[3] | 1 | ; File name : HCapacity.asm
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| 2 | ; Project name : IDE BIOS
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| 3 | ; Created date : 16.3.2010
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[32] | 4 | ; Last update : 3.8.2010
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[3] | 5 | ; Author : Tomi Tilli
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| 6 | ; Description : Functions for hard disk capacity calculations.
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| 7 |
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| 8 | ; Section containing code
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| 9 | SECTION .text
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| 10 |
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| 11 | ;--------------------------------------------------------------------
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| 12 | ; Calculates sector count from L-CHS values returned by INT 13h, AH=08h.
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| 13 | ;
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| 14 | ; HCapacity_GetSectorCountFromForeignAH08h:
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| 15 | ; HCapacity_GetSectorCountFromOurAH08h:
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| 16 | ; Parameters:
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| 17 | ; DL: Drive number
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| 18 | ; DS: RAMVARS segment
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| 19 | ; Returns:
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| 20 | ; DX:AX: Total sector count
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| 21 | ; BX: Zero
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| 22 | ; Corrupts registers:
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| 23 | ; CX
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| 24 | ;--------------------------------------------------------------------
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| 25 | ALIGN JUMP_ALIGN
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| 26 | HCapacity_GetSectorCountFromForeignAH08h:
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| 27 | mov ah, 08h ; Get Drive Parameters
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[32] | 28 | call Int13h_CallPreviousInt13hHandler
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[3] | 29 | jmp SHORT HCapacity_ConvertAH08hReturnValuesToSectorCount
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| 30 |
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| 31 | ALIGN JUMP_ALIGN
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| 32 | HCapacity_GetSectorCountFromOurAH08h:
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| 33 | push di
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| 34 | call AH8h_GetDriveParameters
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| 35 | pop di
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| 36 | ; Fall to HCapacity_ConvertAH08hReturnValuesToSectorCount
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| 37 |
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| 38 | ALIGN JUMP_ALIGN
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| 39 | HCapacity_ConvertAH08hReturnValuesToSectorCount:
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| 40 | call HAddress_ExtractLCHSFromBiosParams
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| 41 | xor ax, ax ; Zero AX
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| 42 | inc cx ; Max cylinder number to cylinder count
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| 43 | xchg al, bh ; AX=Max head number, BX=Sectors per track
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| 44 | inc ax ; AX=Head count
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| 45 | mul bx ; AX=Head count * Sectors per track
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| 46 | mul cx ; DX:AX = Total sector count
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| 47 | xor bx, bx ; Zero BX for 48-bit sector count
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| 48 | ret
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| 49 |
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| 50 |
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| 51 | ;--------------------------------------------------------------------
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| 52 | ; Converts sector count to hard disk size.
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| 53 | ;
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| 54 | ; HCapacity_ConvertSectorCountToSize:
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| 55 | ; Parameters:
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| 56 | ; BX:DX:AX: Total sector count
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| 57 | ; Returns:
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| 58 | ; AX: Size in magnitude
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| 59 | ; SI: Tenths
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| 60 | ; CX: Magnitude character:
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| 61 | ; 'k' = *1024 B = kiB
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| 62 | ; 'M' = *1024 kiB = MiB
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| 63 | ; 'G' = *1024 MiB = GiB
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| 64 | ; 'T' = *1024 GiB = TiB
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| 65 | ; 'P' = *1024 TiB = PiB
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| 66 | ; Corrupts registers:
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| 67 | ; BX, DX
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| 68 | ;--------------------------------------------------------------------
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| 69 | ALIGN JUMP_ALIGN
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| 70 | HCapacity_ConvertSectorCountToSize:
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| 71 | call HCapacity_ConvertSectorCountToKiB
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| 72 | mov cx, 1 ; Magnitude is 1 for kiB
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| 73 | ALIGN JUMP_ALIGN
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| 74 | .MagnitudeLoop:
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| 75 | test bx, bx ; Bits 32...47 in use?
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| 76 | jnz SHORT .ShiftByMagnitude ; If so, jump to shift
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| 77 | test dx, dx ; Bits 16...31 in use?
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| 78 | jnz SHORT .ShiftByMagnitude ; If so, jump to shift
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| 79 | cmp ax, 10000 ; 5 digits needed?
