1/* $NetBSD: getcontext.S,v 1.1 2003/01/19 19:32:39 matt 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39#include "SYS.h" 40 41ENTRY(getcontext, 0) 42 chmk $SYS_getcontext /* getcontext(oucp) */ 43 jcc 1f 44 jmp CERROR+2 /* badness happened */ 45 461: movl 4(%ap),%r2 /* ptr to ucontext */ 47 movl 16(%fp),%r3 /* PC to return to */ 48 movab 2f,16(%fp) /* let's return early */ 49 ret 50 /* 51 * Now we have the blown away the callframe and argument 52 * list so it's as if we've return from the function except 53 * we aren't executing the caller's code (yet). So it's 54 * the callers state but we still have control. 55 */ 56 .align 2 572: movq %ap,(36+12*4)(%r2) /* adjust AP + SP */ 58 movl %fp,(36+14*4)(%r2) /* adjust FP */ 59 movl %r3,(36+15*4)(%r2) /* adjust PC */ 60 jmp (%r3) /* and return */ 61