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PARTMAIN.ASM@ 43

Last change on this file since 43 was 43, checked in by Ben Rietbroek, 12 years ago

BSS Corruption Problem located (auxdebug on) [2012-02-21]

WARNING!!

All commits upto and including the commit of [2012-05-13] contain
a severe bug!! Building from these sources and then disabling
the 'force LBA' feature while also using the drive-letter feature or
editing the label can DESTROY THE MBR on ALL ATTACHED DISKS!!
DO NOT DISABLE 'FORCE LBA USAGE' WHEN BUILT FROM THE THESE COMMITS!!

Problem

o Function with Xrefs goes out-of-bounds because hideparttable is too small

Has only 30 entries and should be 45.
Lost partition checker initializes out-of-bounds.

Info

o About the hideparttable

For each partition it can be specified which other partitions need to
be hidden when that partition is booted. This is useful for legacy DOS
but also braindead Windows that presents HPFS/JFS partitions as
unformatted and tries to persuade the user to format them.
With v1.07 the numer of partitions that can be handled was expanded from
30 to 45, but the size of the hideparttable was overseen.

o The need to compress the hideparttable

The old size was 30x30=900 bytes while the required size is 45x45=2045 bytes.
This amount of space is not available in the image.
Since 6 bits are enough to identify the partition number to be hidden,
the solution is to devide the table into bitfields. This will result
in a table of (45*45*6)/8=1519 bytes, which can be fitted.

Changes

Revamped the sources quite a bit and moved the history to a separate
file. (AIR-BOOT.HIS)

New

o FIXCODE script for Linux

Just until the C version is ready...

