xref: /netbsd-src/lib/libc/arch/powerpc/gen/swapcontext.S (revision 8e33e1ffffe892b4afe0721ef033d7f81598afd6)
1*8e33e1ffSuwe/*	$NetBSD: swapcontext.S,v 1.8 2018/02/28 20:51:58 uwe Exp $	*/
23fdac2b8Sthorpej
33fdac2b8Sthorpej/*-
43fdac2b8Sthorpej * Copyright (c) 2001 The NetBSD Foundation, Inc.
53fdac2b8Sthorpej * All rights reserved.
63fdac2b8Sthorpej *
73fdac2b8Sthorpej * This code is derived from software contributed to The NetBSD Foundation
83fdac2b8Sthorpej * by Klaus Klein.
93fdac2b8Sthorpej *
103fdac2b8Sthorpej * Redistribution and use in source and binary forms, with or without
113fdac2b8Sthorpej * modification, are permitted provided that the following conditions
123fdac2b8Sthorpej * are met:
133fdac2b8Sthorpej * 1. Redistributions of source code must retain the above copyright
143fdac2b8Sthorpej *    notice, this list of conditions and the following disclaimer.
153fdac2b8Sthorpej * 2. Redistributions in binary form must reproduce the above copyright
163fdac2b8Sthorpej *    notice, this list of conditions and the following disclaimer in the
173fdac2b8Sthorpej *    documentation and/or other materials provided with the distribution.
183fdac2b8Sthorpej *
193fdac2b8Sthorpej * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
203fdac2b8Sthorpej * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
213fdac2b8Sthorpej * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
223fdac2b8Sthorpej * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
233fdac2b8Sthorpej * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
243fdac2b8Sthorpej * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
253fdac2b8Sthorpej * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
263fdac2b8Sthorpej * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
273fdac2b8Sthorpej * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
283fdac2b8Sthorpej * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
293fdac2b8Sthorpej * POSSIBILITY OF SUCH DAMAGE.
303fdac2b8Sthorpej */
313fdac2b8Sthorpej
323fdac2b8Sthorpej#include "SYS.h"
33cf88c389Smatt#include "assym.h"
343fdac2b8Sthorpej
35*8e33e1ffSuwe__RCSID("$NetBSD: swapcontext.S,v 1.8 2018/02/28 20:51:58 uwe Exp $")
36cf88c389Smatt
37b79441d4Smatt#define	XCALLFRAMELEN	(((2+3)*SZREG + CALLFRAMELEN - 1) & -CALLFRAMELEN)
38b79441d4Smatt#define	XCALLFRAME_R30	(XCALLFRAMELEN-1*SZREG)
39b79441d4Smatt#define	XCALLFRAME_UCP	(XCALLFRAMELEN-2*SZREG)
40b79441d4Smatt#define	XCALLFRAME_OUCP	(XCALLFRAMELEN-3*SZREG)
413fdac2b8Sthorpej
423fdac2b8SthorpejENTRY(swapcontext)
43b79441d4Smatt	stwu	%r1,-XCALLFRAMELEN(%r1)		# set up new stack frame
4409c5c31fSkleink	mflr	%r0
45b79441d4Smatt	stw	%r0,XCALLFRAMELEN+CALLFRAME_LR(%r1)	# save link register
46b79441d4Smatt	stw	%r3,XCALLFRAME_OUCP(%r1)	# must save oucp
47b79441d4Smatt	stw	%r4,XCALLFRAME_UCP(%r1)		# must save ucp
484d12bfcdSjoerg#ifdef __PIC__
49b79441d4Smatt	stw	%r30,XCALLFRAME_R30(%r1)	# must save r30
50b79441d4Smatt	PIC_TOCSETUP(swapcontext,%r30)		# setup toc pointer
51b79441d4Smatt#endif
523fdac2b8Sthorpej	bl	PIC_PLT(_C_LABEL(_getcontext))	# getcontext(oucp)
5309c5c31fSkleink	cmpwi	%r3,0
543fdac2b8Sthorpej	bne	1f
55b79441d4Smatt	lwz	%r11,XCALLFRAME_OUCP(%r1)	# load oucp for adjustment
56b79441d4Smatt	lwz	%r0,XCALLFRAMELEN+CALLFRAME_LR(%r1)
57cf88c389Smatt	stw	%r0,UC_GREGS_PC(%r11)		# pc <- lr
58b79441d4Smatt	addi	%r0,%r1,XCALLFRAMELEN
59b79441d4Smatt	stw	%r0,UC_GREGS_R1(%r11)		# adjust sp
60*8e33e1ffSuwe#ifdef __PIC__
61*8e33e1ffSuwe	lwz	%r0,XCALLFRAME_R30(%r1)
62*8e33e1ffSuwe	stw	%r0,UC_GREGS_R30(%r11)		# caller's r30
63*8e33e1ffSuwe#endif
64b79441d4Smatt	lwz	%r3,XCALLFRAME_UCP(%r1)		# load ucp
653fdac2b8Sthorpej	bl	PIC_PLT(_C_LABEL(setcontext))	# setcontext(ucp)
663fdac2b8Sthorpej1:
67b79441d4Smatt	lwz	%r0,XCALLFRAMELEN+CALLFRAME_LR(%r1)
684d12bfcdSjoerg#ifdef __PIC__
69b79441d4Smatt	lwz	%r30,XCALLFRAME_R30(%r1)
70b79441d4Smatt#endif
7109c5c31fSkleink	mtlr	%r0
72b79441d4Smatt	addi	%r1,%r1,XCALLFRAMELEN
733fdac2b8Sthorpej	blr
74cf88c389SmattEND(swapcontext)
75