| 1 | ; Project name : XTIDE Universal BIOS
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| 2 | ; Description : Functions for finding Disk Parameter Table.
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| 3 |
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| 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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| 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 | ; Checks if drive is handled by this BIOS, and return DPT pointer.
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| 25 | ;
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| 26 | ; FindDPT_ForDriveNumberInDL
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| 27 | ; Parameters:
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| 28 | ; DL: Drive number
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| 29 | ; DS: RAMVARS segment
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| 30 | ; Returns:
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| 31 | ; CF: Cleared if drive is handled by this BIOS
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| 32 | ; Set if drive belongs to some other BIOS
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| 33 | ; DI: DPT Pointer if drive is handled by this BIOS
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| 34 | ; Zero if drive belongs to some other BIOS
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| 35 | ; Corrupts registers:
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| 36 | ; Nothing
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| 37 | ;--------------------------------------------------------------------
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| 38 | ALIGN JUMP_ALIGN
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| 39 | FindDPT_ForDriveNumberInDL:
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| 40 | xchg di, ax ; Save the contents of AX in DI
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| 41 |
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| 42 | ;
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| 43 | ; Check Our Hard Disks
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| 44 | ;
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| 45 | mov ax, [RAMVARS.wFirstDrvAndCount] ; Drive count to AH, First number to AL
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| 46 | add ah, al ; One past last drive to AH
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| 47 |
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| 48 | %ifdef MODULE_SERIAL_FLOPPY
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| 49 | cmp dl, ah ; Above last supported?
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| 50 | jae SHORT .HardDiskNotHandledByThisBIOS
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| 51 |
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| 52 | cmp dl, al ; Below first supported?
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| 53 | jae SHORT .CalcDPTForDriveNumber
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| 54 |
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| 55 | ALIGN JUMP_ALIGN
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| 56 | .HardDiskNotHandledByThisBIOS:
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| 57 | ;
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| 58 | ; Check Our Floppy Disks
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| 59 | ;
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| 60 | call RamVars_UnpackFlopCntAndFirstToAL
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| 61 | js SHORT .DiskIsNotHandledByThisBIOS
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| 62 |
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| 63 | cbw ; Always 0h (no floppy drive covered above)
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| 64 | adc ah, al ; Add in first drive number and number of drives
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| 65 |
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| 66 | cmp ah, dl ; Check second drive if two, first drive if only one
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| 67 | jz SHORT .CalcDPTForDriveNumber
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| 68 | cmp al, dl ; Check first drive in all cases, redundant but OK to repeat
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| 69 | jnz SHORT .DiskIsNotHandledByThisBIOS
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| 70 | %else
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| 71 | cmp dl, ah ; Above last supported?
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| 72 | jae SHORT .DiskIsNotHandledByThisBIOS
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| 73 |
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| 74 | cmp dl, al ; Below first supported?
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| 75 | jb SHORT .DiskIsNotHandledByThisBIOS
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| 76 | %endif
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| 77 | ; fall-through to CalcDPTForDriveNumber
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| 78 |
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| 79 | ;--------------------------------------------------------------------
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| 80 | ; Finds Disk Parameter Table for drive number.
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| 81 | ; Not intended to be called except by FindDPT_ForDriveNumberInDL
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| 82 | ;
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| 83 | ; CalcDPTForDriveNumber
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| 84 | ; Parameters:
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| 85 | ; DL: Drive number
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| 86 | ; DS: RAMVARS segment
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| 87 | ; DI: Saved copy of AX from entry at FindDPT_ForDriveNumberInDL
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| 88 | ; Returns:
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| 89 | ; DS:DI: Ptr to DPT
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| 90 | ; CF: Clear
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| 91 | ; Corrupts registers:
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| 92 | ; Nothing
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| 93 | ;--------------------------------------------------------------------
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| 94 | ALIGN JUMP_ALIGN
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| 95 | .CalcDPTForDriveNumber:
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| 96 | push dx
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| 97 |
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| 98 | %ifdef MODULE_SERIAL_FLOPPY
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| 99 | mov ax, [RAMVARS.wFirstDrvAndCount]
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| 100 |
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| 101 | test dl, dl
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| 102 | js .harddisk
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| 103 |
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| 104 | call RamVars_UnpackFlopCntAndFirstToAL
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| 105 | add dl, ah ; add in end of hard disk DPT list, floppies start immediately after
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| 106 |
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| 107 | ALIGN JUMP_ALIGN
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| 108 | .harddisk:
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| 109 | sub dl, al ; subtract off beginning of either hard disk or floppy list (as appropriate)
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| 110 | %else
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| 111 | sub dl, [RAMVARS.bFirstDrv] ; subtract off beginning of hard disk list
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| 112 | %endif
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| 113 |
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| 114 | .CalcDPTForNewDrive:
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| 115 | mov al, LARGEST_DPT_SIZE
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| 116 |
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| 117 | mul dl
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| 118 | add ax, BYTE RAMVARS_size ; Clears CF (will not overflow)
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| 119 |
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| 120 | pop dx
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| 121 |
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| 122 | xchg di, ax ; Restore AX from entry at FindDPT_ForDriveNumber, put DPT pointer in DI
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| 123 | ret
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| 124 |
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| 125 | ALIGN JUMP_ALIGN
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| 126 | .DiskIsNotHandledByThisBIOS:
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| 127 | ;
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| 128 | ; Drive not found...