File size: 66.4 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 / PARTiTiON REGULAR ROUTINES
20	;---------------------------------------------------------------------------
21
22	IFDEF ModuleNames
23	DB 'PARTMAIN',0
24	ENDIF
25
26	PART_FixUpDefaultPartitionValues Proc Near Uses dx si di
27	; Fix-Up Default and Last Partition - If lost, search for Bootable
28	xor bl, bl
29	mov dl, CFG_PartDefault
30	call PART_FixUpSelectionNumber
31	mov CFG_PartDefault, dl
32	mov dl, CFG_PartLast
33	call PART_FixUpSelectionNumber
34	mov CFG_PartLast, dl
35	mov dl, CFG_PartAutomatic
36	call PART_FixUpSelectionNumber
37	mov CFG_PartAutomatic, dl
38
39	; [Linux support removed since v1.02]
40	; ; Fix-Up Linux Kernel Partition - If lost, search for FAT-16
41	; mov bl, 06h
42	; mov dl, CFG_LinuxKrnlPartition
43	; call PART_FixUpPartitionNumber
44	; mov CFG_LinuxKrnlPartition, dl
45	;
46	; ; Fix-Up Linux Root Partition - If lost, search for Linux partition (83h)
47	; mov bl, 83h
48	; mov dl, CFG_LinuxRootPartition
49	; call PART_FixUpPartitionNumber
50	; mov CFG_LinuxRootPartition, dl
51	ret
52	PART_FixUpDefaultPartitionValues EndP
53
54	; Our resync process for partition number is as specified:
55	;==========================================================
56	; - If 0FFh -> Partition Disabled, so don't do anything to it...
57	; - Try to use GetXref to get the new partition no via X-Ref Table
58	; - If failed, increase partition no, till overflow or hit on specific
59	; characteristic
60	; On overflow -> Resume search from partition no 0
61	;
62	; Characteristic is a partition id. If this id is 0, then a bootable partition
63	; is searched for.
64
65	; Fixes a partition number, adjusting it to the new IPT after redetect
66	; In: DL - Number of partition
67	; BL - Requested Partition ID
68	; Out: DL - New number of partition (guessed normally ;)
69	PART_FixUpSelectionNumber Proc Near Uses ax cx
70	cmp dl, 080h
71	je PFUPN_SelectionDisabled
72	ja PFUPN_SpecialSelection
73	call PARTSCAN_GetXref ; DL - PartitionNo prev IPT
74	cmp dh, 0FFh ; DH -> Partition No in new IPT
75	je PFUPN_SelectionGone
76	mov dl, dh
77	PFUPN_SelectionDisabled:
78	ret
79
80	PFUPN_SpecialSelection:
81	cmp dl, 0FEh ; Resume-BIOS?
82	ja PFUPN_SpecialSelectionFloppy
83	cmp CFG_ResumeBIOSbootSeq, 0
84	je PFUPN_SelectionGone
85	jmp PFUPN_Found
86	PFUPN_SpecialSelectionFloppy:
87	cmp CFG_IncludeFloppy, 0
88	je PFUPN_SelectionGone
89	jmp PFUPN_Found
90
91	; Partition is not referenced in New-IPT or Resume-BIOS/Floppy selected, but
92	; actual media is disabled...so dig for requested partition
93	PFUPN_SelectionGone:
94	mov cl, CFG_Partitions
95	or cl, cl
96	jz PFUPN_NothingFound ; No partitions available -> so fail
97	or bl, bl
98	jz PFUPN_BootableSearchLoop
99	; Search for Partition ID "BL"
100	PFUPN_PartIDsearchLoop:
101	call PART_GetPartitionPointer ; Gets SI for partition DL
102	cmp bptr ds:[si+LocIPT_SystemID], bl
103	je PFUPN_Found
104	dec cl
105	jz PFUPN_NothingFound
106	inc dl ; Increase
107	cmp CFG_Partitions, dl
108	ja PFUPN_PartIDsearchLoop
109	xor dl, dl
110	jmp PFUPN_PartIDsearchLoop
111
112	; Search for Partition ID "BL"
113	PFUPN_BootableSearchLoop:
114	call PART_GetPartitionPointer ; Gets SI for partition DL
115	mov al, ds:[si+LocIPT_Flags]
116	and al, Flags_Bootable
117	jnz PFUPN_Found
118	dec cl
119	jz PFUPN_NothingFound
120	inc dl ; Increase
121	cmp CFG_Partitions, dl
122	ja PFUPN_PartIDsearchLoop
123	xor dl, dl
124	jmp PFUPN_PartIDsearchLoop
125
126	PFUPN_NothingFound:
127	mov dl, 080h ; Now being Disabled
128	PFUPN_Found:
129	ret
130	PART_FixUpSelectionNumber EndP
131
132	; ============================================================================
133	; In: DS:SI - IPT-Entry of partition
134	; DS:PartitionSector - Actual Boot-Record of partition
135	; Out: none (BootRecordCRD updated)
136	PART_UpdateBootRecordCRC Proc Near Uses bx
137	mov si, offset PartitionSector
138	mov bx, 4B4Dh ; Magic: 'MK'
139	call MBR_GetCheckOfSector
140	mov [si+LocIPT_BootRecordCRC], bx
141	ret
142	PART_UpdateBootRecordCRC EndP
143
144	; Copies the device-name to the Resume-BIOS IPT entry
145	PART_UpdateResumeBIOSName Proc Near Uses ax bx cx si di
146	;movzx bx, CFG_ResumeBIOSbootSeq
147	mov bl,CFG_ResumeBIOSbootSeq
148	mov bh,0
149
150	dec bx
151	shl bx, 1
152	mov si, wptr [ContinueBIOSbootTable+bx]
153	mov di, offset BIOScontIPTentry+LocIPT_Name
154	push di
155	mov cx, 11
156	mov al, ' '
157	rep stosb
158	pop di
159	PURBN_BootDeviceCopyLoop:
160	lodsb
161	or al, al
162	jz PURBN_NoResumeBootSeq
163	stosb
164	jmp PURBN_BootDeviceCopyLoop
165	PURBN_NoResumeBootSeq:
166	ret
167	PART_UpdateResumeBIOSName EndP
168
169	; ============================================================================
170	; Partition-Pointer Functions
171	; ============================================================================
172
173	; Builds Pointer-Table straight (without filtering, w/o Floppy/CD-ROM/Kernels)
174	PART_CalculateStraightPartPointers Proc Near
175	mov ax, offset PartitionTable
176	mov bx, offset PartitionPointers
177	mov cx, LocIPT_MaxPartitions
178	PCSPP_Loop:
179	mov ds:[bx], ax
180	add bx, 2
181	add ax, LocIPT_LenOfIPT
182	dec cx
183	jnz PCSPP_Loop
184	mov al, ds:[CFG_Partitions]
185	mov ds:[PartitionPointerCount], al
186	ret
187	PART_CalculateStraightPartPointers EndP
188
189	; This here does PartitionPointers in order for displaying in BootMenu
190	; [this means filtering and including Floppy/CD-ROM/Kernels, if wanted]
191	PART_CalculateMenuPartPointers Proc Near Uses si
192	mov si, offset PartitionTable
193	mov bx, offset PartitionPointers
194	test CFG_IncludeFloppy, 1
195	jz PCMPP_NoFloppyInclude
196	mov ax, offset FloppyIPTentry
197	mov ds:[bx], ax
198	add bx, 2
199	PCMPP_NoFloppyInclude:
200
201	test CFG_ResumeBIOSbootSeq, 0FFh
202	jz PCMPP_NoResumeBootSeqInclude
203	mov ax, offset BIOScontIPTentry
204	mov ds:[bx], ax
205	add bx, 2
206	PCMPP_NoResumeBootSeqInclude:
