source: trunk/bootcode/regular/driveio.asm@ 105

Last change on this file since 105 was 105, checked in by Ben Rietbroek, 8 years ago

Moved the INT13X DAP to the BSS [v1.1.1-testing]

No need to have this in the image, eating up precious code-space.
The byte holding the packet size is now initialized from PRERAP.

CAUTION:
This is a testbuild !
AirBoot uses the BIOS to access disks and a small coding error can trash
partition tables or other vital disk structures. You are advised to make
backups of TRACK0 and EBRs before using this testbuild. More info at:
https://rousseaux.github.io/netlabs.air-boot/pdf/AirBoot-v1.1.0-manual.pdf

File size: 49.2 KB
Line 
1; AiR-BOOT (c) Copyright 1998-2008 M. Kiewitz
2;
3; This file is part of AiR-BOOT
4;
5; AiR-BOOT is free software: you can redistribute it and/or modify it under
6; the terms of the GNU General Public License as published by the Free
7; Software Foundation, either version 3 of the License, or (at your option)
8; any later version.
9;
10; AiR-BOOT is distributed in the hope that it will be useful, but WITHOUT ANY
11; WARRANTY: without even the implied warranty of MERCHANTABILITY or FITNESS
12; FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
13; details.
14;
15; You should have received a copy of the GNU General Public License along with
16; AiR-BOOT. If not, see <http://www.gnu.org/licenses/>.
17;
18;---------------------------------------------------------------------------
19; AiR-BOOT / DRIVE I/O
20;---------------------------------------------------------------------------
21
22
23
24IFDEF MODULE_NAMES
25DB 'DRIVEIO',0
26ENDIF
27
28;
29; Check if INT13X extensions are supported.
30; AirBoot requires these extensions, and will halt if they are not available.
31; Modified: AX, BX, CX, DX, CF
32DriveIO_CheckFor13extensions Proc Near
33 mov ah, 41h
34 mov bx, 55AAh
35 mov dl, [BIOS_BootDisk] ; We check using the boot-disk
36 int 13h
37 jc PCCF13E_NotFound ; Error occured
38 cmp bx, 0AA55h
39 je PCCF13E_Found
40 PCCF13E_NotFound:
41 ret
42 PCCF13E_Found:
43 and cx, 1 ; Check 42h-44h,47h,48h supported
44 jz PCCF13E_NotFound ; Sig OK but no support, strange beast
45 mov byte ptr [CurIO_UseExtension], 1
46 ret
47DriveIO_CheckFor13extensions EndP
48
49
50; Note: Some routines set DS/ES to CS or even address via CS, even if its not
51; needed. This was done for SECURITY. So DO NOT remove it.
52; Its there to make sure the correct data is loaded/written to/from
53; harddrive.
54;
55; IF YOU MODIFY ANYTHING IN HERE, YOU MAY EASILY BREAK YOUR HARDDRIVE!
56
57; Will only load base-configuration, will NOT load IPT nor Hide-Config
58; Those are originally loaded on startup and will NOT get reloaded.
59DriveIO_LoadConfiguration Proc Near Uses ax bx cx dx es
60 mov ax, cs
61 mov es, ax
62 mov bx, offset Configuration
63 xor dh, dh
64 mov dl, [BIOS_BootDisk] ; Disk we booted from
65 mov cx, 0037h ; Sector 55 (CHS)
66 mov ax, 0201h ; Function 02, read 1 sector...
67 int 13h
68 jnc DIOLC_NoError
69 call MBR_LoadError ; Will Abort BootUp
70 DIOLC_NoError:
71 ret
72DriveIO_LoadConfiguration EndP
73
74DriveIO_SaveConfiguration Proc Near Uses ax bx cx dx ds es si
75 mov ax, cs
76 mov ds, ax
77 mov es, ax ; Safety first (CS==DS==ES)
78 ; --- Overwrite Floppy-Name with "FloppyDrive"
79 mov si, offset TXT_Floppy_Drive
80 mov di, offset PartitionTable
81 sub di, 30 ; Adjust to Floppy-Name
82 mov cx, 11
83 rep movsb
84 mov si, offset Configuration ; Calculate new checksum
85 xor bx, bx
86
87 ; Changed from 5 to calculated value (not here, see compat. issue below)
88 ; Fixes issue: #2987 -- "air-boot doesn't remember drive letter"
89 ; Size of the ab-configuration in 512 byte sectors
90 ;mov cx, (MBR_BackUpMBR - Configuration) / 200h
91
92 ; AB v1.07 stores a 5 sector configuration with a 5 sector checksum.
93 ; AB v1.0.8+ *should* stores a 7 sector configuration with a
94 ; 7 sector checksum.
95 ; Because 5 was hardcoded here, SET(A)BOOT v1.07 will see see an AB v1.0.8+
96 ; config as corrupted, while this is not the case.
97 ; So, for compatibility reasons, in v1.0.8+, the checksum stored is over
98 ; 5 sectors, to be compatible with v1.07.
99 ; This may change (be corrected) in future versions !
100 mov cx,5
101
102 mov dx, [CFG_CheckConfig]
103 mov [CFG_CheckConfig], bx
104 DIOSC_Loop:
105 call MBR_GetCheckOfSector
106 loop DIOSC_Loop
107 mov [CFG_CheckConfig], bx
108 ; --------------------------------------------------------------------
109 ; ES == CS
110 mov bx, offset Configuration
111 xor dh, dh
112 mov dl, [BIOS_BootDisk] ; Disk we booted from
113 mov cx, 0037h ; Sector 55 (CHS)
114
115 ; Changed from 5 to calculated value
116 ; Fixes issue: #2987 -- "air-boot doesn't remember drive letter"
117 ; Size of the ab-configuration in 512 byte sectors
118 mov al, (MBR_BackUpMBR - Configuration) / 200h
119 mov ah,03h
120
121 int 13h
122 jnc DIOSC_NoError
123 call MBR_SaveError ; Will Abort BootUp
124 DIOSC_NoError:
125 ret
126DriveIO_SaveConfiguration EndP
127
128DriveIO_UpdateFloppyName Proc Near Uses bx cx dx ds si es di
129 mov ax, cs
130 mov ds, ax
131 mov es, ax
132
133 mov ah, 00h ; Function 0 - Reset Drive
134 xor dl, dl
135 int 13h
136 xor dx, dx ; Cylinder=0, Head=0
137 mov cx, 1 ; Sector=1, Drive=0
138 mov bx, offset TmpSector ; ES:BX - TmpSector
139 mov ax, 0201h ; Function 2 - Load Sector
140 int 13h
141 jnc DIOUFN_AllFine
142
143 ; --- Overwrite Floppy-Name with "No Disc"
144 mov si, offset TXT_Floppy_NoDisc
145 xor ax, ax
146 DIOUFN_WriteFloppyName:
147 mov di, offset PartitionTable
148 sub di, 30 ; Adjust to Floppy-Name
149 mov cl, 11
150 rep movsb
151 ret ; AX=-1 -> GotDisc, =0 -> NoDisc
152
153 ; --- Floppy found and read, data in TempSector
154 DIOUFN_AllFine:
155 mov ax, -1
156 mov si, offset TXT_Floppy_NoName
157 cmp wptr es:[bx+54], 'AF'
158 jne DIOUFN_WriteFloppyName
159 cmp wptr es:[bx+56], '1T'
160 jne DIOUFN_WriteFloppyName
161 cmp bptr es:[bx+58], '2'
162 jne DIOUFN_WriteFloppyName
163 mov si, bx
164 add si, 43 ; FAT12 - Volume Label Location
165 jmp DIOUFN_WriteFloppyName
166DriveIO_UpdateFloppyName EndP
167
168; =============================================================================
169; HARDDRIVE / GENERAL ACCESS
170; =============================================================================
171; The following routines are used for harddisc/floppy access.
