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driveio.asm@ 175

Last change on this file since 175 was 175, checked in by Ben Rietbroek, 8 years ago

Reenable interrupts after disk i/o -- trac #11 [v1.1.1-testing]

Some old or quirky BIOSses return with interrupts disabled after INT13
and/or INT13X calls. That blocks the timer interrupt which makes
AiR-BOOT wait forever when building the BOOT-MENU.
This should fix trac issue #11:
http://trac.netlabs.org/air-boot/ticket/11

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: 75.1 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
24	IFDEF MODULE_NAMES
25	DB 'DRIVEIO',0
26	ENDIF
27
28	;
29	; Check if INT13X extensions are supported.
30	; AirBoot requires these extensions, and will halt if they are not available.
31	; Modified: [CurIO_UseExtension]
32	DriveIO_CheckFor13extensions Proc Near Uses ax bx cx dx
33	mov ah, 41h
34	mov bx, 55AAh
35	mov dl, [BIOS_BootDisk] ; We check using the boot-disk
36	int 13h
37	sti
38
39	IFDEF AUX_DEBUG
40	IF 0
41	DBG_TEXT_OUT_AUX 'DriveIO_CheckFor13extensions:'
42	PUSHRF
43	call DEBUG_DumpRegisters
44	;~ call AuxIO_DumpParagraph
45	;~ call AuxIO_TeletypeNL
46	mov si, offset [Scratch]
47	mov word ptr [si], 50h
48	mov ah, 48h
49	int 13h
50	sti
51	call DEBUG_DumpRegisters
52	;~ call AuxIO_DumpSector
53	POPRF
54	ENDIF
55	ENDIF
56
57	jc PCCF13E_NotFound ; Error occured
58	cmp bx, 0AA55h
59	je PCCF13E_Found
60	PCCF13E_NotFound:
61	ret
62	PCCF13E_Found:
63	and cx, 1 ; Check 42h-44h,47h,48h supported
64	jz PCCF13E_NotFound ; Sig OK but no support, strange beast
65	mov byte ptr [CurIO_UseExtension], 1
66	ret
67	DriveIO_CheckFor13extensions EndP
68
69
70	; Note: Some routines set DS/ES to CS or even address via CS, even if its not
71	; needed. This was done for SECURITY. So DO NOT remove it.
72	; Its there to make sure the correct data is loaded/written to/from
73	; harddrive.
74	;
75	; IF YOU MODIFY ANYTHING IN HERE, YOU MAY EASILY BREAK YOUR HARDDRIVE!
76
77	; Will only load base-configuration, will NOT load IPT nor Hide-Config
78	; Those are originally loaded on startup and will NOT get reloaded.
79	DriveIO_LoadConfiguration Proc Near Uses ax bx cx dx es
80
81	IFDEF AUX_DEBUG
82	IF 0
83	DBG_TEXT_OUT_AUX 'DriveIO_LoadConfiguration:'
84	PUSHRF
85	;~ call DEBUG_DumpRegisters
86	;~ call AuxIO_DumpParagraph
87	;~ call AuxIO_TeletypeNL
88	POPRF
89	ENDIF
90	ENDIF
91
92	;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
93	mov ax, cs
94	mov es, ax
95	mov bx, offset Configuration
96	xor dh, dh
97	mov dl, [BIOS_BootDisk] ; Disk we booted from
98	mov cx, 0037h ; Sector 55 (CHS)
99	mov ax, 0201h ; Function 02, read 1 sector...
100	int 13h
101	sti ; Enable ints
102	jnc DIOLC_NoError
103	call MBR_LoadError ; Will Abort BootUp
104
105
106	DIOLC_NoError:
107	ret
108	DriveIO_LoadConfiguration EndP
109
110	DriveIO_SaveConfiguration Proc Near Uses ax bx cx dx ds es si
111
112	IFDEF AUX_DEBUG
113	IF 0
114	DBG_TEXT_OUT_AUX 'DriveIO_SaveConfiguration:'
115	PUSHRF
116	call DEBUG_DumpRegisters
117	;~ call AuxIO_DumpParagraph
118	;~ call AuxIO_TeletypeNL
119	POPRF
120	ENDIF
121	ENDIF
122
123	mov ax, cs
124	mov ds, ax
125	mov es, ax ; Safety first (CS==DS==ES)
126	; --- Overwrite Floppy-Name with "FloppyDrive"
127	mov si, offset TXT_Floppy_Drive
128	mov di, offset PartitionTable
129	sub di, 30 ; Adjust to Floppy-Name
130	mov cx, 11
131	rep movsb
132	mov si, offset Configuration ; Calculate new checksum
133	xor bx, bx
134
135	; Changed from 5 to calculated value (not here, see compat. issue below)
136	; Fixes issue: #2987 -- "air-boot doesn't remember drive letter"
137	; Size of the ab-configuration in 512 byte sectors
138	;mov cx, (MBR_BackUpMBR - Configuration) / 200h
139
140	; AB v1.07 stores a 5 sector configuration with a 5 sector checksum.
141	; AB v1.0.8+ should stores a 7 sector configuration with a
142	; 7 sector checksum.
143	; Because 5 was hardcoded here, SET(A)BOOT v1.07 will see see an AB v1.0.8+
144	; config as corrupted, while this is not the case.
145	; So, for compatibility reasons, in v1.0.8+, the checksum stored is over
146	; 5 sectors, to be compatible with v1.07.
147	; This may change (be corrected) in future versions !
148	mov cx,5
149
150	mov dx, [CFG_CheckConfig]
151	mov [CFG_CheckConfig], bx
152	DIOSC_Loop:
153	call MBR_GetCheckOfSector
154	loop DIOSC_Loop
155	mov [CFG_CheckConfig], bx
156	; --------------------------------------------------------------------
157	; ES == CS
158	mov bx, offset Configuration
159	xor dh, dh
160	mov dl, [BIOS_BootDisk] ; Disk we booted from
161	mov cx, 0037h ; Sector 55 (CHS)
162
163	; Changed from 5 to calculated value
164	; Fixes issue: #2987 -- "air-boot doesn't remember drive letter"
165	; Size of the ab-configuration in 512 byte sectors
166	mov al, (MBR_BackUpMBR - Configuration) / 200h
167	mov ah,03h
168	;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
169	int 13h
170	sti
171	jnc DIOSC_NoError
172	call MBR_SaveError ; Will Abort BootUp
173	DIOSC_NoError:
174	ret
175	DriveIO_SaveConfiguration EndP
176
177	DriveIO_UpdateFloppyName Proc Near Uses bx cx dx ds si es di
178	mov ax, cs
179	mov ds, ax
180	mov es, ax
181
182	mov ah, 00h ; Function 0 - Reset Drive
183	xor dl, dl
184	int 13h
185	sti
186	xor dx, dx ; Cylinder=0, Head=0
187	mov cx, 1 ; Sector=1, Drive=0
188	mov bx, offset TmpSector ; ES:BX - TmpSector
189	mov ax, 0201h ; Function 2 - Load Sector
190	int 13h
191	jnc DIOUFN_AllFine
192
193	; --- Overwrite Floppy-Name with "No Disc"
194	mov si, offset TXT_Floppy_NoDisc
195	xor ax, ax
196	DIOUFN_WriteFloppyName:
197	mov di, offset PartitionTable
198	sub di, 30 ; Adjust to Floppy-Name
199	mov cl, 11
200	rep movsb
201	ret ; AX=-1 -> GotDisc, =0 -> NoDisc
202
203	; --- Floppy found and read, data in TempSector
204	DIOUFN_AllFine:
205	mov ax, -1
206	mov si, offset TXT_Floppy_NoName
207	cmp wptr es:[bx+54], 'AF'
208	jne DIOUFN_WriteFloppyName
209	cmp wptr es:[bx+56], '1T'
210	jne DIOUFN_WriteFloppyName
211	cmp bptr es:[bx+58], '2'
212	jne DIOUFN_WriteFloppyName
213	mov si, bx
214	add si, 43 ; FAT12 - Volume Label Location
215	jmp DIOUFN_WriteFloppyName
216	DriveIO_UpdateFloppyName EndP
217
218	; =============================================================================
219	; HARDDRIVE / GENERAL ACCESS
220	; =============================================================================
221	; The following routines are used for harddisc/floppy access.
222	; The access is done via INT 13h/CHS or INT 13h/LBA.
223	; Access will be done prefered by INT 13h/CHS, because it's (I wonder!) much
224	; faster, than the LBA-method. I don't know, why LBA is so slow. Perhaps BIOS.
225	;
226	; Internal access (to AiR-BOOT) is always done via INT 13h/CHS.
227
228	DriveIO_GetHardDriveCount Proc Near Uses ds si
229	push ds
230	push si
231	push 0040h
232	pop ds
233	mov si, 0075h
234	mov dh, ds:[si] ; 40:75 -> POST: Total Harddiscs == DH
235	pop si
236	pop ds
237	mov [TotalHarddiscs], dh
238	ret
239	DriveIO_GetHardDriveCount EndP
240
241
242	; Fills our LBA-Usage table. It holds the LBA-address, where BIOS/CHS access is
243	; stopped and BIOS/LBA access is started.
244	; This is calculated by Sector*Heads. Comparing will get done with Bit 25-10
245	; on LBA sectors, so we actually divide sector number by 1024.
