1/* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30#if defined(SYSLIBC_SCCS) && !defined(lint) 31 /* .asciz "@(#)Ovfork.s 8.1 (Berkeley) 6/4/93" */ 32 .asciz "$NetBSD: __vfork14.S,v 1.5 2003/08/07 16:42:33 agc Exp $" 33#endif /* SYSLIBC_SCCS and not lint */ 34 35/* 36 * @(#)vfork.s 4.1 (Berkeley) 12/21/80 37 * C library -- vfork 38 */ 39 40#include "SYS.h" 41 42/* 43 * pid = vfork(); 44 * 45 * %r1 == 0 in parent process, %r1 == 1 in child process. 46 * %r0 == pid of child in parent, %r0 == pid of parent in child. 47 * 48 * trickery here, due to keith sklower, uses ret to clear the stack, 49 * and then returns with a jump indirect, since only one person can return 50 * with a ret off this stack... we do the ret before we vfork! 51 */ 52 53ENTRY(__vfork14, 0) 54 movl 16(%fp),%r2 # save return address before we smash it 55 movab here,16(%fp) 56 ret 57here: 58 chmk $ SYS___vfork14 59 bcs err # if failed, set errno and return -1 60 /* this next trick is Chris Torek's fault */ 61 mnegl %r1,%r1 # %r1 = 0xffffffff if child, 0 if parent 62 bicl2 %r1,%r0 # %r0 &= ~%r1, i.e., 0 if child, else unchanged 63 jmp (%r2) 64 65err: 66#ifdef _REENTRANT 67 pushr $0x5 68 calls $0,_C_LABEL(__errno) 69 movl (%sp)+,(%r0) 70 mnegl $1,%r0 71 rsb 72#else 73 movl %r0,_C_LABEL(errno) 74 mnegl $1,%r0 75 jmp (%r2) 76#endif 77