sysdeps/arm/linuxthreads/pt-machine.h

   1 /* Machine-dependent pthreads configuration and inline functions.
   2    ARM version.
   3    Copyright (C) 1997, 1998, 2000, 2002, 2003 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Philip Blundell <philb@gnu.org>.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public License as
   9    published by the Free Software Foundation; either version 2.1 of the
  10    License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  19    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #ifndef _PT_MACHINE_H
  23 #define _PT_MACHINE_H   1
  24
  25 #ifndef PT_EI
  26 # define PT_EI extern inline __attribute__ ((always_inline))
  27 #endif
  28
  29 extern long int testandset (int *spinlock);
  30 extern int __compare_and_swap (long int *p, long int oldval, long int newval);
  31
  32 /* This will not work on ARM1 or ARM2 because SWP is lacking on those
  33    machines.  Unfortunately we have no way to detect this at compile
  34    time; let's hope nobody tries to use one.  */
  35
  36 /* Spinlock implementation; required.  */
  37 PT_EI long int
  38 testandset (int *spinlock)
  39 {
  40   register unsigned int ret;
  41
  42   __asm__ __volatile__("swp %0, %1, [%2]"
  43                        : "=r"(ret)
  44                        : "0"(1), "r"(spinlock));
  45
  46   return ret;
  47 }
  48
  49
  50 /* Get some notion of the current stack.  Need not be exactly the top
  51    of the stack, just something somewhere in the current frame.  */
  52 #define CURRENT_STACK_FRAME  stack_pointer
  53 register char * stack_pointer __asm__ ("sp");
  54
  55 #endif /* pt-machine.h */