[3] | 1 | ; File name : HAddress.asm
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| 2 | ; Project name : IDE BIOS
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| 3 | ; Created date : 11.3.2010
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| 4 | ; Last update : 4.4.2010
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| 5 | ; Author : Tomi Tilli
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| 6 | ; Description : Functions for address translations.
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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 | ; Outputs sector count, L-CHS address and command to IDE registers.
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| 13 | ; This function does not wait until command has been completed.
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| 14 | ;
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| 15 | ; HAddress_ConvertParamsFromBiosLCHStoIDE
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| 16 | ; Parameters:
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| 17 | ; CH: Cylinder number, bits 7...0
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| 18 | ; CL: Bits 7...6: Cylinder number bits 9 and 8
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| 19 | ; Bits 5...0: Starting sector number (1...63)
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| 20 | ; DH: Starting head number (0...255)
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| 21 | ; DS:DI: Ptr to DPT
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| 22 | ; Returns:
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| 23 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0)
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| 24 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8)
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| 25 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16)
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| 26 | ; BH: Drive and Head Register (LBA 27...24)
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| 27 | ; Corrupts registers:
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| 28 | ; AX, DX
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| 29 | ;--------------------------------------------------------------------
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| 30 | ALIGN WORD_ALIGN
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| 31 | g_rgfnAddressTranslation:
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| 32 | dw HAddress_DoNotConvertLCHS ; 0, ADDR_DPT_LCHS
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| 33 | dw HAddress_ConvertLCHStoPCHS ; 1, ADDR_DPT_PCHS
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| 34 | dw HAddress_ConvertLCHStoLBARegisterValues ; 2, ADDR_DPT_LBA28
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| 35 | dw HAddress_ConvertLCHStoLBARegisterValues ; 3, ADDR_DPT_LBA48
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| 36 |
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| 37 | ALIGN JUMP_ALIGN
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| 38 | HAddress_ConvertParamsFromBiosLCHStoIDE:
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| 39 | mov bl, [di+DPT.bFlags]
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| 40 | and bx, BYTE MASK_DPT_ADDR ; Addressing mode to BX
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| 41 | push WORD [cs:bx+g_rgfnAddressTranslation] ; Push return address
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| 42 | ; Fall to HAddress_ExtractLCHSFromBiosParams
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| 43 |
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| 44 | ;---------------------------------------------------------------------
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| 45 | ; Extracts L-CHS parameters from BIOS function parameters.
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| 46 | ;
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| 47 | ; HAddress_ExtractLCHSFromBiosParams:
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| 48 | ; Parameters:
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| 49 | ; CH: Cylinder number, bits 7...0
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| 50 | ; CL: Bits 7...6: Cylinder number bits 9 and 8
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| 51 | ; Bits 5...0: Sector number
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| 52 | ; DH: Head number
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| 53 | ; Returns:
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| 54 | ; BL: Sector number (1...63)
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| 55 | ; BH: Head number (0...255)
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| 56 | ; CX: Cylinder number (0...1023)
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| 57 | ; Corrupts registers:
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| 58 | ; Nothing
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| 59 | ;--------------------------------------------------------------------
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| 60 | ALIGN JUMP_ALIGN
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| 61 | HAddress_ExtractLCHSFromBiosParams:
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| 62 | mov bl, cl ; Copy sector number...
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| 63 | and bl, 3Fh ; ...and limit to 1...63
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| 64 | sub cl, bl ; Remove from cylinder number high
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| 65 | eROL_IM cl, 2 ; High bits to beginning
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| 66 | mov bh, dh ; Copy Head number
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| 67 | xchg cl, ch ; Cylinder number now in CX
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| 68 | ret
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| 69 |
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| 70 |
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| 71 | ;---------------------------------------------------------------------
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| 72 | ; Converts BIOS LCHS parameters to IDE P-CHS parameters.
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| 73 | ; PCylinder = (LCylinder << n) + (LHead / PHeadCount)
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| 74 | ; PHead = LHead % PHeadCount
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| 75 | ; PSector = LSector
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| 76 | ;
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| 77 | ; HAddress_ConvertLCHStoPCHS:
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| 78 | ; Parameters:
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| 79 | ; BL: Sector number (1...63)
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| 80 | ; BH: Head number (0...255)
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| 81 | ; CX: Cylinder number (0...1023)
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| 82 | ; DS:DI: Ptr to Disk Parameter Table
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| 83 | ; Returns:
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| 84 | ; BL: Sector number (1...63)
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| 85 | ; BH: Head number (0...15)
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| 86 | ; CX: Cylinder number (0...16382)
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| 87 | ; Corrupts registers:
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| 88 | ; AX, DX
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| 89 | ;--------------------------------------------------------------------
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| 90 | ALIGN JUMP_ALIGN
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| 91 | HAddress_ConvertLCHStoPCHS:
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| 92 | ; LHead / PHeadCount and LHead % PHeadCount
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| 93 | eMOVZX ax, bh ; Copy L-CHS Head number to AX
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| 94 | div BYTE [di+DPT.bPHeads] ; AL = LHead / PHeadCount, AH = LHead % PHeadCount
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| 95 | mov bh, ah ; Copy P-CHS Head number to BH
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| 96 | xor ah, ah ; AX = LHead / PHeadCount
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| 97 |
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| 98 | ; (LCylinder << n) + (LHead / PHeadCount)
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| 99 | mov dx, cx ; Copy L-CHS Cylinder number to DX
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| 100 | mov cl, [di+DPT.bShLtoP] ; Load shift count
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| 101 | shl dx, cl ; DX = LCylinder << n
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| 102 | add ax, dx ; AX = P-CHS Cylinder number
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| 103 | mov cx, ax ; Copy P-CHS Cylinder number to CX
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| 104 | ALIGN JUMP_ALIGN
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| 105 | HAddress_DoNotConvertLCHS:
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| 106 | ret
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| 107 |
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| 108 |
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| 109 | ;---------------------------------------------------------------------
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| 110 | ; Converts LCHS parameters to 28-bit LBA address.
