1*27620987Smatt/* $NetBSD: swapcontext.S,v 1.1 2014/09/03 19:34:25 matt Exp $ */ 2*27620987Smatt 3*27620987Smatt/*- 4*27620987Smatt * Copyright (c) 2001 The NetBSD Foundation, Inc. 5*27620987Smatt * All rights reserved. 6*27620987Smatt * 7*27620987Smatt * This code is derived from software contributed to The NetBSD Foundation 8*27620987Smatt * by Klaus Klein. 9*27620987Smatt * 10*27620987Smatt * Redistribution and use in source and binary forms, with or without 11*27620987Smatt * modification, are permitted provided that the following conditions 12*27620987Smatt * are met: 13*27620987Smatt * 1. Redistributions of source code must retain the above copyright 14*27620987Smatt * notice, this list of conditions and the following disclaimer. 15*27620987Smatt * 2. Redistributions in binary form must reproduce the above copyright 16*27620987Smatt * notice, this list of conditions and the following disclaimer in the 17*27620987Smatt * documentation and/or other materials provided with the distribution. 18*27620987Smatt * 19*27620987Smatt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20*27620987Smatt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21*27620987Smatt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22*27620987Smatt * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23*27620987Smatt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24*27620987Smatt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25*27620987Smatt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26*27620987Smatt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27*27620987Smatt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28*27620987Smatt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29*27620987Smatt * POSSIBILITY OF SUCH DAMAGE. 30*27620987Smatt */ 31*27620987Smatt 32*27620987Smatt#include "SYS.h" 33*27620987Smatt#include "assym.h" 34*27620987Smatt 35*27620987Smatt__RCSID("$NetBSD: swapcontext.S,v 1.1 2014/09/03 19:34:25 matt Exp $") 36*27620987Smatt 37*27620987Smatt#define CALLFRAME_LR (-1*4) 38*27620987Smatt#define CALLFRAME_UCP (-2*4) 39*27620987Smatt#define CALLFRAME_OUCP (-3*4) 40*27620987Smatt#define CALLFRAME_GP (-4*4) 41*27620987Smatt#define CALLFRAME_SP (-5*4) 42*27620987Smatt#define CALLFRAME_LEN (-CALLFRAME_SP) 43*27620987Smatt 44*27620987SmattENTRY(swapcontext) 45*27620987Smatt l.sw CALLFRAME_LR(r1),lr # save link register 46*27620987Smatt l.sw CALLFRAME_OUCP(r1),r3 # save oucp 47*27620987Smatt l.sw CALLFRAME_UCP(r1),r4 # save ucp 48*27620987Smatt l.sw CALLFRAME_SP(r1),r1 # set up stack chain 49*27620987Smatt#ifdef __PIC__ 50*27620987Smatt l.sw CALLFRAME_GP(r1),r16 # save r16 51*27620987Smatt PIC_GOTSETUP(r16) # setup got pointer 52*27620987Smatt#endif 53*27620987Smatt l.addi r1,r1,-CALLFRAME_LEN # adjust stack 54*27620987Smatt l.jal PLT(_C_LABEL(_getcontext)) # getcontext(oucp) 55*27620987Smatt l.nop # -- delay slot -- 56*27620987Smatt l.sfeqi r11,0 # error? 57*27620987Smatt l.bnf 1f # yes, cleanup 58*27620987Smatt l.nop # -- delay slot -- 59*27620987Smatt l.addi r5,r1,CALLFRAME_LEN # adjust stack 60*27620987Smatt l.lwz r4,CALLFRAME_OUCP(r5) # load oucp for adjustment 61*27620987Smatt l.sw UC_GREGS_PC(r4),lr # pc <- lr 62*27620987Smatt l.sw UC_GREGS_SP(r4),r1 # adjust sp 63*27620987Smatt l.lwz r3,CALLFRAME_UCP(r5) # load ucp 64*27620987Smatt # can't do a tail call due to needing r16 for PLT 65*27620987Smatt l.jal PLT(_C_LABEL(setcontext)) # setcontext(ucp) 66*27620987Smatt l.nop # -- delay slot -- 67*27620987Smatt1: 68*27620987Smatt l.addi r1,r1,CALLFRAME_LEN # restore stack 69*27620987Smatt#ifdef __PIC__ 70*27620987Smatt l.lwz r16,CALLFRAME_GP(r1) # restore r16 71*27620987Smatt#endif 72*27620987Smatt l.lwz lr,CALLFRAME_LR(r1) # refetch lr 73*27620987Smatt l.jr lr # simply return 74*27620987Smatt l.nop # -- delay slot -- 75*27620987SmattEND(swapcontext) 76