view target-utils/libbase/serio.S @ 1030:194967e11b2b

fc-shell: tch record and tch play reworked for libgsm-compatible file format
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 31 May 2016 18:39:06 +0000
parents a7b0b426f9ca
children
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#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