diff options
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_barrier_wait.S')
| -rw-r--r-- | nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_barrier_wait.S | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_barrier_wait.S b/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_barrier_wait.S new file mode 100644 index 0000000000..a385adc5f9 --- /dev/null +++ b/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_barrier_wait.S @@ -0,0 +1,122 @@ +/* Copyright (C) 2002 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> + +#define SYS_futex 240 +#define FUTEX_WAIT 0 +#define FUTEX_WAKE 1 + +#ifndef UP +# define LOCK lock +#else +# define LOCK +#endif + +#define CURR_EVENT 0 +#define MUTEX 4 +#define LEFT 8 +#define INIT_COUNT 12 + + + .text + + .globl pthread_barrier_wait + .type pthread_barrier_wait,@function + .align 16 +pthread_barrier_wait: + pushl %esi + pushl %ebx + + movl 12(%esp), %ebx + xorl %esi, %esi + + /* Get the mutex. */ + orl $-1, %eax + LOCK + xaddl %eax, MUTEX(%ebx) + jne 1f + + /* One less waiter. If this was the last one needed wake + everybody. */ +2: decl LEFT(%ebx) + je 3f + + /* There are more threads to come. */ + movl CURR_EVENT(%ebx), %edx + + /* Release the mutex. */ + LOCK + incl MUTEX(%ebx) + jng 6f + + /* Wait for the remaining threads. The call will return immediately + if the CURR_EVENT memory has meanwhile been changed. */ +7: movl %esi, %ecx /* movl $FUTEX_WAIT, %ecx */ +8: movl $SYS_futex, %eax + int $0x80 + + /* 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. */ + cmpl %edx, CURR_EVENT(%ebx) + je,pn 8b + + /* Note: %esi is still zero. */ + movl %esi, %eax /* != PTHREAD_BARRIER_SERIAL_THREAD */ + + popl %ebx + popl %esi + ret + + /* The necessary number of threads arrived. */ +3: movl INIT_COUNT(%ebx), %eax + movl %eax, LEFT(%ebx) + incl CURR_EVENT(%ebx) + + /* 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, %ecx + movl $SYS_futex, %eax + int $0x80 + + /* Release the mutex. */ + LOCK + incl MUTEX(%ebx) + jng 4f + +5: orl $-1, %eax /* == PTHREAD_BARRIER_SERIAL_THREAD */ + + popl %ebx + popl %esi + ret + +1: leal MUTEX(%ebx), %ecx + call __lll_lock_wait + jmp 2b + +4: leal MUTEX(%ebx), %eax + call __lll_unlock_wake + jmp 5b + +6: leal MUTEX(%ebx), %eax + call __lll_unlock_wake + jmp 7b + .size pthread_barrier_wait,.-pthread_barrier_wait |