172; The access is done via INT 13h/CHS or INT 13h/LBA.
173; Access will be done prefered by INT 13h/CHS, because it's (I wonder!) much
174; faster, than the LBA-method. I don't know, why LBA is so slow. Perhaps BIOS.
175;
176; Internal access (to AiR-BOOT) is always done via INT 13h/CHS.
177
178DriveIO_GetHardDriveCount Proc Near Uses ds si
179 push ds
180 push si
181 push 0040h
182 pop ds
183 mov si, 0075h
184 mov dh, ds:[si] ; 40:75 -> POST: Total Harddiscs == DL
185 pop si
186 pop ds
187 mov [TotalHarddiscs], dh
188 ret
189DriveIO_GetHardDriveCount EndP
190
191
192; Fills our LBA-Usage table. It holds the LBA-address, where BIOS/CHS access is
193; stopped and BIOS/LBA access is started.
194; This is calculated by Sector*Heads. Comparing will get done with Bit 25-10
195; on LBA sectors, so we actually divide sector number by 1024.
196DriveIO_InitLBASwitchTable Proc Near Uses es di
197 mov di, offset LBASwitchTable
198 mov dh, [TotalHarddiscs]
199 mov dl, 80h ; First disk to process
200 DIOILUT_DriveLoop:
201 push dx
202 push di
203 mov ah, 08h
204 int 13h ; DISK - GET DRIVE PARAMETERS
205 mov ah, 0FBh ; Assume 255 heads/63 sectors, if error
206 jc DIOILUT_Error
207 and cl, 111111b ; Isolate lower 6 bits of CL -> sector count
208
209 ;movzx ax, cl
210 mov al,cl
211 mov ah,0
212
213 mov bl, dh ; DH -> max head number
214 mul bl ; AX = Sectors*Heads
215 shl ah, 1
216 shl ah, 1 ; Shift 2 bits, so we are able to compare to
217 ; bit 16-23 of the LBA address
218 DIOILUT_Error:
219 pop di
220 pop dx
221 mov bptr ds:[di], ah ; Save that value
222 inc di ; Go to next BYTE
223 inc dl ; Next disk
224 dec dh ; Decrease disks to process
225 jnz DIOILUT_DriveLoop ; Next disk if DH != 0
226 ret
227DriveIO_InitLBASwitchTable EndP
228
229
230
231
232;FIXME: Only LBA gets updated, need to update CHS too !!!!!!!
233
234; Adjusts BX:AX / CX:DX to meet LVM sector location
235; BX:AX / CX:DX point to MBR or EBR !
236; Destroys SI
237; Rousseau: Enhanced to handle sector-numbers 127 and 255 besides 63 for LVM-info sectors.
238; Ugly, need to cleanup.
239DriveIO_LVMAdjustToInfoSector Proc Near
240 push cx ; Save Cyl/Sec part
241 xor ch,ch ; Clear low Cyl part
242 and cl,63 ; Clear high Cyl part
243 push bx ; We need BX...
244 push dx ; and DX temoraily
245 mov bx,offset [TrueSecs] ; Offset of sector table
246 xor dh,dh ; Clear DH because we use DL as index
247 and dl,01111111b ; Remove high bit of BIOS disk-nr
248 shl dx,2 ; Index to DWORD table
249 add bx,dx ; Point to TrueSecs for this disk
250 mov si,[bx] ; Get SPT for this disk
251 pop dx ; Restore DX...
252 pop bx ; and BX
253 ;~ sub si,cx ; Adjust offset !! INCORRECT FOR LBA (TP CX != 0 !!)
254 dec si
255 pop cx ; Restore Cyl/Sec part
256 add ax,si ; Add offset to low part...
257 adc bx,0 ; and high part of LBA address
258 or cl,63 ; Adjust CHS part !FIX ME for > 63! !! FIX HUGE DRIVE !!
259
260
261 ret
262
263DriveIO_LVMAdjustToInfoSector EndP
264
265
266
267
268
269
270; #########################################################################
271; Routine: Loads partition to ExecBase and checks for validity
272; #########################################################################
273; Calling : bx:ax - Absolute sector
274; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
275; Returns : Carry Set if invalid partition encountered
276; Preserve: all registers
277; #########################################################################
278DriveIO_LoadPartition Proc Near Uses si
279 mov wptr cs:[CurPartition_Location+0], ax
280 mov wptr cs:[CurPartition_Location+2], bx
281 mov wptr cs:[CurPartition_Location+4], dx
282 mov wptr cs:[CurPartition_Location+6], cx ; Saves the location
283 mov si, offset PartitionSector ; DS:SI - ExecBase
284 call DriveIO_LoadSector
285 clc
286 cmp wptr [si+LocBR_Magic], 0AA55h
287 je DIOLP_Success
288 ; We check, if we are scanning partitions. In that case, if CHS is not 0/0/1
289 ; we will display a "bad partition table" message and halt the system.
