1 /* Startup code compliant to the ELF RISC-V ABI.
2 Copyright (C) 1995-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.)
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
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.
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/>. */
36 #define __ASSEMBLY__ 1
41 /* The entry point's job is to call __libc_start_main. Per the ABI,
42 a0 contains the address of a function to be passed to atexit.
43 __libc_start_main wants this in a5. */
46 /* Terminate call stack by noting ra is undefined. Use a dummy
47 .cfi_label to force starting the FDE. */
51 mv a5, a0 /* rtld_fini. */
52 /* main may be in a shared library. */
54 REG_L a1, 0(sp) /* argc. */
55 addi a2, sp, SZREG /* argv. */
56 andi sp, sp, ALMASK /* Align stack. */
57 li a3, 0 /* Used to be init. */
58 li a4, 0 /* Used to be fini. */
59 mv a6, sp /* stack_end. */
61 call __libc_start_main@plt
65 /* Dynamic links need the global pointer to be initialized prior to calling
66 any shared library's initializers, so we use preinit_array to load it.
67 This doesn't cut it for static links, though, since the global pointer
68 needs to be initialized before calling __libc_start_main in that case.
69 So we redundantly initialize it at the beginning of _start. */
74 lla gp, __global_pointer$
78 .section .preinit_array,"aw"
81 /* Define a symbol for the first piece of initialized data. */
86 data_start = __data_start