1 /* $NetBSD: makecontext.c,v 1.3 2008/04/28 20:22:57 martin 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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 __RCSID("$NetBSD: makecontext.c,v 1.3 2008/04/28 20:22:57 martin Exp $");
35 #endif
36
37 #include <inttypes.h>
38 #include <stddef.h>
39 #include <ucontext.h>
40 #include "extern.h"
41
42 #include <stdarg.h>
43
44 void
makecontext(ucontext_t * ucp,void (* func)(void),int argc,...)45 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
46 {
47 __greg_t *gr = ucp->uc_mcontext.__gregs;
48 int i;
49 unsigned long *sp;
50 va_list ap;
51
52 sp = (unsigned long *)
53 ((unsigned long)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
54 /* Make room for: rwindow, struct return pointer, argd, argx */
55 sp -= 8 + 8 + 1 + 6 + 1; /* CCFSZ, only in words */
56 /* CCFSZ provides space for up to 7 arguments, add more if necessary */
57 if (argc > 7)
58 sp -= argc - 7;
59 /* Align on double-word boundary. */
60 sp = (unsigned long *)((unsigned long)sp & ~0x7);
61
62 gr[_REG_O6] = (__greg_t)sp;
63 gr[_REG_PC] = (__greg_t)func;
64 gr[_REG_nPC] = (__greg_t)func + 4;
65 gr[_REG_O7] = (__greg_t)_resumecontext - 8;
66
67 va_start(ap, argc);
68 /* Pass up to 6 arguments in %o0..%o5. */
69 for (i = 0; i < argc && i < 6; i++)
70 gr[_REG_O0 + i] = va_arg(ap, unsigned long);
71 /* Pass any additional arguments on the stack. */
72 for (/* i = 6 */; i < argc; i++)
73 sp[8 + 8 + 1 + 6 + (i - 6)] = va_arg(ap, unsigned long);
74 va_end(ap);
75 }
76