learn_riscv/chuckstechtalk/hello_asm/hello.s

.equ UART_BASE, 0x10000000 # a constant containing the base address for the uart that we will send data. 
# This UART is defined as a NS16550 Uart in https://www.qemu.org/docs/master/system/riscv/virt.html
# UART16550 Core technical manual

.section .text
    la a0, helloworld # Load address of string
    li a1, UART_BASE # Load uart tx base address. This will be used to send characters to the uart
    call puts   # Print string

loop: j loop  # This loop never exits, so the program will just continue to loop.

# This is function
puts:
    # a0 - String address
    # a1 - UART Base address
1:                      # While string bytes is no null
    lb t0, 0(a0)        # Get byte at current string pos
    beq zero, t0, 2f    # is null?
    sb t0, (a1)         # Since not null write byte to port
    addi a0, a0, 1      # Implement string pointer moving us to the next character in the string.
    j 1b                # Loop
2:                      # String byte is null.
    ret

.section .data
helloworld: .string "Hello Chuck!\n"