xref: /minix3/lib/libc/arch/vax/sys/getcontext.S (revision e415d488727a332a2c69df018aa35e2cecf4148a)
1*e415d488SLionel Sambuc/*	$NetBSD: getcontext.S,v 1.6 2011/11/21 16:17:48 chs Exp $	*/
22fe8fb19SBen Gras
32fe8fb19SBen Gras/*-
42fe8fb19SBen Gras * Copyright (c) 2003 The NetBSD Foundation, Inc.
52fe8fb19SBen Gras * All rights reserved.
62fe8fb19SBen Gras *
72fe8fb19SBen Gras * This code is derived from software contributed to The NetBSD Foundation
82fe8fb19SBen Gras * by Matt Thomas.
92fe8fb19SBen Gras *
102fe8fb19SBen Gras * Redistribution and use in source and binary forms, with or without
112fe8fb19SBen Gras * modification, are permitted provided that the following conditions
122fe8fb19SBen Gras * are met:
132fe8fb19SBen Gras * 1. Redistributions of source code must retain the above copyright
142fe8fb19SBen Gras *    notice, this list of conditions and the following disclaimer.
152fe8fb19SBen Gras * 2. Redistributions in binary form must reproduce the above copyright
162fe8fb19SBen Gras *    notice, this list of conditions and the following disclaimer in the
172fe8fb19SBen Gras *    documentation and/or other materials provided with the distribution.
182fe8fb19SBen Gras *
192fe8fb19SBen Gras * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
202fe8fb19SBen Gras * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
212fe8fb19SBen Gras * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
222fe8fb19SBen Gras * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
232fe8fb19SBen Gras * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
242fe8fb19SBen Gras * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
252fe8fb19SBen Gras * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
262fe8fb19SBen Gras * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
272fe8fb19SBen Gras * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
282fe8fb19SBen Gras * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
292fe8fb19SBen Gras * POSSIBILITY OF SUCH DAMAGE.
302fe8fb19SBen Gras */
312fe8fb19SBen Gras
322fe8fb19SBen Gras#include "SYS.h"
332fe8fb19SBen Gras
34*e415d488SLionel Sambuc#ifdef SYSLIBC_SCCS
35*e415d488SLionel SambucRCSID("$NetBSD: getcontext.S,v 1.6 2011/11/21 16:17:48 chs Exp $")
36*e415d488SLionel Sambuc#endif
37*e415d488SLionel Sambuc
382fe8fb19SBen Gras#ifdef WEAK_ALIAS
392fe8fb19SBen GrasWEAK_ALIAS(getcontext, _getcontext)
402fe8fb19SBen Gras#endif
412fe8fb19SBen Gras
422fe8fb19SBen Gras/*
432fe8fb19SBen Gras * Can't use R4 or R5 since those needed by the phread_switch code.
442fe8fb19SBen Gras */
452fe8fb19SBen GrasENTRY(_getcontext, 0)
462fe8fb19SBen Gras	clrl	%r0			/* assume success */
472fe8fb19SBen Gras	chmk	$SYS_getcontext		/* getcontext(oucp) */
482fe8fb19SBen Gras	jcc	1f
492fe8fb19SBen Gras	jmp	CERROR+2		/* badness happened */
502fe8fb19SBen Gras
51*e415d488SLionel Sambuc1:	movl	4(%ap),%r0		/* ptr to ucontext */
52*e415d488SLionel Sambuc	movl	16(%fp),%r1		/* PC to return to */
532fe8fb19SBen Gras	movab	2f,16(%fp)		/* let's return early */
542fe8fb19SBen Gras	ret
552fe8fb19SBen Gras	/*
562fe8fb19SBen Gras	 * Now we have the blown away the callframe and argument
572fe8fb19SBen Gras	 * list so it's as if we've return from the function except
582fe8fb19SBen Gras	 * we aren't executing the caller's code (yet).  So it's
592fe8fb19SBen Gras	 * the callers state but we still have control.
602fe8fb19SBen Gras	 */
612fe8fb19SBen Gras	_ALIGN_TEXT
62*e415d488SLionel Sambuc2:	movq	%ap,(36+12*4)(%r0)	/* adjust AP + SP */
63*e415d488SLionel Sambuc	movl	%fp,(36+14*4)(%r0)	/* adjust FP */
64*e415d488SLionel Sambuc	movl	%r3,(36+15*4)(%r0)	/* adjust PC */
65*e415d488SLionel Sambuc	clrl	%r0
66*e415d488SLionel Sambuc	jmp	(%r1)			/* and return */
67*e415d488SLionel SambucEND(_getcontext)
68