246	DriveIO_InitLBASwitchTable Proc Near Uses es di
247	mov di, offset LBASwitchTable
248	mov dh, [TotalHarddiscs]
249	mov dl, 80h ; First disk to process
250	DIOILUT_DriveLoop:
251	push dx
252	push di
253	mov ah, 08h
254	int 13h ; DISK - GET DRIVE PARAMETERS
255	sti ; Enable ints
256	mov ah, 0FBh ; Assume 255 heads/63 sectors, if error
257	jc DIOILUT_Error
258	and cl, 111111b ; Isolate lower 6 bits of CL -> sector count
259	;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
260	;movzx ax, cl
261	mov al,cl
262	mov ah,0
263
264	mov bl, dh ; DH -> max head number
265	mul bl ; AX = Sectors*Heads
266	shl ah, 1
267	shl ah, 1 ; Shift 2 bits, so we are able to compare to
268	; bit 16-23 of the LBA address
269	DIOILUT_Error:
270	pop di
271	pop dx
272	mov bptr ds:[di], ah ; Save that value
273	inc di ; Go to next BYTE
274	inc dl ; Next disk
275	dec dh ; Decrease disks to process
276	jnz DIOILUT_DriveLoop ; Next disk if DH != 0
277	ret
278	DriveIO_InitLBASwitchTable EndP
279
280	; #########################################################################
281	; Routine: Loads partition to ExecBase and checks for validity
282	; #########################################################################
283	; Calling : bx:ax - Absolute sector
284	; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
285	; Returns : Carry Set if invalid partition encountered
286	; Preserve: all registers
287	; #########################################################################
288	DriveIO_LoadPartition Proc Near Uses si
289
290	IFDEF AUX_DEBUG
291	IF 0
292	DBG_TEXT_OUT_AUX 'DriveIO_LoadPartition:'
293	PUSHRF
294	call DEBUG_DumpRegisters
295	;~ call AuxIO_DumpParagraph
296	;~ call AuxIO_TeletypeNL
297	POPRF
298	ENDIF
299	ENDIF
300
301	mov wptr cs:[CurPartition_Location+0], ax
302	mov wptr cs:[CurPartition_Location+2], bx
303	mov wptr cs:[CurPartition_Location+4], dx
304	mov wptr cs:[CurPartition_Location+6], cx ; Saves the location
305	mov si, offset [PartitionSector] ; DS:SI - ExecBase
306
307
308	;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
309	call DriveIO_LoadSector
310
311	clc
312	cmp wptr [si+LocBR_Magic], 0AA55h
313	je DIOLP_Success
314	; We check, if we are scanning partitions. In that case, if CHS is not 0/0/1
315	; we will display a "bad partition table" message and halt the system.
316	cmp cx, 0001h
317	jne DIOLP_Failed
318	or dh, dh
319	jnz DIOLP_Failed
320	stc ; Set carry, so no partition table
321	DIOLP_Success:
322
323
324
325	ret
326	DIOLP_Failed:
327	jmp DriveIO_GotLoadError
328	DriveIO_LoadPartition EndP
329
330	; #########################################################################
331	; Routine: Writes a partition from ExecBase to its original sector
332	; #########################################################################
333	; Calling : none
334	; Returns : none
335	; Preserve: all registers
336	; #########################################################################
337	DriveIO_SavePartition Proc Near Uses ax bx cx dx si
338
339	IFDEF AUX_DEBUG
340	IF 0
341	DBG_TEXT_OUT_AUX 'DriveIO_SavePartition:'
342	PUSHRF
343	call DEBUG_DumpRegisters
344	;~ call AuxIO_DumpParagraph
345	;~ call AuxIO_TeletypeNL
346	POPRF
347	ENDIF
348	ENDIF
349
350	mov ax, wptr cs:[CurPartition_Location+0]
351	mov bx, wptr cs:[CurPartition_Location+2]
352	mov dx, wptr cs:[CurPartition_Location+4]
353	mov cx, wptr cs:[CurPartition_Location+6] ; Gets prev. saved location
354	mov si, offset PartitionSector ; DS:SI - ExecBase
355	cmp wptr [si+LocBR_Magic], 0AA55h ; Checks for signature, if not found
356	jne DIOSP_SevereError ; we assume a really bad error
357	call DriveIO_SaveSector
358	DIOSP_SevereError:
359	ret
360	DriveIO_SavePartition EndP
361
362
363
364	;##############################################################################
365	;# The location of LVM sectors depends on the OS/2 geometry used when the disk
366	;# was prepared. This geometry is present in the Master LVM sector, which has
367	;# already been located if it exists. All partitions, whether primary or
368	;# logical, have an entry in a partition table. For primary partitions this
369	;# table is located in the MBR, while for logical partitions this table is
370	;# located in the EBR for that logical partition. An LVM record is located
371	;# LVM_SPT-1 sectors above an MBR or EBR. The Master LVM record contains the
372	;# information for all primary partitions. For logical partitions, the LVM
373	;# sector only has one entry, because EBRs are chained. The global LVM info,
374	;# like disk-name, sectors per track, etc. is replicated between the Master
375	;# LVM sector and LVM sectors corresponding to logical partitions. This info
376	;# is kept in sync by the OS/2 LVM Engine.
377	;##############################################################################
378	;# ACTION : Attempts to load the corresponding LVM sector for a partition
379	;# ----------------------------------------------------------------------------
380	;# EFFECTS : Modifies DAP structure and fills or clears sector buffer
381	;# ----------------------------------------------------------------------------
382	;# IN : MEM - Location info is in [CurPartition_Location]
383	;# ----------------------------------------------------------------------------
384	;# OUT : CF=1 - failure, no valid LVM sector was loaded
385	;# : SI - Points to the sector buffer ([LVMSector])
386	;##############################################################################
387	DriveIO_LoadLVMSector Proc Near Uses ax bx cx dx di
388
389	IFDEF AUX_DEBUG
390	IF 0
391	DBG_TEXT_OUT_AUX 'DriveIO_LoadLVMSector:'
392	PUSHRF
393	call DEBUG_DumpRegisters
394	;~ call AuxIO_DumpSector
395	;~ call AuxIO_DumpParagraph
396	;~ call AuxIO_TeletypeNL
397	POPRF
398	ENDIF
399	ENDIF
400
401	; Clear the sector buffer
402	mov si, offset [LVMSector]
403	call ClearSectorBuffer
404
405	; Quit with CY if LVM is ignored in SETUP
406	test byte ptr [CFG_IgnoreLVM], 1 ; ZF=0 means ignore LVM
407	jnz DIOLLVMS_NoLVMSector ; Quit if so
408
409	; Load the location of the current partition being acted upon.
410	; Note that this is not the actual LBA of the partition, but the
411	; sector that has the partition table that contains the entry
412	; for the partition. In other words, for primary partitions the LBA
413	; address points to the MBR while for extended partitions it points
414	; to an EBR. In both cases the LVM sector is located LVM_SPT-1 above.
415	; Also note that the BIOS CHS values (DH and CX) below are not used,
416	; because we explicitly use LBA sector loading.
417	mov ax, wptr cs:[CurPartition_Location+0] ; LBA lo of MBR/EBR
418	mov bx, wptr cs:[CurPartition_Location+2] ; LBA hi of MBR/EBR
419	mov dx, wptr cs:[CurPartition_Location+4] ; BIOS disk num & head
420	mov cx, wptr cs:[CurPartition_Location+6] ; BIOS cyl & sec
421
422	; Do the actual loading.
423	; This is in a separate function so that LVM records can also be
424	; loaded using the MBR/EBR LBA addresses from IPT entries.
425	call DriveIO_LoadLVMSectorXBR
426	jc DIOLLVMS_NoLVMSector
427
428	; We're done, indicate success and return
429	clc
430	jmp DIOLLVMS_Done
431
432	DIOLLVMS_NoLVMSector:
433
434	; Clear the sector buffer
435	mov si, offset [LVMSector]
436	call ClearSectorBuffer
437	mov bptr [si+LocLVM_SignatureStart], 0
438
439	; Indicate no valid LVM sector was loaded
440	stc
441
442	DIOLLVMS_Done:
443
444	ret
445	DriveIO_LoadLVMSector EndP
446
447
448
449
450
451	;------------------------------------------------------------------------------
452	; Attempts to load the corresponding LVM sector for a partition
453	;------------------------------------------------------------------------------
454	; IN : AX - LBA lo of MBR or EBR
455	; : BX - LBA hi of MBR or EBR
456	; ; DL - BIOS disk number
457	; ; SI - Pointer to sector buffer (usually [LVMSec])
458	; OUT : CF=0 - A valid LVM sector was loaded
459	; NOTE : LocIPT_AbsolutePartTable and LocIPT_Drive can provide LBA and DISK
460	;------------------------------------------------------------------------------
461	DriveIO_LoadLVMSectorXBR Proc Near
462
463	IFDEF AUX_DEBUG
464	IF 0
465	DBG_TEXT_OUT_AUX 'DriveIO_LoadLVMSectorXBR:'
466	PUSHRF
467	call DEBUG_DumpRegisters
468	;~ call AuxIO_DumpSector
469	;~ call AuxIO_DumpParagraph
470	;~ call AuxIO_TeletypeNL
471	POPRF
472	ENDIF
473	ENDIF
474
475	; Save all registers
476	pusha
477
478	; Calculate the entry in the DISKINFO array for this disk,
479	; and put the LVM_SPT in DI
480	push bx
481	call DriveIO_CalcDiskInfoPointer
482	mov di, [bx+LocDISKINFO_LVM_Secs]
483	pop bx
484
485	; If the LVM_SPT is ZERO, no LVM info is present and we quit with CY
486	test di, di ; See if it is 0
487	jz DriveIO_LoadLVMSectorXBR_no_lvm ; Quit if so
488
489	; Adjust the location to point to the LVM sector
490	add ax, di ; Add the LVM sectors-per-track
491	adc bx, 0 ; Propagate LBA lo overflow to LBA hi
492	sub ax, 1 ; LVM sector is located one sector below
493	sbb bx, 0 ; Propagate borrow to LBA hi
494
495	; Load the LVM sector into sector buffer pointed to by SI
496	mov di, ds ; Segment of that buffer
497	call DriveIO_ReadSectorLBA ; Read the LVM sector
498
499	IFDEF AUX_DEBUG
500	IF 0
501	DBG_TEXT_OUT_AUX 'LVMSecLoaded'
502	PUSHRF
503	call DEBUG_DumpRegisters
504	;~ call AuxIO_DumpSector
505	mov cx, 3
506	@@:
507	call AuxIO_DumpParagraph
508	call AuxIO_TeletypeNL
509	add si, 16
510	loop @B
511	;~ call AuxIO_DumpParagraph
512	;~ call AuxIO_TeletypeNL
513	POPRF
514	ENDIF
515	ENDIF
516
517	jc DriveIO_LoadLVMSectorXBR_no_lvm ; Quit on error
518
519	; Check the validity of the LVM sector, quit with CY if invalid
520	call LVM_ValidateSector ; Check signature and CRC
521	jnc DriveIO_LoadLVMSectorXBR_no_lvm ; Quit if not valid
522
523	; We're done, indicate success and return
524	clc
525	jmp DriveIO_LoadLVMSectorXBR_done
526
527	DriveIO_LoadLVMSectorXBR_no_lvm:
528	; Indicate no valid LVM sector was loaded
529	stc
530
531	DriveIO_LoadLVMSectorXBR_done:
532	; Restore all registers
533	popa
534
535	ret
536	DriveIO_LoadLVMSectorXBR EndP
537
538
539	;##############################################################################
540	;# The location of LVM sectors depends on the OS/2 geometry used when the disk
541	;# was prepared. This geometry is present in the Master LVM sector, which has
542	;# already been located if it exists. All partitions, whether primary or
543	;# logical, have an entry in a partition table. For primary partitions this
544	;# table is located in the MBR, while for logical partitions this table is
545	;# located in the EBR for that logical partition. An LVM record is located
546	;# LVM_SPT-1 sectors above an MBR or EBR. The Master LVM record contains the
547	;# information for all primary partitions. For logical partitions, the LVM
548	;# sector only has one entry, because EBRs are chained. The global LVM info,
549	;# like disk-name, sectors per track, etc. is replicated between the Master
550	;# LVM sector and LVM sectors corresponding to logical partitions. This info
551	;# is kept in sync by the OS/2 LVM Engine.
