getcontext.S revision 1.6 
11.6Schs/*	$NetBSD: getcontext.S,v 1.6 2011/11/21 16:17:48 chs 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 *
191.1Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
201.1Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
211.1Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
221.1Smatt * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
231.1Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
241.1Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
251.1Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
261.1Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
271.1Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
281.1Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
291.1Smatt * POSSIBILITY OF SUCH DAMAGE.
301.1Smatt */
311.1Smatt
321.1Smatt#include "SYS.h"
331.1Smatt
341.5Smatt#ifdef SYSLIBC_SCCS
351.6SchsRCSID("$NetBSD: getcontext.S,v 1.6 2011/11/21 16:17:48 chs Exp $")
361.5Smatt#endif
371.5Smatt
381.3Smatt#ifdef WEAK_ALIAS
391.3SmattWEAK_ALIAS(getcontext, _getcontext)
401.3Smatt#endif
411.3Smatt
421.2Smatt/*
431.2Smatt * Can't use R4 or R5 since those needed by the phread_switch code.
441.2Smatt */
451.3SmattENTRY(_getcontext, 0)
461.2Smatt	clrl	%r0			/* assume success */
471.1Smatt	chmk	$SYS_getcontext		/* getcontext(oucp) */
481.1Smatt	jcc	1f
491.1Smatt	jmp	CERROR+2		/* badness happened */
501.1Smatt
511.6Schs1:	movl	4(%ap),%r0		/* ptr to ucontext */
521.6Schs	movl	16(%fp),%r1		/* PC to return to */
531.1Smatt	movab	2f,16(%fp)		/* let's return early */
541.1Smatt	ret
551.1Smatt	/*
561.1Smatt	 * Now we have the blown away the callframe and argument
571.1Smatt	 * list so it's as if we've return from the function except
581.1Smatt	 * we aren't executing the caller's code (yet).  So it's
591.1Smatt	 * the callers state but we still have control.
601.1Smatt	 */
611.2Smatt	_ALIGN_TEXT
621.6Schs2:	movq	%ap,(36+12*4)(%r0)	/* adjust AP + SP */
631.6Schs	movl	%fp,(36+14*4)(%r0)	/* adjust FP */
641.6Schs	movl	%r3,(36+15*4)(%r0)	/* adjust PC */
651.6Schs	clrl	%r0
661.6Schs	jmp	(%r1)			/* and return */
671.5SmattEND(_getcontext)
68