| 1 | ; Project name : Assembly Library
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| 2 | ; Description : Functions to operate with
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| 3 | ; 8254 Programmable Interval Timer.
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| 4 |
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| 5 | ;
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| 6 | ; XTIDE Universal BIOS and Associated Tools
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| 7 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team.
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| 8 | ;
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| 9 | ; This program is free software; you can redistribute it and/or modify
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| 10 | ; it under the terms of the GNU General Public License as published by
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| 11 | ; the Free Software Foundation; either version 2 of the License, or
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| 12 | ; (at your option) any later version.
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| 13 | ;
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| 14 | ; This program is distributed in the hope that it will be useful,
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| 15 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 16 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 17 | ; GNU General Public License for more details.
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| 18 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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| 19 | ;
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| 20 |
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| 21 | ; Section containing code
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| 22 | SECTION .text
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| 23 |
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| 24 | ;--------------------------------------------------------------------
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| 25 | ; SystemTimer_IntializePreciseEventTimer
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| 26 | ; Parameters:
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| 27 | ; Nothing
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| 28 | ; Returns:
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| 29 | ; Nothing
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| 30 | ; Corrupts registers:
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| 31 | ; AX
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| 32 | ;--------------------------------------------------------------------
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| 33 | ALIGN JUMP_ALIGN
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| 34 | SystemTimer_IntializePreciseEventTimer:
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| 35 | STOP_PRECISE_EVENT_TIMER
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| 36 | OUTPUT_COUNTER_COMMAND_TO TIMER_2, READ_OR_WRITE_LSB_THEN_MSB, MODE_0_SINGLE_TIMEOUT, BINARY_COUNTER
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| 37 | xor ax, ax
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| 38 | WRITE_COUNT_FROM_AX_TO TIMER_2
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| 39 | ret
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| 40 |
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| 41 |
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| 42 | ;--------------------------------------------------------------------
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| 43 | ; This is how to use precise event timer:
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| 44 | ; 1. Call SystemTimer_IntializePreciseEventTimer
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| 45 | ; 2. Use START_PRECISE_EVENT_TIMER macro to start timer
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| 46 | ; 3. Use STOP_PRECISE_EVENT_TIMER to stop timer (optional)
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| 47 | ; 4. Call SystemTimer_GetPreciseEventTimerTicksToAX to get event duration
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| 48 | ;
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| 49 | ; SystemTimer_GetPreciseEventTimerTicksToAX
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| 50 | ; Parameters:
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| 51 | ; Nothing
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| 52 | ; Returns:
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| 53 | ; AX: Event duration in timer ticks
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| 54 | ; Corrupts registers:
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| 55 | ; Nothing
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| 56 | ;--------------------------------------------------------------------
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| 57 | ALIGN JUMP_ALIGN
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| 58 | SystemTimer_GetPreciseEventTimerTicksToAX:
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| 59 | OUTPUT_COUNTER_COMMAND_TO TIMER_2, LATCH, MODE_0_SINGLE_TIMEOUT, BINARY_COUNTER
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| 60 | READ_COUNT_TO_AX_FROM TIMER_2
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| 61 | neg ax ; 0 - count (Mode 0 counts toward zero)
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| 62 | ret
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