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| 129 | ;
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| 130 | xor ax, ax ; Clear DPT pointer
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| 131 | stc ; Is not supported by our BIOS
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| 132 |
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| 133 | xchg di, ax ; Restore AX from save at top
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| 134 | ret
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| 135 |
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| 136 |
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| 137 | ;--------------------------------------------------------------------
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| 138 | ; FindDPT_ForIdevarsOffsetInDL
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| 139 | ; Parameters:
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| 140 | ; DL: Offset to IDEVARS to search for
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| 141 | ; DS: RAMVARS segment
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| 142 | ; Returns:
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| 143 | ; DS:DI: Ptr to first DPT with same IDEVARS as in DL
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| 144 | ; CF: Clear if wanted DPT found
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| 145 | ; Set if DPT not found, or no DPTs present
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| 146 | ; Corrupts registers:
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| 147 | ; SI
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| 148 | ;--------------------------------------------------------------------
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| 149 | FindDPT_ForIdevarsOffsetInDL:
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| 150 | mov si, IterateFindFirstDPTforIdevars ; iteration routine (see below)
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| 151 | jmp SHORT FindDPT_IterateAllDPTs ; look for the first drive on this controller, if any
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| 152 |
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| 153 | ;--------------------------------------------------------------------
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| 154 | ; Iteration routine for FindDPT_ForIdevarsOffsetInDL,
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| 155 | ; for use with IterateAllDPTs
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| 156 | ;
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| 157 | ; Returns when DPT is found on the controller with Idevars offset in DL
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| 158 | ;
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| 159 | ; IterateFindFirstDPTforIdevars
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| 160 | ; DL: Offset to IDEVARS to search from DPTs
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| 161 | ; DS:DI: Ptr to DPT to examine
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| 162 | ; Returns:
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| 163 | ; CF: Clear if wanted DPT found
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| 164 | ; Set if wrong DPT
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| 165 | ;--------------------------------------------------------------------
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| 166 | IterateFindFirstDPTforIdevars:
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| 167 | cmp dl, [di+DPT.bIdevarsOffset] ; Clears CF if matched
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| 168 | je .done
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| 169 | stc ; Set CF for not found
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| 170 | .done:
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| 171 | ret
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| 172 |
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| 173 |
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| 174 | ;--------------------------------------------------------------------
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| 175 | ; Finds pointer to first unused Disk Parameter Table.
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| 176 | ; Should only be used before DetectDrives is complete (not valid after this time).
