1/*	$NetBSD: getcontext.S,v 1.5 2011/01/25 02:38:15 matt Exp $	*/
2
3/*-
4 * Copyright (c) 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matt Thomas.
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.h"
33
34#ifdef SYSLIBC_SCCS
35RCSID("$NetBSD: getcontext.S,v 1.5 2011/01/25 02:38:15 matt Exp $")
36#endif
37
38#ifdef WEAK_ALIAS
39WEAK_ALIAS(getcontext, _getcontext)
40#endif
41
42/*
43 * Can't use R4 or R5 since those needed by the phread_switch code.
44 */
45ENTRY(_getcontext, 0)
46	clrl	%r0			/* assume success */
47	chmk	$SYS_getcontext		/* getcontext(oucp) */
48	jcc	1f
49	jmp	CERROR+2		/* badness happened */
50
511:	movl	4(%ap),%r0		/* ptr to ucontext */
52	movl	16(%fp),%r1		/* PC to return to */
53	movab	2f,16(%fp)		/* let's return early */
54	ret
55	/*
56	 * Now we have the blown away the callframe and argument
57	 * list so it's as if we've return from the function except
58	 * we aren't executing the caller's code (yet).  So it's
59	 * the callers state but we still have control.
60	 */
61	_ALIGN_TEXT
622:	movq	%ap,(36+12*4)(%r0)	/* adjust AP + SP */
63	movl	%fp,(36+14*4)(%r0)	/* adjust FP */
64	movl	%r3,(36+15*4)(%r0)	/* adjust PC */
65	clrl	%r0
66	jmp	(%r1)			/* and return */
67END(_getcontext)
68