1 /*
2 * arch/alpha/lib/dec_and_lock.c
3 *
4 * ll/sc version of atomic_dec_and_lock()
5 *
6 */
7
8 #include <linux/spinlock.h>
9 #include <asm/atomic.h>
10
11 asm (".text \n\
12 .global _atomic_dec_and_lock \n\
13 .ent _atomic_dec_and_lock \n\
14 .align 4 \n\
15 _atomic_dec_and_lock: \n\
16 .prologue 0 \n\
17 1: ldl_l $1, 0($16) \n\
18 subl $1, 1, $1 \n\
19 beq $1, 2f \n\
20 stl_c $1, 0($16) \n\
21 beq $1, 4f \n\
22 mb \n\
23 clr $0 \n\
24 ret \n\
25 2: br $29, 3f \n\
26 3: ldgp $29, 0($29) \n\
27 br $atomic_dec_and_lock_1..ng \n\
28 .subsection 2 \n\
29 4: br 1b \n\
30 .previous \n\
31 .end _atomic_dec_and_lock");
32
atomic_dec_and_lock_1(atomic_t * atomic,spinlock_t * lock)33 static int __used atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock)
34 {
35 /* Slow path */
36 spin_lock(lock);
37 if (atomic_dec_and_test(atomic))
38 return 1;
39 spin_unlock(lock);
40 return 0;
41 }
42