[165] | 1 | ; Project name : XTIDE Universal BIOS |
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| 2 | ; Description : Functions for address translations. |
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| 3 | |
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[376] | 4 | ; |
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| 5 | ; XTIDE Universal BIOS and Associated Tools |
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| 6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team. |
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| 7 | ; |
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| 8 | ; This program is free software; you can redistribute it and/or modify |
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| 9 | ; it under the terms of the GNU General Public License as published by |
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| 10 | ; the Free Software Foundation; either version 2 of the License, or |
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| 11 | ; (at your option) any later version. |
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| 12 | ; |
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| 13 | ; This program is distributed in the hope that it will be useful, |
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| 14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 16 | ; GNU General Public License for more details. |
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| 17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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| 18 | ; |
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| 19 | |
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[165] | 20 | ; Section containing code |
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| 21 | SECTION .text |
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| 22 | |
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| 23 | ;--------------------------------------------------------------------- |
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| 24 | ; Address_ExtractLCHSparametersFromOldInt13hAddress |
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| 25 | ; Parameters: |
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| 26 | ; CH: Cylinder number, bits 7...0 |
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| 27 | ; CL: Bits 7...6: Cylinder number bits 9 and 8 |
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| 28 | ; Bits 5...0: Sector number |
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| 29 | ; DH: Head number |
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| 30 | ; Returns: |
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| 31 | ; BL: Sector number (1...63) |
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| 32 | ; BH: Head number (0...255) |
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| 33 | ; CX: Cylinder number (0...1023) |
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| 34 | ; Corrupts registers: |
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| 35 | ; Nothing |
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| 36 | ;-------------------------------------------------------------------- |
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[191] | 37 | ALIGN JUMP_ALIGN |
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[165] | 38 | Address_ExtractLCHSparametersFromOldInt13hAddress: |
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| 39 | mov bl, cl ; Copy sector number... |
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| 40 | and bl, 3Fh ; ...and limit to 1...63 |
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| 41 | sub cl, bl ; Remove from cylinder number high |
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| 42 | eROL_IM cl, 2 ; High bits to beginning |
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| 43 | mov bh, dh ; Copy Head number |
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| 44 | xchg cl, ch ; Cylinder number now in CX |
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| 45 | ret |
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| 46 | |
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| 47 | |
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| 48 | ;--------------------------------------------------------------------- |
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[421] | 49 | ; Converts LARGE addressing mode LCHS parameters to IDE P-CHS parameters. |
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[165] | 50 | ; PCylinder = (LCylinder << n) + (LHead / PHeadCount) |
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| 51 | ; PHead = LHead % PHeadCount |
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| 52 | ; PSector = LSector |
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| 53 | ; |
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[421] | 54 | ; ConvertLargeModeLCHStoPCHS: |
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[165] | 55 | ; Parameters: |
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| 56 | ; BL: Sector number (1...63) |
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[421] | 57 | ; BH: Head number (0...239) |
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[165] | 58 | ; CX: Cylinder number (0...1023) |
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| 59 | ; DS:DI: Ptr to Disk Parameter Table |
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| 60 | ; Returns: |
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| 61 | ; BL: Sector number (1...63) |
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| 62 | ; BH: Head number (0...15) |
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| 63 | ; CX: Cylinder number (0...16382) |
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| 64 | ; Corrupts registers: |
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| 65 | ; AX, DX |
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| 66 | ;-------------------------------------------------------------------- |
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| 67 | ALIGN JUMP_ALIGN |
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[421] | 68 | ConvertLargeModeLCHStoPCHS: |
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[165] | 69 | ; LHead / PHeadCount and LHead % PHeadCount |
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| 70 | eMOVZX ax, bh ; Copy L-CHS Head number to AX |
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[227] | 71 | div BYTE [di+DPT.bPchsHeads]; AL = LHead / PHeadCount, AH = LHead % PHeadCount |
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[165] | 72 | mov bh, ah ; Copy P-CHS Head number to BH |
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| 73 | xor ah, ah ; AX = LHead / PHeadCount |
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| 74 | |
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| 75 | ; (LCylinder << n) + (LHead / PHeadCount) |
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| 76 | mov dx, cx ; Copy L-CHS Cylinder number to DX |
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| 77 | mov cl, [di+DPT.bFlagsLow] ; Load shift count |
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| 78 | and cl, MASKL_DPT_CHS_SHIFT_COUNT |
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| 79 | shl dx, cl ; DX = LCylinder << n |
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| 80 | add ax, dx ; AX = P-CHS Cylinder number |
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| 81 | xchg cx, ax ; Move P-CHS Cylinder number to CX |
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| 82 | DoNotConvertLCHS: |
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| 83 | ret |
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| 84 | |
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[421] | 85 | |
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[191] | 86 | ;-------------------------------------------------------------------- |
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| 87 | ; Address_OldInt13hAddressToIdeAddress |
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| 88 | ; Parameters: |
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| 89 | ; CH: Cylinder number, bits 7...0 |
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| 90 | ; CL: Bits 7...6: Cylinder number bits 9 and 8 |
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| 91 | ; Bits 5...0: Starting sector number (1...63) |
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| 92 | ; DH: Starting head number (0...255) |
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| 93 | ; DS:DI: Ptr to DPT |
