annotate target-utils/libcommon/serio.S @ 165:9dbf3248a197

starting to compile ETM
author Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
date Tue, 19 Nov 2013 04:23:29 +0000
parents 40f607bb0a2c
children d7591faa1258
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1 #include "ns16550.h"
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2
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3 @ this module implements the elementary serial I/O operations
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4
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5 .text
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6 .code 32
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7 .global serial_out
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8 serial_out:
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9 ldr r1, =uart_base
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10 ldr r2, [r1]
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11 1: ldrb r3, [r2, #NS16550_LSR]
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12 tst r3, #NS16550_LSR_THRE
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13 beq 1b
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14 strb r0, [r2, #NS16550_THR]
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15 bx lr
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16
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17 .global serial_in_poll
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18 serial_in_poll:
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19 ldr r1, =uart_base
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20 ldr r2, [r1]
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21 ldrb r3, [r2, #NS16550_LSR]
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22 tst r3, #NS16550_LSR_DR
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23 mvneq r0, #1
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24 bxeq lr
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25 ldrb r0, [r2, #NS16550_RBR]
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26 bx lr