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5f51e113 | 1 | /* Startup code compliant to the ELF m68k ABI. |
dff8da6b | 2 | Copyright (C) 1996-2024 Free Software Foundation, Inc. |
fb1efdea | 3 | This file is part of the GNU C Library. |
5f51e113 | 4 | |
fb1efdea | 5 | The GNU C Library is free software; you can redistribute it and/or |
3214b89b AJ |
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. | |
5f51e113 | 9 | |
0bec0145 RM |
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 | ||
fb1efdea UD |
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 | |
3214b89b | 30 | Lesser General Public License for more details. |
5f51e113 | 31 | |
3214b89b | 32 | You should have received a copy of the GNU Lesser General Public |
ab84e3ff | 33 | License along with the GNU C Library. If not, see |
5a82c748 | 34 | <https://www.gnu.org/licenses/>. */ |
5f51e113 RM |
35 | |
36 | /* This is the canonical entry point, usually the first thing in the text | |
37 | segment. The SVR4/m68k ABI says that when the entry point runs, | |
38 | most registers' values are unspecified, except for: | |
39 | ||
40 | %a1 Contains a function pointer to be registered with `atexit'. | |
fb1efdea | 41 | This is how the dynamic linker arranges to have DT_FINI |
5f51e113 RM |
42 | functions called for shared libraries that have been loaded |
43 | before this code runs. | |
44 | ||
45 | %sp The stack contains the arguments and environment: | |
fb1efdea | 46 | 0(%sp) argc |
5f51e113 RM |
47 | 4(%sp) argv[0] |
48 | ... | |
49 | (4*argc)(%sp) NULL | |
50 | (4*(argc+1))(%sp) envp[0] | |
51 | ... | |
52 | NULL | |
53 | */ | |
54 | ||
ed4c9939 AS |
55 | #include <sysdep.h> |
56 | ||
fb1efdea | 57 | .text |
5f51e113 | 58 | .globl _start |
13906e12 | 59 | .type _start,@function |
5f51e113 RM |
60 | _start: |
61 | /* Clear the frame pointer. The ABI suggests this be done, to mark | |
62 | the outermost frame obviously. */ | |
63 | sub.l %fp, %fp | |
64 | ||
69235f76 AS |
65 | /* Extract the arguments as encoded on the stack and set up the |
66 | arguments for `main': argc, argv. envp will be determined | |
67 | later in __libc_start_main. */ | |
68 | move.l (%sp)+, %d0 /* Pop the argument count. */ | |
69 | move.l %sp, %a0 /* The argument vector starts just at the | |
70 | current stack top. */ | |
5f51e113 | 71 | |
08016d92 AS |
72 | /* Provide the highest stack address to the user code (for stacks |
73 | which grow downward). */ | |
74 | pea (%sp) | |
75 | ||
69235f76 AS |
76 | pea (%a1) /* Push address of the shared library |
77 | termination function. */ | |
5f51e113 | 78 | |
035c012e FW |
79 | /* These used to be addresses of the .fini and .init entry points. */ |
80 | clr.l -(%sp) | |
81 | clr.l -(%sp) | |
82 | ||
4027a4fd | 83 | #ifdef PIC |
ed4c9939 AS |
84 | /* Load PIC register. */ |
85 | LOAD_GOT (%a5) | |
86 | ||
ed4c9939 AS |
87 | pea (%a0) /* Push second argument: argv. */ |
88 | move.l %d0, -(%sp) /* Push first argument: argc. */ | |
89 | ||
90 | move.l main@GOT(%a5), -(%sp) | |
91 | ||
92 | /* Call the user's main function, and exit with its value. But | |
93 | let the libc call main. */ | |
7d0c5ed0 | 94 | jbsr __libc_start_main@PLTPC |
ed4c9939 | 95 | #else |
69235f76 AS |
96 | |
97 | pea (%a0) /* Push second argument: argv. */ | |
5f51e113 RM |
98 | move.l %d0, -(%sp) /* Push first argument: argc. */ |
99 | ||
69235f76 AS |
100 | pea main |
101 | ||
102 | /* Call the user's main function, and exit with its value. But | |
103 | let the libc call main. */ | |
104 | jbsr __libc_start_main | |
ed4c9939 | 105 | #endif |
5f51e113 | 106 | |
69235f76 | 107 | illegal /* Crash if somehow `exit' does return. */ |
5f51e113 RM |
108 | |
109 | /* Define a symbol for the first piece of initialized data. */ | |
110 | .data | |
111 | .globl __data_start | |
112 | __data_start: | |
113 | .long 0 | |
114 | .weak data_start | |
115 | data_start = __data_start |