; Project name : XTIDE Universal BIOS ; Description : Int 13h function AH=48h, Get Extended Drive Parameters. ; ; XTIDE Universal BIOS and Associated Tools ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. ; ; This program is free software; you can redistribute it and/or modify ; it under the terms of the GNU General Public License as published by ; the Free Software Foundation; either version 2 of the License, or ; (at your option) any later version. ; ; This program is distributed in the hope that it will be useful, ; but WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ; GNU General Public License for more details. ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html ; ; Section containing code SECTION .text ;-------------------------------------------------------------------- ; Int 13h function AH=48h, Get Extended Drive Parameters. ; ; It is not completely clear what this function should return as total sector count in some cases. ; What is certain is that: ; A) Phoenix Enhanced Disk Drive Specification v3.0 says that P-CHS values ; are never returned for drives with more than 15,482,880 sectors (16384*15*63). ; For those drives we can simply return total sector count from ; ATA ID WORDs 60 and 61 (LBA28) or WORDs 100-103 (LBA48). ; B) IBM PC DOS 7.1 fdisk32 displays warning message if P-CHS values multiplied ; together are different than total sector count. Therefore for drives with less ; than or equal 15,482,880 sectors we MUST NOT return total sector count from ; ATA ID WORDs 60 and 61. ; ; Lets take an example. 6 GB Hitachi microdrive reports following values in ATA ID: ; Sector count from WORDs 60 and 61 : 12,000,556 ; Cylinders : 11905 ; Heads : 16 ; Sectors per track : 63 ; ; When multiplying C*H*S we get : 12,000,240 ; So the CHS size is a little bit less than LBA size. But we must use ; the smaller value since C*H*S must equal total sector count! ; ; Now we get to the uncertain area where I could not find any information. ; Award BIOS from 1997 Pentium motherboard returns following values: ; AH=08h L-CHS: 745, 255, 63 (exactly the same as what we return) ; => Total Sector Count: 745*255*63 = 11,968,425 ; AH=48h P-CHS: 11873, 16, 63 ; AH=48h Total Sector Count: 11873* 16*63 = 11,967,984 ; ; Notice how AH=48h returns lesser total sector count than AH=08h! The only ; way I could think of to get 11873 cylinders is to divide AH=08h sector ; count with P-CHS heads and sectors: (745*255*63) / (16*63) = 11873 ; ; The only reason I can think of is that the Award BIOS has a bug and ; uses L-CHS when it should use P-CHS values in the calculation. ; ; ; AH48h_GetExtendedDriveParameters ; Parameters: ; SI: Same as in INTPACK ; DL: Translated Drive number ; DS:DI: Ptr to DPT (in RAMVARS segment) ; SS:BP: Ptr to IDEPACK ; Parameters on INTPACK: ; DS:SI: Ptr to Extended Drive Information Table to fill ; Returns with INTPACK: ; AH: Int 13h return status ; DS:SI: Ptr to Extended Drive Information Table ; CF: 0 if successful, 1 if error ;-------------------------------------------------------------------- AH48h_HandlerForGetExtendedDriveParameters: mov si, di push ds pop es ; ES = RAMVARS segment xor bx, bx dec bx ; Set to FFFFh to assume we do not return DPTE ; Create DPTE (hardware information for device drivers) %ifdef MODULE_COMPATIBLE_TABLES call AH41h_GetSupportBitsToCX test cl, ENHANCED_DISK_DRIVE_SUPPORT jz SHORT .DoNotCreateDPTE call CompatibleDPT_CreateDeviceParameterTableExtensionToESBXfromDPTinDSSI .DoNotCreateDPTE: %endif ; MODULE_COMPATIBLE_TABLES ; Point DS:DI to Extended Drive Information Table to fill mov di, [bp+IDEPACK.intpack+INTPACK.si] mov ds, [bp+IDEPACK.intpack+INTPACK.ds] ; Check and adjust Extended Drive Information Table size ; to MINIMUM_EDRIVEINFO_SIZE or EDRIVEINFO_SIZE_WITH_DPTE mov ax, MINIMUM_EDRIVEINFO_SIZE mov cx, [di+EDRIVE_INFO.wSize] cmp cx, ax jb Prepare_ReturnFromInt13hWithInvalidFunctionError mov [di+EDRIVE_INFO.wSize], ax mov al, EDRIVEINFO_SIZE_WITH_DPTE cmp cx, ax jb SHORT .SkipEddConfigurationParameters mov [di+EDRIVE_INFO.wSize], al ; Store DPTE for standard controllers only, ; FFFF:FFFF for non standard controllers %ifdef MODULE_COMPATIBLE_TABLES mov [di+EDRIVE_INFO.fpDPTE], bx mov [di+EDRIVE_INFO.fpDPTE+2], es inc bx jnz SHORT .SkipEddConfigurationParameters ; Already stored dec bx mov [di+EDRIVE_INFO.fpDPTE+2], bx ; Segment = FFFFh %else mov [di+EDRIVE_INFO.fpDPTE], bx mov [di+EDRIVE_INFO.fpDPTE+2], bx %endif ; MODULE_COMPATIBLE_TABLES ; Fill Extended Drive Information Table in DS:DI from DPT in ES:SI .SkipEddConfigurationParameters: mov WORD [di+EDRIVE_INFO.wFlags], FLG_DMA_BOUNDARY_ERRORS_HANDLED_BY_BIOS ; Store total sector count call Registers_ExchangeDSSIwithESDI call AccessDPT_GetLbaSectorCountToBXDXAX call Registers_ExchangeDSSIwithESDI mov [di+EDRIVE_INFO.qwTotalSectors], ax mov [di+EDRIVE_INFO.qwTotalSectors+2], dx mov [di+EDRIVE_INFO.qwTotalSectors+4], bx xor cx, cx mov [di+EDRIVE_INFO.qwTotalSectors+6], cx ; Always zero mov WORD [di+EDRIVE_INFO.wSectorSize], 512 ; Store P-CHS. Based on phoenix specification this is returned only if ; total sector count is 15,482,880 or less. sub ax, (MAX_SECTOR_COUNT_TO_RETURN_PCHS+1) & 0FFFFh sbb dx, (MAX_SECTOR_COUNT_TO_RETURN_PCHS+1) >> 16 sbb bx, cx ; Zero jnc SHORT .DoNotSetChsFlag or BYTE [di+EDRIVE_INFO.wFlags], FLG_CHS_INFORMATION_IS_VALID ; We store something to P-CHS anyway since some HW detection programs ; ignore the CHS flag. And we should at least clear the variables anyway ; since the same buffer is used for all drives so it contains parameters ; from previously scanned drive. .DoNotSetChsFlag: eMOVZX dx, [es:si+DPT.bPchsHeads] mov [di+EDRIVE_INFO.dwHeads], dx mov [di+EDRIVE_INFO.dwHeads+2], cx mov dl, [es:si+DPT.bPchsSectorsPerTrack] mov [di+EDRIVE_INFO.dwSectorsPerTrack], dx mov [di+EDRIVE_INFO.dwSectorsPerTrack+2], cx mov dx, [es:si+DPT.wPchsCylinders] mov [di+EDRIVE_INFO.dwCylinders], dx mov [di+EDRIVE_INFO.dwCylinders+2], cx xchg ax, cx ; Success jmp Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH