uclibc-ng/libpthread/linuxthreads/sysdeps/mips/pt-machine.h

/* Machine-dependent pthreads configuration and inline functions.

   Copyright (C) 1996, 1997, 1998, 2000, 2002, 2003, 2004
   Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ralf Baechle <ralf@gnu.org>.
   Based on the Alpha version 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 Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If
   not, see <http://www.gnu.org/licenses/>.  */

#ifndef _PT_MACHINE_H
#define _PT_MACHINE_H   1

#include <features.h>
#include <sgidefs.h>
#include <sys/tas.h>

#ifndef PT_EI
# define PT_EI __extern_always_inline
#endif

/* Spinlock implementation; required.  */

PT_EI long int
testandset (int *spinlock)
{
  return _test_and_set (spinlock, 1);
}


/* 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__ ("$29");


/* Compare-and-swap for semaphores. */

#define HAS_COMPARE_AND_SWAP
PT_EI int
__compare_and_swap (long int *p, long int oldval, long int newval)
{
  long int ret, temp;

  __asm__ __volatile__
    ("/* Inline compare & swap */\n"
     "1:\n\t"
     ".set	push\n\t"
#if _MIPS_SIM == _ABIO32
     ".set	mips2\n\t"
#endif
#if _MIPS_SIM == _ABI64
     "lld	%1,%5\n\t"
#else
     "ll	%1,%5\n\t"
#endif
     "move	%0,$0\n\t"
     "bne	%1,%3,2f\n\t"
     "move	%0,%4\n\t"
#if _MIPS_SIM == _ABI64
     "scd	%0,%2\n\t"
#else
     "sc	%0,%2\n\t"
#endif
     ".set	pop\n\t"
     "beqz	%0,1b\n"
     "2:\n\t"
     "/* End compare & swap */"
     : "=&r" (ret), "=&r" (temp), "=m" (*p)
     : "r" (oldval), "r" (newval), "m" (*p)
     : "memory");

  return ret;
}

#endif /* pt-machine.h */