207
208	; [Linux support removed since v1.02]
209	; ; Now include all Linux Kernels, if any available...
210	; movzx cx, LINUX_KernelNo
211	; or cx, cx
212	; jz PCMPP_NoLinuxKernels
213	; mov ax, offset LINUX_KernelEntries
214	; PCMPP_KernelLoop:
215	; mov ds:[bx], ax
216	; add bx, 2
217	; add ax, LocIPT_LenOfIPT
218	; dec cx
219	; jnz PCMPP_KernelLoop
220	; PCMPP_NoLinuxKernels:
221
222	;movzx cx, CFG_Partitions ; LocIPT_MaxPartitions
223	mov cl,CFG_Partitions ; LocIPT_MaxPartitions
224	mov ch,0
225
226	or cx, cx
227	jz PCMPP_NoPartitions
228	PCMPP_Loop:
229	mov al, ds:[si+LocIPT_Flags]
230	and al, Flags_Bootable
231	jz PCMPP_IsNotBootable
232	mov ds:[bx], si
233	add bx, 2
234	PCMPP_IsNotBootable:
235	add si, LocIPT_LenOfIPT
236	dec cx
237	jnz PCMPP_Loop
238	PCMPP_NoPartitions:
239	sub bx, offset PartitionPointers
240	shr bx, 1
241	mov ds:[PartitionPointerCount], bl
242	ret
243	PART_CalculateMenuPartPointers EndP
244
245	; Gets a pointer to the given partition
246	; In: DL - Number of partition
247	; Out: SI - Pointer to it
248	PART_GetPartitionPointer Proc Near Uses bx
249	cmp dl, 0FEh
250	je PGPP_IsBIOSbootSeq ; FEh -> Resume BIOS boot Sequence
251	ja PGPP_IsFloppy ; FFh -> Floppy
252	;movzx bx, dl
253	mov bl,dl
254	mov bh,0
255
256	shl bx, 1
257	mov si, wptr [PartitionPointers+bx]
258	ret
259	PGPP_IsBIOSbootSeq:
260	mov si, offset BIOScontIPTentry
261	ret
262	PGPP_IsFloppy:
263	mov si, offset FloppyIPTentry ; PartitionTable-LocIPT_LenOfIPT
264	ret
265	PART_GetPartitionPointer EndP
266
267	; Gets the number of a partition pointer
268	; In: SI - Pointer to Partition
269	; Out: DL - Number of partition
270	PART_GetPartitionNumber Proc Near Uses bx
271	mov dl, ds:[PartitionPointerCount]
272	mov bx, offset PartitionPointers
273	PGPN_SearchLoop:
274	cmp wptr ds:[bx], si
275	je PGPN_Found
276	add bx, 2
277	dec dl
278	jnz PGPN_SearchLoop
279	mov dl, 0FFh
280	ret
281	PGPN_Found:
282	sub dl, ds:[PartitionPointerCount]
283	dec dl
284	not dl
285	ret
286	PART_GetPartitionNumber EndP
287
288	; Following functions are only usable, when Partition-Pointer-View is filtered
289	; They will convert from and to unfiltered view (used in Boot-Menu)
290	; In: DL - Number of partition in filtered view
291	; Out: DL - Number of partition in straight view
292	PART_ConvertToStraight Proc Near
293	;movzx bx, dl
294	mov bl,dl ; partition number to bl
295	mov bh,0 ; zero extend to word
296
297	shl bx, 1 ; convert to word index
298	mov ax, wptr cs:[PartitionPointers+bx] ; get the partition pointer
299	cmp ax, offset FloppyIPTentry
300	jb PCTS_IsBIOSbootSeq
301	je PCTS_IsFloppy
302	; [Linux support removed since v1.02]
303	; cmp ax, offset LINUX_KernelEntries
304	; jae PCTS_IsKernelEntry
305	sub ax, offset PartitionTable
306	mov bl, LocIPT_LenOfIPT
307	div bl ; Divide with IPTlength
308	mov dl, al
309	ret
310	; [Linux support removed since v1.02]
311	; PCTS_IsKernelEntry:
312	; mov dl, 0FDh
313	; ret
314	PCTS_IsBIOSbootSeq:
315	mov dl, 0FEh
316	ret
317	PCTS_IsFloppy:
318	mov dl, 0FFh
319	ret
320	PART_ConvertToStraight EndP
321
322	; In: DL - Number of partition in straight view
323	; Out: DL - Number of partition in filtered view
324	PART_ConvertFromStraight Proc Near Uses es di
325	cmp dl, 0FEh
326	jb PCFS_IsPartition
327	mov ax, offset BIOScontIPTentry
328	je PCFS_DoSearch
329	mov ax, offset FloppyIPTentry
330	jmp PCFS_DoSearch
331	PCFS_IsPartition:
332	; First we get Partition-Offset in AX
333	;movzx ax, dl
334	mov al,dl
335	mov ah,0
336
337	mov bl, LocIPT_LenOfIPT
338	mul bl
339	add ax, offset PartitionTable
340	PCFS_DoSearch:
341	; Now search for this offset in our filtered Partition-Pointer-Table
342	push cs
343	pop es
344	mov di, offset PartitionPointers
345	mov cx, LocIPT_MaxPartitions
346	xor dl, dl ; Reply on Not-Found = Partition==0
347	repne scasw ; Compare-Loop
348	jne PCFS_NotFound
349	sub di, 2 ; One Back, so point to compared value
350	mov dx, di
351	sub dx, offset PartitionPointers
352	shr dx, 1
353	; Adjust for IncludeFloppy/etc. is automatically done, due Pointer-LookUp
354	PCFS_NotFound:
355	ret
356	PART_ConvertFromStraight EndP
357
358	; In: AX - Pointer to IPT Entry
359	; Out: SI - Pointer to corresponding Size-Element
360	; Destroyed: AX
361	PART_GetSizeElementPointer Proc Near Uses bx
362	; [Linux support removed since v1.02]
363	; cmp ax, offset LINUX_KernelEntries
364	; jae PGSEP_IsKernelEntry
365	mov si, offset PartitionSizeTable
366	sub ax, offset PartitionTable
367	; jmp PGSEP_Continue
368	; [Linux support removed since v1.02]
369	; PGSEP_IsKernelEntry:
370	; mov si, offset LINUX_KernelSizeTable
371	; sub ax, offset LINUX_KernelEntries
372	; PGSEP_Continue:
373	mov bl, LocIPT_LenOfIPT
374	div bl ; Divide with IPTlength
375	;movzx bx, al
376	mov bl,al
377	mov bh,0
378
379	shl ax, 1
380	shl bx, 2
381	add ax, bx ; My way of multiplying with 6
382	add si, ax ; SI - Partition Size-Element
383	ret
384	PART_GetSizeElementPointer EndP
385
386	; In: BX:AX - Sector Size (1=512 Bytes, 2=1024 Bytes, etc.)
387	; ES:DI - Pointer to Size-Element (6 bytes)
388	; Out: None, Size-Element filled out
389	; Destroyed: AX, BX, DI
390	PART_FillOutSizeElement Proc Near Uses cx dx
391	add di, 3 ; ES:DI - Last Digit of Size Digits
392	shr bx, 1
393	rcr ax, 1 ; /2 -> Sector Size is now KByte Size
394	xor cl, cl ; 0 - KByte, 1 - MByte, 2 - GByte
395	PFOSE_MakeSmallerLoop:
396	or bx, bx
397	jnz PFOSE_MakeSmaller
398	cmp ax, 9999
399	jbe PFOSE_IsSmallEnough
400	PFOSE_MakeSmaller:
401	mov dx, bx
402	and dx, 1023 ; My crazy way of dividing a 32-bit
403	shr ax, 10 ; value through 1024 using 16-bit
404	shr bx, 10 ; instructions...
405	shl dx, 6
406	or ax, dx
407	inc cl ; Value got smaller...
408	jmp PFOSE_MakeSmallerLoop
409
410	PFOSE_IsSmallEnough:
411	; First write the type of this Size-Element (KB/MB/GB)
412	mov bx, 'BK'
413	cmp cl, 1
414	jb PFOSE_WriteType
415	je PFOSE_IsMBtype
416	mov bx, 'BG'
417	jmp PFOSE_WriteType
418	PFOSE_IsMBtype:
