getcontext.S revision 1.3 
11.3Smatt/*	$NetBSD: getcontext.S,v 1.3 2003/01/23 23:56:13 matt Exp $	*/
21.1Smatt
31.1Smatt/*-
41.1Smatt * Copyright (c) 2003 The NetBSD Foundation, Inc.
51.1Smatt * All rights reserved.
61.1Smatt *
71.1Smatt * This code is derived from software contributed to The NetBSD Foundation
81.1Smatt * by Matt Thomas.
91.1Smatt *
101.1Smatt * Redistribution and use in source and binary forms, with or without
111.1Smatt * modification, are permitted provided that the following conditions
121.1Smatt * are met:
131.1Smatt * 1. Redistributions of source code must retain the above copyright
141.1Smatt *    notice, this list of conditions and the following disclaimer.
151.1Smatt * 2. Redistributions in binary form must reproduce the above copyright
161.1Smatt *    notice, this list of conditions and the following disclaimer in the
171.1Smatt *    documentation and/or other materials provided with the distribution.
181.1Smatt * 3. All advertising materials mentioning features or use of this software
191.1Smatt *    must display the following acknowledgement:
201.1Smatt *        This product includes software developed by the NetBSD
211.1Smatt *        Foundation, Inc. and its contributors.
221.1Smatt * 4. Neither the name of The NetBSD Foundation nor the names of its
231.1Smatt *    contributors may be used to endorse or promote products derived
241.1Smatt *    from this software without specific prior written permission.
251.1Smatt *
261.1Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
271.1Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
281.1Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
291.1Smatt * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
301.1Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
311.1Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
321.1Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
331.1Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
341.1Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
351.1Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
361.1Smatt * POSSIBILITY OF SUCH DAMAGE.
371.1Smatt */
381.1Smatt
391.1Smatt#include "SYS.h"
401.1Smatt
411.3Smatt#ifdef WEAK_ALIAS
421.3SmattWEAK_ALIAS(getcontext, _getcontext)
431.3Smatt#endif
441.3Smatt
451.2Smatt/*
461.2Smatt * Can't use R4 or R5 since those needed by the phread_switch code.
471.2Smatt */
481.3SmattENTRY(_getcontext, 0)
491.2Smatt	clrl	%r0			/* assume success */
501.1Smatt	chmk	$SYS_getcontext		/* getcontext(oucp) */
511.1Smatt	jcc	1f
521.1Smatt	jmp	CERROR+2		/* badness happened */
531.1Smatt
541.1Smatt1:	movl	4(%ap),%r2		/* ptr to ucontext */
551.1Smatt	movl	16(%fp),%r3		/* PC to return to */
561.1Smatt	movab	2f,16(%fp)		/* let's return early */
571.1Smatt	ret
581.1Smatt	/*
591.1Smatt	 * Now we have the blown away the callframe and argument
601.1Smatt	 * list so it's as if we've return from the function except
611.1Smatt	 * we aren't executing the caller's code (yet).  So it's
621.1Smatt	 * the callers state but we still have control.
631.1Smatt	 */
641.2Smatt	_ALIGN_TEXT
651.1Smatt2:	movq	%ap,(36+12*4)(%r2)	/* adjust AP + SP */
661.1Smatt	movl	%fp,(36+14*4)(%r2)	/* adjust FP */
671.1Smatt	movl	%r3,(36+15*4)(%r2)	/* adjust PC */
681.1Smatt	jmp	(%r3)			/* and return */
69