1/* $NetBSD: fork.S,v 1.3 2023/05/07 12:41:47 skrll Exp $ */ 2 3 4/*- 5 * Copyright (c) 2014 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Matt Thomas of 3am Software Foundry. 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 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32#include "SYS.h" 33 34#if defined(LIBC_SCCS) && !defined(lint) 35 RCSID("$NetBSD: fork.S,v 1.3 2023/05/07 12:41:47 skrll Exp $") 36#endif /* LIBC_SCCS and not lint */ 37 38/* 39 * pid = fork(); 40 * 41 * On return from the SYSTRAP: 42 * a1 == 0 in parent process, a1 == 1 in child process. 43 * a0 == pid of child in parent, a0 == pid of parent in child. 44 */ 45 46ENTRY(__fork) 47 SYSTRAP(fork) // pid = fork() 48 JUMP_TO_CERROR() /* error */ 49 /* success */ 50 addi a1, a1, -1 // a1 0->0xffffffff in parent, 1->0 in child 51 and a0, a0, a1 // a0 = child pid in parent, 0 in child 52 ret 53END(__fork) 54