summaryrefslogtreecommitdiff
path: root/echo.S
blob: 337c26bd510fb11d702335b9ce26cf921e5112e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
.section .text
.globl _start

.equ UART_DATA, 0
.equ UART_STATUS, 1
.equ UART_RX_READY, 0b10
.equ UART_TX_READY, 0b01

_start:
    li a0, 0x10000

loop:
    lbu t0, UART_STATUS(a0)
    andi t0, t0, UART_RX_READY
    beqz t0, loop
    lbu t0, UART_DATA(a0)
    sb t0, UART_DATA(a0)
    j loop