419	mov bx, 'BM'
420	PFOSE_WriteType:
421	mov wptr es:[di+1], bx
422	mov bx, 10 ; Digits are 10-Based
423	xor dx, dx
424	PFOSE_DigitLoop:
425	xor dx, dx
426	div bx ; AX - Digit, DX - Remainder
427	add dl, '0' ; Convert digit to ASCII digit
428	mov es:[di], dl
429	or ax, ax
430	jz PFOSE_EndOfDigitLoop
431	dec di ; Go to previous char
432	jmp PFOSE_DigitLoop
433
434	PFOSE_EndOfDigitLoop:
435	ret
436	PART_FillOutSizeElement EndP
437
438
439
440
441
442
443
444
445
446
447
448	; This routine is called to hide a partition
449	; In: DL - Partition to hide
450	; Destroyed: None
451	PART_HidePartition Proc Near Uses ax bx cx dx si di
452	call PART_GetPartitionPointer ; Pointer to partition (DL) -> SI
453
454	; First load the partition table of that partition...
455	mov ax, wptr [si+LocIPT_AbsolutePartTable+0]
456	mov bx, wptr [si+LocIPT_AbsolutePartTable+2]
457	mov cx, wptr [si+LocIPT_LocationPartTable+1]
458	mov dh, bptr [si+LocIPT_LocationPartTable+0]
459	mov dl, [si+LocIPT_Drive]
460	call DriveIO_LoadPartition
461	; Partition-Table now LOADED
462	mov di, offset PartitionSector+446 ; ES:DI - 1st partitionentry...
463
464	; Put our partition's location into registers...
465	mov ax, wptr [si+LocIPT_AbsoluteBegin+0]
466	mov bx, wptr [si+LocIPT_AbsoluteBegin+2]
467	sub ax, wptr [si+LocIPT_AbsolutePartTable+0]
468	sbb bx, wptr [si+LocIPT_AbsolutePartTable+2]
469	; BX:AX - absolute position of partition relative to partition table
470	; ...and search for it...
471	PHP_SearchLoop:
472	cmp ax, wptr es:[di+LocBRPT_RelativeBegin]
473	jne PHP_SearchMismatch
474	cmp bx, wptr es:[di+LocBRPT_RelativeBegin+2]
475	jne PHP_SearchMismatch
476	jmp PHP_SearchMatch
477	PHP_SearchMismatch:
478	add di, LocBRPT_LenOfEntry ; 16 Bytes per partition entry
479	cmp di, 500+offset PartitionSector
480	jb PHP_SearchLoop
481	jmp MBR_HaltSystem ; not found, something is wrong here
482
483	; Found entry...
484	PHP_SearchMatch:
485	mov al, bptr es:[di+LocBRPT_SystemID] ; Partition-ID into AL
486	call PART_SearchFileSysHiddenID ; Put on =STEALTH=
487	mov bptr es:[di+LocBRPT_SystemID], al
488	IFDEF ReleaseCode
489	call DriveIO_SavePartition ; Saves Partition-Table
490	ENDIF
491	ret
492	PART_HidePartition EndP
493
494	; This here is for marking the first "good" non-hidden partition as being
495	; active. It requires the partition table at EXECBASE.
496	; Some BIOSes have problems with no primary marked active. Actually this is
497	; a buggy implementation, because the MBR-code should normally check,
498	; not the BIOS. This one could cause havoc to some systems, but I can't
499	; do anything else.
500	PART_MarkFirstGoodPrimary Proc Near Uses ax si di
501	mov di, offset PartitionSector+446 ; DS:SI - 1st partitionentry
502	; First action to do: Remove the active flag from every partition
503	push di
504	mov cl, 4
505	PMPP_RemoveActiveFlagLoop:
506	and bptr es:[di+LocBRPT_Flags], 7Fh
507	add di, LocBRPT_LenOfEntry
508	dec cl
509	jnz PMPP_RemoveActiveFlagLoop
510	pop di
511	; First Search, will hit on any PartitionID that is:
512	; a) not 0
513	; b) not hidden
514	; c) not extended partition (05h or 0Fh)
515	PMPP_Search1Loop:
516	mov al, bptr es:[di+LocBRPT_SystemID]
517	or al, al
518	jz PMPP_Search1NoHit
519	cmp al, 05h
520	je PMPP_Search1NoHit
521	cmp al, 0Fh
522	je PMPP_Search1NoHit
523	mov bl, al ; BL == AL == PartitionID
524	push si
525	call PART_SearchFileSysName
526	pop si ; AL == UnhiddenPartitionID
527	cmp al, bl ; if ID is unhidden...
528	je PMPP_SearchHit
529	PMPP_Search1NoHit:
530	add di, LocBRPT_LenOfEntry ; 16 Bytes per Partition-Entry
531	cmp di, 500+offset PartitionSector
532	jb PMPP_Search1Loop
533
534	mov di, offset PartitionSector+446 ; DS:SI - 1st Partition-Entry
535	; Second Search, hit on anything that is not an extended partition
536	; (05 or 0Fh)
537	PMPP_Search2Loop:
538	mov al, bptr es:[di+LocBRPT_SystemID]
539	or al, al
540	jz PMPP_Search2NoHit
541	cmp al, 05h
542	je PMPP_Search2NoHit
543	cmp al, 0Fh
544	jne PMPP_SearchHit
545	PMPP_Search2NoHit:
546	add di, LocBRPT_LenOfEntry ; 16 Bytes per Partition-Entry
547	cmp di, 500+offset PartitionSector
548	jb PMPP_Search2Loop
549	jmp PMPP_SearchFailed
550
551	PMPP_SearchHit:
552	or bptr es:[di], 80h ; SET ACTIVE PARTITION
553	PMPP_SearchFailed:
554	ret
555	PART_MarkFirstGoodPrimary EndP
556
557	; Searches the Name and Flags to a FileSysID (PartitionID)
558	; In: AL - FileSysID
559	; Out: AL - Unhidden File-System-ID, AH - Flags for this File-System
560	; SI - Pointer to Name (8char)
561	; Destroyed: none
562	PART_SearchFileSysName Proc Near Uses bx dx
563	;movzx bx, al
564	mov bl,al
565	mov bh,0
566
567	mov si, offset FileSysIDs
568	PSFSN_SearchLoop:
569	lodsw ; AL - NormalID, AH-HiddenID
570	mov dl, ds:[si] ; DL - File-System-Flags
571	inc si
572	cmp al, bl ; Check, if Unhidden-ID matches...
573	je PSFSN_Match
574	cmp ah, bl ; Check, if Hidden-ID matches...
575	je PSFSN_Match
576	mov al, bl ; So Unhidden-ID will be Original-ID
577	cmp ah, 0 ; Unknown (last ID in table)
578	je PSFSN_Match
579	inc bh
580	jmp PSFSN_SearchLoop
581
582	PSFSN_Match:
583	; AL is already Unhidden-ID
584	mov ah, dl
585	; AH is now the FileSystem-Flag
586	;movzx bx, bh
587	mov bl,bh
588	mov bh,0
589
590	shl bx, 3 ; Offsets * 8
591	mov si, offset FileSysNames
592	add si, bx
593	ret
594	PART_SearchFileSysName EndP
595
596	; Searches the Hidden ID corresponding to a FileSysID (PartitionID)
597	; In: AL - FileSysID
598	; Out: AL - Hidden File-System-ID
599	PART_SearchFileSysHiddenID Proc Near Uses bx
600	;movzx bx, al
601	mov bl,al
602	mov bh,0
603
604	mov si, offset FileSysIDs
605	PSFSHI_SearchLoop:
606	lodsw ; AL - NormalID, AH-HiddenID
607	inc si
608	cmp al, bl ; Check, if Unhidden-ID matches...
609	je PSFSHI_Match
610	cmp ah, bl ; Check, if Hidden-ID matches...
611	je PSFSHI_Match
612	mov ah, bl ; So Unhidden-ID will get replied...
613	cmp ah, 0 ; Unknown (last ID in table)
614	je PSFSHI_Match
615	inc bh
