[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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[526] | 5 | ; XTIDE Universal BIOS and Associated Tools |
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| 6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. |
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[376] | 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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[526] | 12 | ; |
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[376] | 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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[526] | 17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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| 18 | ; |
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[376] | 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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[568] | 39 | mov bl, 3Fh ; Load sector number mask |
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| 40 | and bl, cl ; Sector number now in BL |
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[165] | 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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[568] | 77 | mov cl, MASKL_DPT_CHS_SHIFT_COUNT ; Load shift count mask |
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| 78 | and cl, [di+DPT.bFlagsLow] ; Shift count now in CL |
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[165] | 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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[568] | 85 | ; *FIXME* The above function description doesn't match the code. |
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| 86 | ; If CX has a maximum value of 1023 on entry then there is no way CX can be 16382 on return. |
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| 87 | ; 1023 SHL 3 (MASKL_DPT_CHS_SHIFT_COUNT) is 8184. With the addition of AX (at most 255?) |
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| 88 | ; the result is 8439. |
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[421] | 89 | |
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[191] | 90 | ;-------------------------------------------------------------------- |
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| 91 | ; Address_OldInt13hAddressToIdeAddress |
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| 92 | ; Parameters: |
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| 93 | ; CH: Cylinder number, bits 7...0 |
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| 94 | ; CL: Bits 7...6: Cylinder number bits 9 and 8 |
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| 95 | ; Bits 5...0: Starting sector number (1...63) |
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| 96 | ; DH: Starting head number (0...255) |
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| 97 | ; DS:DI: Ptr to DPT |
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| 98 | ; Returns: |
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| 99 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0) |
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| 100 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8) |
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| 101 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16) |
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| 102 | ; BH: Drive and Head Register (LBA 27...24) |
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| 103 | ; Corrupts registers: |
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| 104 | ; AX, DX |
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| 105 | ;-------------------------------------------------------------------- |
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| 106 | ALIGN JUMP_ALIGN |
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| 107 | Address_OldInt13hAddressToIdeAddress: |
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[568] | 108 | call Address_ExtractLCHSparametersFromOldInt13hAddress |
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| 109 | mov al, [di+DPT.bFlagsLow] |
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| 110 | and al, MASKL_DPT_TRANSLATEMODE |
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[230] | 111 | |
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[421] | 112 | ;;; 0: ADDRESSING_MODE_NORMAL |
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[568] | 113 | jz SHORT DoNotConvertLCHS |
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[230] | 114 | |
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[421] | 115 | ;;; 1: ADDRESSING_MODE_LARGE |
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[568] | 116 | test al, FLGL_DPT_ASSISTED_LBA |
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| 117 | jz SHORT ConvertLargeModeLCHStoPCHS |
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[230] | 118 | |
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[421] | 119 | ;;; 2: ADDRESSING_MODE_ASSISTED_LBA |
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[568] | 120 | ; Fall to ConvertAssistedLBAModeLCHStoLBARegisterValues |
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[194] | 121 | |
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[230] | 122 | |
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[165] | 123 | ;--------------------------------------------------------------------- |
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| 124 | ; Converts LCHS parameters to 28-bit LBA address. |
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| 125 | ; Only 24-bits are used since LHCS to LBA28 conversion has 8.4GB limit. |
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| 126 | ; LBA = ((cylToSeek*headsPerCyl+headToSeek)*sectPerTrack)+sectToSeek-1 |
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[542] | 127 | ; headsPerCyl and sectPerTrack are the current translation values (L-CHS). |
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[165] | 128 | ; |
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| 129 | ; Returned address is in same registers that |
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[421] | 130 | ; DoNotConvertLCHS and ConvertLargeModeLCHStoPCHS returns. |
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[165] | 131 | ; |
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[421] | 132 | ; ConvertAssistedLBAModeLCHStoLBARegisterValues: |
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[165] | 133 | ; Parameters: |
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| 134 | ; BL: Sector number (1...63) |
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[421] | 135 | ; BH: Head number (0...254) |
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[165] | 136 | ; CX: Cylinder number (0...1023) |
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| 137 | ; DS:DI: Ptr to Disk Parameter Table |
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| 138 | ; Returns: |
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| 139 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0) |
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| 140 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8) |
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| 141 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16) |
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| 142 | ; BH: Drive and Head Register (LBA 27...24) |
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| 143 | ; Corrupts registers: |
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| 144 | ; AX, DX |
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| 145 | ;-------------------------------------------------------------------- |
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[421] | 146 | ConvertAssistedLBAModeLCHStoLBARegisterValues: |
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[165] | 147 | ; cylToSeek*headsPerCyl (18-bit result) |
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[421] | 148 | ; Max = 1023 * 255 = 260,865 = 3FB01h |
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[294] | 149 | mov ax, LBA_ASSIST_SPT ; Load Sectors per Track |
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| 150 | xchg cx, ax ; Cylinder number to AX, Sectors per Track to CX |
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| 151 | %ifdef USE_386 |
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[421] | 152 | movzx dx, [di+DPT.bLchsHeads] |
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[294] | 153 | %else |
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| 154 | cwd |
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[421] | 155 | mov dl, [di+DPT.bLchsHeads] |
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[294] | 156 | %endif |
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[165] | 157 | mul dx ; DX:AX = cylToSeek*headsPerCyl |
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| 158 | |
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| 159 | ; +=headToSeek (18-bit result) |
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[421] | 160 | ; Max = 260,865 + 254 = 261,119 = 3FBFFh |
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[165] | 161 | add al, bh ; Add Head number to DX:AX |
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| 162 | adc ah, dh ; DH = Zero after previous multiplication |
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| 163 | adc dl, dh |
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| 164 | |
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| 165 | ; *=sectPerTrack (18-bit by 6-bit multiplication with 24-bit result) |
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[421] | 166 | ; Max = 261,119 * 63 = 16,450,497 = FB03C1h |
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[165] | 167 | xchg ax, dx ; Hiword to AX, loword to DX |
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| 168 | mul cl ; AX = hiword * Sectors per Track |
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| 169 | mov bh, al ; Backup hiword * Sectors per Track |
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| 170 | xchg ax, dx ; Loword back to AX |
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| 171 | mul cx ; DX:AX = loword * Sectors per Track |
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| 172 | add dl, bh ; DX:AX = (cylToSeek*headsPerCyl+headToSeek)*sectPerTrack |
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| 173 | |
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| 174 | ; +=sectToSeek-1 (24-bit result) |
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[421] | 175 | ; Max = 16,450,497 + 63 - 1 = 16,450,559 = FB03FFh |
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[589] | 176 | mov bh, ch ; Sector number now in BX, CH=zero |
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[165] | 177 | dec bx ; sectToSeek-=1 |
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[589] | 178 | add bx, ax ; Add loword to BX (BL = Sector Number Register (LBA 7...0)) |
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| 179 | adc ch, dl ; Add possible carry to byte2 (CH = High Cylinder Register (LBA 23...16)) |
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| 180 | mov cl, bh ; CL = Low Cylinder Register (LBA 15...8) |
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| 181 | mov bh, dh ; BH = Drive and Head Register (LBA 27...24) |
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[165] | 182 | ret |
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