1 /* $NetBSD: makecontext.c,v 1.2 2003/01/18 11:15:08 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 11:15:08 thorpej Exp $"); 42 #endif 43 44 #include <inttypes.h> 45 #include <stddef.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 __greg_t *gr = ucp->uc_mcontext.__gregs; 55 int i; 56 unsigned long *sp; 57 va_list ap; 58 59 sp = (unsigned long *) 60 ((unsigned long)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); 61 /* Make room for: rwindow, struct return pointer, argd, argx */ 62 sp -= 8 + 8 + 1 + 6 + 1; /* CCFSZ, only in words */ 63 /* CCFSZ provides space for up to 7 arguments, add more if necessary */ 64 if (argc > 7) 65 sp -= argc - 7; 66 /* Align on double-word boundary. */ 67 sp = (unsigned long *)((unsigned long)sp & ~0x7); 68 69 gr[_REG_O6] = (__greg_t)sp; 70 gr[_REG_PC] = (__greg_t)func; 71 gr[_REG_nPC] = (__greg_t)func + 4; 72 gr[_REG_O7] = (__greg_t)_resumecontext - 8; 73 74 va_start(ap, argc); 75 /* Pass up to 6 arguments in %o0..%o5. */ 76 for (i = 0; i < argc && i < 6; i++) 77 gr[_REG_O0 + i] = va_arg(ap, unsigned long); 78 /* Pass any additional arguments on the stack. */ 79 for (/* i = 6 */; i < argc; i++) 80 sp[8 + 8 + 1 + 6 + (i - 6)] = va_arg(ap, unsigned long); 81 va_end(ap); 82 } 83