552	;##############################################################################
553	;# ACTION : Attempts to save the corresponding LVM sector for a partition
554	;# ----------------------------------------------------------------------------
555	;# EFFECTS : Modifies DAP structure and writes LVM sector to disk
556	;# ----------------------------------------------------------------------------
557	;# IN : MEM - Location info is in [CurPartition_Location]
558	;# : SI - Pointer to sector buffer
559	;# ----------------------------------------------------------------------------
560	;# OUT : CF=1 - failure, no valid LVM sector was saved
561	;##############################################################################
562	DriveIO_SaveLVMSector Proc Near Uses ax bx cx dx di
563
564	IFDEF AUX_DEBUG
565	IF 0
566	DBG_TEXT_OUT_AUX 'DriveIO_SaveLVMSector:'
567	PUSHRF
568	call DEBUG_DumpRegisters
569	;~ call AuxIO_DumpParagraph
570	;~ call AuxIO_TeletypeNL
571	POPRF
572	ENDIF
573	ENDIF
574
575	; Quit with CY if LVM is ignored in SETUP
576	test byte ptr [CFG_IgnoreLVM], 1 ; ZF=0 means ignore LVM
577	jnz DIOSLVMS_NoLVMSector ; Quit if so
578
579	; Load the location of the current partition being acted upon.
580	; Note that this is not the actual LBA of the partition, but the
581	; sector that has the partition table that contains the entry
582	; for the partition. In other words, for primary partitions the LBA
583	; address points to the MBR while for extended partitions it points
584	; to an EBR. In both cases the LVM sector is located LVM_SPT-1 above.
585	; Also note that the BIOS CHS values (DH and CX) below are not used,
586	; because we explicitly use LBA sector loading.
587	mov ax, wptr cs:[CurPartition_Location+0] ; LBA lo of MBR/EBR
588	mov bx, wptr cs:[CurPartition_Location+2] ; LBA hi of MBR/EBR
589	mov dx, wptr cs:[CurPartition_Location+4] ; BIOS disk num & head
590	mov cx, wptr cs:[CurPartition_Location+6] ; BIOS cyl & sec
591
592	; Do the actual saving.
593	; This is in a separate function so that LVM records can also be
594	; saved using the MBR/EBR LBA addresses from IPT entries.
595	call DriveIO_SaveLVMSectorXBR
596	jc DIOSLVMS_NoLVMSector
597
598	; We're done, indicate success and return
599	clc
600	jmp DIOSLVMS_Done
601
602	DIOSLVMS_NoLVMSector:
603	; Indicate no valid LVM sector was saved
604	stc
605
606	DIOSLVMS_Done:
607	ret
608	DriveIO_SaveLVMSector EndP
609
610
611	;------------------------------------------------------------------------------
612	; Attempts to save the corresponding LVM sector for a partition
613	;------------------------------------------------------------------------------
614	; IN : AX - LBA lo of MBR or EBR
615	; : BX - LBA hi of MBR or EBR
616	; ; DL - BIOS disk number
617	; ; SI - Pointer to sector buffer (usually [LVMSec])
618	; OUT : CF=0 - A valid LVM sector was saved
619	; NOTE : LocIPT_AbsolutePartTable and LocIPT_Drive can provide LBA and DISK
620	;------------------------------------------------------------------------------
621	DriveIO_SaveLVMSectorXBR Proc Near
622
623	IFDEF AUX_DEBUG
624	IF 1
625	DBG_TEXT_OUT_AUX 'DriveIO_SaveLVMSectorXBR:'
626	PUSHRF
627	call DEBUG_DumpRegisters
628	call AuxIO_DumpSector
629	;~ call AuxIO_DumpParagraph
630	;~ call AuxIO_TeletypeNL
631	POPRF
632	ENDIF
633	ENDIF
634
635	; Save all registers
636	pusha
637
638	; Check the validity of the LVM sector, quit with CY if invalid
639	push ax ; Save LBA lo
640	call LVM_ValidateSector ; Check signature and CRC
641	pop ax ; Restore LBA lo
642	jnc DriveIO_SaveLVMSectorXBR_no_lvm ; Quit if not valid
643
644	; Calculate the entry in the DISKINFO array for this disk,
645	; and put the LVM_SPT in DI
646	push bx
647	call DriveIO_CalcDiskInfoPointer
648	mov di, [bx+LocDISKINFO_LVM_Secs]
649	pop bx
650
651	; If the LVM_SPT is ZERO, no LVM info is present and we quit with CY
652	test di, di ; See if it is 0
653	jz DriveIO_SaveLVMSectorXBR_no_lvm ; Quit if so
654
655	; Adjust the location to point to the LVM sector
656	add ax, di ; Add the LVM sectors-per-track
657	adc bx, 0 ; Propagate LBA lo overflow to LBA hi
658	sub ax, 1 ; LVM sector is located one sector below
659	sbb bx, 0 ; Propagate borrow to LBA hi
660
661	; Writing an LVM sector is always the result of modifications to a
662	; previously loaded one. So, now that we have the LBA address of the
663	; LVM sector, the one about to be overwritten should be there.
664	; If it's not, something is seriously wrong and we quit immetiately.
665	pusha ; Push our context except the flags
666	mov si, offset [Scratch] ; Sector buffer to load the LVM sector
667	call ClearSectorBuffer ; Make sure no old LVM info is present
668	mov di, ds ; Segment of buffer
669	call DriveIO_ReadSectorLBA ; Load the old LVM sector
670	call LVM_ValidateSector ; CF=1 if valid
671	cmc ; Complement for disk i/o semantics
672	popa ; Restore our context except the flags
673
674	; OOPS, There was no LVM sector there !!
675	jc DriveIO_SaveLVMSectorXBR_no_lvm
676
677	; Save the LVM sector pointed to by SI
678	mov di, ds ; Segment of that buffer
679	call DriveIO_WriteSectorLBA ; Write the LVM sector
680
681	IFDEF AUX_DEBUG
682	IF 1
683	DBG_TEXT_OUT_AUX 'LVMSecSaved'
684	PUSHRF
685	call DEBUG_DumpRegisters
686	call AuxIO_DumpSector
687	;~ call AuxIO_DumpParagraph
688	;~ call AuxIO_TeletypeNL
689	POPRF
690	ENDIF
691	ENDIF
692
693	jc DriveIO_SaveLVMSectorXBR_no_lvm ; Quit on error
694
695	; We're done, indicate success and return
696	clc
697	jmp DriveIO_SaveLVMSectorXBR_done
698
699	DriveIO_SaveLVMSectorXBR_no_lvm:
700	; Indicate no valid LVM sector was saved
701	stc
702
703	DriveIO_SaveLVMSectorXBR_done:
704	; Restore all registers
705	popa
706
707	ret
708	DriveIO_SaveLVMSectorXBR EndP
709
710
711
712	; Special error message instead of "LOAD ERROR" during partition scanning,
713	; so users will notice that something is bad with their partition table(s)
714	DriveIO_GotLoadError Proc Near
715	IFDEF AUX_DEBUG
716	IF 1
717	DBG_TEXT_OUT_AUX 'DriveIO_GotLoadError:'
718	PUSHRF
719	call DEBUG_DumpRegisters
720	;~ call AuxIO_DumpParagraph
721	;~ call AuxIO_TeletypeNL
722	POPRF
723	ENDIF
724	ENDIF
725	test byte ptr cs:[CurIO_Scanning], 1 ; Must be CS:, cause DS!=CS maybe here
726	jnz InScanMode
727	jmp MBR_LoadError
728	InScanMode:
729	mov si, offset TXT_BrokenPartitionTable
730	push cs
731	pop ds
732	call MBR_Teletype
733	mov si, offset BrokenHDD
734	sub dl, 50h ; 80h -> '0'
735	cmp dl, 39h
736	jbe DIOGLE_BelowA
737	add dl, 7 ; 3Ah -> 'A'
738	DIOGLE_BelowA:
739	mov bptr [si+5], dl
740	call MBR_Teletype
741
742	; JWasm: cannot jump to local label in other procedure.
