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swapcontext.S revision 1.2 
      1 /*	$NetBSD: swapcontext.S,v 1.2 2003/01/18 11:12:54 thorpej 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.h"
     40 
     41 #if defined(LIBC_SCCS) && !defined(lint)
     42 	.text
     43 	.asciz "$NetBSD: swapcontext.S,v 1.2 2003/01/18 11:12:54 thorpej Exp $"
     44 #endif /* LIBC_SCCS && !lint */
     45 
     46 ENTRY(swapcontext)
     47 	stwu	1, -16(1)			# set up new stack frame
     48 	mflr	0
     49 	stw	0, 20(1)			# save link register
     50 	stw	3, 8(1)				# must save oucp
     51 	stw	4, 12(1)			# must save ucp
     52 	bl	PIC_PLT(_C_LABEL(_getcontext))	# getcontext(oucp)
     53 	cmpwi	3, 0
     54 	bne	1f
     55 	lwz	11, 8(1)			# load oucp for adjustment
     56 	lwz	0, 20(1)
     57 	stw	0, (48 + 34 * 4)(11)		# pc <- lr
     58 	la	0, 16(1)
     59 	stw	0, (48 +  1 * 4)(11)		# adjust sp
     60 	lwz	3, 12(1)			# load ucp
     61 	bl	PIC_PLT(_C_LABEL(setcontext))	# setcontext(ucp)
     62 1:
     63 	lwz	0, 20(1)
     64 	mtlr	0
     65 	la	1, 16(1)
     66 	blr
     67