94 lines
2.5 KiB
C
94 lines
2.5 KiB
C
/* POSIX spinlock implementation. ia64 version.
|
|
Copyright (C) 2000 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Jes Sorensen <jes@linuxcare.com>
|
|
|
|
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 "internals.h"
|
|
|
|
/* This implementation is inspired by the implementation used in the
|
|
Linux kernel. */
|
|
|
|
int
|
|
__pthread_spin_lock (pthread_spinlock_t *lock)
|
|
{
|
|
asm volatile
|
|
("mov ar.ccv = r0\n\t"
|
|
"mov r3 = 1\n\t"
|
|
";;\n"
|
|
"1:\n\t"
|
|
"ld4 r2 = %0\n\t"
|
|
";;\n\t"
|
|
"cmp4.eq p0, p7 = r0, r2\n\t"
|
|
"(p7) br.cond.spnt.few 1b \n\t"
|
|
"cmpxchg4.acq r2 = %0, r3, ar.ccv\n\t"
|
|
";;\n\t"
|
|
"cmp4.eq p0, p7 = r0, r2\n\t"
|
|
"(p7) br.cond.spnt.few 1b\n\t"
|
|
";;\n"
|
|
:: "m" (lock) : "r2", "r3", "p7", "memory");
|
|
return 0;
|
|
}
|
|
weak_alias (__pthread_spin_lock, pthread_spin_lock)
|
|
|
|
|
|
int
|
|
__pthread_spin_trylock (pthread_spinlock_t *lock)
|
|
{
|
|
int oldval;
|
|
|
|
asm volatile
|
|
("mov ar.ccv = r0\n\t"
|
|
"mov r2 = 1\n\t"
|
|
";;\n\t"
|
|
"cmpxchg4.acq %0 = %1, r2, ar.ccv\n\t"
|
|
";;\n"
|
|
: "=r" (oldval) : "m" (lock) : "r2", "memory");
|
|
return oldval > 0 ? 0 : EBUSY;
|
|
}
|
|
weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
|
|
|
|
|
|
int
|
|
__pthread_spin_unlock (pthread_spinlock_t *lock)
|
|
{
|
|
return *lock = 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. */
|
|
return *lock = 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)
|