vfork.S revision 1849 
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	$Id: Ovfork.S,v 1.3 1994/02/21 05:19:08 rgrimes Exp $
37 */
38
39#if defined(SYSLIBC_SCCS) && !defined(lint)
40	.asciz "@(#)Ovfork.s	5.1 (Berkeley) 4/23/90"
41#endif /* SYSLIBC_SCCS and not lint */
42
43#include "SYS.h"
44
45/*
46 * pid = vfork();
47 *
48 * %edx == 0 in parent process, %edx == 1 in child process.
49 * %eax == pid of child in parent, %eax == pid of parent in child.
50 *
51 */
52	.set	vfork,66
53.globl	_vfork
54.type	_vfork,@function
55
56_vfork:
57	popl	%ecx		/* my rta into ecx */
58	movl	$vfork, %eax
59	LCALL(7,0)
60	jb	verror
61vforkok:
62	cmpl	$0,%edx		/* child process? */
63	jne	child		/* yes */
64	jmp 	parent
65.globl	_errno
66verror:
67#ifdef PIC
68	PIC_PROLOGUE
69	movl	PIC_GOT(_errno), %edx
70	movl	%eax,(%edx)
71	PIC_EPILOGUE
72#else
73	movl	%eax,_errno
74#endif
75	movl	$-1,%eax
76	jmp	%ecx
77child:
78	movl	$0,%eax
79parent:
80	jmp	%ecx
81