1 /* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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.
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.
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
21 #include <lowlevelbarrier.h>
36 .globl pthread_barrier_wait
37 .type pthread_barrier_wait,@function
48 cmpxchgl %edx, MUTEX(%ebx)
51 /* One less waiter. If this was the last one needed wake
53 2: subl $1, LEFT(%ebx)
56 /* There are more threads to come. */
62 movl CURR_EVENT(%ebx), %edx
65 /* Release the mutex. */
70 /* Wait for the remaining threads. The call will return immediately
71 if the CURR_EVENT memory has meanwhile been changed. */
72 7: xorl %ecx, %ecx /* movl $FUTEX_WAIT, %ecx */
74 8: movl $SYS_futex, %eax
77 /* Don't return on spurious wakeups. The syscall does not change
78 any register except %eax so there is no need to reload any of
83 cmpl %edx, CURR_EVENT(%ebx)
87 /* Increment LEFT. If this brings the count back to the
88 initial count unlock the object. */
90 movl INIT_COUNT(%ebx), %ecx
92 xaddl %edx, LEFT(%ebx)
97 /* Release the mutex. We cannot release the lock before
98 waking the waiting threads since otherwise a new thread might
99 arrive and gets waken up, too. */
104 /* Note: %esi is still zero. */
105 10: movl %esi, %eax /* != PTHREAD_BARRIER_SERIAL_THREAD */
111 /* The necessary number of threads arrived. */
116 addl $1, CURR_EVENT(%ebx)
119 /* Wake up all waiters. The count is a signed number in the kernel
120 so 0x7fffffff is the highest value. */
121 movl $0x7fffffff, %edx
122 movl $FUTEX_WAKE, %ecx
123 movl $SYS_futex, %eax
126 /* Increment LEFT. If this brings the count back to the
127 initial count unlock the object. */
129 movl INIT_COUNT(%ebx), %ecx
131 xaddl %edx, LEFT(%ebx)
136 /* Release the mutex. We cannot release the lock before
137 waking the waiting threads since otherwise a new thread might
138 arrive and gets waken up, too. */
143 5: orl $-1, %eax /* == PTHREAD_BARRIER_SERIAL_THREAD */
148 1: leal MUTEX(%ebx), %ecx
149 call __lll_mutex_lock_wait
152 4: leal MUTEX(%ebx), %eax
153 call __lll_mutex_unlock_wake
156 6: leal MUTEX(%ebx), %eax
157 call __lll_mutex_unlock_wake
160 9: leal MUTEX(%ebx), %eax
161 call __lll_mutex_unlock_wake
163 .size pthread_barrier_wait,.-pthread_barrier_wait