xref: /onnv-gate/usr/src/lib/libc/sparcv9/gen/swapctxt.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*	Copyright (c) 1988 AT&T	*/
23*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
24*0Sstevel@tonic-gate 
25*0Sstevel@tonic-gate 
26*0Sstevel@tonic-gate /*
27*0Sstevel@tonic-gate  * Copyright 1996-2003 Sun Microsystems, Inc.  All rights reserved.
28*0Sstevel@tonic-gate  * Use is subject to license terms.
29*0Sstevel@tonic-gate  */
30*0Sstevel@tonic-gate 
31*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
32*0Sstevel@tonic-gate 
33*0Sstevel@tonic-gate #pragma weak swapcontext = _swapcontext
34*0Sstevel@tonic-gate 
35*0Sstevel@tonic-gate #include "synonyms.h"
36*0Sstevel@tonic-gate #include <ucontext.h>
37*0Sstevel@tonic-gate #include <sys/types.h>
38*0Sstevel@tonic-gate #include "libc.h"
39*0Sstevel@tonic-gate 
40*0Sstevel@tonic-gate int
41*0Sstevel@tonic-gate swapcontext(ucontext_t *oucp, const ucontext_t *nucp)
42*0Sstevel@tonic-gate {
43*0Sstevel@tonic-gate 	greg_t *reg;
44*0Sstevel@tonic-gate 
45*0Sstevel@tonic-gate 	if (__getcontext_syscall(oucp))
46*0Sstevel@tonic-gate 		return (-1);
47*0Sstevel@tonic-gate 
48*0Sstevel@tonic-gate 	/*
49*0Sstevel@tonic-gate 	 * Note that %o1 and %g1 are modified by the system call
50*0Sstevel@tonic-gate 	 * routine. ABI calling conventions specify that the caller
51*0Sstevel@tonic-gate 	 * can not depend upon %o0 thru %o5 nor g1, so no effort is
52*0Sstevel@tonic-gate 	 * made to maintain these registers. %o0 is forced to reflect
53*0Sstevel@tonic-gate 	 * an affirmative return code.
54*0Sstevel@tonic-gate 	 */
55*0Sstevel@tonic-gate 	reg = oucp->uc_mcontext.gregs;
56*0Sstevel@tonic-gate 	reg[REG_SP] = getfp();
57*0Sstevel@tonic-gate 	reg[REG_O7] = caller();
58*0Sstevel@tonic-gate 	reg[REG_PC] = reg[REG_O7] + 8;
59*0Sstevel@tonic-gate 	reg[REG_nPC] = reg[REG_PC] + 4;
60*0Sstevel@tonic-gate 	reg[REG_O0] = 0;
61*0Sstevel@tonic-gate 
62*0Sstevel@tonic-gate 	return (setcontext((ucontext_t *)nucp));
63*0Sstevel@tonic-gate }
64