290 cmp cx, 0001h
291 jne DIOLP_Failed
292 or dh, dh
293 jnz DIOLP_Failed
294 stc ; Set carry, so no partition table
295 DIOLP_Success:
296
297 IFDEF AUX_DEBUG
298 ; show current partition location
299 ;~ pushf
300 ;~ pusha
301 ;~ call AuxIO_TeletypeNL
302 ;~ mov si,offset db_curpartloc
303 ;~ call AuxIO_Print
304 ;~ mov dx,word ptr [CurPartition_Location+02]
305 ;~ mov ax,word ptr [CurPartition_Location+00]
306 ;~ call AuxIO_TeletypeHexDWord
307 ;~ call AuxIO_TeletypeNL
308 ;~ mov si,offset PartitionSector
309 ;~ call AuxIO_DumpSector
310 ;~ call AuxIO_TeletypeNL
311 ;~ popa
312 ;~ popf
313 ENDIF
314
315 ret
316 DIOLP_Failed:
317 jmp DriveIO_GotLoadError
318DriveIO_LoadPartition EndP
319
320; #########################################################################
321; Routine: Writes a partition from ExecBase to its original sector
322; #########################################################################
323; Calling : none
324; Returns : none
325; Preserve: all registers
326; #########################################################################
327DriveIO_SavePartition Proc Near Uses ax bx cx dx si
328 mov ax, wptr cs:[CurPartition_Location+0]
329 mov bx, wptr cs:[CurPartition_Location+2]
330 mov dx, wptr cs:[CurPartition_Location+4]
331 mov cx, wptr cs:[CurPartition_Location+6] ; Gets prev. saved location
332 mov si, offset PartitionSector ; DS:SI - ExecBase
333 cmp wptr [si+LocBR_Magic], 0AA55h ; Checks for signature, if not found
334 jne DIOSP_SevereError ; we assume a really bad error
335 call DriveIO_SaveSector
336 DIOSP_SevereError:
337 ret
338DriveIO_SavePartition EndP
339
340; Keeps DS:SI for caller
341DriveIO_LoadTmpSector Proc Near
342 mov si, offset TmpSector
343 call DriveIO_LoadSector
344 ret
345DriveIO_LoadTmpSector EndP
346
347; Keeps DS:SI for caller
348DriveIO_SaveTmpSector Proc Near
349 mov si, offset TmpSector
350 call DriveIO_SaveSector
351 ret
352DriveIO_SaveTmpSector EndP
353
354
355
356; Keeps DS:SI for caller, sets carry if valid LVM sector encountered
357DriveIO_LoadLVMSector Proc Near Uses ax bx cx dx
358 test byte ptr [CFG_IgnoreLVM], 1 ; We are supposed to ignore LVM, so
359 jnz DIOLLVMS_NoLVMSector ; don't load but declare as bad!
360 mov ax, wptr cs:[CurPartition_Location+0]
361 mov bx, wptr cs:[CurPartition_Location+2]
362 mov dx, wptr cs:[CurPartition_Location+4]
363 mov cx, wptr cs:[CurPartition_Location+6] ; Gets cur. partition location
364
365 call DriveIO_LVMAdjustToInfoSector
366
367 mov si, offset LVMSector
368 call DriveIO_LoadSector
369
370 IFDEF AUX_DEBUG
371 ; show current partition location
372 ;~ pushf
373 ;~ pusha
374 ;~ call AuxIO_TeletypeNL
375 ;~ mov si,offset db_curlvmsec
376 ;~ call AuxIO_Print
377 ;~ mov dx,bx
378 ;~ call AuxIO_TeletypeHexDWord
379 ;~ call AuxIO_TeletypeNL
380 ;~ mov si,offset LVMSector
381 ;~ call AuxIO_DumpSector
382 ;~ call AuxIO_TeletypeNL
383 ;~ popa
384 ;~ popf
385 ENDIF
386
387 call LVM_CheckSectorSignature
388 jnc DIOLLVMS_NoLVMSector
389 call LVM_CheckSectorCRC
390 jnc DIOLLVMS_NoLVMSector
391 ret
392 ; This here is called, if an invalid (or no) LVM information sector is found
393 ; It will truncate the first byte of the sector, so all other routines
394 ; will notice it easily by just comparing the first byte.
395 DIOLLVMS_NoLVMSector:
396 mov bptr [si+LocLVM_SignatureStart], 0
397 ret
398DriveIO_LoadLVMSector EndP
399
400
401
402; Keeps DS:SI for caller, saves at anytime w/o checks (!)
403DriveIO_SaveLVMSector Proc Near Uses ax bx cx dx
404 test byte ptr [CFG_IgnoreLVM], 1 ; We are supposed to ignore LVM, so
405 jnz DIOSLVMS_SevereError ; don't save at anytime (security!)
406 mov ax, wptr cs:[CurPartition_Location+0]
407 mov bx, wptr cs:[CurPartition_Location+2]
408 mov dx, wptr cs:[CurPartition_Location+4]
409 mov cx, wptr cs:[CurPartition_Location+6] ; Gets cur. partition location
410 call LVM_CheckSectorSignature
411 jnc DIOSLVMS_SevereError ; LVM Signature must be there
412
413 IFDEF AUX_DEBUG
414;~ dioatlvm db 'DriveIO_LVMAdjustToInfoSector',10,0
415 ;~ pushf
416 ;~ pusha
417 ;~ mov si,offset dioatlvm
418 ;~ call AuxIO_Print
419 ;~ popa
420 ;~ popf
421 call DEBUG_DumpRegisters
422 call DEBUG_DumpCHS
423 ENDIF
424
425 call DriveIO_LVMAdjustToInfoSector
426
427 IFDEF AUX_DEBUG
428 call DEBUG_DumpRegisters
429 call DEBUG_DumpCHS
430 ENDIF
431
432 mov si, offset LVMSector
433 call DriveIO_SaveSector
434 DIOSLVMS_SevereError:
435 ret
436DriveIO_SaveLVMSector EndP
437
438
439
440; Special error message instead of "LOAD ERROR" during partition scanning,
441; so users will notice that something is bad with their partition table(s)
442DriveIO_GotLoadError Proc Near
443 test byte ptr cs:[CurIO_Scanning], 1 ; Must be CS:, cause DS!=CS maybe here
444 jnz InScanMode
445 jmp MBR_LoadError
446 InScanMode:
447 mov si, offset TXT_BrokenPartitionTable
448 push cs
449 pop ds
450 call MBR_Teletype
451 mov si, offset BrokenHDD
452 sub dl, 50h ; 80h -> '0'
453 cmp dl, 39h
454 jbe DIOGLE_BelowA
455 add dl, 7 ; 3Ah -> 'A'
456 DIOGLE_BelowA:
457 mov bptr [si+5], dl
458 call MBR_Teletype
459
460 ; JWasm: cannot jump to local label in other procedure.
461 ; Changed to halt here.
462 ;jmp MBRLE_Halt
463 DriveIO_GotLoadError_halt:
464 jmp DriveIO_GotLoadError_halt
465DriveIO_GotLoadError EndP
466
467; #########################################################################
468; Routine: Loads a specified sector to DS:DI
469; #########################################################################
470; Calling : bx:ax - Absolute sector
471; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
472; ds:si - Destination-Adress
473; Returns : none
474; Preserve: all registers
475; #########################################################################
476DriveIO_LoadSector Proc Near Uses ax bx cx dx ds si es di
477 ; Is the drive not a harddrive?
