glibc/linuxthreads/sysdeps/hppa/pt-machine.h

/* Machine-dependent pthreads configuration and inline functions.
   hppa version.
   Copyright (C) 2000, 2002 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Richard Henderson <rth@tamu.edu>.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <bits/initspin.h>

#ifndef PT_EI
# define PT_EI extern inline
#endif

extern long int testandset (int *spinlock);
extern int __compare_and_swap (long int *p, long int oldval, long int newval);

/* 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__ ("%r30");


/* The hppa only has one atomic read and modify memory operation,
   load and clear, so hppa spinlocks must use zero to signify that
   someone is holding the lock.  */

#define xstr(s) str(s)
#define str(s) #s
/* Spinlock implementation; required.  */
PT_EI long int
testandset (int *spinlock)
{
  int ret;

  __asm__ __volatile__(
       "ldcw 0(%2),%0"
       : "=r"(ret), "=m"(*spinlock)
       : "r"(spinlock));

  return ret == 0;
}
#undef str
#undef xstr