[41] | 1 | ; File name : TimerTicks.asm |
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| 2 | ; Project name : Assembly Library |
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| 3 | ; Created date : 24.7.2010 |
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[60] | 4 | ; Last update : 22.11.2010 |
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[41] | 5 | ; Author : Tomi Tilli |
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| 6 | ; Description : Functions for system timer related operations. |
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| 7 | |
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| 8 | ; System timer ticks 18.2 times per second = 54.9 ms / tick |
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| 9 | TICKS_PER_HOUR EQU 65520 |
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| 10 | TICKS_PER_MINUTE EQU 1092 |
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| 11 | TICKS_PER_SECOND EQU 18 |
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| 12 | |
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| 13 | |
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| 14 | ; Section containing code |
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| 15 | SECTION .text |
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| 16 | |
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| 17 | ;-------------------------------------------------------------------- |
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| 18 | ; TimerTicks_GetHoursToAXfromTicksInDXAX |
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| 19 | ; TimerTicks_GetMinutesToAXfromTicksInDX |
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| 20 | ; TimerTicks_GetSecondsToAXfromTicksInDX |
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| 21 | ; Parameters |
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| 22 | ; DX(:AX): Timer ticks to convert |
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| 23 | ; Returns: |
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| 24 | ; AX: Hours, minutes or seconds |
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| 25 | ; DX: Remainder ticks |
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| 26 | ; Corrupts registers: |
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| 27 | ; CX |
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| 28 | ;-------------------------------------------------------------------- |
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| 29 | ALIGN JUMP_ALIGN |
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| 30 | TimerTicks_GetHoursToAXfromTicksInDXAX: |
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| 31 | mov cx, TICKS_PER_HOUR |
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| 32 | div cx ; Divide DX:AX by CX, Hours to AX, remainder ticks to DX |
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| 33 | ret |
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| 34 | |
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| 35 | ALIGN JUMP_ALIGN |
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| 36 | TimerTicks_GetMinutesToAXfromTicksInDX: |
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| 37 | xor ax, ax |
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| 38 | xchg ax, dx ; Ticks now in DX:AX |
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| 39 | mov cx, TICKS_PER_MINUTE |
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| 40 | div cx ; Divide DX:AX by CX, Minutes to AX, remainder ticks to DX |
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| 41 | ret |
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| 42 | |
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| 43 | ALIGN JUMP_ALIGN |
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| 44 | TimerTicks_GetSecondsToAXfromTicksInDX: |
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| 45 | xchg ax, dx ; Ticks now in AX |
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| 46 | mov cl, TICKS_PER_SECOND |
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| 47 | div cl ; Divide AX by CL, Seconds to AL, remainder ticks to AH |
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| 48 | xor dx, dx |
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| 49 | xchg dl, ah ; Seconds in AX, remainder in DX |
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| 50 | ret |
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| 51 | |
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| 52 | |
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| 53 | ;-------------------------------------------------------------------- |
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| 54 | ; First tick might take 0...54.9 ms and remaining ticks |
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| 55 | ; will occur at 54.9 ms intervals. Use delay of two (or more) ticks to |
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| 56 | ; ensure at least 54.9 ms timeout. |
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| 57 | ; |
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| 58 | ; TimerTicks_InitializeTimeoutFromAX |
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| 59 | ; Parameters: |
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| 60 | ; AX: Timeout ticks (54.9 ms) before timeout |
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| 61 | ; DS:BX: Ptr to timeout variable WORD |
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| 62 | ; Returns: |
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| 63 | ; [DS:BX]: Initialized for TimerTicks_SetCarryIfTimeoutFromDSBX |
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| 64 | ; Corrupts registers: |
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| 65 | ; AX |
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| 66 | ;-------------------------------------------------------------------- |
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| 67 | ALIGN JUMP_ALIGN |
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| 68 | TimerTicks_InitializeTimeoutFromAX: |
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| 69 | mov [bx], ax ; Store timeout ticks |
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| 70 | call TimerTicks_ReadFromBdaToAX |
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| 71 | add [bx], ax ; Add latest time to timeout ticks |
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| 72 | ret |
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| 73 | |
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[60] | 74 | |
