/* $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) |