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/* $NetBSD: swapcontext.S,v 1.3 2015/03/27 23:23:14 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 1.3 2015/03/27 23:23:14 matt Exp $")
#define CALLFRAME_UCP CALLFRAME_S1
#define CALLFRAME_OUCP CALLFRAME_S0
ENTRY(swapcontext)
addi sp, sp, -CALLFRAME_SIZ # adjust stack
REG_S ra, CALLFRAME_RA(sp) # save return address
REG_S a0, CALLFRAME_OUCP(sp) # save oucp
REG_S a1, CALLFRAME_UCP(sp) # save ucp
call PLT(_C_LABEL(_getcontext)) # getcontext(oucp)
mv t0, a0 # save return value
REG_L ra, CALLFRAME_RA(sp) # restore return address
REG_L a0, CALLFRAME_UCP(sp) # load ucp
REG_L a1, CALLFRAME_OUCP(sp) # load oucp for adjustment
addi sp, sp, CALLFRAME_SIZ # restore stack
bnez t0, 1f # error? yes, cleanup
REG_S ra, UC_GREGS_PC(a1) # pc <- ra
REG_S sp, UC_GREGS_SP(a1) # adjust sp
tail PLT(_C_LABEL(setcontext)) # setcontext(ucp)
1: ret # simply return
END(swapcontext)
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