xref: /netbsd-src/lib/libc/arch/arm/sys/fork.S (revision 14df2d6c20b54c62cdb0f7e18ffa076a70640f2f)
1*14df2d6cSmatt/*	$NetBSD: fork.S,v 1.7 2013/08/16 22:28:05 matt Exp $	*/
25aefcfdcSbjh21
35aefcfdcSbjh21/*-
45aefcfdcSbjh21 * Copyright (c) 1990 The Regents of the University of California.
55aefcfdcSbjh21 * All rights reserved.
65aefcfdcSbjh21 *
75aefcfdcSbjh21 * Redistribution and use in source and binary forms, with or without
85aefcfdcSbjh21 * modification, are permitted provided that the following conditions
95aefcfdcSbjh21 * are met:
105aefcfdcSbjh21 * 1. Redistributions of source code must retain the above copyright
115aefcfdcSbjh21 *    notice, this list of conditions and the following disclaimer.
125aefcfdcSbjh21 * 2. Redistributions in binary form must reproduce the above copyright
135aefcfdcSbjh21 *    notice, this list of conditions and the following disclaimer in the
145aefcfdcSbjh21 *    documentation and/or other materials provided with the distribution.
15eb7c1594Sagc * 3. Neither the name of the University nor the names of its contributors
165aefcfdcSbjh21 *    may be used to endorse or promote products derived from this software
175aefcfdcSbjh21 *    without specific prior written permission.
185aefcfdcSbjh21 *
195aefcfdcSbjh21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
205aefcfdcSbjh21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
215aefcfdcSbjh21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
225aefcfdcSbjh21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
235aefcfdcSbjh21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
245aefcfdcSbjh21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
255aefcfdcSbjh21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
265aefcfdcSbjh21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
275aefcfdcSbjh21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
285aefcfdcSbjh21 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
295aefcfdcSbjh21 * SUCH DAMAGE.
305aefcfdcSbjh21 *
315aefcfdcSbjh21 *	from: @(#)fork.s	5.1 (Berkeley) 4/23/90
325aefcfdcSbjh21 */
335aefcfdcSbjh21
345aefcfdcSbjh21#include "SYS.h"
355aefcfdcSbjh21
36f5fadef6Sbjh21/*
37f5fadef6Sbjh21 * pid = fork();
38f5fadef6Sbjh21 *
39f5fadef6Sbjh21 * On return from the SWI:
40f5fadef6Sbjh21 * r1 == 0 in parent process, r1 == 1 in child process.
41f5fadef6Sbjh21 * r0 == pid of child in parent, r0 == pid of parent in child.
42f5fadef6Sbjh21 */
43f5fadef6Sbjh21
444fb740b8Snathanw_SYSCALL(__fork,fork)
45*14df2d6cSmatt	subs	r1, r1, #1	/* r1 == 0xffffffff if parent, 0 if child */
46*14df2d6cSmatt	ands	r0, r0, r1	/* r0 == 0 if child, else unchanged */
47ed6e0e9eSrearnsha	RET
48*14df2d6cSmattEND(__fork)
49