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

   1 /* Copyright (C) 2002, 2003, 2005 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 <pthread-errnos.h>
  23
  24 #ifndef UP
  25 # define LOCK lock
  26 #else
  27 # define
  28 #endif
  29
  30 #define SYS_futex               202
  31 #define FUTEX_WAKE              1
  32
  33
  34         .text
  35
  36         .globl  sem_post
  37         .type   sem_post,@function
  38         .align  16
  39 sem_post:
  40         movl    $1, %edx
  41         LOCK
  42         xaddl   %edx, (%rdi)
  43
  44         movl    $SYS_futex, %eax
  45         movl    $FUTEX_WAKE, %esi
  46         incl    %edx
  47         syscall
  48
  49         testq   %rax, %rax
  50         js      1f
  51
  52         xorl    %eax, %eax
  53         retq
  54
  55 1:
  56 #if USE___THREAD
  57         movq    errno@gottpoff(%rip), %rdx
  58         movl    $EINVAL, %fs:(%rdx)
  59 #else
  60         callq   __errno_location@plt
  61         movl    $EINVAL, (%rax)
  62 #endif
  63
  64         orl     $-1, %eax
  65         retq
  66         .size   sem_post,.-sem_post