Ovfork.S revision 21673 
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 *	$FreeBSD: head/lib/libc/i386/sys/Ovfork.S 21673 1997-01-14 07:20:47Z jkh $
37 */
38
39#if defined(SYSLIBC_RCS) && !defined(lint)
40	.text
41	.asciz "$FreeBSD: head/lib/libc/i386/sys/Ovfork.S 21673 1997-01-14 07:20:47Z jkh $"
42#endif /* SYSLIBC_RCS and not lint */
43
44#include "DEFS.h"
45#include "SYS.h"
46
47/*
48 * pid = vfork();
49 *
50 * %edx == 0 in parent process, %edx == 1 in child process.
51 * %eax == pid of child in parent, %eax == pid of parent in child.
52 *
53 */
54
55ENTRY(vfork)
56	popl	%ecx		/* my rta into ecx */
57	lea	SYS_vfork,%eax
58	KERNCALL
59	jb	verror
60vforkok:
61	cmpl	$0,%edx		/* child process? */
62	jne	child		/* yes */
63	jmp 	parent
64#ifdef	_THREAD_SAFE
65	/*
66	 * Threaded version using __error().
67	 */
68	.globl	CNAME(__error)
69	.type	CNAME(__error),@function
70verror:
71	pushl	%eax
72#ifdef PIC
73	call	PIC_PLT(CNAME(__error))
74#else
75	call	CNAME(__error)
76#endif
77	popl	%ecx
78	movl	%ecx,(%eax)
79	movl	$-1,%eax
80	movl	$-1,%edx
81#else	/* !_THREAD_SAFE */
82	/*
83	 * Non-threaded version using global errno.
84	 */
85	.globl	CNAME(errno)
86verror:
87#ifdef PIC
88	PIC_PROLOGUE
89	movl	PIC_GOT(CNAME(errno)), %edx
90	movl	%eax,(%edx)
91	PIC_EPILOGUE
92#else
93	movl	%eax,CNAME(errno)
94#endif
95	movl	$-1,%eax
96#endif	/* !_THREAD_SAFE */
97	jmp	%ecx
98child:
99	movl	$0,%eax
100parent:
101	jmp	%ecx
102