minix/lib/libc/arch/vax/sys/getcontext.S

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/* $NetBSD: getcontext.S,v 1.4 2008/04/28 20:22:58 martin Exp $ */
/*-
* Copyright (c) 2003 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas.
*
* 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"
#ifdef WEAK_ALIAS
WEAK_ALIAS(getcontext, _getcontext)
#endif
/*
* Can't use R4 or R5 since those needed by the phread_switch code.
*/
ENTRY(_getcontext, 0)
clrl %r0 /* assume success */
chmk $SYS_getcontext /* getcontext(oucp) */
jcc 1f
jmp CERROR+2 /* badness happened */
1: movl 4(%ap),%r2 /* ptr to ucontext */
movl 16(%fp),%r3 /* PC to return to */
movab 2f,16(%fp) /* let's return early */
ret
/*
* Now we have the blown away the callframe and argument
* list so it's as if we've return from the function except
* we aren't executing the caller's code (yet). So it's
* the callers state but we still have control.
*/
_ALIGN_TEXT
2: movq %ap,(36+12*4)(%r2) /* adjust AP + SP */
movl %fp,(36+14*4)(%r2) /* adjust FP */
movl %r3,(36+15*4)(%r2) /* adjust PC */
jmp (%r3) /* and return */