1/* Startup code for ARC.
2 Copyright (C) 2020-2024 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 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#define __ASSEMBLY__ 1
37#include <entry.h>
38#include <sysdep.h>
39
40#ifndef ENTRY_POINT
41# error ENTRY_POINT needs to be defined for ARC
42#endif
43
44/* When we enter this piece of code, the program stack looks like this:
45 argc argument counter (integer)
46 argv[0] program name (pointer)
47 argv[1...N] program args (pointers)
48 argv[argc-1] end of args (integer)
49 NULL
50 env[0...N] environment variables (pointers)
51 NULL. */
52
53ENTRY (ENTRY_POINT)
54
55 /* Needed to make gdb backtraces stop here. */
56 .cfi_label .Ldummy
57 cfi_undefined (blink)
58
59 mov fp, 0
60 ld_s r1, [sp] /* argc. */
61
62 mov_s r5, r0 /* rltd_fini. */
63 add_s r2, sp, 4 /* argv. */
64 and sp, sp, -8
65 mov r6, sp
66
67 /* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end). */
68
69 mov_s r3, 0 /* Used to be init. */
70 mov r4, 0 /* Used to be fini. */
71
72#ifdef SHARED
73 ld r0, [pcl, @main@gotpc]
74 bl __libc_start_main@plt
75#else
76 mov_s r0, main
77 bl __libc_start_main
78#endif
79
80 /* Should never get here. */
81 flag 1
82END (ENTRY_POINT)
83
84/* Define a symbol for the first piece of initialized data. */
85 .data
86 .globl __data_start
87__data_start:
88 .long 0
89 .weak data_start
90 data_start = __data_start
91

source code of glibc/sysdeps/arc/start.S