xref: /freebsd/lib/libsys/arm/vfork.S (revision b985c9ca)
1/*	$NetBSD: Ovfork.S,v 1.6 2003/08/07 16:42:03 agc Exp $	*/
2
3/*-
4 * Copyright (c) 1990 The Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <machine/asm.h>
33#include "SYS.h"
34
35/*
36 * pid = vfork();
37 *
38 * On return from the SWI:
39 * r1 == 0 in parent process, r1 == 1 in child process.
40 * r0 == pid of child in parent, r0 == pid of parent in child.
41 */
42	.text
43	.align	0
44
45ENTRY(__sys_vfork)
46	.weak _C_LABEL(vfork);
47	.set _C_LABEL(vfork), _C_LABEL(__sys_vfork);
48	.weak _C_LABEL(_vfork);
49	.set _C_LABEL(_vfork), _C_LABEL(__sys_vfork);
50	mov	r2, r14
51	_SYSCALL(vfork)
52	bcs	PIC_SYM(CERROR, PLT)
53	sub	r1, r1, #1	/* r1 == 0xffffffff if parent, 0 if child */
54	and	r0, r0, r1	/* r0 == 0 if child, else unchanged */
55	mov	r15, r2
56END(__sys_vfork)
57
58	.section .note.GNU-stack,"",%progbits
59