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author | jb <jb@FreeBSD.org> | 1998-06-09 08:21:55 +0000 |
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committer | jb <jb@FreeBSD.org> | 1998-06-09 08:21:55 +0000 |
commit | 6433b7908438fd70c18a0384701f3e97a084e5eb (patch) | |
tree | 7b8acc704ba3e2450bd7d16f83049980d019cfe7 /lib/libpthread | |
parent | cd35d4abdfb3dff3bad152e8488a9d4d5d0bdb32 (diff) | |
download | FreeBSD-src-6433b7908438fd70c18a0384701f3e97a084e5eb.zip FreeBSD-src-6433b7908438fd70c18a0384701f3e97a084e5eb.tar.gz |
Atomic lock asm code for the alpha version of libc_r.
Diffstat (limited to 'lib/libpthread')
-rw-r--r-- | lib/libpthread/arch/alpha/alpha/_atomic_lock.S | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/lib/libpthread/arch/alpha/alpha/_atomic_lock.S b/lib/libpthread/arch/alpha/alpha/_atomic_lock.S new file mode 100644 index 0000000..7ca46f7 --- /dev/null +++ b/lib/libpthread/arch/alpha/alpha/_atomic_lock.S @@ -0,0 +1,57 @@ +/* + * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>. + * All rights reserved. + * copyright Douglas Santry 1996 + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the above copyright is retained + * in the source form. + * + * THIS SOFTWARE IS PROVIDED BY Douglas Santry AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL Douglas Santry OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $Id: _atomic_lock.S,v 1.1 1998/04/29 09:36:03 jb Exp $ + * + */ + +#include "SYS.h" + +/* + * Atomicly lock a location with an identifier provided the location + * is not currently locked. + * + * long _atomic_lock(long *); + * v0 will contain the return value (zero if lock obtained). + */ +LEAF(_atomic_lock,0) + LDGP(pv) + + /* Get the existing lock value and lock memory: */ + ldq_l v0, 0(a0) + + /* Branch if already locked: */ + bne v0, already_locked + + /* Not locked, so store 1: */ + mov 1, t0 + stq_c t0, 0(a0) + + /* Obtained the lock: */ + br done + +already_locked: + /* Already locked so put the value back and unlock memory: */ + stq_c v0, 0(a0) + +done: + RET +END(_atomic_lock) |