source: mainline/uspace/lib/c/generic/setjmp.c@ 850fd32

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 850fd32 was e0a4686, checked in by Jiří Zárevúcky <zarevucky.jiri@…>, 8 years ago

Introduce context_swap() and use it to simplify fibril implementation.

This wraps the use of context_save()/context_restore(), to provide a more
natural (and easier to understand) control flow. The patch also hides the
details of the underlying context, requiring the use of context_get_pc()
to acquire program counter. This might allow context_swap() to only store
one pointer in the context, storing the remaining information in its stack
frame. However, that is not done in this patch.

  • Property mode set to 100644
File size: 2.3 KB
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1/*
2 * Copyright (c) 2013 Vojtech Horky
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup libc
30 * @{
31 */
32/** @file Long jump implementation.
33 *
34 * Implementation inspired by Jiri Zarevucky's code from
35 * http://bazaar.launchpad.net/~zarevucky-jiri/helenos/stdc/revision/1544/uspace/lib/posix/setjmp.h
36 */
37
38#include <setjmp.h>
39#include <context.h>
40
41// TODO: setjmp/longjmp are basically a stronger version of
42// context_save/context_restore. It would be preferable to turn
43// those two into setjmp/longjmp (all it would need is preserving the
44// return value).
45
46/**
47 * Restore environment previously stored by setjmp.
48 *
49 * This function never returns.
50 *
51 * @param env Variable with the environment previously stored by call
52 * to setjmp.
53 * @param val Value to fake when returning from setjmp (0 is transformed to 1).
54 */
55void longjmp(jmp_buf env, int val) {
56 env[0].return_value = (val == 0) ? 1 : val;
57 context_restore(&env[0].context);
58}
59
60/** @}
61 */
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