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| 80 | jb SHORT .ShiftComplete ; If less, all done
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| 81 | ALIGN JUMP_ALIGN
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| 82 | .ShiftByMagnitude:
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| 83 | call HCapacity_ShiftForNextMagnitude
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| 84 | jmp SHORT .MagnitudeLoop
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| 85 | ALIGN JUMP_ALIGN
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| 86 | .ShiftComplete:
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| 87 | mov bx, cx ; Copy shift count to BX
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| 88 | mov cl, [cs:bx+.rgbMagnitudeToChar]
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| 89 | jmp SHORT HCapacity_ConvertSizeRemainderToTenths
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| 90 | ALIGN WORD_ALIGN
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| 91 | .rgbMagnitudeToChar: db " kMGTP"
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| 92 |
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| 93 | ;--------------------------------------------------------------------
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| 94 | ; Converts 48-bit sector count to size in kiB.
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| 95 | ;
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| 96 | ; HCapacity_ConvertSectorCountToKiB:
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| 97 | ; Parameters:
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| 98 | ; BX:DX:AX: Total sector count
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| 99 | ; Returns:
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| 100 | ; BX:DX:AX: Total size in kiB
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| 101 | ; CF: Remainder from division
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| 102 | ; Corrupts registers:
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| 103 | ; Nothing
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| 104 | ;--------------------------------------------------------------------
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| 105 | ALIGN JUMP_ALIGN
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| 106 | HCapacity_ConvertSectorCountToKiB:
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| 107 | HCapacity_DivideSizeByTwo:
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| 108 | shr bx, 1 ; Divide sector count by 2...
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| 109 | rcr dx, 1 ; ...to get disk size in...
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| 110 | rcr ax, 1 ; ...kiB
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| 111 | ret
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| 112 |
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| 113 | ;--------------------------------------------------------------------
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| 114 | ; Divides size by 1024 and increments magnitude.
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| 115 | ;
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| 116 | ; HCapacity_ShiftForNextMagnitude:
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| 117 | ; Parameters:
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| 118 | ; BX:DX:AX: Size in magnitude
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| 119 | ; CX: Magnitude (0=B, 1=kiB, 2=MiB...)
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| 120 | ; Returns:
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| 121 | ; BX:DX:AX: Size in magnitude
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| 122 | ; SI: Remainder (0...1023)
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| 123 | ; CX: Magnitude (1=kiB, 2=MiB...)
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| 124 | ; Corrupts registers:
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| 125 | ; Nothing
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| 126 | ;--------------------------------------------------------------------
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| 127 | ALIGN JUMP_ALIGN
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| 128 | HCapacity_ShiftForNextMagnitude:
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| 129 | push cx
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| 130 | xor si, si ; Zero remainder
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| 131 | mov cl, 10 ; Divide by 1024
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| 132 | ALIGN JUMP_ALIGN
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| 133 | .ShiftLoop:
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| 134 | call HCapacity_DivideSizeByTwo
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| 135 | rcr si, 1 ; Update remainder
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| 136 | loop .ShiftLoop
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| 137 | eSHR_IM si, 6 ; Remainder to SI beginning
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| 138 | pop cx
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| 139 | inc cx ; Increment shift count
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| 140 | ret
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| 141 |
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| 142 | ;--------------------------------------------------------------------
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| 143 | ; Converts remainder from HCapacity_ShiftForNextMagnitude to tenths.
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| 144 | ;
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| 145 | ; HCapacity_ConvertSizeRemainderToTenths:
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| 146 | ; Parameters:
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| 147 | ; BX:DX:AX: Size in magnitude
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| 148 | ; SI: Remainder from last magnitude division (0...1023)
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| 149 | ; Returns:
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| 150 | ; BX:DX:AX: Size in magnitude
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| 151 | ; SI: Tenths
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| 152 | ; Corrupts registers:
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| 153 | ; Nothing
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| 154 | ;--------------------------------------------------------------------
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| 155 | ALIGN JUMP_ALIGN
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| 156 | HCapacity_ConvertSizeRemainderToTenths:
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| 157 | push dx
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| 158 | push ax
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| 159 |
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| 160 | mov ax, 10
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| 161 | mul si ; DX:AX = remainder * 10
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| 162 | eSHR_IM ax, 10 ; Divide AX by 1024
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| 163 | xchg si, ax ; SI = tenths
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| 164 |
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| 165 | pop ax
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| 166 | pop dx
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| 167 | ret
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