743	; Changed to halt here.
744	;jmp MBRLE_Halt
745	DriveIO_GotLoadError_halt:
746	jmp DriveIO_GotLoadError_halt
747	DriveIO_GotLoadError EndP
748
749	; #########################################################################
750	; Routine: Loads a specified sector to DS:DI
751	; #########################################################################
752	; Calling : bx:ax - Absolute sector
753	; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
754	; ds:si - Destination-Adress
755	; Returns : none
756	; Preserve: all registers
757	; #########################################################################
758	DriveIO_LoadSector Proc Near Uses ax bx cx dx ds si es di
759
760	IFDEF AUX_DEBUG
761	IF 0
762	DBG_TEXT_OUT_AUX 'DriveIO_LoadSector:'
763	PUSHRF
764	call DEBUG_DumpRegisters
765	;~ call AuxIO_DumpParagraph
766	;~ call AuxIO_TeletypeNL
767	POPRF
768	ENDIF
769	ENDIF
770
771	; Is the drive not a harddrive?
772	cmp dl, 80h
773	jb DIOLS_UseNormal
774
775	test byte ptr cs:[CurIO_UseExtension], 1
776	jz DIOLS_UseNormal
777	; Are we forced do use LBA via Setting?
778	jnz DIOLS_UseExtension
779
780	; Upper 8 bits of LBA-address set?
781	; Then use LBA (maximum boundary is 16320x16x63 = FB0400h)
782	or bh, bh
783	jnz DIOLS_UseExtension
784	; Compare Switch-Table value to bit 16-23 of LBA-address
785	mov di, dx
786	and di, 007Fh
787	cmp bptr cs:[LBASwitchTable+di], bl
788	jbe DIOLS_UseExtension
789
790	DIOLS_UseNormal:
791
792	IFDEF AUX_DEBUG
793	IF 0
794	DBG_TEXT_OUT_AUX 'DriveIO_ReadSectorCHS:'
795	PUSHRF
796	call DEBUG_DumpRegisters
797	call AuxIO_DumpParagraph
798	call AuxIO_TeletypeNL
799	POPRF
800	ENDIF
801	ENDIF
802
803	mov di, 3 ; retry count
804	DIOLS_ErrorLoop:
805	push ds
806	pop es
807	mov bx, si ; ES:BX - Destination
808	mov ax, 0201h ; Function 2 - Load Sector
809	int 13h
810	sti ; enable ints
811	jnc DIOLS_Success
812	dec di ; decrement retry count
813	jnz DIOLS_ErrorLoop
814
815	; Sector load failed...
816	jmp DriveIO_GotLoadError
817
818	DIOLS_UseExtension:
819
820	mov di, ds ; segment for transfer address
821	call DriveIO_ReadSectorLBA ; extended read
822	jc DriveIO_GotLoadError ; halt on error
823
824	;~ push cx
825	;~ mov cs:[INT13X_DAP_NumBlocks], 1 ; Copy ONE sector
826	;~ mov wptr cs:[INT13X_DAP_Transfer+0], si
827	;~ mov cx, ds
828	;~ mov wptr cs:[INT13X_DAP_Transfer+2], cx ; Fill out Transfer Adress
829	;~ mov wptr cs:[INT13X_DAP_Absolute+0], ax
830	;~ mov wptr cs:[INT13X_DAP_Absolute+2], bx ; Fill out Absolute Sector
831	;~ push cs
832	;~ pop ds
833	;~ mov si, offset [INT13X_DAP]
834	;~ mov ah, 42h ; Extended Read
835	;~ int 13h
836	;~ pop cx
837	;~ jnc DIOLS_Success
838
839	; Sector load failed...
840	;~ jmp DriveIO_GotLoadError
841
842	DIOLS_Success:
843
844	IFDEF AUX_DEBUG
845	IF 0
846	DBG_TEXT_OUT_AUX 'sector loaded'
847	PUSHRF
848	;~ call DEBUG_DumpRegisters
849	;~ call AuxIO_DumpSector
850	mov cx, 32
851	@@:
852	call AuxIO_DumpParagraph
853	call AuxIO_TeletypeNL
854	add si, 16
855	loop @B
856	POPRF
857	ENDIF
858	ENDIF
859	ret
860	DriveIO_LoadSector EndP
861
862
863	;##############################################################################
864	;# ACTION : Loads the Master Boot Record from the specified drive into buffer
865	;# ----------------------------------------------------------------------------
866	;# EFFECTS : Modifies DAP structure and fills or clears transfer buffer
867	;# ----------------------------------------------------------------------------
868	;# IN : DL - BIOS disk number (80h,81h,etc)
869	;# : SI - Pointer to transfer buffer
870	;# ----------------------------------------------------------------------------
871	;# OUT : CF=1 - failure
872	;# : AL.0 - MBR signature present
873	;# : AL.1 - Primary partitions present
874	;# : AL.2 - Extended partitions present
875	;# : AL.3 - AiR-BOOT signature present
876	;# : AL.4:7 - Reserved, returned as 0
877	;# : AH.0:7 - Reserved, returned as 0
878	;##############################################################################
879	DriveIO_LoadMBR Proc Near uses bx cx dx si di
880
881	; Always clear the transfer buffer first
882	call ClearSectorBuffer
883
884	; Assume an invalid MBR
885	xor ax, ax
886
887	; Accept only valid harddisks
888	call DriveIO_IsValidHarddisk
889	jc DriveIO_LoadMBR_exit
890
891	; Save the address of the transfer buffer
892	mov di, si
893
894	; Read the MBR from disk
895	xor ax, ax ; LBA low
896	xor bx, bx ; LBA high
897	xor dh, dh ; Head 0
898	mov cx, 1 ; Sector 1
899	call DriveIO_LoadSector ; Read the sector from disk
900
901	; Check the loaded MBR for a signature
902	xor ax, ax ; Assume an invalid MBR
903	mov dx, [si+LocBR_Magic] ; Get word from MBR signature location
904	cmp dx, 0aa55h ; Is it the magic value ?
905	jne DriveIO_LoadMBR_exit ; Nope, no need to test anything else
906
907	; Indicate we have a MBR signature
908	or al, 01h
909
910	; Advance to the partition table
911	add si, 01beh
912
913	; Total of 4 entries to check
914	mov cx, 4
915
916	DriveIO_LoadMBR_next_entry:
917	mov dl, [si+LocBRPT_SystemID] ; Get partition-type / system-id
918	add si, 10h ; Point to next entry
919	test dl, dl ; Nothing in this one ?
920	loopz DriveIO_LoadMBR_next_entry ; Then check next entry
921
922	; All entries checked and last one was also empty, we're done
923	jz DriveIO_LoadMBR_check_ab
924
925	; Found a non-empty entry, set bits according to its type
926	cmp dl, 05h ; Old style extended container ?
927	jne @F ; Nope...
928	or al, 04h ; Yep, mark ext. container present
929	@@: cmp dl, 0fh ; New style extended container ?
930	jne @F ; Nope...
