FreeCalypso > hg > freecalypso-sw

view target-utils/libcommon/serio.S @ 369:e2a05eb3129f

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
OSL: the bogus event group code appears to be unused aside from the os_EvGrpInit() call in os_Initialize(), so let's table it aside for now, and thus spare the boatload of compiler warnings.
author Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
date Thu, 29 May 2014 06:41:52 +0000
parents 40f607bb0a2c
children d7591faa1258
line wrap: on
line source

#include "ns16550.h"

@ this module implements the elementary serial I/O operations

	.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
	mvneq	r0, #1
	bxeq	lr
	ldrb	r0, [r2, #NS16550_RBR]
	bx	lr