1/* $OpenBSD: Ovfork.S,v 1.3 2005/08/07 16:40:15 espie Exp $ */ 2/*- 3 * Copyright (c) 1991, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Ralph Campbell. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include "SYS.h" 35 36/* 37 * pid = vfork(); 38 * 39 * v1 == 0 in parent process, v1 == 1 in child process. 40 * v0 == pid of child in parent, v0 == pid of parent in child. 41 */ 42 43FRAMESZ= MKFSIZ(1,1) 44GPOFF= FRAMESZ-2*REGSZ 45 46SYSLEAF(vfork, FRAMESZ) 47 PTR_SUBU sp, FRAMESZ 48 SETUP_GP64(GPOFF, vfork) 49 .set reorder 50 li v0, SYS_vfork # system call number for vfork 51 syscall 52 beq a3, zero, 1f # jump if no errors 53 la t9, cerror 54 RESTORE_GP64 55 PTR_ADDU sp, FRAMESZ 56 jr t9 571: 58 beq v1, zero, 2f # parent process ? 59 move v0, zero # return zero in child 602: 61 RESTORE_GP64 62 PTR_ADDU sp, FRAMESZ 63 j ra 64SYSEND(vfork) 65