嵌入式Linux

开发平台：

Unix_Linux

dec_and_lock.c：源码内容

							/*
 * arch/alpha/lib/dec_and_lock.c
 *
 * ll/sc version of atomic_dec_and_lock()
 * 
 */
#include <linux/spinlock.h>
#include <asm/atomic.h>
  asm (".text					n
	.global atomic_dec_and_lock		n
	.ent atomic_dec_and_lock		n
	.align	4				n
atomic_dec_and_lock:				n
	.prologue 0				n
1:	ldl_l	$1, 0($16)			n
	subl	$1, 1, $1			n
	beq	$1, 2f				n
	stl_c	$1, 0($16)			n
	beq	$1, 4f				n
	mb					n
	clr	$0				n
	ret					n
2:	br	$29, 3f				n
3:	ldgp	$29, 0($29)			n
	br	$atomic_dec_and_lock_1..ng	n
	.subsection 2				n
4:	br	1b				n
	.previous				n
	.end atomic_dec_and_lock");
static int __attribute__((unused))
atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock)
{
	/* Slow path */
	spin_lock(lock);
	if (atomic_dec_and_test(atomic))
		return 1;
	spin_unlock(lock);
	return 0;
}

						