1*2fe8fb19SBen Gras /* $NetBSD: makecontext.c,v 1.3 2008/04/28 20:22:56 martin Exp $ */
2*2fe8fb19SBen Gras
3*2fe8fb19SBen Gras /*-
4*2fe8fb19SBen Gras * Copyright (c) 2001 The NetBSD Foundation, Inc.
5*2fe8fb19SBen Gras * All rights reserved.
6*2fe8fb19SBen Gras *
7*2fe8fb19SBen Gras * This code is derived from software contributed to The NetBSD Foundation
8*2fe8fb19SBen Gras * by Klaus Klein.
9*2fe8fb19SBen Gras *
10*2fe8fb19SBen Gras * Redistribution and use in source and binary forms, with or without
11*2fe8fb19SBen Gras * modification, are permitted provided that the following conditions
12*2fe8fb19SBen Gras * are met:
13*2fe8fb19SBen Gras * 1. Redistributions of source code must retain the above copyright
14*2fe8fb19SBen Gras * notice, this list of conditions and the following disclaimer.
15*2fe8fb19SBen Gras * 2. Redistributions in binary form must reproduce the above copyright
16*2fe8fb19SBen Gras * notice, this list of conditions and the following disclaimer in the
17*2fe8fb19SBen Gras * documentation and/or other materials provided with the distribution.
18*2fe8fb19SBen Gras *
19*2fe8fb19SBen Gras * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*2fe8fb19SBen Gras * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*2fe8fb19SBen Gras * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*2fe8fb19SBen Gras * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*2fe8fb19SBen Gras * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*2fe8fb19SBen Gras * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*2fe8fb19SBen Gras * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*2fe8fb19SBen Gras * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*2fe8fb19SBen Gras * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*2fe8fb19SBen Gras * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*2fe8fb19SBen Gras * POSSIBILITY OF SUCH DAMAGE.
30*2fe8fb19SBen Gras */
31*2fe8fb19SBen Gras
32*2fe8fb19SBen Gras #include <sys/cdefs.h>
33*2fe8fb19SBen Gras #if defined(LIBC_SCCS) && !defined(lint)
34*2fe8fb19SBen Gras __RCSID("$NetBSD: makecontext.c,v 1.3 2008/04/28 20:22:56 martin Exp $");
35*2fe8fb19SBen Gras #endif
36*2fe8fb19SBen Gras
37*2fe8fb19SBen Gras #include <sys/types.h>
38*2fe8fb19SBen Gras #include <inttypes.h>
39*2fe8fb19SBen Gras #include <ucontext.h>
40*2fe8fb19SBen Gras #include "extern.h"
41*2fe8fb19SBen Gras
42*2fe8fb19SBen Gras #include <stdarg.h>
43*2fe8fb19SBen Gras
44*2fe8fb19SBen Gras void
makecontext(ucontext_t * ucp,void (* func)(void),int argc,...)45*2fe8fb19SBen Gras makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
46*2fe8fb19SBen Gras {
47*2fe8fb19SBen Gras mcontext_t *mcp = &ucp->uc_mcontext;
48*2fe8fb19SBen Gras int *sp;
49*2fe8fb19SBen Gras va_list ap;
50*2fe8fb19SBen Gras
51*2fe8fb19SBen Gras mcp->__gregs[_REG_PC] = (__greg_t)func;
52*2fe8fb19SBen Gras
53*2fe8fb19SBen Gras sp = (int *)((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
54*2fe8fb19SBen Gras sp = (int *)((uintptr_t)sp & ~0x3); /* Align on word boundary. */
55*2fe8fb19SBen Gras sp -= (argc + 1); /* Make room for retaddr and args. */
56*2fe8fb19SBen Gras mcp->__gregs[_REG_A7] = (__greg_t)sp;
57*2fe8fb19SBen Gras mcp->__gregs[_REG_A6] = 0; /* Wipe out frame pointer. */
58*2fe8fb19SBen Gras
59*2fe8fb19SBen Gras *sp++ = (int)_resumecontext;
60*2fe8fb19SBen Gras
61*2fe8fb19SBen Gras va_start(ap, argc);
62*2fe8fb19SBen Gras while (argc-- > 0)
63*2fe8fb19SBen Gras *sp++ = va_arg(ap, int);
64*2fe8fb19SBen Gras va_end(ap);
65*2fe8fb19SBen Gras }
66