view target-utils/libbase/serio.S @ 231:a58a7bbc0618

CHANGES: first changes since fc-host-tools-r5
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 03 Aug 2017 03:21:39 +0000
parents e7502631a0f9
children da6df2c626cf
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