931	or al, 04h ; Yep, mark ext. container present
932	@@: or al, 02h ; Then is must be a primary
933	jcxz DriveIO_LoadMBR_check_ab ; CX=0? Then all entries processed,
934	jmp DriveIO_LoadMBR_next_entry ; otherwise check next entry
935
936	; Check if an AiR-BOOT signature is present
937	DriveIO_LoadMBR_check_ab:
938	mov si, offset [MBR_ABSig] ; Offset of AiR-BOOT signature
939	inc di ; Advance buffer pointer
940	inc di ; to AiR-BOOT signature location
941	mov cx, 7 ; Length of AiR-BOOT signature
942	cld ; Direction upwards
943	repe cmpsb ; Compare 7 bytes
944	jne DriveIO_LoadMBR_exit ; Nope, no AiR-BOOT on this disk
945	or al, 08h ; Yep, AiR-BOOT is on this disk
946	;~ jmp DriveIO_LoadMBR_exit
947
948	DriveIO_LoadMBR_exit:
949	ret
950	DriveIO_LoadMBR EndP
951
952
953	;##############################################################################
954	;# ACTION : Reads a sector from disk using INT13 extensions
955	;# ----------------------------------------------------------------------------
956	;# EFFECTS : Modifies DAP structure and fills transfer buffer
957	;# ----------------------------------------------------------------------------
958	;# IN : BX:AX - LBA address of sector
959	;# : DI:SI - SEG:OFF of transfer buffer
960	;# ----------------------------------------------------------------------------
961	;# OUT : CF=1 - failure
962	;##############################################################################
963	DriveIO_ReadSectorLBA Proc Near
964
965	IFDEF AUX_DEBUG
966	IF 0
967	DBG_TEXT_OUT_AUX 'DriveIO_ReadSectorLBA:'
968	PUSHRF
969	call DEBUG_DumpRegisters
970	call AuxIO_DumpParagraph
971	call AuxIO_TeletypeNL
972	POPRF
973	ENDIF
974	ENDIF
975
976	; Push all registers
977	pusha
978	push ds
979	push es
980
981	; One sector to read
982	mov cs:[INT13X_DAP_NumBlocks], 1
983
984	; Setup transfer address
985	mov wptr cs:[INT13X_DAP_Transfer+0], si ; offset
986	mov wptr cs:[INT13X_DAP_Transfer+2], di ; segment
987
988	; Setup LBA64 address of requested sector
989	mov wptr cs:[INT13X_DAP_Absolute+0], ax ; low word lower part
990	mov wptr cs:[INT13X_DAP_Absolute+2], bx ; high word lower part
991	mov wptr cs:[INT13X_DAP_Absolute+4], 0 ; low word upper part
992	mov wptr cs:[INT13X_DAP_Absolute+6], 0 ; high word upper part
993
994	; Address of packet
995	mov si, offset [INT13X_DAP] ; disk address packet
996
997	; Do the extended read
998	mov ah, 42h ; read function
999	int 13h ; transfer to bios
1000	sti ; enable ints
1001
1002	; Error occured
1003	jc DriveIO_ReadSectorLBA_exit
1004
1005	; AH should also be zero
1006	test ah, ah
1007	stc
1008	jnz DriveIO_ReadSectorLBA_exit
1009
1010	; Disk read succeeded, clear CF
1011	clc
1012
1013	DriveIO_ReadSectorLBA_exit:
1014
1015	; Pop all registers
1016	pop es
1017	pop ds
1018	popa
1019
1020	ret
1021	DriveIO_ReadSectorLBA EndP
1022
1023
1024
1025	;##############################################################################
1026	;# ACTION : Writes a sector to disk using INT13 extensions
1027	;# ----------------------------------------------------------------------------
1028	;# EFFECTS : Modifies DAP structure and mofifies the disk
1029	;# ----------------------------------------------------------------------------
1030	;# IN : BX:AX - LBA address of sector
1031	;# : DI:SI - SEG:OFF of transfer buffer
1032	;# ----------------------------------------------------------------------------
1033	;# OUT : CF=1 - failure
1034	;##############################################################################
1035	DriveIO_WriteSectorLBA Proc Near
1036
1037	IFDEF AUX_DEBUG
1038	IF 0
1039	DBG_TEXT_OUT_AUX 'DriveIO_WriteSectorLBA:'
1040	PUSHRF
1041	call DEBUG_DumpRegisters
1042	call AuxIO_DumpParagraph
1043	call AuxIO_TeletypeNL
1044	POPRF
1045	ENDIF
1046	ENDIF
1047
1048	; Push all registers
1049	pusha
1050	push ds
1051	push es
1052
1053	; One sector to read
1054	mov cs:[INT13X_DAP_NumBlocks], 1
1055
1056	; Setup transfer address
1057	mov wptr cs:[INT13X_DAP_Transfer+0], si ; offset
1058	mov wptr cs:[INT13X_DAP_Transfer+2], di ; segment
1059
1060	; Setup LBA64 address of requested sector
1061	mov wptr cs:[INT13X_DAP_Absolute+0], ax ; low word lower part
1062	mov wptr cs:[INT13X_DAP_Absolute+2], bx ; high word lower part
1063	mov wptr cs:[INT13X_DAP_Absolute+4], 0 ; low word upper part
1064	mov wptr cs:[INT13X_DAP_Absolute+6], 0 ; high word upper part
1065
1066	; Address of packet
1067	mov si, offset [INT13X_DAP] ; disk address packet
1068
1069	; Do the extended write
1070	xor al, al ; no write verify
1071	mov ah, 43h ; write function
1072	int 13h ; transfer to bios
1073	sti ; enable ints
1074
1075	; Error occured
1076	jc DriveIO_WriteSectorLBA_exit
1077
1078	; AH should also be zero
1079	test ah, ah
1080	stc
1081	jnz DriveIO_WriteSectorLBA_exit
1082
1083	; Disk write succeeded, clear CF
1084	clc
1085
1086	DriveIO_WriteSectorLBA_exit:
1087
1088	; Skip the removable drive check on success
1089	jnc @F
1090
1091	; Here, CF=1 because of a failure.
1092	; This could be from a removable drive that is set to read-only,
1093	; in which case we want to fake success. What this boils down to
1094	; is that CY must be set to !IsRemovable.
1095	call DriveIO_CalcDiskInfoPointer ; Get DISKINFO pointer
1096	mov dx, [bx+LocDISKINFO_I13X_Flags] ; Get INT13X flags
1097	xor dl, 04h ; Invert 'removable' bit
1098	and dl, 04h ; Mask it out
1099	rcr dl, 3 ; Move it to CY
1100
1101	@@:
1102
1103	; Pop all registers
1104	pop es
1105	pop ds
1106	popa
1107
1108	ret
1109	DriveIO_WriteSectorLBA EndP
1110
1111
1112
1113
1114	;##############################################################################
1115	;# The Master LVM sector is not necessarily located at the end of the BIOS
1116	;# view of TRACK0. Its location depends on the OS/2 geometry active when the
1117	;# disk was partitioned. For disks < 502MiB this will most likely be LBA sector
1118	;# 62, but for disks >502MiB, extended OS/2 geometry was used and DANIS506
1119	;# uses SPT=127 for disks < 1TiB while IBMS506 uses SPT=255.
1120	;# When a huge disk < 1TiB was partitioned with IBMS506, thus using SPT=255,
1121	;# and the driver was later changed to DANIS506, DANI uses SPT=255, eventhough
1122	;# the disk < 1TiB. Whether it is DANI that is LVM aware or something else
1123	;# (maybe LVM itself) that makes DANI use the correct geometry has yet to be
1124	;# investigated.
1125	;#
1126	;# Related geometry issues are also present with USB sticks, which can get
1127	;# assigned a geometry by OS/2, which can depend if the stick was partitioned
1128	;# on foreign systems or not, or even OS/2 manufacturing a geometry that is not
1129	;# the same as the BIOS reports to us here. In both cases, fixed disks and
1130	;# removable disks, the geometry recorded in the BPB of a partition can also
1131	;# influence the geometry that OS/2 assigns. This is the case when 'preparing'
1132	;# disks for LVM use, in which case BPB values could be incorporated.
1133	;#
1134	;# What this all boils down to, is that the geometry reported by the BIOS is
1135	;# of no practical use, especially not when taking BIOS USB MSD emulation into
1136	;# account. These are among the reasons why AirBoot needs to use LBA addressing
1137	;# when handling LVM stuff and why LBA use cannot be disabled in the SETUP
1138	;# anymore.
1139	;#
1140	;# So, a Master LVM sector can be present on any sector from LBA 254 downwards
1141	;# and the only way to locate the correct one is to scan all the way down and,
1142	;# if one is found, do proper validation on its values, because it may also be
1143	;# a 'phantom' LVM sector left over from previous partition layouts.
1144	;# Most of such 'phantoms' can be filtered out by verifying the location of
1145	;# the found sector against the OS/2 geometry it specifies itself, which means
1146	;# it must be located at the LBA of the SPT-1 it specifies.
1147	;##############################################################################
1148	;# ACTION : Locates the Master LVM sector on the specified disk
1149	;# ----------------------------------------------------------------------------
1150	;# EFFECTS : Leaves [Scratch] with last sector read or cleared
1151	;# ----------------------------------------------------------------------------
1152	;# IN : DL - BIOS disk number of drive to search
1153	;# ----------------------------------------------------------------------------
1154	;# OUT : CF=1 - found
1155	;# : BX:AX - LBA address of LVM sector if found, 0 otherwise
1156	;##############################################################################
1157	DriveIO_LocateMasterLVMSector Proc Near uses cx dx si di ds es
1158
1159	IFDEF AUX_DEBUG
1160	IF 0
1161	DBG_TEXT_OUT_AUX 'DriveIO_LocateMasterLVMSector:'
1162	PUSHRF
1163	call DEBUG_DumpRegisters
1164	;~ call AuxIO_DumpSector
1165	;~ call AuxIO_DumpParagraph
1166	;~ call AuxIO_TeletypeNL
1167	POPRF
1168	ENDIF
1169	ENDIF
1170
1171	; LBA address to start scanning down from
1172	mov cx, 255
1173
1174	; Make sure ES==DS
1175	push ds
1176	pop es
1177
1178	; Because JCXZ is used, LBA sector 0 is never loaded and checked.
1179	; This is of course no problem since it is the MBR.
1180	DriveIO_LocateMasterLVMSector_next:
1181	mov si, offset [Scratch] ; Use scratch area to load sectors
1182	call ClearSectorBuffer ; Clear the scratch area
1183	clc ; Indicate Master LVM sector not found
1184	jcxz DriveIO_LocateMasterLVMSector_done
1185
1186	; Read the LBA sector specified in CX
1187	mov ax, cx ; LBA low
1188	xor bx, bx ; LBA high
1189	mov di, ds ; Segment of scratch buffer
1190	mov si, offset [Scratch] ; Offset of scratch buffer
1191	call DriveIO_ReadSectorLBA ; Read the sector
1192	lahf ; Save CF
1193	dec cx ; Prepare LBA of next sector to read
1194	sahf ; Restore CF
1195	; No need to do any LVM sector validation when read error, read next
1196	jc DriveIO_LocateMasterLVMSector_next
1197
1198	; See if the read sector has a valid signature and checksum
1199	call LVM_ValidateSector
1200
1201	; NC indicates invalid or none-LVM sector, read next
1202	jnc DriveIO_LocateMasterLVMSector_next
1203
1204	; We have found a valid LVM sector !
1205	; So it contains the OS/2 geometry for the disk.
1206	; That means this LVM sector itself must be located on the last sector
1207	; of the SPT value its OS/2 geometery specifies, which, in LBA terms
1208	; is LVM SPT-1 -- let's check that...
1209	mov bx, offset [Scratch] ; Offset of the loaded LVM sector
1210	mov al, [bx+LocLVM_Secs] ; Get the LVM SPT value (<=255)
1211	dec al ; Adjust to LVM LBA
1212	mov ah, cl ; Get next LVM LBA to search
1213	inc ah ; This one was found here
1214	cmp al, ah ; If same, LVM LBA location OK
1215	jne DriveIO_LocateMasterLVMSector_next
1216
1217	; The LVM sector we found is at the location it should be on disk,
1218	; so it's almost 99% sure this is the correct one.
1219	; Now we should compare the start and sizes of the partitions in the
1220	; MBR with the partitions specified in this LVM record.
1221	; We'll implement that later after some more research.
1222	; For now we assume this is the correct Master LVM sector for the disk.
