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fork.S revision 1.3 
      1  1.3  nathanw /*	$NetBSD: fork.S,v 1.3 2003/02/13 02:50:48 nathanw Exp $	*/
      2  1.1    bjh21 
      3  1.1    bjh21 /*-
      4  1.1    bjh21  * Copyright (c) 1990 The Regents of the University of California.
      5  1.1    bjh21  * All rights reserved.
      6  1.1    bjh21  *
      7  1.1    bjh21  * Redistribution and use in source and binary forms, with or without
      8  1.1    bjh21  * modification, are permitted provided that the following conditions
      9  1.1    bjh21  * are met:
     10  1.1    bjh21  * 1. Redistributions of source code must retain the above copyright
     11  1.1    bjh21  *    notice, this list of conditions and the following disclaimer.
     12  1.1    bjh21  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.1    bjh21  *    notice, this list of conditions and the following disclaimer in the
     14  1.1    bjh21  *    documentation and/or other materials provided with the distribution.
     15  1.1    bjh21  * 3. All advertising materials mentioning features or use of this software
     16  1.1    bjh21  *    must display the following acknowledgement:
     17  1.1    bjh21  *	This product includes software developed by the University of
     18  1.1    bjh21  *	California, Berkeley and its contributors.
     19  1.1    bjh21  * 4. Neither the name of the University nor the names of its contributors
     20  1.1    bjh21  *    may be used to endorse or promote products derived from this software
     21  1.1    bjh21  *    without specific prior written permission.
     22  1.1    bjh21  *
     23  1.1    bjh21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  1.1    bjh21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  1.1    bjh21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  1.1    bjh21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  1.1    bjh21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  1.1    bjh21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  1.1    bjh21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  1.1    bjh21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  1.1    bjh21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  1.1    bjh21  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  1.1    bjh21  * SUCH DAMAGE.
     34  1.1    bjh21  *
     35  1.1    bjh21  *	from: @(#)fork.s	5.1 (Berkeley) 4/23/90
     36  1.1    bjh21  */
     37  1.1    bjh21 
     38  1.1    bjh21 #include "SYS.h"
     39  1.1    bjh21 
     40  1.2    bjh21 /*
     41  1.2    bjh21  * pid = fork();
     42  1.2    bjh21  *
     43  1.2    bjh21  * On return from the SWI:
     44  1.2    bjh21  * r1 == 0 in parent process, r1 == 1 in child process.
     45  1.2    bjh21  * r0 == pid of child in parent, r0 == pid of parent in child.
     46  1.2    bjh21  */
     47  1.2    bjh21 
     48  1.3  nathanw _SYSCALL(__fork,fork)
     49  1.2    bjh21 	sub	r1, r1, #1	/* r1 == 0xffffffff if parent, 0 if child */
     50  1.2    bjh21 	and	r0, r0, r1	/* r0 == 0 if child, else unchanged */
     51  1.1    bjh21 #ifdef __APCS_26__
     52  1.1    bjh21 	movs	r15, r14
     53  1.1    bjh21 #else
     54  1.1    bjh21 	mov	r15, r14
     55  1.1    bjh21 #endif
     56