Functions
use sbi call to getchar from console (qemu uart handler)
use sbi call to putchar in console (qemu uart handler)
use sbi call to set timer
use sbi call to shutdown the kernel
use sbi call to getchar from console (qemu uart handler)
use sbi call to putchar in console (qemu uart handler)
use sbi call to set timer
use sbi call to shutdown the kernel