1223	inc cx ; CX was prepared to read next, correct that
1224	stc ; Indicate we have found the Master LVM sector
1225
1226	DriveIO_LocateMasterLVMSector_done:
1227	mov bx, 0 ; A Master LVM sector always has high LBA=0
1228	mov ax, cx ; Low LBA of Master LVM sector
1229
1230	; We leave it up to the caller to store the value in a proper place
1231	ret
1232	DriveIO_LocateMasterLVMSector EndP
1233
1234
1235
1236	;
1237	; ############################################################
1238	; # Check for a valid MBR-sector to be written to disk #
1239	; ############################################################
1240	;
1241	; In
1242	; --
1243	; DL = Physical Disk
1244	; BX:CX = LBA sector
1245	; DI:SI = Source buffer
1246	;
1247	; Out
1248	; ---
1249	; CY = 1 if invalid MBR in source buffer, 0 if valid
1250	;
1251	; This routine is called when DriveIO_SaveSector attempts to write to the MBR.
1252	; It checks if the sector to be written has some sensible values in certain
1253	; places. In fact, if the sector is written to the boot-disk, the AiR-BOOT
1254	; signature should be present and the partition table should be the same
1255	; as the one at the start of the AiR-BOOT code in memory, except maybe for the
1256	; active flags.
1257	; For other disks, only the active flags are checked to be 00h or 80h and
1258	; the AA55h MBR signature.
1259	;
1260	DriveIO_ProtectMBR Proc Near
1261	pusha ; Push all registers
1262	push es ; Push ES because we need it for string instructions
1263	push cs ; Make ES point...
1264	pop es ; to CS
1265
1266	; Save the pointer to the sector to write in BX
1267	mov bx,si
1268
1269	;
1270	; If the sector to be written is not the boot-disk, then skip
1271	; checking the AiR-BOOT MBR.
1272	;
1273	cmp dl, [BIOS_BootDisk]
1274	jne DriveIO_ProtectMBR_is_not_bootdisk
1275
1276	;
1277	; The boot-disk is accessed so the sector to be written must be
1278	; the AiR-BOOT MBR. This is the same as the first 512 bytes
1279	; relocated to 8000:0000 and this the start of the AB-code.
1280	;
1281	mov si,bx ; Get pointer to sector to write
1282	xor di,di ; Point DI to start of AB-code (MBR)
1283	mov cx, offset [MBR_PartTable] ; Bytes upto P-table must be same
1284	cld ; Compare upwards
1285	repe cmpsb ; Compare upto P-table
1286
1287	; If not the same this is not the an AiR-BOOT boot-disk MBR !
1288	jne DriveIO_ProtectMBR_not_valid_MBR ; SEVERE ERROR !
1289
1290	; Continue with signature check
1291	jmp DriveIO_ProtectMBR_check_signature
1292
1293
1294	;
1295	; The disk is not the boot-disk so we don't know what kind of MBR is on it.
1296	; Some sanity checks should be here.
1297	;
1298	DriveIO_ProtectMBR_is_not_bootdisk:
1299
1300	;
1301	; sanity checks...
1302	;
1303
1304	; Continue with signature check
1305	jmp DriveIO_ProtectMBR_check_signature
1306
1307
1308	DriveIO_ProtectMBR_check_signature:
1309	; See if the sector to write contains a valid signature
1310	mov si,bx ; Get pointer to sector to write
1311	mov di, offset [MBR_Sig] ; Offset to MBR signature
1312	add si,di ; Make SI point to it in sec to write
1313	lodsw ; Load it
1314	cmp ax,0aa55h ; See if it is valid
1315
1316	; If no signature this cannot be a valid MBR !
1317	jne DriveIO_ProtectMBR_not_valid_MBR ; SEVERE ERROR !
1318
1319
1320	;
1321	; The sector to be written seems to be valid.
1322	; Set CY=0 to indicate a valid MBR.
1323	;
1324	DriveIO_ProtectMBR_is_valid_MBR:
1325	clc
1326	jmp DriveIO_ProtectMBR_end
1327
1328	;
1329	; Something is terribly wrong; a non-MBR sector seems about to be written.
1330	; Set CY=1 and let the calling code handle this situation.
1331	;
1332	DriveIO_ProtectMBR_not_valid_MBR:
1333	stc
1334	jmp DriveIO_ProtectMBR_end
1335
1336	;
1337	; Return to the caller with no registers modyfied except FLAGS.
1338	;
1339	DriveIO_ProtectMBR_end:
1340	pop es
1341	popa
1342	ret
1343	DriveIO_ProtectMBR Endp
1344
1345
1346
1347	; #########################################################################
1348	; Routine: Checks if the MBR is addressed by either CHS or LBA
1349	; #########################################################################
1350	; Calling : bx:ax - Absolute sector
1351	; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
1352	; Returns : ZF=1 if MBR is addressed, else ZF=0
1353	; Preserve: all registers
1354	; #########################################################################
1355	DriveIO_MBR_Addressed Proc
1356	push ax
1357	push bx
1358
1359	or bx,ax ; Results in 0 in BX if MBR is addressed by LBA
1360	jz DriveIO_MBR_Addressed_done
1361
1362	mov ax,cx ; Results in 1 in AX if CYL 0, SEC 1 is addressed
1363	add al,dh ; Results in 1 in AX if HEAD 0 is addressed
1364	dec ax ; Results in 0 in AX if MBR is addressed by CHS
1365
1366	DriveIO_MBR_Addressed_done:
1367	pop bx
1368	pop ax
1369	ret
1370	DriveIO_MBR_Addressed EndP
1371
1372
1373
1374
1375	; #########################################################################
1376	; Routine: Writes DS:SI to a specified sector
1377	; #########################################################################
1378	; Calling : bx:ax - Absolute sector
1379	; cx:dx - Cylinder/Sector, Side/Drive (hi/lo-byte)
1380	; ds:si - Source-Adress
1381	; Returns : none
1382	; Preserve: all registers
1383	; #########################################################################
1384	DriveIO_SaveSector Proc Near Uses ax bx cx dx ds si es di
1385
1386	IFDEF AUX_DEBUG
1387	IF 0
1388	DBG_TEXT_OUT_AUX 'DriveIO_SaveSector:'
1389	PUSHRF
1390	call DEBUG_DumpRegisters
1391	;~ call AuxIO_DumpParagraph
1392	;~ call AuxIO_TeletypeNL
1393	POPRF
1394	ENDIF
1395	ENDIF
1396
1397
1398	;!
1399	;! DEBUG_BLOCK
1400	;! Force write to LBA0 to test interception routine.
1401	;! Do NOT enable unless you are debugging, will overwrite MBR !
1402	;!
1403	IFDEF AUX_DEBUG
1404	IF 0
1405	pushf
1406	pusha
1407	xor ax,ax
1408	xor bx,bx
1409	xor cx,cx
1410	inc cx
1411	xor dh,dh
1412	popa
1413	popf
1414	ENDIF
1415	ENDIF
1416
1417	;
1418	; Check if the MBR is the destination for the write.
1419	; ZF=1 if so.
1420	;
1421	call DriveIO_MBR_Addressed
1422	jnz DriveIO_SaveSector_continue_write
1423
1424
1425	; MBR is addressed, check the sector that is requested to be written.
1426	; For the bootdisk it should contain the AiR-BOOT signature, valid
1427	; partition-table entries and the AA55h signature.
1428	; If not, something is terribly wrong in some piece of the AB code.
1429	; For any other disk (80h+) at least a valid partition table should
1430	; be present together with the AA55h signature.
1431	call DriveIO_ProtectMBR
1432	jnc DriveIO_SaveSector_continue_write
1433
1434
1435	;
1436	; WE HAVE A SEVERE ERROR CONDITION !
1437	; SOME AB CODE TRIES TO WRITE A NON-MBR TO THE DISK !
1438	; ASK THE USER TO REPORT THIS !
1439	; HALT THE SYSTEM !
1440	;
1441
1442	; Show error-box
1443	mov cx, 0C04h
1444	mov si, offset NonMBRwrite
1445	call SETUP_ShowErrorBox
1446	mov cx, 0C04h
1447	mov si, offset NonMBRwrite_rep
1448	call SETUP_ShowErrorBox
1449
1450
1451	IFDEF AUX_DEBUG
1452	IF 0
1453	pushf
1454	pusha
1455	mov si, offset [NonMBRwrite]
1456	call AuxIO_TeletypeNL
1457	call AuxIO_Print
1458	call AuxIO_TeletypeNL
1459	popa
1460	popf
1461	ENDIF
1462	ENDIF
1463
1464	; Show popup and halt the system.
1465	jmp HaltSystem
1466
1467
1468
1469	;
1470	; Continue the write if not MBR sector or MBR to write is validated.
1471	;
1472	DriveIO_SaveSector_continue_write:
1473	test byte ptr cs:[CurIO_UseExtension], 1
1474	jz DIOSS_UseNormal
1475	; Are we forced do use LBA via Setting?
1476	; Always use INT13X on v1.0.8+.
1477	;~ test byte ptr cs:[CFG_ForceLBAUsage], 1
1478	;~ jnz DIOSS_UseExtension
1479	jmp DIOSS_UseExtension
1480	; Is the drive not a harddrive?
