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/* POSIX spinlock implementation. SPARC v9 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 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,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <pthread.h>
#include "internals.h"
/* This implementation is similar to the one used in the Linux kernel. */
int
__pthread_spin_lock (pthread_spinlock_t *lock)
{
asm volatile
("1: ldstub [%0], %%g2\n"
" brnz,pn %%g2, 2f\n"
" membar #StoreLoad | #StoreStore\n"
".subsection 2\n"
"2: ldub [%0], %%g2\n"
" brnz,pt %%g2, 2b\n"
" membar #LoadLoad\n"
" b,a,pt %%xcc, 1b\n"
".previous"
: /* no outputs */
: "r" (lock)
: "g2", "memory");
return 0;
}
weak_alias (__pthread_spin_lock, pthread_spin_lock)
int
__pthread_spin_trylock (pthread_spinlock_t *lock)
{
int result;
asm volatile
("ldstub [%1], %0\n"
"membar #StoreLoad | #StoreStore"
: "=r" (result)
: "r" (lock)
: "memory");
return result == 0 ? 0 : EBUSY;
}
weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
int
__pthread_spin_unlock (pthread_spinlock_t *lock)
{
asm volatile
("membar #StoreStore | #LoadStore\n"
"stb %%g0, [%0]"
:
: "r" (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 = 0;
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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