nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S

   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.
   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 <shlib-compat.h>
  22 #include <lowlevelcond.h>
  23 #include <kernel-features.h>
  24
  25 #ifdef UP
  26 # define LOCK
  27 #else
  28 # define LOCK lock
  29 #endif
  30
  31 #define SYS_futex               202
  32 #define FUTEX_WAIT              0
  33 #define FUTEX_WAKE              1
  34 #define FUTEX_REQUEUE           3
  35
  36 #define EINVAL                  22
  37
  38
  39         .text
  40
  41         /* int pthread_cond_signal (pthread_cond_t *cond) */
  42         .globl  __pthread_cond_signal
  43         .type   __pthread_cond_signal, @function
  44         .align  16
  45 __pthread_cond_signal:
  46
  47         /* Get internal lock.  */
  48         movq    %rdi, %r8
  49         movl    $1, %esi
  50         xorl    %eax, %eax
  51         LOCK
  52 #if cond_lock == 0
  53         cmpxchgl %esi, (%rdi)
  54 #else
  55         cmpxchgl %esi, cond_lock(%rdi)
  56 #endif
  57         jnz     1f
  58
  59 2:      addq    $cond_futex, %rdi
  60         movq    total_seq(%r8), %rcx
  61         cmpq    wakeup_seq(%r8), %rcx
  62         jbe     4f
  63
  64         /* Bump the wakeup number.  */
  65         addq    $1, wakeup_seq(%r8)
  66         addl    $1, (%rdi)
  67
  68         /* Wake up one thread.  */
  69         movq    $FUTEX_WAKE, %rsi
  70         movq    $SYS_futex, %rax
  71         movq    $1, %rdx
  72         syscall
  73
  74         /* Unlock.  */
  75 4:      LOCK
  76 #if cond_lock == 0
  77         decl    (%r8)
  78 #else
  79         decl    cond_lock(%r8)
  80 #endif
  81         jne     5f
  82
  83 6:      xorl    %eax, %eax
  84         retq
  85
  86         /* Initial locking failed.  */
  87 1:
  88 #if cond_lock != 0
  89         addq    $cond_lock, %rdi
  90 #endif
  91         callq   __lll_mutex_lock_wait
  92 #if cond_lock != 0
  93         subq    $cond_lock, %rdi
  94 #endif
  95         jmp     2b
  96
  97         /* Unlock in loop requires wakeup.  */
  98 5:
  99         movq    %r8, %rdi
 100         callq   __lll_mutex_unlock_wake
 101         jmp     6b
 102         .size   __pthread_cond_signal, .-__pthread_cond_signal
 103 versioned_symbol (libpthread, __pthread_cond_signal, pthread_cond_signal,
 104                   GLIBC_2_3_2)