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| 94 | ; Returns: |
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| 95 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0) |
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| 96 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8) |
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| 97 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16) |
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| 98 | ; BH: Drive and Head Register (LBA 27...24) |
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| 99 | ; Corrupts registers: |
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| 100 | ; AX, DX |
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| 101 | ;-------------------------------------------------------------------- |
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| 102 | ALIGN JUMP_ALIGN |
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| 103 | Address_OldInt13hAddressToIdeAddress: |
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[194] | 104 | call Address_ExtractLCHSparametersFromOldInt13hAddress |
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[422] | 105 | ACCESSDPT__GET_UNSHIFTED_TRANSLATE_MODE_TO_AXZF |
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[230] | 106 | |
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[421] | 107 | ;;; 0: ADDRESSING_MODE_NORMAL |
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| 108 | jz SHORT DoNotConvertLCHS |
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[230] | 109 | |
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[421] | 110 | ;;; 1: ADDRESSING_MODE_LARGE |
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| 111 | test al, FLGL_DPT_ASSISTED_LBA |
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| 112 | jz SHORT ConvertLargeModeLCHStoPCHS |
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[230] | 113 | |
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[421] | 114 | ;;; 2: ADDRESSING_MODE_ASSISTED_LBA |
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| 115 | ; Fall through to ConvertAssistedLBAModeLCHStoLBARegisterValues |
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[194] | 116 | |
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[230] | 117 | |
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[165] | 118 | ;--------------------------------------------------------------------- |
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| 119 | ; Converts LCHS parameters to 28-bit LBA address. |
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| 120 | ; Only 24-bits are used since LHCS to LBA28 conversion has 8.4GB limit. |
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| 121 | ; LBA = ((cylToSeek*headsPerCyl+headToSeek)*sectPerTrack)+sectToSeek-1 |
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| 122 | ; |
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| 123 | ; Returned address is in same registers that |
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[421] | 124 | ; DoNotConvertLCHS and ConvertLargeModeLCHStoPCHS returns. |
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[165] | 125 | ; |
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[421] | 126 | ; ConvertAssistedLBAModeLCHStoLBARegisterValues: |
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[165] | 127 | ; Parameters: |
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| 128 | ; BL: Sector number (1...63) |
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[421] | 129 | ; BH: Head number (0...254) |
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[165] | 130 | ; CX: Cylinder number (0...1023) |
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| 131 | ; DS:DI: Ptr to Disk Parameter Table |
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| 132 | ; Returns: |
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| 133 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0) |
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| 134 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8) |
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| 135 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16) |
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| 136 | ; BH: Drive and Head Register (LBA 27...24) |
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| 137 | ; Corrupts registers: |
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| 138 | ; AX, DX |
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| 139 | ;-------------------------------------------------------------------- |
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[421] | 140 | ConvertAssistedLBAModeLCHStoLBARegisterValues: |
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[165] | 141 | ; cylToSeek*headsPerCyl (18-bit result) |
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[421] | 142 | ; Max = 1023 * 255 = 260,865 = 3FB01h |
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[294] | 143 | mov ax, LBA_ASSIST_SPT ; Load Sectors per Track |
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| 144 | xchg cx, ax ; Cylinder number to AX, Sectors per Track to CX |
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| 145 | %ifdef USE_386 |
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[421] | 146 | movzx dx, [di+DPT.bLchsHeads] |
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[294] | 147 | %else |
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| 148 | cwd |
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[421] | 149 | mov dl, [di+DPT.bLchsHeads] |
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[294] | 150 | %endif |
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[165] | 151 | mul dx ; DX:AX = cylToSeek*headsPerCyl |
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| 152 | |
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| 153 | ; +=headToSeek (18-bit result) |
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[421] | 154 | ; Max = 260,865 + 254 = 261,119 = 3FBFFh |
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[165] | 155 | add al, bh ; Add Head number to DX:AX |
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| 156 | adc ah, dh ; DH = Zero after previous multiplication |
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| 157 | adc dl, dh |
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| 158 | |
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| 159 | ; *=sectPerTrack (18-bit by 6-bit multiplication with 24-bit result) |
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[421] | 160 | ; Max = 261,119 * 63 = 16,450,497 = FB03C1h |
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[165] | 161 | xchg ax, dx ; Hiword to AX, loword to DX |
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| 162 | mul cl ; AX = hiword * Sectors per Track |
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| 163 | mov bh, al ; Backup hiword * Sectors per Track |
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| 164 | xchg ax, dx ; Loword back to AX |
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| 165 | mul cx ; DX:AX = loword * Sectors per Track |
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| 166 | add dl, bh ; DX:AX = (cylToSeek*headsPerCyl+headToSeek)*sectPerTrack |
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| 167 | |
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| 168 | ; +=sectToSeek-1 (24-bit result) |
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[421] | 169 | ; Max = 16,450,497 + 63 - 1 = 16,450,559 = FB03FFh |
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[165] | 170 | xor bh, bh ; Sector number now in BX |
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| 171 | dec bx ; sectToSeek-=1 |
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| 172 | add ax, bx ; Add to loword |
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| 173 | adc dl, bh ; Add possible carry to byte2, BH=zero |
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| 174 | |
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| 175 | ; Copy DX:AX to proper return registers |
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| 176 | xchg bx, ax ; BL = Sector Number Register (LBA 7...0) |
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| 177 | mov cl, bh ; Low Cylinder Register (LBA 15...8) |
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| 178 | mov ch, dl ; High Cylinder Register (LBA 23...16) |
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| 179 | mov bh, dh ; Drive and Head Register (LBA 27...24) |
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| 180 | ret |
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