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/* POSIX spinlock implementation. MIPS version.
Copyright (C) 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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 <errno.h>
#include <pthread.h>
#include <sgidefs.h>
#include <sys/tas.h>
#if (_MIPS_ISA >= _MIPS_ISA_MIPS2)
/* This implementation is similar to the one used in the Linux kernel. */
int
__pthread_spin_lock (pthread_spinlock_t *lock)
{
unsigned int tmp;
asm volatile
("\t\t\t# spin_lock\n\t"
"1:\n\t"
"ll %1,%2\n\t"
".set push\n\t"
".set noreorder\n\t"
"bnez %1,1b\n\t"
" li %1,1\n\t"
".set pop\n\t"
"sc %1,%0\n\t"
"beqz %1,1b"
: "=m" (*lock), "=&r" (tmp)
: "m" (*lock)
: "memory");
return 0;
}
#else /* !(_MIPS_ISA >= _MIPS_ISA_MIPS2) */
int
__pthread_spin_lock (pthread_spinlock_t *lock)
{
while (_test_and_set (lock, 1));
return 0;
}
#endif /* !(_MIPS_ISA >= _MIPS_ISA_MIPS2) */
weak_alias (__pthread_spin_lock, pthread_spin_lock)
int
__pthread_spin_trylock (pthread_spinlock_t *lock)
{
/* To be done. */
return 0;
}
weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
int
__pthread_spin_unlock (pthread_spinlock_t *lock)
{
asm volatile
("\t\t\t# spin_unlock\n\t"
"sw $0,%0"
: "=m" (*lock)
:
: "memory");
return 0;
}
weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
int
__pthread_spin_init (pthread_spinlock_t *lock, int pshared)
{
/* We can ignore the `pshared' parameter. Since we are busy-waiting
all processes which can access the memory location `lock' points
to can use the spinlock. */
*lock = 1;
return 0;
}
weak_alias (__pthread_spin_init, pthread_spin_init)
int
__pthread_spin_destroy (pthread_spinlock_t *lock)
{
/* Nothing to do. */
return 0;
}
weak_alias (__pthread_spin_destroy, pthread_spin_destroy)
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