1 | /* Startup code for SH & ELF. |
2 | Copyright (C) 1999-2022 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 | In addition to the permissions in the GNU Lesser General Public |
11 | License, the Free Software Foundation gives you unlimited |
12 | permission to link the compiled version of this file with other |
13 | programs, and to distribute those programs without any restriction |
14 | coming from the use of this file. (The GNU Lesser General Public |
15 | License restrictions do apply in other respects; for example, they |
16 | cover modification of the file, and distribution when not linked |
17 | into another program.) |
18 | |
19 | Note that people who make modified versions of this file are not |
20 | obligated to grant this special exception for their modified |
21 | versions; it is their choice whether to do so. The GNU Lesser |
22 | General Public License gives permission to release a modified |
23 | version without this exception; this exception also makes it |
24 | possible to release a modified version which carries forward this |
25 | exception. |
26 | |
27 | The GNU C Library is distributed in the hope that it will be useful, |
28 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
29 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
30 | Lesser General Public License for more details. |
31 | |
32 | You should have received a copy of the GNU Lesser General Public |
33 | License along with the GNU C Library; if not, see |
34 | <https://www.gnu.org/licenses/>. */ |
35 | |
36 | /* This is the canonical entry point, usually the first thing in the text |
37 | segment. |
38 | |
39 | Note that the code in the .init section has already been run. |
40 | This includes _init and _libc_init |
41 | |
42 | |
43 | At this entry point, most registers' values are unspecified, except: |
44 | |
45 | r4 Contains a function pointer to be registered with `atexit'. |
46 | This is how the dynamic linker arranges to have DT_FINI |
47 | functions called for shared libraries that have been loaded |
48 | before this code runs. |
49 | |
50 | sp The stack contains the arguments and environment: |
51 | 0(sp) argc |
52 | 4(sp) argv[0] |
53 | ... |
54 | (4*argc)(sp) NULL |
55 | (4*(argc+1))(sp) envp[0] |
56 | ... |
57 | NULL |
58 | */ |
59 | |
60 | .text |
61 | .globl _start |
62 | .type _start,@function |
63 | _start: |
64 | /* Clear the frame pointer since this is the outermost frame. */ |
65 | mov #0, r14 |
66 | |
67 | /* Pop argc off the stack and save a pointer to argv */ |
68 | mov.l @r15+,r5 |
69 | mov r15, r6 |
70 | |
71 | /* Push the last arguments to main() onto the stack */ |
72 | mov.l r4,@-r15 |
73 | mov.l r14,@-r15 /* Used to be fini. */ |
74 | |
75 | /* Set up the other arguments for main() that go in registers */ |
76 | mov.l L_main,r4 |
77 | mov #0,r7 /* Used to be init. */ |
78 | |
79 | /* __libc_start_main (main, argc, argv, init, fini, rtld_fini) */ |
80 | |
81 | /* Let the libc call main and exit with its return code. */ |
82 | mov.l L_libc_start_main,r1 |
83 | jsr @r1 |
84 | nop |
85 | /* should never get here....*/ |
86 | mov.l L_abort,r1 |
87 | jsr @r1 |
88 | nop |
89 | .align 2 |
90 | L_main: |
91 | .long main |
92 | L_libc_start_main: |
93 | .long __libc_start_main |
94 | L_abort: |
95 | .long abort |
96 | /* Define a symbol for the first piece of initialized data. */ |
97 | .data |
98 | .globl __data_start |
99 | __data_start: |
100 | .long 0 |
101 | .weak data_start |
102 | data_start = __data_start |
103 | .global __fpscr_values |
104 | __fpscr_values: |
105 | .long 0 |
106 | .long 0x80000 |
107 | |