1 /* $NetBSD: makecontext.c,v 1.2 2003/01/18 11:09:36 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Klaus Klein. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 __RCSID("$NetBSD: makecontext.c,v 1.2 2003/01/18 11:09:36 thorpej Exp $"); 42 #endif 43 44 #include <sys/types.h> 45 #include <inttypes.h> 46 #include <ucontext.h> 47 #include "extern.h" 48 49 #include <stdarg.h> 50 51 void 52 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...) 53 { 54 mcontext_t *mcp = &ucp->uc_mcontext; 55 int *sp; 56 va_list ap; 57 58 mcp->__gregs[_REG_PC] = (__greg_t)func; 59 60 sp = (int *)((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 61 sp = (int *)((uintptr_t)sp & ~0x3); /* Align on word boundary. */ 62 sp -= (argc + 1); /* Make room for retaddr and args. */ 63 mcp->__gregs[_REG_A7] = (__greg_t)sp; 64 mcp->__gregs[_REG_A6] = 0; /* Wipe out frame pointer. */ 65 66 *sp++ = (int)_resumecontext; 67 68 va_start(ap, argc); 69 while (argc-- > 0) 70 *sp++ = va_arg(ap, int); 71 va_end(ap); 72 } 73