makecontext.c revision 178580 
1/*	$NetBSD: makecontext.c,v 1.3 2003/01/19 08:53:36 matt 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__FBSDID("$FreeBSD: head/lib/libc/mips/gen/makecontext.c 178580 2008-04-26 12:08:02Z imp $");
41#if defined(LIBC_SCCS) && !defined(lint)
42__RCSID("$NetBSD: makecontext.c,v 1.3 2003/01/19 08:53:36 matt Exp $");
43#endif
44
45#include <sys/types.h>
46#include <ucontext.h>
47#include <stdarg.h>
48
49void
50makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
51{
52	/* XXXMIPS: Implement me */
53#if 0
54	__greg_t *gr = ucp->uc_mcontext.__gregs;
55	uintptr_t *sp;
56	int i;
57	va_list ap;
58
59	void __resumecontext(void);
60
61	/* LINTED uintptr_t is safe */
62	sp  = (uintptr_t *)
63	    ((uintptr_t)ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
64	/* LINTED uintptr_t is safe */
65	sp -= (argc >= 4 ? argc : 4);	/* Make room for >=4 arguments. */
66	sp  = (uintptr_t *)
67	      ((uintptr_t)sp & ~0x7);	/* Align on double-word boundary. */
68
69	gr[_REG_SP]  = (__greg_t)sp;
70	gr[_REG_RA]  = (__greg_t)__resumecontext;
71	gr[_REG_T9]  = (__greg_t)func;	/* required for .abicalls */
72	gr[_REG_EPC] = (__greg_t)func;
73
74	/* Construct argument list. */
75	va_start(ap, argc);
76	/* Up to the first four arguments are passed in $a0-3. */
77	for (i = 0; i < argc && i < 4; i++)
78		/* LINTED uintptr_t is safe */
79		gr[_REG_A0 + i] = va_arg(ap, uintptr_t);
80	/* Pass remaining arguments on the stack above the $a0-3 gap. */
81	for (sp += 4; i < argc; i++)
82		/* LINTED uintptr_t is safe */
83		*sp++ = va_arg(ap, uintptr_t);
84	va_end(ap);
85#endif
86}
87