[358] | 1 | ; Project name : XTIDE Universal BIOS |
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| 2 | ; Description : Functions for generating L-CHS parameters for |
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[421] | 3 | ; drives with more than 1024 cylinders. |
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[358] | 4 | ; |
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[421] | 5 | ; These algorithms are taken from: http://www.mossywell.com/boot-sequence |
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[445] | 6 | ; Take a look at it for more detailed information. |
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[421] | 7 | ; |
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[358] | 8 | ; This file is shared with BIOS Drive Information Tool. |
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| 9 | |
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[376] | 10 | ; |
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[445] | 11 | ; XTIDE Universal BIOS and Associated Tools |
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[526] | 12 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. |
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[376] | 13 | ; |
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| 14 | ; This program is free software; you can redistribute it and/or modify |
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| 15 | ; it under the terms of the GNU General Public License as published by |
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| 16 | ; the Free Software Foundation; either version 2 of the License, or |
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| 17 | ; (at your option) any later version. |
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[445] | 18 | ; |
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[376] | 19 | ; This program is distributed in the hope that it will be useful, |
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| 20 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 21 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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[445] | 22 | ; GNU General Public License for more details. |
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[376] | 23 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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| 24 | ; |
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[445] | 25 | |
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[358] | 26 | ; Section containing code |
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| 27 | SECTION .text |
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| 28 | |
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[421] | 29 | %ifdef MODULE_EBIOS |
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[358] | 30 | ;-------------------------------------------------------------------- |
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[421] | 31 | ; AtaGeometry_GetLbaSectorCountToBXDXAXfromAtaInfoInESSI |
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| 32 | ; Parameters: |
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| 33 | ; ES:SI: Ptr to 512-byte ATA information read from the drive |
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| 34 | ; Returns: |
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[445] | 35 | ; BX:DX:AX: 48-bit sector count |
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[422] | 36 | ; CL: FLGL_DPT_LBA48 if LBA48 supported |
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| 37 | ; Zero if only LBA28 is supported |
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[421] | 38 | ; Corrupts registers: |
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| 39 | ; Nothing |
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| 40 | ;-------------------------------------------------------------------- |
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| 41 | AtaGeometry_GetLbaSectorCountToBXDXAXfromAtaInfoInESSI: |
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| 42 | mov bx, Registers_ExchangeDSSIwithESDI |
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| 43 | call bx ; ATA info now in DS:DI |
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| 44 | push bx ; We will return via Registers_ExchangeDSSIwithESDI |
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| 45 | |
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| 46 | ; Check if LBA48 supported |
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| 47 | test BYTE [di+ATA6.wSetSup83+1], A6_wSetSup83_LBA48>>8 |
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| 48 | jz SHORT .GetLba28SectorCount |
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| 49 | |
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| 50 | ; Get LBA48 sector count |
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| 51 | mov cl, FLGL_DPT_LBA48 |
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| 52 | mov ax, [di+ATA6.qwLBACnt] |
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| 53 | mov dx, [di+ATA6.qwLBACnt+2] |
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| 54 | mov bx, [di+ATA6.qwLBACnt+4] |
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| 55 | ret |
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| 56 | |
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| 57 | .GetLba28SectorCount: |
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| 58 | xor cl, cl |
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| 59 | xor bx, bx |
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| 60 | mov ax, [di+ATA1.dwLBACnt] |
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| 61 | mov dx, [di+ATA1.dwLBACnt+2] |
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| 62 | ret |
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| 63 | %endif ; MODULE_EBIOS |
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| 64 | |
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| 65 | |
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| 66 | ;-------------------------------------------------------------------- |
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[422] | 67 | ; AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX |
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[421] | 68 | ; Parameters: |
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[422] | 69 | ; DX: Wanted translate mode or TRANSLATEMODE_AUTO to autodetect |
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[421] | 70 | ; ES:SI: Ptr to 512-byte ATA information read from the drive |
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| 71 | ; Returns: |
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| 72 | ; AX: Number of L-CHS cylinders (1...1027, yes 1027) |
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| 73 | ; BL: Number of L-CHS heads (1...255) |
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| 74 | ; BH: Number of L-CHS sectors per track (1...63) |
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| 75 | ; CX: Number of bits shifted (0...3) |
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[422] | 76 | ; DL: CHS Translate Mode |
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[421] | 77 | ; Corrupts registers: |
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| 78 | ; DH |
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| 79 | ;-------------------------------------------------------------------- |
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[422] | 80 | AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX: |
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[421] | 81 | call AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI |
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| 82 | |
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[422] | 83 | ; Check if user defined translate mode |
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[491] | 84 | dec dx ; Set ZF if TRANSLATEMODE_LARGE, SF if TRANSLATEMODE_NORMAL |
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| 85 | jns SHORT .CheckIfLargeTranslationWanted |
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[422] | 86 | MIN_U ax, MAX_LCHS_CYLINDERS ; TRANSLATEMODE_NORMAL maximum cylinders |
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| 87 | inc dx |
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| 88 | .CheckIfLargeTranslationWanted: |
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| 89 | jz SHORT ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL |
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| 90 | dec dx ; Set ZF if TRANSLATEMODE_ASSISTED_LBA |
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| 91 | jz SHORT .UseAssistedLBA |
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| 92 | ; TRANSLATEMODE_AUTO set |
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| 93 | |
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[421] | 94 | ; Generate L-CHS using simple bit shift algorithm (ECHS) if |
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| 95 | ; 8192 or less cylinders. |
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| 96 | cmp ax, 8192 |
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[422] | 97 | jbe SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL |
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[421] | 98 | |
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| 99 | ; We have 8193 or more cylinders so two algorithms are available: |
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| 100 | ; Revised ECHS or Assisted LBA. The Assisted LBA provides larger |
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| 101 | ; capacity but requires LBA support from drive (drives this large |
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[422] | 102 | ; always support LBA but user might have unintentionally set LBA). |
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| 103 | .UseAssistedLBA: |
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[421] | 104 | test BYTE [es:si+ATA1.wCaps+1], A1_wCaps_LBA>>8 |
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[422] | 105 | jz SHORT ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL |
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[421] | 106 | |
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| 107 | ; Drive supports LBA |
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[422] | 108 | call GetSectorCountToDXAXfromCHSinAXBLBH |
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[421] | 109 | call ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH |
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| 110 | xor cx, cx ; No bits to shift |
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[422] | 111 | mov dl, TRANSLATEMODE_ASSISTED_LBA |
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[421] | 112 | ret |
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| 113 | |
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| 114 | |
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| 115 | ;-------------------------------------------------------------------- |
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| 116 | ; AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI |
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| 117 | ; Parameters: |
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| 118 | ; ES:SI: Ptr to 512-byte ATA information read from the drive |
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| 119 | ; Returns: |
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| 120 | ; AX: Number of P-CHS cylinders (1...16383) |
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| 121 | ; BL: Number of P-CHS heads (1...16) |
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| 122 | ; BH: Number of P-CHS sectors per track (1...63) |
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| 123 | ; Corrupts registers: |
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| 124 | ; Nothing |
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| 125 | ;-------------------------------------------------------------------- |
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| 126 | AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI: |
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| 127 | mov ax, [es:si+ATA1.wCylCnt] ; Cylinders (1...16383) |
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| 128 | mov bl, [es:si+ATA1.wHeadCnt] ; Heads (1...16) |
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| 129 | mov bh, [es:si+ATA1.wSPT] ; Sectors per Track (1...63) |
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| 130 | ret |
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| 131 | |
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| 132 | |
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| 133 | ;-------------------------------------------------------------------- |
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[422] | 134 | ; GetSectorCountToDXAXfromCHSinAXBLBH |
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[421] | 135 | ; Parameters: |
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| 136 | ; ES:SI: Ptr to 512-byte ATA information read from the drive |
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| 137 | ; AX: Number of cylinders (1...16383) |
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| 138 | ; BL: Number of heads (1...255) |
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| 139 | ; BH: Number of sectors per track (1...63) |
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| 140 | ; Returns: |
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| 141 | ; DX:AX: Total number of CHS addressable sectors |
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| 142 | ; Corrupts registers: |
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| 143 | ; BX |
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| 144 | ;-------------------------------------------------------------------- |
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[422] | 145 | GetSectorCountToDXAXfromCHSinAXBLBH: |
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[421] | 146 | xchg ax, bx |
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| 147 | mul ah ; AX = Heads * Sectors per track |
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| 148 | mul bx |
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| 149 | ret |
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| 150 | |
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| 151 | |
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| 152 | ;-------------------------------------------------------------------- |
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| 153 | ; Revised Enhanced CHS calculation (Revised ECHS) |
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[358] | 154 | ; |
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[421] | 155 | ; This algorithm translates P-CHS sector count to L-CHS sector count |
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| 156 | ; with bit shift algorithm. Since 256 heads are not allowed |
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| 157 | ; (DOS limit), this algorithm makes translations so that maximum of |
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| 158 | ; 240 L-CHS heads can be used. This makes the maximum addressable capacity |
