source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DetectDrives.asm@ 597

Last change on this file since 597 was 597, checked in by Tomi Tilli, 6 years ago

Windows 95 CMOS hack now works with Award BIOSes.
Some small optimizations to INT 19h and INT 19h reset handlers.
Added menuitem to configurator for clearing BDA drive count.

File size: 10.3 KB
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1; Project name : XTIDE Universal BIOS
2; Description : Functions for detecting drive for the BIOS.
3
4;
5; XTIDE Universal BIOS and Associated Tools
6; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
7;
8; This program is free software; you can redistribute it and/or modify
9; it under the terms of the GNU General Public License as published by
10; the Free Software Foundation; either version 2 of the License, or
11; (at your option) any later version.
12;
13; This program is distributed in the hope that it will be useful,
14; but WITHOUT ANY WARRANTY; without even the implied warranty of
15; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16; GNU General Public License for more details.
17; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
18;
19
20; Section containing code
21SECTION .text
22
23;--------------------------------------------------------------------
24; Detects all IDE hard disks to be controlled by this BIOS.
25;
26; DetectDrives_FromAllIDEControllers
27; Parameters:
28; DS: RAMVARS segment
29; ES: BDA segment (zero)
30; Returns:
31; Nothing
32; Corrupts registers:
33; All (not segments)
34;--------------------------------------------------------------------
35DetectDrives_FromAllIDEControllers:
36 call RamVars_GetIdeControllerCountToCX
37 mov bp, ROMVARS.ideVars0 ; CS:BP now points to first IDEVARS
38
39.DriveDetectLoop: ; Loop through IDEVARS
40 push cx
41
42 mov cx, g_szDetectMaster
43 mov bh, MASK_DRVNHEAD_SET ; Select Master drive
44 call StartDetectionWithDriveSelectByteInBHandStringInCX ; Detect and create DPT + BOOTNFO
45
46 mov cx, g_szDetectSlave
47 mov bh, MASK_DRVNHEAD_SET | FLG_DRVNHEAD_DRV
48 call StartDetectionWithDriveSelectByteInBHandStringInCX
49
50%ifdef MODULE_HOTKEYS
51%ifdef MODULE_SERIAL
52 ; This is only needed for hotkey F6 (ComDtct) to work
53 call ScanHotkeysFromKeyBufferAndStoreToBootvars ; Done here while CX is still protected
54%endif
55%endif
56
57 pop cx
58
59 add bp, BYTE IDEVARS_size ; Point to next IDEVARS
60
61%ifdef MODULE_SERIAL
62 jcxz .AddHardDisks ; Set to zero on .ideVarsSerialAuto iteration (if any)
63%endif
64 loop .DriveDetectLoop
65
66%ifdef MODULE_SERIAL
67;----------------------------------------------------------------------
68;
69; if serial drive detected, do not scan (avoids duplicate drives and isn't needed - we already have a connection)
70;
71 call FindDPT_ToDSDIforSerialDevice ; Does not modify AX
72 jnc .AddHardDisks
73
74 mov bp, ROMVARS.ideVarsSerialAuto ; Point to our special IDEVARS structure, just for serial scans
75
76%ifdef MODULE_HOTKEYS
77 cmp al, COM_DETECT_HOTKEY_SCANCODE ; Set by last call to ScanHotkeysFromKeyBufferAndStoreToBootvars above
78 je .DriveDetectLoop
79%endif
80
81 mov al, [cs:ROMVARS.wFlags] ; Configurator set to always scan?
82 or al, [es:BDA.bKBFlgs1] ; Or, did the user hold down the ALT key?
83 and al, 8 ; 8 = alt key depressed, same as FLG_ROMVARS_SERIAL_SCANDETECT
84 jnz .DriveDetectLoop
85%endif ; MODULE_SERIAL
86
87.AddHardDisks:
88;----------------------------------------------------------------------
89;
90; Add in hard disks to BDA, finalize our Count and First variables
91;
92; Note that we perform the add to bHDCount and store bFirstDrv even if the count is zero.
93; This is done because we use the value of .bFirstDrv to know how many drives were in the system
94; at the time of boot, and to return that number on int13h/8h calls. Because the count is zero,
95; FindDPT_ForDriveNumber will not find any drives that are ours.
