/* Startup code compliant to the ELF RISC-V ABI.
Copyright (C) 1995-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
In addition to the permissions in the GNU Lesser General Public
License, the Free Software Foundation gives you unlimited
permission to link the compiled version of this file with other
programs, and to distribute those programs without any restriction
coming from the use of this file. (The GNU Lesser General Public
License restrictions do apply in other respects; for example, they
cover modification of the file, and distribution when not linked
into another program.)
Note that people who make modified versions of this file are not
obligated to grant this special exception for their modified
versions; it is their choice whether to do so. The GNU Lesser
General Public License gives permission to release a modified
version without this exception; this exception also makes it
possible to release a modified version which carries forward this
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
#define __ASSEMBLY__ 1
/* The entry point's job is to call __libc_start_main. Per the ABI,
a0 contains the address of a function to be passed to atexit.
__libc_start_main wants this in a5. */
/* Terminate call stack by noting ra is undefined. Use a dummy
.cfi_label to force starting the FDE. */
mv a5, a0 /* rtld_fini. */
/* main may be in a shared library. */
la a0, main
REG_L a1, 0(sp) /* argc. */
addi a2, sp, SZREG /* argv. */
andi sp, sp, ALMASK /* Align stack. */
lla a3, __libc_csu_init
lla a4, __libc_csu_fini
mv a6, sp /* stack_end. */
/* Dynamic links need the global pointer to be initialized prior to calling
any shared library's initializers, so we use preinit_array to load it.
This doesn't cut it for static links, though, since the global pointer
needs to be initialized before calling __libc_start_main in that case.
So we redundantly initialize it at the beginning of _start. */
lla gp, __global_pointer$
/* Define a symbol for the first piece of initialized data. */
data_start = __data_start