616	jmp PSFSHI_SearchLoop
617
618	PSFSHI_Match:
619	mov al, ah ; AL = Hidden ID
620	ret
621	PART_SearchFileSysHiddenID EndP
622
623	; In: DS:SI - Partition-Name, CX - Maximum/Total Length
624	; Out: Carry-Flag set, if valid Partition-Name
625	; Destroyed: None
626	PART_CheckForValidPartName Proc Near Uses ax cx dx si
627	; Our logic is as follows:
628	; If all chars are U -> Invalid (due reformated signature)
629	; If anything below 32, but 0 -> Invalid (due invalid chars)
630	; If anything above 165 -> Invalid (due invalid chars)
631	; If anything between 123-128 -> Invalid (due invalid chars)
632	; DX - holds count of 'U's
633	push cx
634	or cx, cx
635	jz PCFVPN_InvalidName
636	xor dx, dx
637	PCFVPN_CheckLoop:
638	lodsb
639	cmp al, 0
640	je PCFVPN_ValidChar
641	cmp al, 32
642	jb PCFVPN_InvalidName
643	cmp al, 165
644	ja PCFVPN_InvalidName
645	cmp al, 123
646	jb PCFVPN_ValidChar
647	cmp al, 128
648	jbe PCFVPN_InvalidName
649	PCFVPN_ValidChar:
650	cmp al, 'U'
651	jne PCFVPN_NoMagic
652	inc dx
653	PCFVPN_NoMagic:
654	dec cx
655	jnz PCFVPN_CheckLoop
656	pop cx
657	cmp cx, dx
658	clc
659	je PCFVPN_WasMagic
660	stc
661	PCFVPN_WasMagic:
662	ret
663	PCFVPN_InvalidName:
664	pop cx
665	clc
666	ret
667	PART_CheckForValidPartName EndP
668
669
670	; Rousseau: added
671	; Compare a volume-label in the IPT to the install-volume
672	; SI holds pointer to entry in IPT
673	; CY set if this entry is also the install-volume
674	PART_IsInstallVolume Proc Near Uses ax cx dx si di
675	cld ; Advance upwards with lodsb
676	mov di, offset eCS_InstallVolume ; Address of install-volume label (max. 11 chars)
677
678	mov cx, 11 ; Maximum length of label
679	xor dl, dl ; Not found yet
680
681	; Compare next character
682	PART_IsInstallVolumeNext:
683	lodsb ; Load byte from SI (IPT-entry)
684	;cmp al,' ' ; If space then use zero
685	;jne PART_IsInstallVolume_skip1
686	;xor al,al
687	PART_IsInstallVolume_skip1:
688	xchg ah,al ; Save char to AH
689	xchg si,di ; Exchange pointers
690	lodsb ; Load byte from SI (install-volume label)
691	;cmp al,' ' ; If space then use zero
692	;jne PART_IsInstallVolume_skip2
693	;xor al,al
694	PART_IsInstallVolume_skip2:
695	xchg si,di ; Reexchange pointers
696	; call AuxIO_Teletype
697	call CONV_ToUpper
698	; call AuxIO_Teletype
699	xchg al,ah
700	; call AuxIO_Teletype
701	call CONV_ToUpper
702	; call AuxIO_Teletype
703	; call AuxIO_TeletypeNL
704
705	; Are both of them zero ?
706	; Then the names could be the same, but cx must not equal 11
707	; because that would indicate a null-string.
708	mov dh,al
709	or dh,ah
710	jz PART_IsInstallVolumeFound
711
712	cmp ah,al ; Are the the same ?
713	jnz PART_IsInstallVolumeNotFound ; Nope, compare ended
714	loop PART_IsInstallVolumeNext ; Yep, Compare next character
715
716	PART_IsInstallVolumeFound:
717	; If CX is still 11 this was a zero string
718	; and thus not a valid volume-name.
719	; This should not occur as this function is only called when the first
720	; byte is non-zero.
721	cmp cx,11
722	je PART_IsInstallVolumeNotFound
723	; Found !
724	mov dl,1 ; Found
725	jmp PART_IsInstallVolumeEnd
726
727
728	PART_IsInstallVolumeNotFound:
729	mov dl,0
730	jmp PART_IsInstallVolumeEnd
731
732
733	PART_IsInstallVolumeEnd:
734	; Set the status in CY
735	mov al,dl
736	add al,'0'
737	; call AuxIO_TeletypeHexByte
738	; call AuxIO_TeletypeNL
739	rcr dl,1 ; Put found-flag in CY
740	ret
741	PART_IsInstallVolume EndP
742
743
744
745
746
747
748	; ###################
749	; # START PARTITION #
750	; ###################
751
752	; Starts Partition DL from Internal Partition Table.
753	; In: DL - Number of partition (filtered view)
754	; Out: No Return...
755	; Destroyed: None, due to no return ;-)
756	; Logic: - Harddrive: loads partition Table
757	; sets partition active
758	; saves partition table
759	; hides partitions, if needed
760	; Linux-Support, if needed
761	; load boot sector
762	; VIBR checking, if wanted
763	; install MBR Protection, if wanted
764	; Special Boot Support, if needed (OS/2 Extended partitions)
765	; Copy boot-sector to StartBase
766	; run boot sector...
767	PART_StartPartition Proc Near Uses ax dx es di
768	local BootPartNo:byte
769	local PhysDiskBpbIndex:word ; Index into BPB to field of phys-disk
770	local FSType:byte ; The FS used on the loaded BPB
771	; Only used for FAT/HPFS/JFS
772
773	; Get Partition-Pointer (SI) to Partition-To-Boot (DL)
774	call PART_GetPartitionPointer
775
776	call PART_ConvertToStraight ; ...we save straight view for later...
777	mov BootPartNo, dl
778	; Straight - FFh -> Floppy boot
779	; FEh -> BIOS continue (CD-ROM, ZIP, etc.)
780
781	; We need straight pointers from now on, so calculate the table...
782	call PART_CalculateStraightPartPointers
783
784	; SI contains the pointer to the IPT to what partition to boot
785	; in this whole routine...it may never get messed up.
786
787	push si
788	mov dl, [si+LocIPT_Drive]
789	mov dh, [si+LocIPT_SystemID]
790	; Copy Partition-Name to BootingNow area for display purposes
791	add si, LocIPT_Name
792
793
794	;pusha
795	;call MBR_Teletype
796	;mov si,offset TXT_BootingNowPartName
797	;call MBR_Teletype
798	;popa
799
800	mov cx, 11
801	call GetLenOfName
802	mov di, offset TXT_BootingNowPartName
803	jz PSP_NoName
804	rep movsb ; Copy label-name to boot
805	PSP_NoName:
806	xor al, al
807	stosb ; Ending Zero
808	mov si, offset TXT_BootingNow1 ; "Booting the system using "
809	call MBR_Teletype
810	; [Linux support removed since v1.02]
811	; cmp dh, 0FDh
812	; je PSP_IsKernel
813
814	;pusha
815	;call MBR_Teletype
816	;mov si,offset TXT_BootingNowPartName
817	;call MBR_Teletype
818	;popa
819
820
821	or dl, dl
822	jnz PSP_IsHarddisc
823	; When booting floppy/CD-ROM/etc., we got other text to be displayed...
824	mov si, offset TXT_BootingNowPartName
825	call MBR_TeletypeVolName
826	jmp PSP_IsFloppyCDROMetc
827
828	; [Linux support removed since v1.02]
829	; PSP_IsKernel:
830	; IFDEF ReleaseCode
