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/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS 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.
*/
#if defined(SYSLIBC_SCCS)
.text
.asciz "$OpenBSD: Ovfork.S,v 1.5 2003/06/02 20:18:33 millert Exp $"
#endif /* SYSLIBC_SCCS */
/*
* @(#)vfork.s 4.1 (Berkeley) 12/21/80
* C library -- vfork
*/
#include "SYS.h"
/*
* pid = vfork();
*
* r1 == 0 in parent process, r1 == 1 in child process.
* r0 == pid of child in parent, r0 == pid of parent in child.
*
* trickery here, due to keith sklower, uses ret to clear the stack,
* and then returns with a jump indirect, since only one person can return
* with a ret off this stack... we do the ret before we vfork!
*/
SYSENTRY(vfork)
movl 16(fp),r2 # save return address before we smash it
movab here,16(fp)
ret
here:
chmk $ SYS_vfork
bcs err # if failed, set errno and return -1
/* this next trick is Chris Torek's fault */
mnegl r1,r1 # r1 = 0xffffffff if child, 0 if parent
bicl2 r1,r0 # r0 &= ~r1, i.e., 0 if child, else unchanged
jmp (r2)
err:
movl r0,_errno
mnegl $1,r0
jmp (r2)
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