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/*

 * sysdeps/v850/pt-machine.h -- v850-specific pthread definitions

 *

 *  Copyright (C) 2002  NEC Electronics Corporation

 *  Copyright (C) 2002  Miles Bader <miles@gnu.org>

 *

 * This file is subject to the terms and conditions of the GNU Lesser

 * General Public License.  See the file COPYING.LIB in the main

 * directory of this archive for more details.

 *

 * Written by Miles Bader <miles@gnu.org>

 */

#ifndef PT_EI

# define PT_EI extern inline

#endif

/* Get some notion of the current stack.  Need not be exactly the top

   of the stack, just something somewhere in the current frame.  */

#define CURRENT_STACK_FRAME  __stack_pointer

register char *__stack_pointer __asm__ ("sp");

#define HAS_COMPARE_AND_SWAP

/* Atomically:  If *PTR == OLD, set *PTR to NEW and return true,

   otherwise do nothing and return false.  */

PT_EI int

__compare_and_swap (long *ptr, long old, long new)

{

  unsigned long psw;

  /* disable interrupts  */

  __asm__ __volatile__ ("stsr psw, %0; di" : "=&r" (psw));

  if (likely (*ptr == old))

    {

      *ptr = new;

      __asm__ __volatile__ ("ldsr %0, psw" :: "r" (psw)); /* re-enable */

      return 1;

    }

  else

    {

      __asm__ __volatile__ ("ldsr %0, psw" :: "r" (psw)); /* re-enable */

      return 0;

    }

}