478 cmp dl, 80h
479 jb DIOLS_UseNormal
480
481 test byte ptr cs:[CurIO_UseExtension], 1
482 jz DIOLS_UseNormal
483 ; Are we forced do use LBA via Setting?
484 jnz DIOLS_UseExtension
485
486 ; Upper 8 bits of LBA-address set?
487 ; Then use LBA (maximum boundary is 16320x16x63 = FB0400h)
488 or bh, bh
489 jnz DIOLS_UseExtension
490 ; Compare Switch-Table value to bit 16-23 of LBA-address
491 mov di, dx
492 and di, 007Fh
493 cmp bptr cs:[LBASwitchTable+di], bl
494 jbe DIOLS_UseExtension
495 DIOLS_UseNormal:
496 mov di, 3
497 DIOLS_ErrorLoop:
498 push ds
499 pop es
500 mov bx, si ; ES:BX - Destination
501 mov ax, 0201h ; Function 2 - Load Sector
502 int 13h
503 jnc DIOLS_Success
504 dec di
505 jnz DIOLS_ErrorLoop
506 ; Sector load failed...
507 jmp DriveIO_GotLoadError
508
509 DIOLS_UseExtension:
510 push cx
511 mov cs:[INT13X_DAP_NumBlocks], 1 ; Copy ONE sector
512 mov wptr cs:[INT13X_DAP_Transfer+0], si
513 mov cx, ds
514 mov wptr cs:[INT13X_DAP_Transfer+2], cx ; Fill out Transfer Adress
515 mov wptr cs:[INT13X_DAP_Absolute+0], ax
516 mov wptr cs:[INT13X_DAP_Absolute+2], bx ; Fill out Absolute Sector
517 push cs
518 pop ds
519 mov si, offset [INT13X_DAP]
520 mov ah, 42h ; Extended Read
521 int 13h
522 pop cx
523 jnc DIOLS_Success
524 ; Sector load failed...
525 jmp DriveIO_GotLoadError
526
527 DIOLS_Success:
528 ret
529DriveIO_LoadSector EndP
530
531
532
533;##############################################################################
534;# ACTION : Reads a sector from disk using INT13 extensions
535;# ----------------------------------------------------------------------------
536;# IN : BX:CX - LBA address of sector
537;# : DI:SI - SEG:OFF of transfer buffer
538;# ----------------------------------------------------------------------------
539;# OUT : CF=1 - failure, AH failure code
540;# ----------------------------------------------------------------------------
541;# EFFECTS : Modifies DAP structure and fills transfer buffer
542;##############################################################################
543DriveIO_ReadSectorLBA Proc Near Uses bx cx dx si di ds es
544
545 ; One sector to read
546 mov cs:[INT13X_DAP_NumBlocks], 1
547
548 ; Setup transfer address
549 mov wptr cs:[INT13X_DAP_Transfer+0], si ; offset
550 mov wptr cs:[INT13X_DAP_Transfer+2], di ; segment
551
552 ; Setup LBA64 address of requested sector
553 mov wptr cs:[INT13X_DAP_Absolute+0], cx ; low word lower part
554 mov wptr cs:[INT13X_DAP_Absolute+2], bx ; high word lower part
555 mov wptr cs:[INT13X_DAP_Absolute+4], 0 ; low word upper part
556 mov wptr cs:[INT13X_DAP_Absolute+6], 0 ; high word upper part
557
558 ; Address of packet
559 mov si, offset [INT13X_DAP] ; disk address packet
560
561 ; Do the extended read
562 mov ah, 42h ; read function
563 int 13h ; transfer to bios
564
565 ; Error occured
566 jc DriveIO_ReadSectorLBA_exit
567
568 ; AH should also be zero
569 test ah, ah
570 stc
571 jnz DriveIO_ReadSectorLBA_exit
572
573 ; Disk read succeeded, clear CF
574 clc
575
576 DriveIO_ReadSectorLBA_exit:
577 ret
578
579DriveIO_ReadSectorLBA EndP
580
581
582
583;##############################################################################
584;# ACTION : Writes a sector to disk using INT13 extensions
585;# ----------------------------------------------------------------------------
586;# IN : AL - write flags, AL.0 verify (1.0,2.0), AL.1 verify (2.1+)
587;# : BX:CX - LBA address of sector
588;# : DI:SI - SEG:OFF of transfer buffer
589;# ----------------------------------------------------------------------------
590;# OUT : CF=1 - failure, AH failure code
591;# ----------------------------------------------------------------------------
592;# EFFECTS : Modifies DAP structure and mofifies the disk
593;##############################################################################
594DriveIO_WriteSectorLBA Proc Near Uses bx cx dx si di ds es
595
596 ; Mask reserved bits for wrte flags -- should check version here
597 and al, 03h
598
599 ; One sector to read
600 mov cs:[INT13X_DAP_NumBlocks], 1
601
602 ; Setup transfer address
603 mov wptr cs:[INT13X_DAP_Transfer+0], si ; offset
604 mov wptr cs:[INT13X_DAP_Transfer+2], di ; segment
605
606 ; Setup LBA64 address of requested sector
607 mov wptr cs:[INT13X_DAP_Absolute+0], cx ; low word lower part
608 mov wptr cs:[INT13X_DAP_Absolute+2], bx ; high word lower part
609 mov wptr cs:[INT13X_DAP_Absolute+4], 0 ; low word upper part
610 mov wptr cs:[INT13X_DAP_Absolute+6], 0 ; high word upper part
611
612 ; Address of packet
613 mov si, offset [INT13X_DAP] ; disk address packet
614
615 ; Do the extended write
616 mov ah, 43h ; write function
617 int 13h ; transfer to bios
618
619 ; Error occured
620 jc DriveIO_WriteSectorLBA_exit
621
622 ; AH should also be zero
623 test ah, ah
624 stc
625 jnz DriveIO_WriteSectorLBA_exit
626
627 ; Disk write succeeded, clear CF
628 clc
629
630 DriveIO_WriteSectorLBA_exit:
631 ret
632
633DriveIO_WriteSectorLBA EndP
634
635
636
637;
638; ############################################################
639; # Check for a valid MBR-sector to be written to disk #
640; ############################################################
641;
642; In
643; --
644; DL = Physical Disk
645; BX:CX = LBA sector
646; DI:SI = Source buffer
647;
648; Out
649; ---
650; CY = 1 if invalid MBR in source buffer, 0 if valid
651;
652; This routine is called when DriveIO_SaveSector attempts to write to the MBR.