831	; ; Save configuration on HDD boots (save CFG_LinuxLastKernel)
832	; call DriveIO_SaveConfiguration
833	; ENDIF
834	; call MBR_Teletype ; Prints out BootingNow2 including KernelName
835	; mov si, offset TXT_BootingNowKernel
836	; call MBR_Teletype
837	; jmp PSP_IsFloppyCDROMetc
838
839	PSP_IsHarddisc:
840	IFDEF ReleaseCode
841	; Save configuration on HDD boots (save CFG_PartLast)
842	call DriveIO_SaveConfiguration ; Rousseau: SAVE CONFIGURATION !
843	ENDIF
844	;call MBR_Teletype ; Prints out BootingNow2 including PartitionName
845	mov si, offset TXT_BootingNowPartName
846	call MBR_TeletypeVolName
847	mov si, offset TXT_BootingNowPartition
848	call MBR_Teletype
849	pop si ; restores SI (IPT-pointer)
850
851	mov ax, wptr [si+LocIPT_AbsolutePartTable+0]
852	mov bx, wptr [si+LocIPT_AbsolutePartTable+2]
853	mov cx, wptr [si+LocIPT_LocationPartTable+1]
854	mov dh, bptr [si+LocIPT_LocationPartTable+0]
855	mov dl, [si+LocIPT_Drive]
856
857
858
859	; This loads the MBR in case of PRI or the EBR in case of LOG partitions.
860	call DriveIO_LoadPartition ; Load Table... [LOAD]
861
862
863
864	; --------------------------------------------------- MODIFY PARTITION TABLE
865	push cs
866	pop es
867	mov di, offset PartitionSector+446 ; ES:DI - First Partitionentry
868
869	; Remove all active-flags for safety reasons, primary partition table will
870	; have one partition set active by ScanPartition-routine.
871	push di
872	mov cl, 4
873	PSP_RemoveActiveFlagLoop:
874	and bptr es:[di+LocBRPT_Flags], 7Fh
875	add di, LocBRPT_LenOfEntry
876	dec cl
877	jnz PSP_RemoveActiveFlagLoop
878	pop di
879
880	; Put the partition-to-be-booted location into registers...
881	mov ax, wptr [si+LocIPT_AbsoluteBegin+0]
882	mov bx, wptr [si+LocIPT_AbsoluteBegin+2]
883	sub ax, wptr [si+LocIPT_AbsolutePartTable+0]
884	sbb bx, wptr [si+LocIPT_AbsolutePartTable+2]
885	; BX:AX - absolute position of partition relative to partition table
886	; ...and search for it...
887	PSP_SearchLoop:
888	cmp ax, wptr es:[di+LocBRPT_RelativeBegin]
889	jne PSP_SearchMismatch
890	cmp bx, wptr es:[di+LocBRPT_RelativeBegin+2]
891	jne PSP_SearchMismatch
892	jmp PSP_SearchMatch
893	PSP_SearchMismatch:
894	add di, LocBRPT_LenOfEntry ; 16 Bytes per Partition-Entry
895	cmp di, 500+offset PartitionSector
896	jb PSP_SearchLoop
897	jmp MBR_HaltSystem
898
899	; -------------------------------------------------------------- ENTRY FOUND
900	PSP_SearchMatch:
901	or byte ptr es:[di+LocBRPT_Flags], 80h ; set ACTIVE partition
902	IFDEF ReleaseCode
903	call DriveIO_SavePartition ; Saves the Partition-Table [SAVE]
904	ENDIF
905
906
907
908	; ---------------------------------------------------------- OS/2 / eCS I13X
909	; Now check if the partition to get booted is above 8 GB.
910	; If yes, set magic bytes 'I13X' at 3000:0 for boot-loader to recognize.
911	; This method is (c) by IBM <g>
912	; Rousseau: Booting IBM-BM also requires the LBA address of the IBM-BM
913	; partitionafter the 'I13X' signature.
914	; Also, FS needs to be set to 3000H.
915	; This info was obtained by examining the LVM 2,x MBR-code.
916	mov ax, wptr [si+LocIPT_AbsoluteBegin+0]
917	mov bx, wptr [si+LocIPT_AbsoluteBegin+2]
918	add ax, wptr es:[di+LocBRPT_AbsoluteLength+0] ; Add length to absolute
919	adc bx, wptr es:[di+LocBRPT_AbsoluteLength+2] ; begin location
920	; BX:AX -> Absolute End-Position of Partition
921
922	test CFG_ForceLBAUsage, 1
923	jnz PSP_ForceI13X
924	; LBA-boundary at 16450560 (FB0400h) (16320x16x63)
925	cmp bx, 00FBh
926	jb PSP_NoI13X
927
928
929	PSP_ForceI13X:
930	push es
931	push di
932	push si
933
934	; Setup ES and FS.
935	; FS needs to keep this address.
936	mov ax, 3000h
937	mov es, ax
938	; mov fs,ax
939	db 08eh
940	db 0e0h
941
942	; Insert signature
943	xor di, di
944	mov wptr es:[di+00], '1I'
945	mov wptr es:[di+02], 'X3'
946
947	;mov wptr es:[di], 0
948	;mov wptr es:[di+2], 0
949
950	; Insert LBA address.
951	mov ax, wptr [si+LocIPT_AbsoluteBegin+0]
952	mov wptr es:[di+04], ax
953	mov ax, wptr [si+LocIPT_AbsoluteBegin+2]
954	mov wptr es:[di+06], ax
955
956	pop si
957	pop di
958	pop es
959
960
961
962	PSP_NoI13X:
963
964	; now check, if we need to hide any partition
965	test byte ptr [si+LocIPT_Flags], Flags_HideFeature
966	jz PSP_NoHideFeature
967	; --------------------------------------------------------- PARTITION HIDING
968	push si
969	mov si, offset TXT_BootingHide
970	call MBR_Teletype ; display "hide active"
971	pop si
972	; First, find Hide-Config
973	mov dl, BootPartNo ; EntryNumber is straight view
974	mov ax, LocIPT_MaxPartitions
975	mul dl
976	mov di, offset HidePartitionTable
977	add di, ax ; We got the pointer
978	; So process Hide-Config. Read out Byte-Entries, each points to a partition
979	; 0FFh is end-marker / maximum entries = CFG_Partitions
980	mov cl, CFG_Partitions
981	PSP_PartitionsHideLoop:
982	mov dl, es:[di]
983	inc di
984	cmp dl, 0FFh
985	je PSP_EndOfHideProcess ; -> End of Hiding
986	call PART_HidePartition ; Now hide that partition
987	dec cl
988	jnz PSP_PartitionsHideLoop
989	PSP_EndOfHideProcess:
990	; --- HIDE COMPLETED ---
991	; So something got hidden and we have to remark a primary partition,
992	; if we are booting something non-primary from 1st hdd.
993	cmp bptr [si+LocIPT_Drive], 80h
994	ja PSP_HideAdjustPrimaryMark ; When booting any hdd, but 1st
995	mov ax, wptr [si+LocIPT_AbsolutePartTable]
996	mov bx, wptr [si+LocIPT_AbsolutePartTable+2]
997	or ax, ax
998	jnz PSP_HideAdjustPrimaryMark ; or booting non-primary partition
999	or bx, bx ; on 1st harddrive.
1000	jz PSP_NoHideAdjustPrimaryMark
1001	PSP_HideAdjustPrimaryMark:
1002	; Load Primary Partition Table...
1003	xor ax, ax
1004	xor bx, bx
1005	mov cx, 0001h ; Cylinder 0, Sector 1
1006	mov dx, 0080h ; First HD, Head 0
1007	; Load MBR
1008	call DriveIO_LoadPartition ; Load Primary Partition Table
1009	call PART_MarkFirstGoodPrimary
1010	IFDEF ReleaseCode
1011	; Save MBR
