copy alpha atomic_lock implementation from libpthread.

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/librthread/arch/alpha/_atomic_lock.S b/lib/librthread/arch/alpha/_atomic_lock.S
new file mode 100644
index 00000000000..41481216c4a
--- /dev/null
+++ b/lib/librthread/arch/alpha/_atomic_lock.S
@@ -0,0 +1,19 @@
+/*	$OpenBSD: _atomic_lock.S,v 1.1 2005/12/04 05:47:38 brad Exp $	*/
+/* David Leonard, <d@csee.uq.edu.au>. Public domain. */
+
+#include <machine/asm.h>
+
+LEAF(_atomic_lock,1)
+        LDGP(pv)
+
+				/* NOTE: using ldl_l/stl_c instead of
+				   ldq_l and ldq_c as machine/spinlock.h
+				   defines _spinlock_lock_t as int */
+0:      ldl_l   v0, 0(a0)       /* read existing lock value */
+        mov     1, t0           /* locked value to store */
+        stl_c   t0, 0(a0)       /* attempt to store, status in t0 */
+        beq     t0, 1f          /* branch forward to optimise prediction */
+        mb                      /* sync with other processors */
+        RET                     /* return with v0==0 if lock obtained */
+1:      br      0b              /* loop to try again */
+END(_atomic_lock)