653; It checks if the sector to be written has some sensible values in certain
654; places. In fact, if the sector is written to the boot-disk, the AiR-BOOT
655; signature should be present and the partition table should be the same
656; as the one at the start of the AiR-BOOT code in memory, except maybe for the
657; active flags.
658; For other disks, only the active flags are checked to be 00h or 80h and
659; the AA55h MBR signature.
660;
661DriveIO_ProtectMBR Proc Near
662 pusha ; Push all registers
663 push es ; Push ES because we need it for string instructions
664 push cs ; Make ES point...
665 pop es ; to CS
666
667 ; Save the pointer to the sector to write in BX
668 mov bx,si
669
670 ;
671 ; If the sector to be written is not the boot-disk, then skip
672 ; checking the AiR-BOOT MBR.
673 ;
674 cmp dl, [BIOS_BootDisk]
675 jne DriveIO_ProtectMBR_is_not_bootdisk
676
677 ;
678 ; The boot-disk is accessed so the sector to be written must be
679 ; the AiR-BOOT MBR. This is the same as the first 512 bytes
680 ; relocated to 8000:0000 and this the start of the AB-code.
681 ;
682 mov si,bx ; Get pointer to sector to write
683 xor di,di ; Point DI to start of AB-code (MBR)
684 mov cx, offset [MBR_PartTable] ; Bytes upto P-table must be same
685 cld ; Compare upwards
686 repe cmpsb ; Compare upto P-table
687
688 ; If not the same this is not the an AiR-BOOT boot-disk MBR !
689 jne DriveIO_ProtectMBR_not_valid_MBR ; SEVERE ERROR !
690
691 ; Continue with signature check
692 jmp DriveIO_ProtectMBR_check_signature
693
694
695 ;
696 ; The disk is not the boot-disk so we don't know what kind of MBR is on it.
697 ; Some sanity checks should be here.
698 ;
699 DriveIO_ProtectMBR_is_not_bootdisk:
700
701 ;
702 ; sanity checks...
703 ;
704
705 ; Continue with signature check
706 jmp DriveIO_ProtectMBR_check_signature
707
708
709 DriveIO_ProtectMBR_check_signature:
710 ; See if the sector to write contains a valid signature
711 mov si,bx ; Get pointer to sector to write
712 mov di, offset [MBR_Sig] ; Offset to MBR signature
713 add si,di ; Make SI point to it in sec to write
714 lodsw ; Load it
715 cmp ax,0aa55h ; See if it is valid
716
717 ; If no signature this cannot be a valid MBR !
718 jne DriveIO_ProtectMBR_not_valid_MBR ; SEVERE ERROR !
719
720
721 ;
722 ; The sector to be written seems to be valid.
723 ; Set CY=0 to indicate a valid MBR.
724 ;
725 DriveIO_ProtectMBR_is_valid_MBR:
726 clc
727 jmp DriveIO_ProtectMBR_end
728
729 ;
730 ; Something is terribly wrong; a non-MBR sector seems about to be written.
731 ; Set CY=1 and let the calling code handle this situation.
732 ;
733 DriveIO_ProtectMBR_not_valid_MBR:
734 stc
735 jmp DriveIO_ProtectMBR_end
736
737 ;
738 ; Return to the caller with no registers modyfied except FLAGS.
739 ;
740 DriveIO_ProtectMBR_end:
741 pop es
742 popa
743 ret
744DriveIO_ProtectMBR Endp
745
746
747
748; #########################################################################
749; Routine: Checks if the MBR is addressed by either CHS or LBA
750; #########################################################################
751; Calling : bx:ax - Absolute sector
752; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
753; Returns : ZF=1 if MBR is addressed, else ZF=0
754; Preserve: all registers
755; #########################################################################
756DriveIO_MBR_Addressed Proc
757 push ax
758 push bx
759
760 or bx,ax ; Results in 0 in BX if MBR is addressed by LBA
761 jz DriveIO_MBR_Addressed_done
762
763 mov ax,cx ; Results in 1 in AX if CYL 0, SEC 1 is addressed
764 add al,dh ; Results in 1 in AX if HEAD 0 is addressed
765 dec ax ; Results in 0 in AX if MBR is addressed by CHS
766
767 DriveIO_MBR_Addressed_done:
768 pop bx
769 pop ax
770 ret
771DriveIO_MBR_Addressed EndP
772
773
774
775
776; #########################################################################
777; Routine: Writes DS:SI to a specified sector
778; #########################################################################
779; Calling : bx:ax - Absolute sector
780; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
781; ds:si - Source-Adress
782; Returns : none
783; Preserve: all registers
784; #########################################################################
785DriveIO_SaveSector Proc Near Uses ax bx cx dx ds si es di
786
787
788 ;!
789 ;! DEBUG_BLOCK
790 ;! Force write to LBA0 to test interception routine.
791 ;! Do *NOT* enable unless you are debugging, will overwrite MBR !
792 ;!
793 ;~ __DIO_FORCE_LBA0_WRITE__ EQU
794 IFDEF AUX_DEBUG
795 IFDEF __DIO_FORCE_LBA0_WRITE__
796 xor ax,ax
797 xor bx,bx
798 xor cx,cx
799 inc cx
800 xor dh,dh
801 ENDIF
802 ENDIF
803
804
805 ;!
806 ;! DEBUG_BLOCK
807 ;! Check what is being written to disk.
808 ;! Uncomment below to activate.
809 ;!
810 __DIO_SS_DMP__ EQU
811 IFDEF AUX_DEBUG
812 IFDEF __DIO_SS_DMP__
813 pusha
814 push si
815 mov si,offset [dioss]
816 call AuxIO_Print
817 pop si
818 call DEBUG_DumpRegisters
819 call AuxIO_DumpSector
820 call AuxIO_TeletypeNL
821 popa
822 ENDIF
823 ENDIF
824
825 ;
826 ; Check if the MBR is the destination for the write.
827 ; ZF=1 if so.
828 ;
829 call DriveIO_MBR_Addressed
830 jnz DriveIO_SaveSector_continue_write
831
832
833 ; MBR is addressed, check the sector that is requested to be written.
834 ; For the bootdisk it should contain the AiR-BOOT signature, valid
835 ; partition-table entries and the AA55h signature.
836 ; If not, something is terribly wrong in some piece of the AB code.
837 ; For any other disk (80h+) at least a valid partition table should
838 ; be present together with the AA55h signature.
839 call DriveIO_ProtectMBR
840 jnc DriveIO_SaveSector_continue_write
841
842
843 ;
844 ; WE HAVE A SEVERE ERROR CONDITION !
845 ; SOME AB CODE TRIES TO WRITE A NON-MBR TO THE DISK !
