xref: /minix3/lib/libc/arch/riscv/sys/fork.S (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)
1*0a6a1f1dSLionel Sambuc/*	$NetBSD: fork.S,v 1.2 2015/03/27 06:44:28 matt Exp $	*/
2*0a6a1f1dSLionel Sambuc
3*0a6a1f1dSLionel Sambuc
4*0a6a1f1dSLionel Sambuc/*-
5*0a6a1f1dSLionel Sambuc * Copyright (c) 2014 The NetBSD Foundation, Inc.
6*0a6a1f1dSLionel Sambuc * All rights reserved.
7*0a6a1f1dSLionel Sambuc *
8*0a6a1f1dSLionel Sambuc * This code is derived from software contributed to The NetBSD Foundation
9*0a6a1f1dSLionel Sambuc * by Matt Thomas of 3am Software Foundry.
10*0a6a1f1dSLionel Sambuc *
11*0a6a1f1dSLionel Sambuc * Redistribution and use in source and binary forms, with or without
12*0a6a1f1dSLionel Sambuc * modification, are permitted provided that the following conditions
13*0a6a1f1dSLionel Sambuc * are met:
14*0a6a1f1dSLionel Sambuc * 1. Redistributions of source code must retain the above copyright
15*0a6a1f1dSLionel Sambuc *    notice, this list of conditions and the following disclaimer.
16*0a6a1f1dSLionel Sambuc * 2. Redistributions in binary form must reproduce the above copyright
17*0a6a1f1dSLionel Sambuc *    notice, this list of conditions and the following disclaimer in the
18*0a6a1f1dSLionel Sambuc *    documentation and/or other materials provided with the distribution.
19*0a6a1f1dSLionel Sambuc *
20*0a6a1f1dSLionel Sambuc * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21*0a6a1f1dSLionel Sambuc * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22*0a6a1f1dSLionel Sambuc * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23*0a6a1f1dSLionel Sambuc * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24*0a6a1f1dSLionel Sambuc * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25*0a6a1f1dSLionel Sambuc * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26*0a6a1f1dSLionel Sambuc * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27*0a6a1f1dSLionel Sambuc * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28*0a6a1f1dSLionel Sambuc * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29*0a6a1f1dSLionel Sambuc * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30*0a6a1f1dSLionel Sambuc * POSSIBILITY OF SUCH DAMAGE.
31*0a6a1f1dSLionel Sambuc */
32*0a6a1f1dSLionel Sambuc#include "SYS.h"
33*0a6a1f1dSLionel Sambuc
34*0a6a1f1dSLionel Sambuc#if defined(LIBC_SCCS) && !defined(lint)
35*0a6a1f1dSLionel Sambuc	RCSID("$NetBSD: fork.S,v 1.2 2015/03/27 06:44:28 matt Exp $")
36*0a6a1f1dSLionel Sambuc#endif /* LIBC_SCCS and not lint */
37*0a6a1f1dSLionel Sambuc
38*0a6a1f1dSLionel SambucENTRY(__fork)
39*0a6a1f1dSLionel Sambuc	SYSTRAP(fork)		// pid = fork()
40*0a6a1f1dSLionel Sambuc	JUMP_TO_CERROR()	/* error */
41*0a6a1f1dSLionel Sambuc	/* success */
42*0a6a1f1dSLionel Sambuc	addi	a1, a1, -1	// a1 0->0xffffffff in parent, 1->0 in child
43*0a6a1f1dSLionel Sambuc	and	a0, a0, a1	// a0 = child pid in parent, 0 in child
44*0a6a1f1dSLionel Sambuc	ret
45*0a6a1f1dSLionel SambucEND(__fork)
46