_start.s

/* Entry point for bare metal programs */
.section .text.start
.global _start
.type _start, @function

_start:
/* initialize global pointer */
.option push
.option norelax
1:	auipc gp, %pcrel_hi(__global_pointer$)
	addi  gp, gp, %pcrel_lo(1b)
.option pop

/* initialize stack pointer */
	la sp, _sp

/* set vector table address and vectored mode */
	la a0, __vector_start
        ori a0, a0, 0x1
	csrw mtvec, a0

/* clear the bss segment */
	la a0, __bss_start
	la a2, __bss_end
	sub a2, a2, a0
	li a1, 0
	call memset

/* new-style constructors and destructors */
	la a0, __libc_fini_array
	call atexit
	call __libc_init_array

/* call main */
	call main
	tail exit

.size  _start, .-_start

.global _init
.type   _init, @function
.global _fini
.type   _fini, @function
_init:
_fini:
 /* These don't have to do anything since we use init_array/fini_array. Prevent
    missing symbol error */
	ret
.size  _init, .-_init
.size _fini, .-_fini