FreeCalypso > hg > freecalypso-sw
view target-utils/libbase/serio.S @ 992:a7b0b426f9ca
target-utils: boot ROM UART autodetection revamped
The new implementation should work with both the familiar Calypso C035
boot ROM version found in our regular targets as well as the older
Calypso F741979B version found on the vintage D-Sample board.
author | Mychaela Falconia <falcon@ivan.Harhan.ORG> |
---|---|
date | Wed, 30 Dec 2015 21:28:41 +0000 |
parents | 5cff3579814c |
children |
line wrap: on
line source
#include "ns16550.h" @ this module implements the elementary serial I/O operations .comm uart_base,4,4 .text .code 32 .global serial_out serial_out: ldr r1, =uart_base ldr r2, [r1] 1: ldrb r3, [r2, #NS16550_LSR] tst r3, #NS16550_LSR_THRE beq 1b strb r0, [r2, #NS16550_THR] bx lr .global serial_in_poll serial_in_poll: ldr r1, =uart_base ldr r2, [r1] ldrb r3, [r2, #NS16550_LSR] tst r3, #NS16550_LSR_DR ldrneb r0, [r2, #NS16550_RBR] mvneq r0, #0 bx lr .global serial_flush serial_flush: ldr r1, =uart_base ldr r2, [r1] 1: ldrb r3, [r2, #NS16550_LSR] tst r3, #NS16550_LSR_TEMP beq 1b bx lr