1 | /* Create new context. C-SKY version. |
2 | Copyright (C) 2018-2024 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library. If not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <stdarg.h> |
20 | #include <ucontext.h> |
21 | |
22 | /* Number of arguments that go in registers. */ |
23 | #define NREG_ARGS 4 |
24 | |
25 | /* Take a context previously prepared via getcontext() and set to |
26 | call func() with the given int only args. */ |
27 | void |
28 | __makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...) |
29 | { |
30 | extern void __startcontext (void); |
31 | unsigned long *funcstack; |
32 | va_list vl; |
33 | unsigned long *regptr; |
34 | unsigned int reg; |
35 | int misaligned; |
36 | |
37 | /* Start at the top of stack. */ |
38 | funcstack = (unsigned long *) (ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); |
39 | |
40 | /* Ensure the stack stays eight byte aligned. */ |
41 | misaligned = ((unsigned long) funcstack & 4) != 0; |
42 | |
43 | if ((argc > NREG_ARGS) && (argc & 1) != 0) |
44 | misaligned = !misaligned; |
45 | |
46 | if (misaligned) |
47 | funcstack -= 1; |
48 | |
49 | va_start (vl, argc); |
50 | |
51 | /* Reserve space for the on-stack arguments. */ |
52 | if (argc > NREG_ARGS) |
53 | funcstack -= (argc - NREG_ARGS); |
54 | |
55 | ucp->uc_mcontext.__gregs.__usp = (unsigned long) funcstack; |
56 | ucp->uc_mcontext.__gregs.__pc = (unsigned long) func; |
57 | |
58 | /* Exit to startcontext() with the next context in R9. */ |
59 | ucp->uc_mcontext.__gregs.__regs[5] = (unsigned long) ucp->uc_link; |
60 | ucp->uc_mcontext.__gregs.__lr = (unsigned long) __startcontext; |
61 | |
62 | /* The first four arguments go into registers. */ |
63 | regptr = &(ucp->uc_mcontext.__gregs.__a0); |
64 | |
65 | for (reg = 0; (reg < argc) && (reg < NREG_ARGS); reg++) |
66 | *regptr++ = va_arg (vl, unsigned long); |
67 | |
68 | /* And the remainder on the stack. */ |
69 | for (; reg < argc; reg++) |
70 | *funcstack++ = va_arg (vl, unsigned long); |
71 | |
72 | va_end (vl); |
73 | } |
74 | weak_alias (__makecontext, makecontext) |
75 | |