1/*        $NetBSD: swapcontext.S,v 1.6 2013/07/17 03:05:17 matt Exp $ */
2
3/*-
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Klaus Klein.
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#include "assym.h"
34
35#if defined(LIBC_SCCS) && !defined(lint)
36          RCSID("$NetBSD: swapcontext.S,v 1.6 2013/07/17 03:05:17 matt Exp $")
37#endif /* LIBC_SCCS && !lint */
38
39ENTRY(swapcontext)
40          movl      4(%sp),-(%sp)                 | push oucp on stack
41          jbsr      PIC_PLT(_C_LABEL(_getcontext))          | getcontext(oucp)
42          tstl      %d0                           | OK?
43          jne       L1
44          movl      (%sp),%a0
45          addql     #8,UC_MCONTEXT_SP(%a0)        | adjust saved stack pointer (again)
46          movl      %sp@(4),UC_MCONTEXT_PC(%a0) | adjust saved program counter (again)
47          movl      12(%sp),(%sp)                 | push ucp on stack
48          jbsr      PIC_PLT(_C_LABEL(setcontext)) | setcontext(ucp)
49L1:       addql     #4,%sp                        | pop ucp
50          rts
51END(swapcontext)
52