sysdeps/x86_64/nptl/pthread_spin_lock.S

   1 /* Copyright (C) 2012-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <lowlevellock.h>
  19
  20         .globl  pthread_spin_lock
  21         .type   pthread_spin_lock,@function
  22         .align  16
  23 pthread_spin_lock:
  24 1:      LOCK
  25         decl    0(%rdi)
  26         jne     2f
  27         xor     %eax, %eax
  28         ret
  29
  30         .align  16
  31 2:      rep
  32         nop
  33         cmpl    $0, 0(%rdi)
  34         jg      1b
  35         jmp     2b
  36         .size   pthread_spin_lock,.-pthread_spin_lock