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comparison target-utils/libbase/serio.S @ 0:e7502631a0f9

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initial import from freecalypso-sw rev 1033:5ab737ac3ad7
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 11 Jun 2016 00:13:35 +0000
parents
children da6df2c626cf
comparison
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-1:000000000000 0:e7502631a0f9
1 #include "ns16550.h"
2
3 @ this module implements the elementary serial I/O operations
4
5 .comm uart_base,4,4
6
7 .text
8 .code 32
9 .global serial_out
10 serial_out:
11 ldr r1, =uart_base
12 ldr r2, [r1]
13 1: ldrb r3, [r2, #NS16550_LSR]
14 tst r3, #NS16550_LSR_THRE
15 beq 1b
16 strb r0, [r2, #NS16550_THR]
17 bx lr
18
19 .global serial_in_poll
20 serial_in_poll:
21 ldr r1, =uart_base
22 ldr r2, [r1]
23 ldrb r3, [r2, #NS16550_LSR]
24 tst r3, #NS16550_LSR_DR
25 ldrneb r0, [r2, #NS16550_RBR]
26 mvneq r0, #0
27 bx lr
28
29 .global serial_flush
30 serial_flush:
31 ldr r1, =uart_base
32 ldr r2, [r1]
33 1: ldrb r3, [r2, #NS16550_LSR]
34 tst r3, #NS16550_LSR_TEMP
35 beq 1b
36 bx lr