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| 159 | ; to 7,927,234,560 bytes ~ 7.38 GiB. LBA addressing needs to be used to |
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| 160 | ; get more capacity. |
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| 161 | ; |
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| 162 | ; L-CHS parameters generated here require the drive to use CHS addressing. |
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| 163 | ; |
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| 164 | ; Here is the algorithm: |
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| 165 | ; If cylinders > 8192 and heads = 16 |
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| 166 | ; Heads = 15 |
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| 167 | ; Cylinders = cylinders * 16 / 15 (losing the fraction component) |
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| 168 | ; Do a standard ECHS translation |
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| 169 | ; |
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[422] | 170 | ; ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL: |
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[421] | 171 | ; Parameters: |
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| 172 | ; AX: Number of P-CHS cylinders (8193...16383) |
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| 173 | ; BL: Number of P-CHS heads (1...16) |
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| 174 | ; Returns: |
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| 175 | ; AX: Number of L-CHS cylinders (?...1024) |
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| 176 | ; BL: Number of L-CHS heads (?...240) |
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| 177 | ; CX: Number of bits shifted (0...3) |
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| 178 | ; DL: ADDRESSING_MODE_NORMAL or ADDRESSING_MODE_LARGE |
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| 179 | ; Corrupts registers: |
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| 180 | ; Nothing |
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| 181 | ;-------------------------------------------------------------------- |
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[422] | 182 | ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL: |
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| 183 | ; Generate L-CHS using simple bit shift algorithm (ECHS) if |
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| 184 | ; 8192 or less cylinders |
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| 185 | cmp ax, 8192 |
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| 186 | jbe SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL |
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[421] | 187 | cmp bl, 16 ; Drives with 8193 or more cylinders can report 15 heads |
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[422] | 188 | jb SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL |
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[421] | 189 | |
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| 190 | eMOVZX cx, bl ; CX = 16 |
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| 191 | dec bx ; Heads = 15 |
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| 192 | mul cx ; DX:AX = Cylinders * 16 |
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| 193 | dec cx ; CX = 15 |
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| 194 | div cx ; AX = (Cylinders * 16) / 15 |
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| 195 | ; Fall to ConvertPCHfromAXBXtoEnhancedCHinAXBX |
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| 196 | |
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| 197 | |
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| 198 | ;-------------------------------------------------------------------- |
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| 199 | ; Enhanced CHS calculation (ECHS) |
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| 200 | ; |
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| 201 | ; This algorithm translates P-CHS sector count to L-CHS sector count |
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| 202 | ; with simple bit shift algorithm. Since 256 heads are not allowed |
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| 203 | ; (DOS limit), this algorithm require that there are at most 8192 |
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| 204 | ; P-CHS cylinders. This makes the maximum addressable capacity |
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| 205 | ; to 4,227,858,432 bytes ~ 3.94 GiB. Use Revised ECHS or Assisted LBA |
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| 206 | ; algorithms if there are more than 8192 P-CHS cylinders. |
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| 207 | ; |
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| 208 | ; L-CHS parameters generated here require the drive to use CHS addressing. |
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| 209 | ; |
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| 210 | ; Here is the algorithm: |
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| 211 | ; Multiplier = 1 |
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| 212 | ; Cylinder = Cylinder - 1 |
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| 213 | ; Is Cylinder < 1024? If not: |
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| 214 | ; Do a right bitwise rotation on the cylinder (i.e., divide by 2) |
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| 215 | ; Do a left bitwise rotation on the multiplier (i.e., multiply by 2) |
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| 216 | ; Use the multiplier on the Cylinder and Head values to obtain the translated values. |
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| 217 | ; |
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[422] | 218 | ; ConvertPCHfromAXBLtoEnhancedCHinAXBL: |
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[421] | 219 | ; Parameters: |
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| 220 | ; AX: Number of P-CHS cylinders (1...8192) |
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| 221 | ; BL: Number of P-CHS heads (1...16) |
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| 222 | ; Returns: |
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| 223 | ; AX: Number of L-CHS cylinders (?...1024) |
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| 224 | ; BL: Number of L-CHS heads (?...128) |
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| 225 | ; CX: Number of bits shifted (0...3) |
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[422] | 226 | ; DL: TRANSLATEMODE_NORMAL or TRANSLATEMODE_LARGE |
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[421] | 227 | ; Corrupts registers: |
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| 228 | ; Nothing |
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| 229 | ;-------------------------------------------------------------------- |
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[422] | 230 | ConvertPCHfromAXBLtoEnhancedCHinAXBL: |
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[421] | 231 | xor cx, cx ; No bits to shift initially |
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[422] | 232 | xor dl, dl ; Assume TRANSLATEMODE_NORMAL |
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[421] | 233 | .ShiftIfMoreThan1024Cylinder: |
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| 234 | cmp ax, MAX_LCHS_CYLINDERS |
