| 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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