1 /* $NetBSD: getcontext.S,v 1.6 2011/11/21 16:17:48 chs Exp $ */
4 * Copyright (c) 2003 The NetBSD Foundation, Inc.
7 * This code is derived from software contributed to The NetBSD Foundation
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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
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35 RCSID("$NetBSD: getcontext.S,v 1.6 2011/11/21 16:17:48 chs Exp $")
39 WEAK_ALIAS(getcontext, _getcontext)
43 * Can't use R4 or R5 since those needed by the phread_switch code.
46 clrl %r0 /* assume success */
47 chmk $SYS_getcontext /* getcontext(oucp) */
49 jmp CERROR+2 /* badness happened */
51 1: movl 4(%ap),%r0 /* ptr to ucontext */
52 movl 16(%fp),%r1 /* PC to return to */
53 movab 2f,16(%fp) /* let's return early */
56 * Now we have the blown away the callframe and argument
57 * list so it's as if we've return from the function except
58 * we aren't executing the caller's code (yet). So it's
59 * the callers state but we still have control.
62 2: movq %ap,(36+12*4)(%r0) /* adjust AP + SP */
63 movl %fp,(36+14*4)(%r0) /* adjust FP */
64 movl %r3,(36+15*4)(%r0) /* adjust PC */
66 jmp (%r1) /* and return */