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| 235 | jbe SHORT ReturnLCHSinAXBLBH |
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[422] | 236 | shr ax, 1 ; Halve cylinders |
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[445] | 237 | eSHL_IM bl, 1 ; Double heads |
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[421] | 238 | inc cx ; Increment bit shift count |
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[422] | 239 | mov dl, TRANSLATEMODE_LARGE |
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[421] | 240 | jmp SHORT .ShiftIfMoreThan1024Cylinder |
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| 241 | |
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| 242 | |
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| 243 | ;-------------------------------------------------------------------- |
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| 244 | ; LBA assist calculation (or Assisted LBA) |
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| 245 | ; |
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| 246 | ; This algorithm translates P-CHS sector count up to largest possible |
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| 247 | ; L-CHS sector count (1024, 255, 63). Note that INT 13h interface allows |
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| 248 | ; 256 heads but DOS supports up to 255 head. That is why BIOSes never |
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| 249 | ; use 256 heads. |
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| 250 | ; |
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| 251 | ; L-CHS parameters generated here require the drive to use LBA addressing. |
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| 252 | ; |
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| 253 | ; Here is the algorithm: |
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[419] | 254 | ; If cylinders > 8192 |
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[421] | 255 | ; Variable CH = Total CHS Sectors / 63 |
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| 256 | ; Divide (CH 1) by 1024 and add 1 |
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[419] | 257 | ; Round the result up to the nearest of 16, 32, 64, 128 and 255. This is the value to be used for the number of heads. |
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| 258 | ; Divide CH by the number of heads. This is the value to be used for the number of cylinders. |
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[358] | 259 | ; |
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[421] | 260 | ; ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH: |
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[358] | 261 | ; Parameters: |
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[421] | 262 | ; DX:AX: Total number of P-CHS sectors for CHS addressing |
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| 263 | ; (max = 16383 * 16 * 63 = 16,514,064) |
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[358] | 264 | ; Returns: |
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[421] | 265 | ; AX: Number of cylinders (?...1027) |
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| 266 | ; BL: Number of heads (16, 32, 64, 128 or 255) |
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[358] | 267 | ; BH: Number of sectors per track (always 63) |
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| 268 | ; Corrupts registers: |
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[421] | 269 | ; CX, DX |
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[358] | 270 | ;-------------------------------------------------------------------- |
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[421] | 271 | ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH: |
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[419] | 272 | ; Value CH = Total sector count / 63 |
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[421] | 273 | ; Max = 16,514,064 / 63 = 262128 |
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| 274 | mov cx, LBA_ASSIST_SPT ; CX = 63 |
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| 275 | call Math_DivDXAXbyCX |
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[358] | 276 | push dx |
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[421] | 277 | push ax ; Value CH stored for later use |
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[358] | 278 | |
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[419] | 279 | ; BX:DX:AX = Value CH - 1 |
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[421] | 280 | ; Max = 262128 - 1 = 262127 |
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| 281 | xor bx, bx |
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| 282 | sub ax, BYTE 1 |
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| 283 | sbb dx, bx |
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[419] | 284 | |
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[421] | 285 | ; AX = Number of heads = ((Value CH - 1) / 1024) + 1 |
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| 286 | ; Max = (262127 / 1024) + 1 = 256 |
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| 287 | push si |
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[358] | 288 | call Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX |
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[421] | 289 | pop si |
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| 290 | inc ax ; + 1 |
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[358] | 291 | |
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[419] | 292 | ; Heads must be 16, 32, 64, 128 or 255 (round up to the nearest) |
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[421] | 293 | ; Max = 255 |
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[419] | 294 | mov cx, 16 ; Min number of heads |
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| 295 | .CompareNextValidNumberOfHeads: |
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[358] | 296 | cmp ax, cx |
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[419] | 297 | jbe SHORT .NumberOfHeadsNowInCX |
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[445] | 298 | eSHL_IM cl, 1 ; Double number of heads |
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| 299 | jnz SHORT .CompareNextValidNumberOfHeads ; Reached 256 heads? |
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| 300 | dec cl ; If so, limit heads to 255 |
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[419] | 301 | .NumberOfHeadsNowInCX: |
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| 302 | mov bx, cx ; Number of heads are returned in BL |
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| 303 | mov bh, LBA_ASSIST_SPT ; Sectors per Track |
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[358] | 304 | |
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[419] | 305 | ; DX:AX = Number of cylinders = Value CH (without - 1) / number of heads |
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[421] | 306 | ; Max = 262128 / 255 = 1027 |
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| 307 | pop ax |
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| 308 | pop dx ; Value CH back to DX:AX |
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| 309 | div cx |
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[358] | 310 | |
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[421] | 311 | ; Return L-CHS |
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| 312 | ReturnLCHSinAXBLBH: |
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[358] | 313 | ret |
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