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[41] | 75 | ;-------------------------------------------------------------------- |
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[60] | 76 | ; TimerTicks_GetTimeoutTicksLeftToAXfromDSBX |
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[41] | 77 | ; Parameters: |
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[60] | 78 | ; AX: Number of ticks left before timeout |
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[41] | 79 | ; DS:BX: Ptr to timeout variable WORD |
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| 80 | ; Returns: |
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| 81 | ; CF: Set if timeout |
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| 82 | ; Cleared if time left |
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| 83 | ; Corrupts registers: |
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| 84 | ; Nothing |
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| 85 | ;-------------------------------------------------------------------- |
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| 86 | ALIGN JUMP_ALIGN |
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[60] | 87 | TimerTicks_GetTimeoutTicksLeftToAXfromDSBX: |
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| 88 | push dx |
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| 89 | mov dx, [bx] |
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[41] | 90 | call TimerTicks_ReadFromBdaToAX |
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[60] | 91 | xchg ax, dx |
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| 92 | sub ax, dx ; AX = End time - current time |
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| 93 | pop dx |
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[41] | 94 | ret |
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| 95 | |
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| 96 | |
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| 97 | ;-------------------------------------------------------------------- |
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| 98 | ; TimerTicks_GetElapsedToAXandResetDSBX |
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| 99 | ; Parameters |
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| 100 | ; DS:BX: Ptr to WORD containing previous reset time |
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| 101 | ; Returns: |
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| 102 | ; AX: 54.9 ms ticks elapsed since last reset |
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| 103 | ; [DS:BX]: Reset to latest time |
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| 104 | ; Corrupts registers: |
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| 105 | ; Nothing |
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| 106 | ;-------------------------------------------------------------------- |
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| 107 | ALIGN JUMP_ALIGN |
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| 108 | TimerTicks_GetElapsedToAXandResetDSBX: |
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| 109 | call TimerTicks_ReadFromBdaToAX |
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| 110 | push ax |
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| 111 | sub ax, [bx] |
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| 112 | pop WORD [bx] ; Latest time to [DS:BX] |
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| 113 | ret |
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| 114 | |
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| 115 | ;-------------------------------------------------------------------- |
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| 116 | ; TimerTicks_GetElapsedToAXfromDSBX |
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| 117 | ; Parameters |
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| 118 | ; DS:BX: Ptr to WORD containing previous update time |
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| 119 | ; Returns: |
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| 120 | ; AX: 54.9 ms ticks elapsed since initializing [DS:BX] |
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| 121 | ; Corrupts registers: |
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| 122 | ; Nothing |
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| 123 | ;-------------------------------------------------------------------- |
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| 124 | ALIGN JUMP_ALIGN |
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| 125 | TimerTicks_GetElapsedToAXfromDSBX: |
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| 126 | call TimerTicks_ReadFromBdaToAX |
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| 127 | sub ax, [bx] |
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| 128 | ret |
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| 129 | |
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| 130 | |
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| 131 | ;-------------------------------------------------------------------- |
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| 132 | ; TimerTicks_ReadFromBdaToAX |
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| 133 | ; Parameters |
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| 134 | ; Nothing |
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| 135 | ; Returns: |
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| 136 | ; AX: System time in 54.9 ms ticks |
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| 137 | ; Corrupts registers: |
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| 138 | ; Nothing |
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| 139 | ;-------------------------------------------------------------------- |
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| 140 | ALIGN JUMP_ALIGN |
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| 141 | TimerTicks_ReadFromBdaToAX: |
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| 142 | push ds |
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| 143 | |
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| 144 | LOAD_BDA_SEGMENT_TO ds, ax |
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| 145 | mov ax, [BDA.dwTimerTicks] ; Read low WORD only |
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| 146 | |
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| 147 | pop ds |
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| 148 | ret |
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