1481	cmp dl, 80h
1482	jb DIOSS_UseNormal
1483	; Upper 8 bits of LBA-address set? -> Use LBA (maximum boundary is FB0400h)
1484	or bh, bh
1485	jnz DIOSS_UseExtension
1486	; Compare Switch-Table value to bit 16-23 of LBA-address
1487	mov di, dx
1488	and di, 007Fh
1489	cmp bptr cs:[LBASwitchTable+di], bl
1490	jbe DIOSS_UseExtension
1491
1492	DIOSS_UseNormal:
1493
1494	IFDEF AUX_DEBUG
1495	IF 0
1496	DBG_TEXT_OUT_AUX 'DriveIO_WriteSectorCHS:'
1497	PUSHRF
1498	call DEBUG_DumpRegisters
1499	call AuxIO_DumpParagraph
1500	call AuxIO_TeletypeNL
1501	POPRF
1502	ENDIF
1503	ENDIF
1504
1505	mov di, 3 ; retry count
1506	DIOSS_ErrorLoop:
1507	push ds
1508	pop es
1509	mov bx, si ; ES:BX - Destination
1510	mov ax, 0301h ; Function 3 - Write Sector
1511	int 13h
1512	sti ; Enable ints
1513	jnc DIOSS_Success
1514	dec di ; decrement retry count
1515	jnz DIOSS_ErrorLoop
1516	call MBR_SaveError
1517
1518	DIOSS_UseExtension:
1519
1520	mov di, ds ; segment for transfer address
1521	call DriveIO_WriteSectorLBA ; extended write
1522	jc MBR_SaveError ; halt on error
1523
1524	;~ push cx
1525	;~ mov cs:[INT13X_DAP_NumBlocks], 1 ; Copy ONE sector
1526	;~ mov wptr cs:[INT13X_DAP_Transfer+0], si
1527	;~ mov cx, ds
1528	;~ mov wptr cs:[INT13X_DAP_Transfer+2], cx ; Fill out Transfer Adress
1529	;~ mov wptr cs:[INT13X_DAP_Absolute+0], ax
1530	;~ mov wptr cs:[INT13X_DAP_Absolute+2], bx ; Fill out Absolute Sector
1531	;~ push cs
1532	;~ pop ds
1533	;~ mov si, offset [INT13X_DAP]
1534	;~ mov ax, 4300h ; Extended Write (No Verify)
1535	;~ int 13h
1536	;~ pop cx
1537	;~ jnc DIOSS_Success
1538	;~ call MBR_SaveError
1539
1540	DIOSS_Success:
1541	ret
1542	DriveIO_SaveSector EndP
1543
1544
1545
1546
1547	;##############################################################################
1548	;# When a disk has a Master LVM sector, it means it has been prepared for use
1549	;# by OS/2 and contains important information about how OS/2 views its geometry
1550	;# and other disk related properties. This function assumes the LBA address
1551	;# of the Master LVM sector has already been located and simply loads the
1552	;# sector into [LVMSector].
1553	;#
1554	;# Note that because this is an operation similar to the regular loading of
1555	;# sectors, the disk I/O semantics are used here. This means CF=0 when an LVM
1556	;# sector is successfully loaded and CF=1 otherwise.
1557	;##############################################################################
1558	;# ACTION : Loads the Master LVM sector if one exists
1559	;# ----------------------------------------------------------------------------
1560	;# EFFECTS : Modifies DAP structure and [LVMSector]
1561	;# ----------------------------------------------------------------------------
1562	;# IN : DL - BIOS disk number (80h,81h,etc)
1563	;# ----------------------------------------------------------------------------
1564	;# OUT : CF=0 - Valid Master LVM sector found and loaded
1565	;##############################################################################
1566	DriveIO_LoadMasterLVMSector Proc Near
1567
1568	IFDEF AUX_DEBUG
1569	IF 0
1570	DBG_TEXT_OUT_AUX 'DriveIO_LoadMasterLVMSector:'
1571	PUSHRF
1572	;~ call DEBUG_DumpRegisters
1573	;~ call AuxIO_DumpParagraph
1574	;~ call AuxIO_TeletypeNL
1575	POPRF
1576	ENDIF
1577	ENDIF
1578
1579	; Save all registers
1580	pusha
1581
1582	; Check if BIOS disk number is valid
1583	call DriveIO_IsValidHarddisk
1584	jc DriveIO_LoadMasterLVMSector_error
1585
1586	; Calculate the entry in the DISKINFO array for this disk
1587	call DriveIO_CalcDiskInfoPointer
1588
1589	; Save the entry for later recalls
1590	mov bp, bx
1591
1592	; Get the LBA address of the Master LVM sector
1593	mov ax, [bx+LocDISKINFO_LVM_MasterLBA+00h]
1594	mov bx, [bx+LocDISKINFO_LVM_MasterLBA+02h]
1595
1596	; LBA of Master LVM sector cannot be 0, so none was found during
1597	; the gathering of disk information.
1598	mov cx, ax
1599	or cx, bx
1600	jz DriveIO_LoadMasterLVMSector_error
1601
1602	; Load it into [LVMSector]
1603	mov di, ds
1604	mov si, offset [LVMSector]
1605	call DriveIO_ReadSectorLBA
1606	jc DriveIO_LoadMasterLVMSector_error
1607
1608	; Validate the Master LVM sector
1609	call LVM_ValidateSector
1610
1611	; Complement success indicator to conform to semantics of this function
1612	cmc
1613
1614	; Master LVM sector was valid and is now loaded in [LVMSector]
1615	jnc DriveIO_LoadMasterLVMSector_ret
1616
1617	DriveIO_LoadMasterLVMSector_error:
1618
1619	; Clear the sector buffer for safety reasons
1620	mov si, offset [LVMSector]
1621	call ClearSectorBuffer
1622
1623	; Indicate no Master LVM sector loaded
1624	stc
1625
1626	DriveIO_LoadMasterLVMSector_ret:
1627
1628	; Restore all registers
1629	popa
1630
1631	ret
1632	DriveIO_LoadMasterLVMSector Endp
1633
1634
1635
1636
1637	;##############################################################################
1638	;# There is much information to know about the connected disks.
1639	;# We also want this information clustered per disk and available before
1640	;# further disk and partition scanning takes place.
1641	;# This function gathers such information like INT13, INT13X, MBR, LVM, more.
1642	;# Especially important is the LVM information, because that contains the
1643	;# geometry OS/2 uses to access the disk. Other important information is the
1644	;# presence of valid MBRs, logical partitions and whatnot.
1645	;# This function gathers such information and stores it in a DISKINFO structure
1646	;# for which an instance exists for every disk found.
1647	;##############################################################################
1648	;# ACTION : Gather disk information and store this in the BSS
1649	;# ----------------------------------------------------------------------------
1650	;# EFFECTS : Modifies DAP structure and the buffers it uses, fills DISKINFO[n]
1651	;# ----------------------------------------------------------------------------
1652	;# IN : DL - BIOS disk number (80h,81h,etc)
1653	;# ----------------------------------------------------------------------------
1654	;# OUT : CF=1 - failure
1655	;##############################################################################
1656	DriveIO_GatherDiskInfo Proc Near
1657
1658	IFDEF AUX_DEBUG
1659	IF 0
1660	DBG_TEXT_OUT_AUX 'DriveIO_GatherDiskInfo:'
1661	PUSHRF
1662	call DEBUG_DumpRegisters
1663	;~ call AuxIO_DumpParagraph
1664	;~ call AuxIO_TeletypeNL
1665	POPRF
1666	ENDIF
1667	ENDIF
1668
1669	; Push all registers we use
1670	pusha
1671	push ds
1672	push es
1673
1674	; Make sure ES=DS
1675	push ds
1676	pop es
1677
1678	; Check if BIOS disk number is valid
1679	call DriveIO_IsValidHarddisk
1680	jc DriveIO_GatherDiskInfo_error
1681
1682	; Calculate the entry in the DISKINFO array for this disk
1683	call DriveIO_CalcDiskInfoPointer
1684
1685	; Save the entry for later recalls
1686	mov bp, bx
1687
1688	; Store the BIOS disk number in the structure
1689	mov [bx+LocDISKINFO_DiskNum], dl
1690
1691	; ------------------------------------------------------------------- [ INT13 ]
1692
1693	; Get BIOS Disk Parameters (legacy method)
1694	mov ah, 08h ; Get Disk Parameters
1695	int 13h ; Call BIOS
1696	sti ; Enable ints
1697
1698	; CF=1 or AH!=0 indicates error
1699	jc DriveIO_GatherDiskInfo_error
1700	test ah, ah
1701	jnz DriveIO_GatherDiskInfo_error
1702
1703	; Recall DISKINFO entry
1704	mov bx, bp
1705
1706	; Store SPT (WORD)
1707	xor ah, ah ; Zero extend SPT to 16 bits
1708	mov al, cl ; Hi 2 bits max cyl and max sec
1709	and al, 3fh ; Mask max sec (1-based)
1710	mov [bx+LocDISKINFO_I13_Secs], ax ; Store SPT
1711
1712	; Store HEADS (WORD)
1713	xor dl, dl ; Zero extend HEADS to 16 bits
1714	xchg dl, dh ; Get max head (0-based)
1715	inc dx ; Head count
1716	mov [bx+LocDISKINFO_I13_Heads], dx ; Store HEADS
1717
1718	; Store CYLS (WORD)
1719	shr cl, 6 ; Hi 2 bits of max cyl to 1:0
1720	xchg cl, ch ; Max cyl (0-based)
1721	inc cx ; Cyl count
1722	mov [bx+LocDISKINFO_I13_Cyls], cx ; Store CYLS
1723
1724	; Recall BIOS disk number
1725	mov dl, [bx+LocDISKINFO_DiskNum]
1726
1727	; ------------------------------------------------------------------ [ INT13X ]
1728
1729	; Get BIOS Disk Parameters (extended method)
1730	mov si, offset [Scratch] ; Buffer to return disk info
1731	mov ax, 80h ; Size of buffer
1732	mov [si], ax ; Store it in first word
1733	mov ah, 48h ; Get Extended Disk Parameters
1734	int 13h ; Call BIOS
1735	sti ; Enable ints
1736
1737	; CF=1 or AH!=0 indicates error
1738	jc DriveIO_GatherDiskInfo_error
1739	test ah, ah
1740	jnz DriveIO_GatherDiskInfo_error
1741
1742	; Store flags (WORD)
1743	cld ; Direction up
1744	lodsw ; Buffersize, discard
1745	lodsw ; Flags (CHS valid etc)
1746	mov [bx+LocDISKINFO_I13X_Flags], ax ; Store them
1747
1748	; Store CYLS (DWORD)
1749	lodsw ; Cyl count low
1750	mov [bx+LocDISKINFO_I13X_Cyls+00h], ax ; Store CYLS low
1751	lodsw ; Cyl count high
1752	mov [bx+LocDISKINFO_I13X_Cyls+02h], ax ; Store CYLS high
1753
1754	; Store HEADS (DWORD)
1755	lodsw ; Head count low
1756	mov [bx+LocDISKINFO_I13X_Heads+00h], ax ; Store HEADS low
1757	lodsw ; Head count high
1758	mov [bx+LocDISKINFO_I13X_Heads+02h], ax ; Store HEADS high
1759
1760	; Store SPT (DWORD)
1761	lodsw ; Secs per track low
1762	mov [bx+LocDISKINFO_I13X_Secs+00h], ax ; Store SPT low
1763	lodsw ; Secs per track high
1764	mov [bx+LocDISKINFO_I13X_Secs+02h], ax ; Store SPT high
1765
1766	; Store total LBA sectors (QWORD)
1767	lea di, [bx+LocDISKINFO_I13X_SecsLBA]
1768	mov cx, 4
1769	rep movsw
1770
1771	; Store sector size (WORD)
1772	lodsw
1773	mov [bx+LocDISKINFO_I13X_SecSize], ax
1774
1775	; Store bus name (4 bytes, space padded, v3.0+)
1776	lea si, [Scratch+24h]
1777	lea di, [bx+LocDISKINFO_I13X_HostBus]
1778	movsw
1779	movsw
1780
1781	; Store interface name (8 bytes, space padded, v3.0+)
1782	lea di, [bx+LocDISKINFO_I13X_Interface]
1783	mov cx, 4
1784	rep movsw
1785
1786	; Should gather some more INT13X info here,
1787	; like maybe Advanced Format stuff or so.