1012	call DriveIO_SavePartition ; Saves the Partition-Table
1013	ENDIF
1014	PSP_NoHideAdjustPrimaryMark:
1015
1016	PSP_NoHideFeature:
1017	; Check, if we are supposed to ignore LVM altogether...
1018	test [CFG_IgnoreLVM], 1
1019	jnz PSP_NoLVMReassignment
1020	; --------------------------------------------------------- LVM REASSIGNMENT
1021	; Driveletter must be set for this partition
1022	test byte ptr [si+LocIPT_Flags], Flags_DriveLetter
1023	jz PSP_NoLVMReassignment
1024	;movzx bx, BootPartNo ; EntryNumber is straight view
1025	mov bl,BootPartNo ; EntryNumber is straight view
1026	mov bh,0
1027
1028	mov al, bptr [DriveLetters+bx]
1029	sub al, 3Dh ; Convert e.g. 80h -> 'C'
1030	cmp al, bptr [PartitionVolumeLetters+bx]
1031	je PSP_NoLVMReassignment ; If driveletters match -> no change
1032	call LVM_DoLetterReassignment ; Give partition SI letter AL
1033	PSP_NoLVMReassignment:
1034	push si
1035	; ------------------------------------------------------- -"PLEASE WAIT..."-
1036	PSP_IsFloppyCDROMetc:
1037	mov si, offset TXT_BootingWait
1038	call MBR_Teletype ; display "please wait"
1039	pop si
1040
1041	; Process Partition Tables, if M$-Hack required (changes Ext Part Type)
1042	call MSHACK_ProcessPartTables
1043
1044	test CFG_BootMenuActive, 0FFh
1045	jz PSP_NoMenuNoSound
1046
1047	; --------------------------------------------------------------- BOOT-SOUND
1048	call SOUND_ExecuteBoot
1049	PSP_NoMenuNoSound:
1050
1051	; -------------------------------------------------- SPECIAL BOOT PROCESSING
1052	; Check here, if the Boot shall be done via resume to BIOS...
1053	mov al, bptr [si+LocIPT_SystemID]
1054	cmp al, 0FEh ; Via BIOS ? (aka resume BIOS boot sequence)
1055	je PSP_ResumeBIOSbootSeq
1056	; [Linux support removed since v1.02]
1057	; cmp al, 0FDh ; Kernel-Booting ?
1058	; je PSP_KernelBooting
1059	jmp PSP_StartNormal
1060
1061	PSP_ResumeBIOSbootSeq:
1062	int 18h ; Give control back to BIOS
1063	db 0EAh ; if return to here -> Reboot
1064	dw 0FFF0h
1065	dw 0F000h
1066
1067	; [Linux support removed since v1.02]
1068	; PSP_KernelBooting:
1069	; call LINUX_LoadKernel ; DS:SI - Entry Pointer to Kernel
1070	; db 0EAh ; if return to here -> Reboot
1071	; dw 0FFF0h
1072	; dw 0F000h
1073
1074	; =======================================================================
1075	; FROM THIS POINT ON, ONLY DS and SI REGISTER IS NEEDED TO BE PRESERVED
1076	; =======================================================================
1077
1078	PSP_StartNormal:
1079	mov ax, wptr [si+LocIPT_AbsoluteBegin+0]
1080	mov bx, wptr [si+LocIPT_AbsoluteBegin+2]
1081	mov cx, [si+LocIPT_LocationBegin+1]
1082	mov dh, [si+LocIPT_LocationBegin+0]
1083	mov dl, [si+LocIPT_Drive]
1084
1085	; This loads the PBR of the partition.
1086	call DriveIO_LoadPartition ; Loads boot-sector... [PARTBOOTSEC]
1087
1088	;
1089	; The JFS PBR-code does not use the passed BPB in memory but uses the BPB
1090	; on disk. This breaks the drive-letter feature on JFS.
1091	; So we make a copy of the PBR in memory, and if the partition is JFS
1092	; we later adjust the physical-disk and boot-drive-letter in this
1093	; copy and write it back to disk.
1094	; Then the JFS PBR-code will see the correct boot-drive-letter.
1095	;
1096	pusha
1097	mov si,offset PartitionSector
1098	mov di,offset JfsPBR
1099	mov cx,100h
1100	cld
1101	rep movsw
1102	popa
1103
1104
1105
1106	; Check if the disk is a harddisk or a floppy.
1107	mov dl,[si+LocIPT_Drive]
1108	cmp dl, 80h
1109	jae is_harddisk
1110
1111	;
1112	; This is a dirty hack to fix booting from a floppy.
1113	; With all the modifications made since v1.06 this feature was broken
1114	; because Int13X is used implicitly now, and that does not work
1115	; for diskette access.
1116	; This jumps to the code that loads and starts the pbr-code.
1117	; Note that it also skips virus checking !
1118	; This will be fixed at a later date.
1119	jmp boot_from_floppy
1120
1121
1122
1123
1124	;
1125	; The disk is a harddisk so we need to do various checks and fixes.
1126	;
1127	is_harddisk:
1128
1129	test CFG_DetectVIBR, 1
1130	jz PSP_NoVIBR
1131	test byte ptr [si+LocIPT_Flags], Flags_VIBR_Detection
1132	jz PSP_NoVIBR
1133	; ---------------------------------------------------------- CHECKS FOR VIBR
1134	push si
1135	mov si, offset PartitionSector
1136	mov bx, 4B4Dh ; Magic: 'MK'
1137	call MBR_GetCheckOfSector
1138	pop si
1139	cmp [si+LocIPT_BootRecordCRC], bx
1140	je PSP_NoVIBR
1141	mov bx, [si+LocIPT_BootRecordCRC]
1142	or bx, bx
1143	jz PSP_NoVIBR
1144	; Oh Oh, got a virus :(
1145	mov si, offset TXT_VirusFoundMain
1146	call MBR_Teletype
1147	mov si, offset TXT_VirusFound2 ; VIBR-Virus
1148	call MBR_Teletype
1149	mov si, offset TXT_VirusFoundEnd
1150	call MBR_Teletype
1151	jmp MBR_HaltSystem
1152
1153	PSP_NoVIBR:
1154	test CFG_ProtectMBR, 1
1155	jz PSP_NoMBRprotect
1156	; -------------------------------------------------- INSTALLS MBR-PROTECTION
1157	; We need DS:SI later...
1158	push ds
1159	push si
1160	; First subtract 1024 bytes from Base-Memory...
1161	push ds
1162	mov ax, 40h
1163	mov ds, ax
1164	mov dx, word ptr ds:[13h]
1165	dec dx ; 1 == 1kbyte
1166	mov word ptr ds:[13h], dx
1167	pop ds
1168	shl dx, 6 ; trick, now DX is a segment
1169
1170	; Now copy in our code (to DX:0)...
1171
1172	mov si, offset MBR_Protection ; DS:SI - Source Image
1173	mov es, dx
1174	xor di, di ; ES:DI - Destination
1175	mov cx, 512
1176	rep movsw ; Move 1024 bytes...
1177
1178	; Now fill in variables...
1179
1180	xor ax, ax
1181	mov ds, ax
1182	mov si, 10h*4
1183	xor di, di ; INT 10h Vector to MBR Protection
1184	;movsd
1185	movsw
1186	movsw
1187
1188	mov si, 13h*4 ; INT 13h Vector to MBR Protection
1189	;movsd
1190	movsw
1191	movsw
1192
1193	mov al, CFG_IgnoreWriteToMBR ; Option to MBR Protection
1194	stosb
1195
1196	; Now switch INT 13h vector to MBR Protection
1197
1198	sub si, 4
1199	mov ax, 9
1200	mov ds:[si], ax
1201	mov ds:[si+2], dx ; Vector hardcoded at DS:0009
1202	; MBR-Protection now active :)