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| 177 | ;
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| 178 | ; FindDPT_ForNewDriveToDSDI
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| 179 | ; Parameters:
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| 180 | ; DS: RAMVARS segment
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| 181 | ; Returns:
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| 182 | ; DS:DI: Ptr to first unused DPT
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| 183 | ; Corrupts registers:
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| 184 | ; AX
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| 185 | ;--------------------------------------------------------------------
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| 186 | ALIGN JUMP_ALIGN
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| 187 | FindDPT_ForNewDriveToDSDI:
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| 188 | push dx
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| 189 |
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| 190 | %ifdef MODULE_SERIAL_FLOPPY
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| 191 | mov dx, [RAMVARS.wDrvCntAndFlopCnt]
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| 192 | add dl, dh
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| 193 | %else
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| 194 | mov dl, [RAMVARS.bDrvCnt]
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| 195 | %endif
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| 196 |
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| 197 | jmp short FindDPT_ForDriveNumberInDL.CalcDPTForNewDrive
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| 198 |
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| 199 | ;--------------------------------------------------------------------
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| 200 | ; IterateToDptWithFlagsHighInBL
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| 201 | ; Parameters:
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| 202 | ; DS:DI: Ptr to DPT to examine
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| 203 | ; BL: Bit(s) to test in DPT.bFlagsHigh
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| 204 | ; Returns:
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| 205 | ; CF: Clear if wanted DPT found
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| 206 | ; Set if wrong DPT
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| 207 | ; Corrupts registers:
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| 208 | ; Nothing
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| 209 | ;--------------------------------------------------------------------
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| 210 | ALIGN JUMP_ALIGN
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| 211 | IterateToDptWithFlagsHighInBL:
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| 212 | test [di+DPT.bFlagsHigh], bl ; Clears CF
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| 213 | jnz SHORT .ReturnRightDPT
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| 214 | stc
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| 215 | .ReturnRightDPT:
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| 216 | ret
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| 217 |
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| 218 | ;--------------------------------------------------------------------
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| 219 | ; FindDPT_ToDSDIforSerialDevice
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| 220 | ; Parameters:
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| 221 | ; DS: RAMVARS segment
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| 222 | ; Returns:
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| 223 | ; DS:DI: Ptr to DPT
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| 224 | ; CF: Set if wanted DPT found
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| 225 | ; Cleared if DPT not found
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| 226 | ; Corrupts registers:
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| 227 | ; SI
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| 228 | ;--------------------------------------------------------------------
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| 229 | %ifdef MODULE_SERIAL
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| 230 | ALIGN JUMP_ALIGN
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| 231 | FindDPT_ToDSDIforSerialDevice:
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| 232 | mov bl, FLGH_DPT_SERIAL_DEVICE
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| 233 | ; fall-through
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| 234 | %endif
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| 235 |
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| 236 | ;--------------------------------------------------------------------
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| 237 | ; FindDPT_ToDSDIforFlagsHigh
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| 238 | ; Parameters:
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| 239 | ; DS: RAMVARS segment
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| 240 | ; BL: Bit(s) to test in DPT.bFlagsHigh
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| 241 | ; Returns:
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| 242 | ; DS:DI: Ptr to DPT
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| 243 | ; CF: Set if wanted DPT found
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| 244 | ; Cleared if DPT not found
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| 245 | ; Corrupts registers:
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| 246 | ; SI
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| 247 | ;--------------------------------------------------------------------
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| 248 | ALIGN JUMP_ALIGN
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| 249 | FindDPT_ToDSDIforFlagsHighInBL:
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| 250 | mov si, IterateToDptWithFlagsHighInBL
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| 251 | ; Fall to IterateAllDPTs
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| 252 |
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| 253 | ;--------------------------------------------------------------------
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| 254 | ; Iterates all Disk Parameter Tables.
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| 255 | ;
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| 256 | ; FindDPT_IterateAllDPTs
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| 257 | ; Parameters:
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| 258 | ; AX,BX,DX: Parameters to callback function
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| 259 | ; CS:SI: Ptr to callback function
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| 260 | ; Callback routine should return CF=clear if found
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| 261 | ; DS: RAMVARS segment
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| 262 | ; Returns:
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| 263 | ; DS:DI: Ptr to wanted DPT (if found)
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| 264 | ; If not found, points to first empty DPT
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| 265 | ; CF: Clear if wanted DPT found
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| 266 | ; Set if DPT not found, or no DPTs present
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| 267 | ; Corrupts registers:
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| 268 | ; Nothing unless corrupted by callback function
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| 269 | ;--------------------------------------------------------------------
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| 270 | ALIGN JUMP_ALIGN
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| 271 | FindDPT_IterateAllDPTs:
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| 272 | push cx
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| 273 |
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| 274 | mov di, RAMVARS_size ; Point DS:DI to first DPT
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| 275 | eMOVZX cx, [RAMVARS.bDrvCnt]
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| 276 | jcxz .NotFound ; Return if no drives
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| 277 |
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| 278 | ALIGN JUMP_ALIGN
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| 279 | .LoopWhileDPTsLeft:
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| 280 | call si ; Is wanted DPT?
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| 281 | jnc SHORT .Found ; If so, return
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| 282 | add di, BYTE LARGEST_DPT_SIZE ; Point to next DPT
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| 283 | loop .LoopWhileDPTsLeft
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| 284 |
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| 285 | ALIGN JUMP_ALIGN
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| 286 | .NotFound:
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| 287 | stc
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| 288 |
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| 289 | ALIGN JUMP_ALIGN
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| 290 | .Found:
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| 291 | pop cx
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| 292 | ret
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| 293 |
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