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f7a9f785 | 1 | /* Copyright (C) 2012-2016 Free Software Foundation, Inc. |
402a76b6 MH |
2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
5 | modify it under the terms of the GNU Lesser General Public | |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
8 | ||
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
15 | License along with the GNU C Library; if not, see | |
16 | <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #include <stdarg.h> | |
19 | #include <ucontext.h> | |
20 | ||
21 | /* Number of arguments that go in registers. */ | |
22 | #define NREG_ARGS 4 | |
23 | ||
24 | /* Take a context previously prepared via getcontext() and set to | |
25 | call func() with the given int only args. */ | |
26 | void | |
27 | __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...) | |
28 | { | |
29 | extern void __startcontext (void); | |
30 | unsigned long *funcstack; | |
31 | va_list vl; | |
32 | unsigned long *regptr; | |
33 | unsigned int reg; | |
34 | int misaligned; | |
35 | ||
36 | /* Start at the top of stack. */ | |
37 | funcstack = (unsigned long *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); | |
38 | ||
39 | /* Ensure the stack stays eight byte aligned. */ | |
40 | misaligned = ((unsigned long) funcstack & 4) != 0; | |
41 | ||
42 | if ((argc > NREG_ARGS) && (argc & 1) != 0) | |
43 | misaligned = !misaligned; | |
44 | ||
45 | if (misaligned) | |
46 | funcstack -= 1; | |
47 | ||
48 | va_start (vl, argc); | |
49 | ||
50 | /* Reserve space for the on-stack arguments. */ | |
51 | if (argc > NREG_ARGS) | |
52 | funcstack -= (argc - NREG_ARGS); | |
53 | ||
54 | ucp->uc_mcontext.arm_sp = (unsigned long) funcstack; | |
55 | ucp->uc_mcontext.arm_pc = (unsigned long) func; | |
56 | ||
57 | /* Exit to startcontext() with the next context in R4 */ | |
58 | ucp->uc_mcontext.arm_r4 = (unsigned long) ucp->uc_link; | |
59 | ucp->uc_mcontext.arm_lr = (unsigned long) __startcontext; | |
60 | ||
61 | /* The first four arguments go into registers. */ | |
62 | regptr = &(ucp->uc_mcontext.arm_r0); | |
63 | ||
64 | for (reg = 0; (reg < argc) && (reg < NREG_ARGS); reg++) | |
65 | *regptr++ = va_arg (vl, unsigned long); | |
66 | ||
67 | /* And the remainder on the stack. */ | |
68 | for (; reg < argc; reg++) | |
69 | *funcstack++ = va_arg (vl, unsigned long); | |
70 | ||
71 | va_end (vl); | |
72 | } | |
73 | weak_alias (__makecontext, makecontext) |