846 ; ASK THE USER TO REPORT THIS !
847 ; HALT THE SYSTEM !
848 ;
849
850 ; Show error-box
851 mov cx, 0C04h
852 mov si, offset NonMBRwrite
853 call SETUP_ShowErrorBox
854 mov cx, 0C04h
855 mov si, offset NonMBRwrite_rep
856 call SETUP_ShowErrorBox
857
858
859 IFDEF AUX_DEBUG
860 pusha
861 mov si, offset NonMBRwrite
862 call AuxIO_TeletypeNL
863 call AuxIO_Print
864 call AuxIO_TeletypeNL
865 popa
866 ENDIF
867
868 ; Show popup and halt the system.
869 jmp HaltSystem
870
871
872
873 ;
874 ; Continue the write if not MBR sector or MBR to write is validated.
875 ;
876 DriveIO_SaveSector_continue_write:
877 test byte ptr cs:[CurIO_UseExtension], 1
878 jz DIOSS_UseNormal
879 ; Are we forced do use LBA via Setting?
880 ; Always use INT13X on v1.0.8+.
881 ;~ test byte ptr cs:[CFG_ForceLBAUsage], 1
882 ;~ jnz DIOSS_UseExtension
883 jmp DIOSS_UseExtension
884 ; Is the drive not a harddrive?
885 cmp dl, 80h
886 jb DIOSS_UseNormal
887 ; Upper 8 bits of LBA-address set? -> Use LBA (maximum boundary is FB0400h)
888 or bh, bh
889 jnz DIOSS_UseExtension
890 ; Compare Switch-Table value to bit 16-23 of LBA-address
891 mov di, dx
892 and di, 007Fh
893 cmp bptr cs:[LBASwitchTable+di], bl
894 jbe DIOSS_UseExtension
895 DIOSS_UseNormal:
896 mov di, 3
897 DIOSS_ErrorLoop:
898 push ds
899 pop es
900 mov bx, si ; ES:BX - Destination
901 mov ax, 0301h ; Function 3 - Write Sector
902 int 13h
903 jnc DIOSS_Success
904 dec di
905 jnz DIOSS_ErrorLoop
906 call MBR_SaveError
907
908 DIOSS_UseExtension:
909 push cx
910 mov cs:[INT13X_DAP_NumBlocks], 1 ; Copy ONE sector
911 mov wptr cs:[INT13X_DAP_Transfer+0], si
912 mov cx, ds
913 mov wptr cs:[INT13X_DAP_Transfer+2], cx ; Fill out Transfer Adress
914 mov wptr cs:[INT13X_DAP_Absolute+0], ax
915 mov wptr cs:[INT13X_DAP_Absolute+2], bx ; Fill out Absolute Sector
916 push cs
917 pop ds
918 mov si, offset [INT13X_DAP]
919 mov ax, 4300h ; Extended Write (No Verify)
920 int 13h
921 pop cx
922 jnc DIOSS_Success
923 call MBR_SaveError
924
925 DIOSS_Success:
926 ret
927DriveIO_SaveSector EndP
928
929
930
931; ------------------------------------------------------
932; Rousseau: # Load the master LVM-sector if one exists #
933; ------------------------------------------------------
934; Load the master LVM-sector to get the number of sectors per track as
935; OS/2 views the drive. If no master LVM-sector is found it is assumed OS/2
936; is not installed. The master LVM-sector can be located at three different
937; places depending on drive size and partitioning scheme and driver used.
938; When DANIS506.ADD is used, the OS/2 extended geometry will be 255/127 for
939; drives >502GiB but <1TiB. Then the location will be sector 127 which
940; is LBA 126 (7Eh).
941; IBM1S506.ADD will always use 255/255 for the extended OS/2 geometry.
942; DANIS506.ADD will use 255/255 for drives >1TiB.
943; Then the location of the master LVM-sector will be 255 which is LBA 254 (FEh).
944; When OS/2 is installed on a huge drive that alread had a system on it, OS/2
945; will be confined to the lower 502GiB of the drive.
946; In this case the normal geometry from Int13X will be used.
947; This is also the case when no valid master LVM-sector can be found.
948;
949; Return CF when valid master LVM sector found, NC if not.
950; Loads sector at [LVMSector] !
951DriveIO_LoadMasterLVMSector Proc Near
952 pusha
953
954 ;~ mov si,offset db_lmlvm
955 ;~ call AuxIO_Print
956
957 ;~ ; Physical disk
958 ;~ mov al,'<'
959 ;~ call VideoIO_PrintSingleChar
960 ;~ mov al,dl
961 ;~ call VideoIO_PrintHexByte
962 ;~ mov al,'>'
963 ;~ call VideoIO_PrintSingleChar
964;~
965 ;~ call AuxIO_TeletypeHexByte
966 ;~ call AuxIO_TeletypeNL
967
968
969 ; Loop over the sector-translation table,
970 ; process the first three values from high (255) to low.
971 ; (bios spt, most likely 63)
972 mov cx,3
973 DriveIO_LoadMasterLVMSector_NextTry:
974 ; Number of sectors to read
975 mov [INT13X_DAP_NumBlocks],1
976
977 ; Setup destination address
978 mov si, offset [LVMSector]
979 mov word ptr [INT13X_DAP_Transfer+0],si
980 mov ax, ds
981 mov word ptr [INT13X_DAP_Transfer+2],ax
982
983 ; Get the sector-number of the next possible LVM sector (255,127,63)
984 ; using the translation table and the counter as the index
985 mov bx,offset secs_per_track_table
986 mov ax,cx
987 dec ax
988 xlatb
989 dec al
990
991 ;
992 ; AX now contains the LBA address of the sector
993 ; that could be an LVM sector.
994 ; This is all in track0 so the address will not exceed 64kiB sectors.
995 ;
996
997 ;~ push ax
998 ;~ push ax
999 ;~ mov al,'$'
1000 ;~ call VideoIO_PrintSingleChar
1001 ;~ pop ax
1002 ;~ call VideoIO_PrintHexByte
1003 ;~ mov al,'$'
1004 ;~ call VideoIO_PrintSingleChar
1005 ;~ pop ax
1006
1007 IFDEF AUX_DEBUG
1008 ; Dump the value
1009 ;~ call AuxIO_TeletypeHexByte
1010 ;~ call AuxIO_TeletypeNL
1011 ENDIF
1012
1013 ; Setup the requested LBA sector number
1014 mov word ptr [INT13X_DAP_Absolute+0],ax ; LBA low NORMAL I/O GEBRUIKEN !
