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__vfork14.S revision 1.10 
      1 /*	$NetBSD: __vfork14.S,v 1.10 2013/07/16 20:49:42 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990 The Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * the Systems Programming Group of the University of Utah Computer
      9  * Science Department.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include "SYS.h"
     37 
     38 #if defined(LIBC_SCCS) && !defined(lint)
     39 #if 0
     40 	RCSID("from: @(#)Ovfork.s	5.1 (Berkeley) 5/12/90")
     41 #else
     42 	RCSID("$NetBSD: __vfork14.S,v 1.10 2013/07/16 20:49:42 matt Exp $")
     43 #endif
     44 #endif /* LIBC_SCCS and not lint */
     45 
     46 /*
     47  * @(#)vfork.s	4.1 (Berkeley) 12/21/80
     48  * C library -- vfork
     49  */
     50 
     51 /*
     52  * pid = vfork();
     53  *
     54  * d1 == 0 in parent process, d1 == 1 in child process.
     55  * d0 == pid of child in parent, d0 == pid of parent in child.
     56  *
     57  * trickery here, due to keith sklower, uses ret to clear the stack,
     58  * and then returns with a jump indirect, since only one person can return
     59  * with a ret off this stack... we do the ret before we vfork!
     60  */
     61 
     62 ENTRY(__vfork14)
     63 	movl	(%sp)+,%a1
     64 	movl	#SYS___vfork14,%d0
     65 	trap	#0
     66 	jcs	err
     67 	subql	#1,%d1	/* from 1 to 0 in child, 0 to -1 in parent */
     68 	andl	%d1,%d0
     69 	jmp	(%a1)
     70 err:
     71 #ifdef	_REENTRANT
     72 	.globl	_C_LABEL(__errno)
     73 	movl	%a1,-(%sp)
     74 	movl	%d0,-(%sp)
     75 	jbsr	PIC_PLT(_C_LABEL(__errno))
     76 #ifdef	__SVR4_ABI__
     77 	movl	(%sp)+,(%a0)
     78 #else
     79 	movl	%d0,%a1
     80 	movl	(%sp)+,(%a1)
     81 #endif
     82 	movl	(%sp)+,%a1
     83 #else
     84 	.globl	_C_LABEL(errno)
     85 #ifdef	PIC
     86 	lea	(_GLOBAL_OFFSET_TABLE_@GOTPC,%pc),%a0
     87 	movl	_C_LABEL(errno)@GOT:w(%a0),%a0
     88 	movl	%d0,(%a0)
     89 #else
     90 	movl	%d0,_C_LABEL(errno)
     91 #endif	/* PIC */
     92 #endif	/* _REENTRANT */
     93 	moveq	#-1,%d0
     94 	jmp	(%a1)
     95