1788	; We'll investigate that at a later time.
1789
1790	; --------------------------------------------------------------------- [ MBR ]
1791
1792	; Load the MBR
1793	mov si, offset [TmpSector]
1794	call DriveIO_LoadMBR
1795
1796	; Store MBR flags (valid sig, partitions present, airboot installed)
1797	mov [bx+LocDISKINFO_MbrFlags], al
1798
1799	; Recall BIOS disk number
1800	mov dl, [bx+LocDISKINFO_DiskNum]
1801
1802	; --------------------------------------------------------------------- [ LVM ]
1803
1804	; Locate the Master LVM sector, if any
1805	call DriveIO_LocateMasterLVMSector
1806
1807	; Save Master LVM sector LBA high
1808	mov cx, bx
1809
1810	; Recall DISKINFO entry
1811	mov bx, bp
1812
1813	; Store Master LVM sector LBA
1814	mov [bx+LocDISKINFO_LVM_MasterLBA+00h], ax
1815	mov [bx+LocDISKINFO_LVM_MasterLBA+02h], cx
1816
1817	; No Master LVM sector found, so skip storing LVM info for this disk
1818	jnc DriveIO_GatherDiskInfo_no_master_lvm
1819
1820	; Load the Master LVM sector into [LVMSector]
1821	call DriveIO_LoadMasterLVMSector
1822
1823	; No valid Master LVM sector, so skip storing LVM info for this disk
1824	jc DriveIO_GatherDiskInfo_no_master_lvm
1825
1826	; A valid Master LVM sector has been loaded into [LVMSector]
1827	mov si, offset [LVMSector]
1828
1829	; Get the number of sectors per track (OS/2 geometry)
1830	mov ax, [si+LocLVM_Secs+00h]
1831	mov cx, [si+LocLVM_Secs+02h]
1832
1833	; Store it
1834	mov [bx+LocDISKINFO_LVM_Secs+00h], ax
1835	mov [bx+LocDISKINFO_LVM_Secs+02h], cx
1836
1837	; Get the number of heads (OS/2 geometry)
1838	mov ax, [si+LocLVM_Heads+00h]
1839	mov cx, [si+LocLVM_Heads+02h]
1840
1841	; Store it
1842	mov [bx+LocDISKINFO_LVM_Heads+00h], ax
1843	mov [bx+LocDISKINFO_LVM_Heads+02h], cx
1844
1845	; Should gather some more LVM info here,
1846	; like OS/2 extended geometry and other flags.
1847	; We'll implement that at a later time.
1848
1849	DriveIO_GatherDiskInfo_no_master_lvm:
1850
1851	; When no Master LVM sector was found,
1852	; the LVM info in the DISKINFO structure for the disk
1853	; will be ZERO because the area was cleared in PRECRAP.
1854
1855	; Indicate success
1856	clc
1857
1858	jmp DriveIO_GatherDiskInfo_ret
1859
1860	DriveIO_GatherDiskInfo_error:
1861	stc
1862	DriveIO_GatherDiskInfo_ret:
1863
1864
1865	IFDEF AUX_DEBUG
1866	IF 0
1867	DBG_TEXT_OUT_AUX '[DISKINFO]'
1868	PUSHRF
1869	call DEBUG_DumpRegisters
1870	;~ call AuxIO_DumpParagraph
1871	;~ call AuxIO_TeletypeNL
1872	mov si, bp
1873	mov cx, 4
1874	@@:
1875	call AuxIO_DumpParagraph
1876	call AuxIO_TeletypeNL
1877	add si, 16
1878	loop @B
1879	mov si, offset [Scratch]
1880	mov cx, 4
1881	@@:
1882	call AuxIO_DumpParagraph
1883	call AuxIO_TeletypeNL
1884	add si, 16
1885	loop @B
1886	mov si, offset [LVMSector]
1887	mov cx, 7
1888	@@:
1889	call AuxIO_DumpParagraph
1890	call AuxIO_TeletypeNL
1891	add si, 16
1892	loop @B
1893	POPRF
1894	ENDIF
1895	ENDIF
1896
1897	; Restore registers
1898	pop es
1899	pop ds
1900	popa
1901
1902	ret
1903	DriveIO_GatherDiskInfo EndP
1904
1905	;------------------------------------------------------------------------------
1906	; Scan all disks to gather information
1907	;------------------------------------------------------------------------------
1908	; IN : None
1909	; OUT : CF=1 - some failure occured
1910	; : ZF=1 - no harddisks
1911	; NOTE : This does the preliminary gathering of disk information
1912	;------------------------------------------------------------------------------
1913	DriveIO_ScanDisks Proc Near
1914
1915	IFDEF AUX_DEBUG
1916	IF 0
1917	DBG_TEXT_OUT_AUX 'DriveIO_ScanDisks:'
1918	PUSHRF
1919	call DEBUG_DumpRegisters
1920	;~ call AuxIO_DumpParagraph
1921	;~ call AuxIO_TeletypeNL
1922	POPRF
1923	ENDIF
1924	ENDIF
1925
1926	; Save all registers
1927	pusha
1928
1929	; Get number of disks in DH
1930	call DriveIO_GetHardDriveCount
1931
1932	; Check if there are any disks to scan
1933	xor cx, cx ; Prepare 16-bit counter
1934	mov cl, dh ; Number of disks now in CX
1935	jcxz DriveIO_ScanDisks_end ; Quit if no disks
1936
1937	; Scan disks from 80h upward
1938	mov dl, 80h ; BIOS number of first disk
1939	DriveIO_ScanDisks_next:
1940	call DriveIO_GatherDiskInfo ; Gather info for this disk
1941	jc DriveIO_ScanDisks_end ; Quit if some error occured
1942	inc dl ; Advance to next disk
1943	loop DriveIO_ScanDisks_next ; Scan next disk if there is one
1944	test dl, dl ; Set ZF=0
1945	clc ; Indicate success
1946
1947	DriveIO_ScanDisks_end:
1948	; Restore all registers
1949	popa
1950
1951	ret
1952	DriveIO_ScanDisks EndP
1953
1954	;------------------------------------------------------------------------------
1955	; Calculate pointer to entry in DISKINFO structure
1956	;------------------------------------------------------------------------------
1957	; IN : DL BIOS disk number (80h etc)
1958	; OUT : BX Pointer to entry
1959	; NOTE : BIOS disk number must be valid
1960	;------------------------------------------------------------------------------
1961	DriveIO_CalcDiskInfoPointer Proc Near
1962	xchg bx, ax ; AX is used for calculation
1963	mov al, DISKINFO_Size ; Size of DISKINFO structure
1964	mov ah, dl ; BIOS disk number
1965	sub ah, 80h ; Now 0-based index
1966	mul ah ; Now offset into DISKINFO array
1967	add ax, offset [DiskInformation] ; Base of DISKINFO array
1968	xchg bx, ax ; BX now points to entry for disk
1969	ret
1970	DriveIO_CalcDiskInfoPointer EndP
1971
1972	;------------------------------------------------------------------------------
1973	; Check if the BIOS disk number in DL is a harddisk and in range
1974	;------------------------------------------------------------------------------
1975	; IN : DL BIOS disk number (80h etc)
1976	; OUT : CF=1 if invalid disk number or out of range
1977	; NOTE : Only modifies flags
1978	;------------------------------------------------------------------------------
1979	DriveIO_IsValidHarddisk Proc Near Uses dx
1980	cmp dl, 80h ; BIOS disk number must be at least 80h
1981	jb @F ; Not a harddisk, exit with CY
1982	mov dh, dl ; Save to do compare
1983	sub dh, 80h ; Now 0 based disk number
1984	inc dh ; Now 1 based disk number
1985	cmp [TotalHarddiscs], dh ; Out of range, exit with CY
1986	@@: ret
1987	DriveIO_IsValidHarddisk EndP
1988
1989
1990	; Values for sectors per track table corresponding to DriveIO_IsHugeDrive return value.
1991	;~ secs_per_track_table db 63,127,255,255,255,255
1992
1993	;~ db_lmlvm db 'Load Master LVM -- disk: ',0

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source: trunk/bootcode/regular/driveio.asm@ 175

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