96;
97
98; Here we might want to replace BIOS configured drives with the ones we detected.
99; Primary reason is to support dynamic overlay feature in the future. Second reason
100; is a hack to get Windows 95 load proper IDE drivers.
101;
102; The Windows hack has two parts. First part is to try to alter CMOS address 12h as that
103; is what Windows 95 driver reads to detect IDE drives. Altering is not possible on all
104; systems since CMOS has a checksum but its location is not standardized. We will first
105; try to detect valid checksum. If it succeeds, then it is safe to assume this system
106; has compatible CMOS and we can alter it.
107; If verify fails, we do the more dirty hack to zero BDA drive count. Then Windows 95 works
108; as long as user has configured at least one drive in the BIOS setup.
109
110%ifdef USE_AT ; FLG_ROMVARS_IGNORE_MOTHERBOARD_DRIVES is for AT builds only
111
112 %ifdef MODULE_WIN95_CMOS_HACK
113 mov dl, HARD_DISK_TYPES
114 call CMOS_ReadFromIndexInDLtoAL
115 test al, al
116 jnz SHORT .ContinueInitialization ; CMOS byte 12h is ready for Windows 95
117 call CMOS_Verify10hTo2Dh ; Can we modify CMOS?
118 jnz SHORT .ClearBdaDriveCount ; Unsupported BIOS, use plan B
119
120 ; Now we can alter CMOS location 12h. Important! We set type for drive 1
121 ; (primary slave) and not for drive 0! Award BIOS locks if we set drive 0 type to Fh.
122 ; We cannot set it to less either since that will fully set predefined hard drive type to the BIOS.
123 ; Windows 95 only cares that the CMOS location 12h is non-zero.
124 mov dl, HARD_DISK_TYPES
125 mov al, 0Fh ; Drive 1 type 16...47 (defined elsewhere in the CMOS)
126 call CMOS_WriteALtoIndexInDL
127 call CMOS_StoreNewChecksumFor10hto2Dh
128.ClearBdaDriveCount:
129 %endif ; MODULE_WIN95_CMOS_HACK
130
131 test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_IGNORE_MOTHERBOARD_DRIVES
132 jz SHORT .ContinueInitialization
133 mov BYTE [es:BDA.bHDCount], 0 ; Set hard disk count to zero
134.ContinueInitialization:
135%endif
136
137 mov cx, [RAMVARS.wDrvCntAndFlopCnt] ; Our count of hard disks
138 mov al, [es:BDA.bHDCount]
139 add [es:BDA.bHDCount], cl ; Add our drives to the system count
140 or al, 80h ; Or in hard disk flag
141 mov [RAMVARS.bFirstDrv], al ; Store first drive number
142
143.AddFloppies:
144%ifdef MODULE_SERIAL_FLOPPY
145;----------------------------------------------------------------------
146;
147; Add in any emulated serial floppy drives, finalize our packed Count and First variables
148;
149 dec ch
150 mov al, ch
151 js .NoFloppies ; if no drives are present, we store 0ffh
152
153 call FloppyDrive_GetCountFromBIOS_or_BDA
154
155 push ax
156
157 add al, ch ; Add our drives to existing drive count
158 cmp al, 3 ; For BDA, max out at 4 drives (ours is zero based)
159 jb .MaxBDAFloppiesExceeded
160 mov al, 3
161.MaxBDAFloppiesExceeded:
162 eROR_IM al, 2 ; move to bits 6-7
163 inc ax ; low order bit, indicating floppy drive exists
164
165 mov ah, 3Eh ; AND mask to AH (all bits set except floppy drive count/present)
166 and ah, [es:BDA.wEquipment] ; Load Equipment WORD low byte and mask off drive number and drives present bit
167 or al, ah ; Or in new values
168 mov [es:BDA.wEquipment], al ; and store
169
170 mov al, 1Eh ; BDA pointer to Floppy DPT
171 mov si, AH8h_FloppyDPT
172 call Interrupts_InstallHandlerToVectorInALFromCSSI
173
174 pop ax
175
176 shr ch, 1 ; number of drives, 1 or 2 only, to CF flag (clear=1, set=2)
177 eRCL_IM al, 1 ; starting drive number in upper 7 bits, number of drives in low bit
178.NoFloppies:
179 mov [RAMVARS.xlateVars+XLATEVARS.bFlopCntAndFirst], al
180%endif
181 ret
182
183%ifndef CHECK_FOR_UNUSED_ENTRYPOINTS
184 %if FLG_ROMVARS_SERIAL_SCANDETECT != 8
185 %error "DetectDrives is currently coded to assume that FLG_ROMVARS_SERIAL_SCANDETECT is the same bit as the ALT key code in the BDA. Changes in the code will be needed if these values are no longer the same."
