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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/alpha/lib/dec_and_lock.c
Linux-2.6.12-rc2v2.6.12-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!
Diffstat (limited to 'arch/alpha/lib/dec_and_lock.c')
-rw-r--r--arch/alpha/lib/dec_and_lock.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/alpha/lib/dec_and_lock.c b/arch/alpha/lib/dec_and_lock.c
new file mode 100644
index 000000000000..6ae2500a9d9e
--- /dev/null
+++ b/arch/alpha/lib/dec_and_lock.c
@@ -0,0 +1,42 @@
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\
171: 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\
252: br $29, 3f \n\
263: ldgp $29, 0($29) \n\
27 br $atomic_dec_and_lock_1..ng \n\
28 .subsection 2 \n\
294: br 1b \n\
30 .previous \n\
31 .end _atomic_dec_and_lock");
32
33static int __attribute_used__
34atomic_dec_and_lock_1(atomic_t *atomic, spinlock_t *lock)
35{
36 /* Slow path */
37 spin_lock(lock);
38 if (atomic_dec_and_test(atomic))
39 return 1;
40 spin_unlock(lock);
41 return 0;
42}