linux/arch/alpha/lib/dec_and_lock.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

43 lines
821 B
C

/*
* 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_used__
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;
}