1015 mov word ptr [INT13X_DAP_Absolute+2],00h ; LBA high
1016 mov si, offset [INT13X_DAP] ; address request packet
1017 mov ah, 42h
1018 int 13h ; do the i/o, CF=1->error, CF=0->success
1019
1020IFDEF AUX_DEBUG
1021 pushf
1022 pusha
1023 pushf
1024 xor ax, ax
1025 mov al, dl
1026 call AuxIO_TeletypeHexWord
1027 mov al, '#'
1028 call AuxIO_Teletype
1029 popf
1030 mov ax,0000h
1031 rcl al, 1
1032 call AuxIO_TeletypeHexWord
1033 mov al, '#'
1034 call AuxIO_Teletype
1035 mov ax,word ptr [INT13X_DAP_Absolute+0]
1036 call AuxIO_TeletypeHexWord
1037 mov al, '#'
1038 call AuxIO_Teletype
1039 popa
1040 popf
1041ENDIF
1042
1043 cmc ; Complement carry so we can exit imm. on error
1044 jnc DriveIO_LoadMasterLVMSector_End ; oops, return with NC
1045
1046
1047 mov si,offset [LVMSector]
1048
1049 ; See if this is a valid LVM-sector
1050 ; ZF=0 if valid
1051 call LVM_ValidateSector
1052
1053; pushf
1054; mov ah,0
1055; rcl ah,1
1056; mov al,'|'
1057; call VideoIO_PrintSingleChar
1058; mov al,ah
1059; call VideoIO_PrintHexByte
1060; mov al,'|'
1061; call VideoIO_PrintSingleChar
1062; popf
1063
1064
1065 ; Yep, we found the master LVM-sector
1066 jnz DriveIO_LoadMasterLVMSector_Found
1067 ; Try next location
1068 loop DriveIO_LoadMasterLVMSector_NextTry
1069
1070 ; No master LVM-sector found, set CF=false
1071 clc
1072
1073 DriveIO_LoadMasterLVMSector_Found:
1074 ; Store the address for later use.
1075 mov ax, word ptr [INT13X_DAP_Absolute]
1076 mov word ptr [MasterLVMLBA], ax
1077
1078 DriveIO_LoadMasterLVMSector_End:
1079 popa
1080 ret
1081DriveIO_LoadMasterLVMSector Endp
1082
1083
1084
1085
1086; ---------------------------------------------------
1087; Rousseau ## Large drives, (OS/2) geometry and LBA ##
1088; ---------------------------------------------------
1089; A sector size of 512 bytes is assumed in the below calculations.
1090; Note that this scheme changes when the sector size will be 4096 or larger,
1091; like with modern drives that do not translate to 512 bytes per sector anymore.
1092; These drives will have a capacity above the 2TiB LBA32 boundary.
1093; For now, we assume drives <=2TiB with a sector size of 512 bytes.
1094
1095; There are a few boundaries that are of importance.
1096; Note that these are disk-boundaries and not partition boundaries.
1097; Even with a small partition, like <502GiB, OS/2 will use extended geometry on
1098; an empty huge disk.
1099; These boundaries are (from high to low):
1100
1101; (code 5)
1102; 2^32 = 4294967296 = 100000000 sectors = 2048 GiB
1103; This is the LBA32 2TiB boundary.
1104; Everything above it must be addressed using LBA48.
1105; OS/2 can currently not address this space above.
1106
1107; (code4)
1108; 65536*255*255 = 4261478400 = FE010000 sectors ~ 2032 GiB
1109; This is the max OS/2 boundary using 255/255 extended geometry.
1110; OS/2 can currently not address this space above.
1111
1112; (code 3)
1113; 2^31 = 2147483648 = 80000000 sectors = 1024 GiB
1114; This is the LBA32 1TiB boundary.
1115; OS/2 can address this space and will use 255/255 extended geometry.
1116
1117; (code 2)
1118; 65536*255*127 = 2122383360 = 7E810000 sectors ~ 1012 GiB
1119; This is the DANI 1TiB boundary.
1120; OS/2 can address this space and will use 255/255 extended geometry.
1121; Below this DANI will use 255/127 extended geometry.
1122; This matters on where the LVM-sectors are located !
1123
1124; (code 1)
1125; 65536*255*63 = 1052835840 = 3EC10000 sectors ~ 502 GiB
1126; This is the current OS/2 limit using this geometry because OS/2 can
1127; currently not address more than 65536 cylinders.
1128; DANI will address space above with 255/127 extended geometry up until
1129; the DANI 1TiB boundary (code 2)
1130
1131; (code 0)
1132; Everything below 65536*255*63 will be addressed using standard geometry.
1133
1134
1135;
1136; This function will return the following values:
1137;
1138
1139; 5 = This drive is above the 2^32 LBA32 (2TB) boundary and has more
1140; than 4294967296 sectors.
1141; LBA48 addressing is needed to access the complete capacity of the drive.
1142; OS/2 is currently unable to do so.
1143
1144; 4 = This drive is above the 65536*255*255 (4261478400) boundary but below 2^32.
1145; This is an OS/2 boundary and OS/2 is not able to access the drive above
1146; this boundary.
1147
1148; 3 = This drive is above the 2^31 (1TB) boundary and has more than
1149; 2147483648 sectors.
1150; OS/2 is able to access the drive using it's extended geometry.
1151; Both DANIS506 and IBM1S506 will use the 255/255 scheme.
1152
1153; 2 = This drive is above the 65536*255*127 (2122383360) boundary but below 2^31.
1154; OS/2 is able to access the drive using it's extended geometry.
1155; Both DANIS506 and IBM1S506 will use the 255/255 scheme.
1156
1157; 1 = This drive is above the 65536*255*63 (1052835840) boundary but
1158; below 65536*255*127.
1159; OS/2 is able to access the drive using it's extended geometry.
1160; Note that DANIS506 will use 255/127 and IBM1S506 will use 255/255 geometry !
1161; Using DANI or IBM influences the location of the LVM info-sectors !
1162
1163; 0 = This drive is below the 65536*255*63 (1052835840) boundary.
1164; OS/2 is able to access this drive using the standard 255/63 geometry.
1165
1166; So, any return value >0 means OS/2 extended geometry will be used.
1167; Value 1 will use 255/127 with DANIS506 but 255/255 with IBM1S506.
1168; Values 2 and 3 will use 255/255 on both drivers.
1169; You can or with 0x01 and check for 3 in this case.
1170; Any value above 3 will be a drive who's capacity cannot be fully used by OS/2
1171; The upper limit of 65536*255*255 will be in effect here.
1172
1173; Note this function currently handles the boot-drive only !
1174; It should be extended and use dl for the drive-number as a parameter.
1175; Because we use this function to get this info in a number of places,
1176; all regs and flags except AX are saved and restored.
