[140] | 1 | ; Project name : XTIDE Universal BIOS |
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| 2 | ; Description : Timeout and delay functions for INT 13h services. |
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| 3 | |
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| 4 | ; Section containing code |
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| 5 | SECTION .text |
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| 6 | |
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| 7 | ;-------------------------------------------------------------------- |
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[155] | 8 | ; Timer_InitializeTimeoutWithTicksInCL |
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[140] | 9 | ; Parameters: |
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[155] | 10 | ; CL: Timeout value in system timer ticks |
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[140] | 11 | ; DS: Segment to RAMVARS |
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| 12 | ; Returns: |
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| 13 | ; Nothing |
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| 14 | ; Corrupts registers: |
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| 15 | ; CX |
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| 16 | ;-------------------------------------------------------------------- |
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| 17 | ALIGN JUMP_ALIGN |
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[155] | 18 | Timer_InitializeTimeoutWithTicksInCL: |
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| 19 | mov [RAMVARS.bTimeoutTicksLeft], cl ; Ticks until timeout |
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[140] | 20 | call ReadTimeFromBdaToCX |
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[155] | 21 | mov [RAMVARS.bLastTimeoutUpdate], cl ; Start time |
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[140] | 22 | ret |
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| 23 | |
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| 24 | |
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| 25 | ;-------------------------------------------------------------------- |
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[155] | 26 | ; Timer_SetCFifTimeout |
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[140] | 27 | ; Parameters: |
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| 28 | ; DS: Segment to RAMVARS |
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| 29 | ; Returns: |
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| 30 | ; CF: Set if timeout |
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| 31 | ; Cleared if time left |
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| 32 | ; Corrupts registers: |
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| 33 | ; CX |
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| 34 | ;-------------------------------------------------------------------- |
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| 35 | ALIGN JUMP_ALIGN |
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[155] | 36 | Timer_SetCFifTimeout: |
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[140] | 37 | call ReadTimeFromBdaToCX |
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[155] | 38 | cmp cl, [RAMVARS.bLastTimeoutUpdate] |
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| 39 | je SHORT .StillPollingTheSameTick |
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| 40 | mov [RAMVARS.bLastTimeoutUpdate], cl |
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| 41 | sub BYTE [RAMVARS.bTimeoutTicksLeft], 1 ; DEC does not update CF |
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| 42 | .StillPollingTheSameTick: |
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[140] | 43 | ret |
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| 44 | |
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| 45 | |
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| 46 | ;-------------------------------------------------------------------- |
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| 47 | ; Delay is always at least one millisecond since |
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| 48 | ; RTC resolution is 977 microsecs. |
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| 49 | ; |
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[155] | 50 | ; Timer_DelayMicrosecondsFromAX |
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[140] | 51 | ; Parameters: |
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| 52 | ; AX: Number of microsecs to wait |
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| 53 | ; Returns: |
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| 54 | ; Nothing |
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| 55 | ; Corrupts registers: |
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| 56 | ; AX |
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| 57 | ;-------------------------------------------------------------------- |
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[155] | 58 | Timer_DelayMicrosecondsFromAX: |
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[140] | 59 | %ifndef USE_AT |
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[150] | 60 | mov ax, 2 |
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[181] | 61 | ; Fall to Timer_DelayTimerTicksFromAX |
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[140] | 62 | %else |
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| 63 | push dx |
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| 64 | push cx |
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| 65 | |
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| 66 | xor cx, cx |
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[148] | 67 | xchg dx, ax ; Microsecs now in CX:DX |
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[140] | 68 | mov ah, EVENT_WAIT |
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| 69 | int BIOS_SYSTEM_INTERRUPT_15h |
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[181] | 70 | sti ; XT BIOSes return with interrupts disabled. TODO: Maybe we can remove this since it's in an AT-only block? |
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[140] | 71 | |
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| 72 | pop cx |
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| 73 | pop dx |
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[148] | 74 | mov ax, 1 ; Prepare to wait 1 timer tick |
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[155] | 75 | jc SHORT Timer_DelayTimerTicksFromAX ; Event Wait was unsupported or busy |
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[140] | 76 | ret |
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| 77 | %endif |
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| 78 | |
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| 79 | |
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| 80 | ;-------------------------------------------------------------------- |
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| 81 | ; First tick might take 0...54.9 ms and remaining ticks |
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| 82 | ; will occur at 54.9 ms intervals. |
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| 83 | ; |
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[155] | 84 | ; Timer_DelayTimerTicksFromAX |
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[140] | 85 | ; Parameters: |
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| 86 | ; AX: Number of timer ticks to wait |
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| 87 | ; Returns: |
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| 88 | ; Nothing |
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| 89 | ; Corrupts registers: |
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| 90 | ; AX |
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| 91 | ;-------------------------------------------------------------------- |
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[155] | 92 | Timer_DelayTimerTicksFromAX: |
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[140] | 93 | sti ; Make sure that interrupts are enabled |
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| 94 | call ReadTimeFromBdaToCX |
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| 95 | add ax, cx ; AX = end time |
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| 96 | .WaitLoop: |
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| 97 | call ReadTimeFromBdaToCX |
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| 98 | cmp cx, ax |
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[155] | 99 | jne SHORT .WaitLoop ; Loop until end time is reached |
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[140] | 100 | ret |
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| 101 | |
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| 102 | |
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| 103 | ;-------------------------------------------------------------------- |
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| 104 | ; ReadTimeFromBdaToCX |
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| 105 | ; Parameters |
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| 106 | ; Nothing |
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| 107 | ; Returns: |
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| 108 | ; CX: System time in 54.9 ms ticks |
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| 109 | ; Corrupts registers: |
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| 110 | ; Nothing |
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| 111 | ;-------------------------------------------------------------------- |
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| 112 | ALIGN JUMP_ALIGN |
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| 113 | ReadTimeFromBdaToCX: |
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| 114 | push ds |
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| 115 | LOAD_BDA_SEGMENT_TO ds, cx |
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| 116 | mov cx, [BDA.dwTimerTicks] ; Read low WORD only |
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| 117 | pop ds |
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| 118 | ret |
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