1/* $NetBSD: getcontext.S,v 1.4 2008/04/28 20:22:58 martin Exp $ */ 2 3/*- 4 * Copyright (c) 2003 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Thomas. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include "SYS.h" 33 34#ifdef WEAK_ALIAS 35WEAK_ALIAS(getcontext, _getcontext) 36#endif 37 38/* 39 * Can't use R4 or R5 since those needed by the phread_switch code. 40 */ 41ENTRY(_getcontext, 0) 42 clrl %r0 /* assume success */ 43 chmk $SYS_getcontext /* getcontext(oucp) */ 44 jcc 1f 45 jmp CERROR+2 /* badness happened */ 46 471: movl 4(%ap),%r2 /* ptr to ucontext */ 48 movl 16(%fp),%r3 /* PC to return to */ 49 movab 2f,16(%fp) /* let's return early */ 50 ret 51 /* 52 * Now we have the blown away the callframe and argument 53 * list so it's as if we've return from the function except 54 * we aren't executing the caller's code (yet). So it's 55 * the callers state but we still have control. 56 */ 57 _ALIGN_TEXT 582: movq %ap,(36+12*4)(%r2) /* adjust AP + SP */ 59 movl %fp,(36+14*4)(%r2) /* adjust FP */ 60 movl %r3,(36+15*4)(%r2) /* adjust PC */ 61 jmp (%r3) /* and return */ 62