1177
1178; DL contains BIOS disk-number; 80h for first, 81h for second, etc.
1179DriveIO_GatherDiskInfo Proc Near
1180 pushf
1181 push bx
1182 push cx
1183 push dx
1184 push si
1185 push di
1186 push es
1187
1188 ; Set ES to CS for buffer clearing
1189 push cs
1190 pop es
1191
1192 ; Clear the buffer
1193 ; Also setup the buffer size.
1194 ; Old Phoenix BIOSses require word (flags) at 02 to be zero,
1195 ; so we clear the whole buffer to be sure.
1196 mov cx, i13xbuf_size ; Dynamically calculated by assembler.
1197 mov di, offset i13xbuf ; Points to size field.
1198 mov [di],cx ; Setup buffer-size.
1199 inc di
1200 inc di ; Now pointing at actual buffer.
1201 xor ah,ah ; Fill value.
1202 cld ; Direction up.
1203 rep stosb ; Clear buffer.
1204
1205 ; Get the drive parameters
1206 mov ah, 48h ; Get Drive Parameters (extended version)
1207 ;mov dl, 80h ; Drive number
1208 mov si, offset i13xbuf ; Buffer for result-info
1209 push dx
1210 int 13h ; Call the BIOS-function
1211 pop dx
1212
1213 ; Do some error-checking
1214 or ah,ah ; AH is zero if no error (ZF=1 if no error)
1215 mov ax,0 ; Setup code for non-huge drive (does not influence ZF)
1216 jz DriveIO_GatherDiskInfo_ok ; Return if error (AL<>0 thus ZF=0) but CY not set, assuming non-huge drive
1217 jnc DriveIO_GatherDiskInfo_ok ; Return if error (CY=1), assuming non-huge drive
1218 jmp DriveIO_GatherDiskInfo_ret
1219
1220
1221 DriveIO_GatherDiskInfo_ok:
1222
1223 ;
1224 ; Store the drive geometry
1225 ;
1226
1227 mov si, offset i13xbuf
1228
1229 xor dh,dh
1230 and dl,01111111b
1231 shl dx,1
1232 shl dx,1
1233
1234 ; Store number of cylinders on disk
1235 mov bx, offset BIOS_Cyls
1236 add bx,dx
1237 mov ax,[si+04h]
1238
1239 mov word ptr [bx+00],ax
1240 mov ax,[si+06]
1241 mov word ptr [bx+02],ax
1242
1243 ; Store number of heads per cylinder
1244 mov bx, offset BIOS_Heads
1245 add bx,dx
1246 mov ax,[si+08h]
1247 mov word ptr [bx+00],ax
1248 mov ax,[si+0ah]
1249 mov word ptr [bx+02],ax
1250
1251 ; Store number of sectors per track
1252 mov bx, offset BIOS_Secs
1253 add bx,dx
1254 mov ax,[si+0ch]
1255 mov word ptr [bx+00],ax
1256
1257 ; Update first byte of translation-table to conform to BIOS SPT
1258 mov byte ptr [secs_per_track_table], al
1259
1260 mov ax,[si+0eh]
1261 mov word ptr [bx+02],ax
1262
1263 ; Store total secs
1264 mov bx, offset BIOS_TotalSecs
1265 add bx,dx
1266 add bx,dx
1267 mov ax,[si+10h]
1268
1269 mov word ptr [bx+00],ax
1270 mov ax,[si+12h]
1271 mov word ptr [bx+02],ax
1272 mov ax,[si+14h]
1273 mov word ptr [bx+04],ax
1274 mov ax,[si+18h]
1275 mov word ptr [bx+06],ax
1276
1277 ; Store number of bytes per sector
1278 mov bx, offset BIOS_Bytes
1279 add bx,dx
1280 mov ax,[si+18h]
1281 mov [bx],ax
1282
1283
1284 ;
1285 ; See of it's a huge drive of not
1286 ;
1287
1288 ; Drive is larger than 2TiB
1289 mov ax,5 ; Drive code (5)
1290 mov bx, [si+14h] ; Low word of high dword of sector-count
1291 or bx, [si+16h] ; High word of high dword of sector-count
1292 jnz DriveIO_GatherDiskInfo_ret ; If non-zero we have a drive with >2^32 sectors and thus LBA48 addressing
1293
1294 ; Drive is larger than max OS/2 capacity
1295 dec ax ; Drive code (4)
1296 mov bx, [si+12h] ; High word of low dword of sector-count
1297 cmp bx, 0fe01h ; Boundary
1298 jae DriveIO_GatherDiskInfo_ret ; If above or equal to boundary,
1299 ; we have a drive larger than to 65536*255*255 = FE010000 sectors
1300
1301 ; Drive can be completely utilized by OS/2
1302 dec ax ; Drive code (3)
1303 cmp bx, 8000h ; Boundary
1304 jae DriveIO_GatherDiskInfo_ret ; If above or equal to boundary,
1305 ; we have a drive larger than 2^31 sectors but smaller than 65536*255*255
1306
1307 ; This is the small area between DANI 1TiB and LBA 1TiB
1308 dec ax ; Drive code (2)
1309 cmp bx, 7e81h ; Boundary
1310 jae DriveIO_GatherDiskInfo_ret ; If above or equal to boundary,
1311 ; we have a drive larger than 65536*255*127 but <65536*255*255
1312 ; DANIS506.ADD will use 255/255 extended geometry
1313
1314 ; DANI will use 255/127 in this area, this could impact the location of LVM-sectors ! (last sec on track)
1315 dec ax ; Drive code (1)
1316 cmp bx, 3ec1h ; Boundary
1317 jae DriveIO_GatherDiskInfo_ret ; If above or equal to boundary,
1318 ; we have a drive larger than 65536*255*63 sectors (OS/2 502GiB Limit!)
1319 ; DANIS506.ADD will use 255/127 extended geometry !
1320 ; IBM1S506.ADD will use 255/255 extended geometry !
1321
1322 ; We have a drive that can be addressed using standard 255/63 geometry
1323 dec ax ; Drive code (0)
1324 ; We have a drive smaller than 65536*255*63 = 3EC10000 sectors
1325
1326 DriveIO_GatherDiskInfo_ret:
1327 pop es
1328 pop di
1329 pop si
1330 pop dx
1331 pop cx
1332 pop bx
1333
1334 mov byte ptr [CurIO_UseExtension],1
1335
1336 popf
1337 ret
1338DriveIO_GatherDiskInfo EndP
1339
1340
1341
1342; Values for sectors per track table corresponding to DriveIO_IsHugeDrive return value.
1343secs_per_track_table db 63,127,255,255,255,255
1344
1345;db_lmlvm: db 'Load Master LVM -- disk: ',0
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