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/* $NetBSD: swapcontext.S,v 1.1 2014/09/03 19:34:25 matt Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Klaus Klein.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "SYS.h"
#include "assym.h"
__RCSID("$NetBSD: swapcontext.S,v 1.1 2014/09/03 19:34:25 matt Exp $")
#define CALLFRAME_LR (-1*4)
#define CALLFRAME_UCP (-2*4)
#define CALLFRAME_OUCP (-3*4)
#define CALLFRAME_GP (-4*4)
#define CALLFRAME_SP (-5*4)
#define CALLFRAME_LEN (-CALLFRAME_SP)
ENTRY(swapcontext)
l.sw CALLFRAME_LR(r1),lr # save link register
l.sw CALLFRAME_OUCP(r1),r3 # save oucp
l.sw CALLFRAME_UCP(r1),r4 # save ucp
l.sw CALLFRAME_SP(r1),r1 # set up stack chain
#ifdef __PIC__
l.sw CALLFRAME_GP(r1),r16 # save r16
PIC_GOTSETUP(r16) # setup got pointer
#endif
l.addi r1,r1,-CALLFRAME_LEN # adjust stack
l.jal PLT(_C_LABEL(_getcontext)) # getcontext(oucp)
l.nop # -- delay slot --
l.sfeqi r11,0 # error?
l.bnf 1f # yes, cleanup
l.nop # -- delay slot --
l.addi r5,r1,CALLFRAME_LEN # adjust stack
l.lwz r4,CALLFRAME_OUCP(r5) # load oucp for adjustment
l.sw UC_GREGS_PC(r4),lr # pc <- lr
l.sw UC_GREGS_SP(r4),r1 # adjust sp
l.lwz r3,CALLFRAME_UCP(r5) # load ucp
# can't do a tail call due to needing r16 for PLT
l.jal PLT(_C_LABEL(setcontext)) # setcontext(ucp)
l.nop # -- delay slot --
1:
l.addi r1,r1,CALLFRAME_LEN # restore stack
#ifdef __PIC__
l.lwz r16,CALLFRAME_GP(r1) # restore r16
#endif
l.lwz lr,CALLFRAME_LR(r1) # refetch lr
l.jr lr # simply return
l.nop # -- delay slot --
END(swapcontext)
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