| /* Copyright (C) 2002, 2003, 2004, 2007 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 <lowlevellock.h> |
| #include <lowlevelbarrier.h> |
| |
| .text |
| |
| .globl pthread_barrier_wait |
| .type pthread_barrier_wait,@function |
| .align 16 |
| pthread_barrier_wait: |
| cfi_startproc |
| pushl %ebx |
| cfi_adjust_cfa_offset(4) |
| cfi_offset(%ebx, -8) |
| |
| movl 8(%esp), %ebx |
| |
| /* Get the mutex. */ |
| movl $1, %edx |
| xorl %eax, %eax |
| LOCK |
| cmpxchgl %edx, MUTEX(%ebx) |
| jnz 1f |
| |
| /* One less waiter. If this was the last one needed wake |
| everybody. */ |
| 2: subl $1, LEFT(%ebx) |
| je 3f |
| |
| /* There are more threads to come. */ |
| pushl %esi |
| cfi_adjust_cfa_offset(4) |
| cfi_offset(%esi, -12) |
| |
| #if CURR_EVENT == 0 |
| movl (%ebx), %edx |
| #else |
| movl CURR_EVENT(%ebx), %edx |
| #endif |
| |
| /* Release the mutex. */ |
| LOCK |
| subl $1, MUTEX(%ebx) |
| 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(%ebx), %ecx |
| #else |
| movl $FUTEX_WAIT, %ecx |
| orl PRIVATE(%ebx), %ecx |
| #endif |
| xorl %esi, %esi |
| 8: movl $SYS_futex, %eax |
| ENTER_KERNEL |
| |
| /* 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, (%ebx) |
| #else |
| cmpl %edx, CURR_EVENT(%ebx) |
| #endif |
| je 8b |
| |
| /* Increment LEFT. If this brings the count back to the |
| initial count unlock the object. */ |
| movl $1, %edx |
| movl INIT_COUNT(%ebx), %ecx |
| LOCK |
| xaddl %edx, LEFT(%ebx) |
| subl $1, %ecx |
| cmpl %ecx, %edx |
| jne 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 |
| subl $1, MUTEX(%ebx) |
| jne 9f |
| |
| /* Note: %esi is still zero. */ |
| 10: movl %esi, %eax /* != PTHREAD_BARRIER_SERIAL_THREAD */ |
| |
| popl %esi |
| cfi_adjust_cfa_offset(-4) |
| cfi_restore(%esi) |
| popl %ebx |
| cfi_adjust_cfa_offset(-4) |
| cfi_restore(%ebx) |
| ret |
| |
| cfi_adjust_cfa_offset(4) |
| cfi_offset(%ebx, -8) |
| |
| /* The necessary number of threads arrived. */ |
| 3: |
| #if CURR_EVENT == 0 |
| addl $1, (%ebx) |
| #else |
| addl $1, CURR_EVENT(%ebx) |
| #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, %ecx |
| orl PRIVATE(%ebx), %ecx |
| movl $SYS_futex, %eax |
| ENTER_KERNEL |
| |
| /* Increment LEFT. If this brings the count back to the |
| initial count unlock the object. */ |
| movl $1, %edx |
| movl INIT_COUNT(%ebx), %ecx |
| LOCK |
| xaddl %edx, LEFT(%ebx) |
| subl $1, %ecx |
| cmpl %ecx, %edx |
| jne 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 |
| subl $1, MUTEX(%ebx) |
| jne 4f |
| |
| 5: orl $-1, %eax /* == PTHREAD_BARRIER_SERIAL_THREAD */ |
| |
| popl %ebx |
| cfi_adjust_cfa_offset(-4) |
| cfi_restore(%ebx) |
| ret |
| |
| cfi_adjust_cfa_offset(4) |
| cfi_offset(%ebx, -8) |
| 1: movl PRIVATE(%ebx), %ecx |
| leal MUTEX(%ebx), %edx |
| xorl $LLL_SHARED, %ecx |
| call __lll_lock_wait |
| jmp 2b |
| |
| 4: movl PRIVATE(%ebx), %ecx |
| leal MUTEX(%ebx), %eax |
| xorl $LLL_SHARED, %ecx |
| call __lll_unlock_wake |
| jmp 5b |
| |
| cfi_adjust_cfa_offset(4) |
| cfi_offset(%esi, -12) |
| 6: movl PRIVATE(%ebx), %ecx |
| leal MUTEX(%ebx), %eax |
| xorl $LLL_SHARED, %ecx |
| call __lll_unlock_wake |
| jmp 7b |
| |
| 9: movl PRIVATE(%ebx), %ecx |
| leal MUTEX(%ebx), %eax |
| xorl $LLL_SHARED, %ecx |
| call __lll_unlock_wake |
| jmp 10b |
| cfi_endproc |
| .size pthread_barrier_wait,.-pthread_barrier_wait |
