65	syscall
	66
	67	/* Don't return on spurious wakeups. The syscall does not change
	68	any register except %eax so there is no need to reload any of
	69	them. */
	70	#if CURR_EVENT == 0
	71	cmpl %edx, (%rdi)
	72	#else
	73	cmpl %edx, CURR_EVENT(%rdi)
	74	#endif
	75	je 8b
	76
37c054c7 UD	77	/* Increment LEFT. If this brings the count back to the
	78	initial count unlock the object. */
	79	movl $1, %edx
	80	movl INIT_COUNT(%rdi), %eax
	81	LOCK
	82	xaddl %edx, LEFT(%rdi)
	83	subl $1, %eax
	84	cmpl %eax, %edx
	85	jne,pt 10f
	86
	87	/* Release the mutex. We cannot release the lock before
	88	waking the waiting threads since otherwise a new thread might
	89	arrive and gets waken up, too. */
	90	LOCK
	91	decl MUTEX(%rdi)
	92	jne 9f
	93
	94	10: xorl %eax, %eax /* != PTHREAD_BARRIER_SERIAL_THREAD */
6a4263e3 UD	95
	96	retq
	97
	98	/* The necessary number of threads arrived. */
37c054c7	99	3:
6a4263e3 UD	100	#if CURR_EVENT == 0
	101	incl (%rdi)
	102	#else
	103	incl CURR_EVENT(%rdi)
	104	#endif
	105
	106	/* Wake up all waiters. The count is a signed number in the kernel
	107	so 0x7fffffff is the highest value. */
	108	movl $0x7fffffff, %edx
ee618985	109	movl $FUTEX_WAKE, %esi
d8ff3792	110	orl PRIVATE(%rdi), %esi
ee618985	111	movl $SYS_futex, %eax
6a4263e3 UD	112	syscall
6a4263e3 UD	113
37c054c7 UD	114	/* Increment LEFT. If this brings the count back to the
	115	initial count unlock the object. */
	116	movl $1, %edx
	117	movl INIT_COUNT(%rdi), %eax
	118	LOCK
	119	xaddl %edx, LEFT(%rdi)
	120	subl $1, %eax
	121	cmpl %eax, %edx
	122	jne,pt 5f
	123
6a4263e3 UD	124	/* Release the mutex. We cannot release the lock before
	125	waking the waiting threads since otherwise a new thread might
	126	arrive and gets waken up, too. */
	127	LOCK
3a226d33 UD	128	decl MUTEX(%rdi)
3a226d33 UD	129	jne 4f
6a4263e3 UD	130
	131	5: orl $-1, %eax /* == PTHREAD_BARRIER_SERIAL_THREAD */
	132
	133	retq
	134
e51deae7 UD	135	1: movl PRIVATE(%rdi), %esi
	136	addq $MUTEX, %rdi
	137	xorl $LLL_SHARED, %esi
	138	callq __lll_lock_wait
6a4263e3 UD	139	subq $MUTEX, %rdi
	140	jmp 2b
	141
e51deae7 UD	142	4: movl PRIVATE(%rdi), %esi
	143	addq $MUTEX, %rdi
	144	xorl $LLL_SHARED, %esi
	145	callq __lll_unlock_wake
6a4263e3 UD	146	jmp 5b
6a4263e3 UD	147
e51deae7 UD	148	6: movl PRIVATE(%rdi), %esi
	149	addq $MUTEX, %rdi
	150	xorl $LLL_SHARED, %esi
	151	callq __lll_unlock_wake
6a4263e3 UD	152	subq $MUTEX, %rdi
6a4263e3 UD	153	jmp 7b
37c054c7	154
e51deae7 UD	155	9: movl PRIVATE(%rdi), %esi
	156	addq $MUTEX, %rdi
	157	xorl $LLL_SHARED, %esi
	158	callq __lll_unlock_wake
37c054c7	159	jmp 10b
6a4263e3	160	.size pthread_barrier_wait,.-pthread_barrier_wait