186 %endif
187%endif
188
189
190;--------------------------------------------------------------------
191; StartDetectionWithDriveSelectByteInBHandStringInCX
192; Parameters:
193; BH: Drive Select byte for Drive and Head Register
194; CX: Offset to "Master" or "Slave" string
195; CS:BP: Ptr to IDEVARS for the drive
196; DS: RAMVARS segment
197; ES: Zero (BDA segment)
198; Returns:
199; Nothing
200; Corrupts registers:
201; AX, BL, CX, DX, SI, DI
202;--------------------------------------------------------------------
203StartDetectionWithDriveSelectByteInBHandStringInCX:
204 call DetectPrint_StartDetectWithMasterOrSlaveStringInCXandIdeVarsInCSBP
205
206%ifdef MODULE_HOTKEYS
207 call HotkeyBar_UpdateDuringDriveDetection
208%endif
209 ; Fall to .ReadAtaInfoFromHardDisk
210
211
212;--------------------------------------------------------------------
213; .ReadAtaInfoFromHardDisk
214; Parameters:
215; BH: Drive Select byte for Drive and Head Register
216; DX: Autodetected port (for devices that support autodetection)
217; CS:BP: Ptr to IDEVARS for the drive
218; DS: RAMVARS segment
219; ES: Zero (BDA segment)
220; Returns:
221; CF: Cleared if ATA-information read successfully
222; Set if any error
223; Corrupts registers:
224; AX, BL, CX, DX, SI, DI
225;--------------------------------------------------------------------
226.ReadAtaInfoFromHardDisk:
227 mov si, BOOTVARS.rgbAtaInfo ; ES:SI now points to ATA info location
228 push es
229 push si
230 push dx
231 push bx
232 call Device_IdentifyToBufferInESSIwithDriveSelectByteInBH
233 pop bx
234 pop dx
235 pop si
236 pop es
237 jnc SHORT CreateBiosTablesForHardDisk
238 ; Fall to .ReadAtapiInfoFromDrive
239
240.ReadAtapiInfoFromDrive: ; Not yet implemented
241 ;call ReadAtapiInfoFromDrive ; Assume CD-ROM
242 ;jnc SHORT _CreateBiosTablesForCDROM
243
244 ;jmp short DetectDrives_DriveNotFound
245;;; fall-through instead of previous jmp instruction
246;--------------------------------------------------------------------
247; DetectDrives_DriveNotFound
248; Parameters:
249; Nothing
250; Returns:
251; CF: Set (from DetectPrint_NullTerminatedStringFromCSSIandSetCF)
252; Corrupts registers:
253; AX, SI
254;--------------------------------------------------------------------
255DetectDrives_DriveNotFound:
256 mov si, g_szNotFound
257 jmp DetectPrint_NullTerminatedStringFromCSSIandSetCF
258
259
260;--------------------------------------------------------------------
261; CreateBiosTablesForHardDisk
262; Parameters:
263; BH: Drive Select byte for Drive and Head Register
264; DX: Autodetected port (for devices that support autodetection)
265; CS:BP: Ptr to IDEVARS for the drive
266; ES:SI Ptr to ATA information for the drive
267; DS: RAMVARS segment
268; ES: BDA segment
269; Returns:
270; Nothing
271; Corrupts registers:
272; AX, BX, CX, DX, SI, DI
273;--------------------------------------------------------------------
274CreateBiosTablesForHardDisk:
275%ifndef NO_ATAID_VALIDATION
276 push bx
277 call AtaID_VerifyFromESSI
278 pop bx
279 jnz SHORT DetectDrives_DriveNotFound
280%endif
281 call CreateDPT_FromAtaInformation
282 jc SHORT DetectDrives_DriveNotFound
283 call DriveDetectInfo_CreateForHardDisk
284 jmp SHORT DetectPrint_DriveNameFromDrvDetectInfoInESBX
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