From f7b2be77220b37fde77a4aba583a8c2ccddf0dd9 Mon Sep 17 00:00:00 2001 From: jb Date: Wed, 29 Apr 1998 09:36:03 +0000 Subject: Atomic lock source. --- lib/libpthread/arch/i386/i386/_atomic_lock.S | 55 ++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 lib/libpthread/arch/i386/i386/_atomic_lock.S (limited to 'lib/libpthread') diff --git a/lib/libpthread/arch/i386/i386/_atomic_lock.S b/lib/libpthread/arch/i386/i386/_atomic_lock.S new file mode 100644 index 0000000..d124fc3 --- /dev/null +++ b/lib/libpthread/arch/i386/i386/_atomic_lock.S @@ -0,0 +1,55 @@ +/* + * Copyright (c) 1995-1998 John Birrell . + * 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. + * + * $Id$ + * + */ + +#if defined(LIBC_RCS) && !defined(lint) + .text + .asciz "$Id$" +#endif /* LIBC_RCS and not lint */ + +#include "DEFS.h" + +/* + * Atomicly lock a location with an identifier provided the location + * is not currently locked. + * + * long _atomic_lock(long *, long); + * eax will contain the return value. + */ +ENTRY(_atomic_lock) + movl 4(%esp), %ecx + movl 8(%esp), %eax + xchg %eax, (%ecx) + ret + +/* + * Unlock a location. + * + * long _atomic_unlock(long *); + */ +ENTRY(_atomic_unlock) + movl 4(%esp), %ecx + movl $0, %eax + xchg %eax, (%ecx) + ret -- cgit v1.1