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# vim: filetype=asm:
/* Copyright (c) 2017 SiFive Inc. All rights reserved.
This copyrighted material is made available to anyone wishing to use,
modify, copy, or redistribute it subject to the terms and conditions
of the FreeBSD License. This program is distributed in the hope that
it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
including the implied warranties of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. A copy of this license is available at
http://www.opensource.org/licenses.
Modified in 2026 by taitep to run bare metal on the TRVE emulator,
*/
#include "newlib.h"
#=========================================================================
# crt0.S : Entry point for RISC-V user programs
#=========================================================================
.text
.global _start, _exit, _heap_end
.type _start, @function
_start:
# Initialize the stack pointer
la sp, _stack_top
# Initialize global pointer
.option push
.option norelax
1:auipc gp, %pcrel_hi(__global_pointer$)
addi gp, gp, %pcrel_lo(1b)
.option pop
# Clear the bss segment
la a0, _bss_start
la a2, _bss_end
sub a2, a2, a0
li a1, 0
call memset
# Clear the sbss segment
la a0, _sbss_start
la a2, _sbss_end
sub a2, a2, a0
li a1, 0
call memset
#ifdef _LITE_EXIT
# Make reference to atexit weak to avoid unconditionally pulling in
# support code. Refer to comments in __atexit.c for more details.
.weak atexit
la a0, atexit
beqz a0, .Lweak_atexit
.weak __libc_fini_array
#endif
la a0, __libc_fini_array # Register global termination functions
call atexit # to be called upon exit
#ifdef _LITE_EXIT
.Lweak_atexit:
#endif
call __libc_init_array # Run global initialization functions
# initialize UART
call uart_init
call main
call exit
_exit: j _exit
.size _start, .-_start
_heap_end:
.dword _heap_start
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