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| 111 | ; Returned address is in same registers that
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| 112 | ; HAddress_DoNotConvertLCHS and HAddress_ConvertLCHStoPCHS returns.
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| 113 | ;
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| 114 | ; HAddress_ConvertLCHStoLBARegisterValues:
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| 115 | ; Parameters:
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| 116 | ; BL: Sector number (1...63)
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| 117 | ; BH: Head number (0...255)
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| 118 | ; CX: Cylinder number (0...1023)
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| 119 | ; DS:DI: Ptr to Disk Parameter Table
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| 120 | ; Returns:
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| 121 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0)
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| 122 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8)
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| 123 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16)
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| 124 | ; BH: Drive and Head Register (LBA 27...24)
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| 125 | ; Corrupts registers:
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| 126 | ; AX, DX
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| 127 | ;--------------------------------------------------------------------
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| 128 | ALIGN JUMP_ALIGN
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| 129 | HAddress_ConvertLCHStoLBARegisterValues:
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| 130 | call HAddress_ConvertLCHStoLBA28
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| 131 | mov bl, al ; Sector Number Register (LBA 7...0)
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| 132 | mov cl, ah ; Low Cylinder Register (LBA 15...8)
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| 133 | mov ch, dl ; High Cylinder Register (LBA 23...16)
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| 134 | mov bh, dh ; Drive and Head Register (LBA 27...24)
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| 135 | ret
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| 136 |
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| 137 | ;---------------------------------------------------------------------
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| 138 | ; Converts LCHS parameters to 28-bit LBA address.
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| 139 | ; Only 24-bits are used since LHCS to LBA28 conversion has 8.4GB limit.
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| 140 | ; LBA = ((cylToSeek*headsPerCyl+headToSeek)*sectPerTrack)+sectToSeek-1
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| 141 | ;
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| 142 | ; HAddress_ConvertLCHStoLBA28:
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| 143 | ; Parameters:
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| 144 | ; BL: Sector number (1...63)
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| 145 | ; BH: Head number (0...255)
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| 146 | ; CX: Cylinder number (0...1023)
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| 147 | ; DS:DI: Ptr to Disk Parameter Table
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| 148 | ; Returns:
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| 149 | ; DX:AX: 28-bit LBA address (DH is always zero)
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| 150 | ; Corrupts registers:
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| 151 | ; BX, CX
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| 152 | ;--------------------------------------------------------------------
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| 153 | ALIGN JUMP_ALIGN
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| 154 | HAddress_ConvertLCHStoLBA28:
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| 155 | ; cylToSeek*headsPerCyl (18-bit result)
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| 156 | mov ax, cx ; Copy Cylinder number to AX
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| 157 | mul WORD [di+DPT.wLHeads] ; DX:AX = cylToSeek*headsPerCyl
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| 158 |
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| 159 | ; +=headToSeek (18-bit result)
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| 160 | add al, bh ; Add Head number to DX:AX
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| 161 | adc ah, dh ; DH = Zero after previous multiplication
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| 162 | adc dl, dh
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| 163 |
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| 164 | ; *=sectPerTrack (18-bit by 6-bit multiplication with 24-bit result)
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| 165 | eMOVZX cx, BYTE [di+DPT.bPSect]; Load Sectors per Track
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| 166 | xchg ax, dx ; Hiword to AX, loword to DX
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| 167 | mul cl ; AX = hiword * Sectors per Track
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| 168 | mov bh, al ; Backup hiword * Sectors per Track
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| 169 | xchg ax, dx ; Loword back to AX
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| 170 | mul cx ; DX:AX = loword * Sectors per Track
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| 171 | add dl, bh ; DX:AX = (cylToSeek*headsPerCyl+headToSeek)*sectPerTrack
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| 172 |
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| 173 | ; +=sectToSeek-1 (24-bit result)
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| 174 | xor bh, bh ; Sector number now in BX
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| 175 | dec bx ; sectToSeek-=1
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| 176 | add ax, bx ; Add to loword
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| 177 | adc dl, bh ; Add possible carry to byte2, BH=zero
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| 178 | ret
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