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| -rw-r--r-- | lib/librthread/arch/alpha/_atomic_lock.S | 19 |
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) |