1203	; Restore DS:SI
1204	pop si
1205	pop ds
1206
1207
1208
1209
1210
1211
1212
1213	PSP_NoMBRprotect:
1214
1215	; Display volume-name in bold
1216	; Just before booting the selected partition
1217	;pushf
1218	;pusha
1219	;push si
1220	;add si, LocIPT_Name
1221	;call MBR_TeletypeVolName
1222	;xor si,si
1223	;call MBR_TeletypeNL
1224	;pop si
1225	;popa
1226	;popf
1227
1228
1229
1230
1231
1232	; ------------------------------------------------ SPECIAL PARTITION SUPPORT
1233	; needed by OS/2 Warp / eComStation
1234
1235
1236	;cmp byte ptr [si+LocIPT_SystemID],08 ; I hate Microsuck NTFS check
1237	mov di, offset PartitionSector ; ES:DI - Actual Boot-Record
1238
1239	; Special Support Detection
1240	;mov ax, word ptr es:[di+18h]
1241	;cmp ax, 003Fh ; Physical Layout-Sectors... Safety check
1242
1243
1244
1245	;
1246	; At this point, SI points to IPT and DI points to the PBR from disk.
1247	; Depending on the type of BPB used, the physical disk field is at
1248	; different locations: 24h for old-style (OS/2) BPB's and 40h for
1249	; FAT32 BPB's.
1250	; The OS/2 boot-drive-letter is located at 25h in an old-style BPB,
1251	; while the corresponding field in a FAT32 BPB is located at 41h but
1252	; used for different purposes.
1253	; In case of HPFS, using old-style BPB's, the boot-drive-letter needs
1254	; to be adjusted if it is zero.
1255	; In that case we trace the LVM-info for that partition and use the
1256	; drive-letter defined there.
1257	; This fixes issues #3067 and #3119.
1258	; Adjusting the physical disk is always done but at different locations
1259	; depending on the BPB used.
1260	; Also, the "hidden sectors" field is adjusted to contain the absolute
1261	; offset from the start of the disk instead of the relative offset to
1262	; the start of the partition.
1263	; http://homepage.ntlworld.com./jonathan.deboynepollard/FGA/bios-parameter-block.html
1264	;
1265
1266
1267	; Get index of phys-disk field in BX
1268	call PART_GetFieldIndex
1269	mov PhysDiskBpbIndex,ax
1270	mov bx,ax
1271
1272	; Locate cursor for output of debug-info
1273	pusha
1274	mov ch,7
1275	mov cl,0
1276	call VideoIO_Color
1277	mov ch,6
1278	mov cl,1
1279	call VideoIO_Locate
1280	popa
1281
1282	; Debug display physdisk, ptype and physdisk offset in BPB
1283	pusha
1284	mov ah,[si+LocIPT_Drive]
1285	mov al,[si+LocIPT_SystemID]
1286	call VideoIO_PrintHexWord
1287	mov ax,bx
1288	call VideoIO_PrintHexWord
1289	mov ax,[si+LocIPT_AbsolutePartTable+02]
1290	call VideoIO_PrintHexWord
1291	mov ax,[si+LocIPT_AbsolutePartTable+00]
1292	call VideoIO_PrintHexWord
1293	mov al,[ExtendedAbsPosSet]
1294	call VideoIO_PrintHexByte
1295	popa
1296
1297
1298	;
1299	; If the partition is IBM-BM we skip all the BPB adjustments.
1300	; IBM-BM does no need them.
1301	;
1302	cmp byte ptr [si+LocIPT_SystemID], 0ah
1303	jnz no_os2_bm
1304	jmp chainload_ibm_bm
1305
1306
1307	no_os2_bm:
1308
1309	;
1310	; Update the phys-disk field
1311	; DI points to PartitionSector
1312	; BX holds index to phys-disk field
1313	;
1314	mov al,byte ptr [si+LocIPT_Drive]
1315	mov es:[di+bx],al
1316
1317
1318	;
1319	; Legacy systems do not put the correct values in the "hidden sectors"
1320	; field. Also, this field will be incorrect if a partition is moved on
1321	; disk by a disktool not accounting for this field.
1322	; Linux does not have a BPB at all, and does not use this field.
1323	; So we set the correct value here obtained by the partition scanner.
1324	; This fixing is done by OS/2 BM as well, according to Martin.
1325	;
1326
1327	;
1328	; Fix hidden sectors field
1329	;
1330
1331	; Low word of 32-bits "hidden sectors"
1332	mov ax,[si+LocIPT_AbsoluteBegin]
1333	mov es:[di+1ch], ax
1334	; High word of 32-bits "hidden sectors"
1335	mov ax,[si+LocIPT_AbsoluteBegin+2]
1336	mov es:[di+1eh], ax
1337
1338
1339
1340
1341
1342	;
1343	; Check partitions to see if boot-drive-letter fixing is needed.
1344	; FAT12/FAT16/HPFS/JFS will have the value at 25h fixed
1345	; to the LVM-info drive-letter. (+3dh to convert to BIOS notation)
1346	;
1347
1348
1349	; Setup partition disk and LBA address
1350	mov dl,byte ptr [si+LocIPT_Drive]
1351	mov cx,[si+LocIPT_AbsoluteBegin+00h]
1352	mov bx,[si+LocIPT_AbsoluteBegin+02h]
1353
1354	; AL is gonna be used to shift-in CY status.
1355	; If the type of file-system is one of FAT12/FAT16/HPFS/JFS then
1356	; AL will be <> 0 and the boot-drive-letter can be tested / fixed.
1357	mov al,0
1358
1359
1360	; FIXME:
1361	; The PBR is already loaded, no need to load it again in the
1362	; calls below.
1363	;
1364	; Better use the already done discovery to determine the system.
1365	;
1366
1367	; When FAT12/FAT16/HPFS/JFS then boot-drive-letter can be tested
1368	; or adjusted.
1369	call PART_IsJFS
1370	rcl al,1
1371	call PART_IsHPFS
1372	rcl al,1
1373	call PART_IsFAT
1374	rcl al,1
1375	mov ah,al
1376
1377	; Store for later reference.
1378	mov [FSType],al
1379
1380
1381	;
1382	; When the phys-disk byte (80h) is put in this BPB in RAM,
1383	; Windows will not find it's loader if Windows itself
1384	; is installed in a logical partition but the loader is on FAT
1385	; in a primary.
1386	; This goes for all NT-based versions ?
1387	;
1388
1389
1390	;
1391	; See if phys-disk / boot-drive-letter fix is needed
1392	; depending on FS used.
1393	; AL will be 0 for any file-system other than FAT12/FAT16/HPFS/JFS.
1394	;
1395	test al,al
1396	jz bdl_ok
1397
1398
1399
1400	; Check if the boot-drive-letter is non-zero.
1401	mov bx,PhysDiskBpbIndex
1402	inc bx
1403	mov al,es:[di+bx]
1404	test al,al
1405	; Non-zero, so no fixing needed.
1406	;jnz bdl_ok ;; Why not always fix ? (so, jnz disabled)
1407
1408
1409	;
1410	; Always fix boot-drive-letter on FAT12/FAT16/HPFS/JFS
1411	;
1412
1413	; Get the drive-letter for the partition from the LVM-info.
1414	mov dl,byte ptr [si+LocIPT_Drive]
1415	mov cx,[si+LocIPT_AbsoluteBegin+00h]
1416	mov bx,[si+LocIPT_AbsoluteBegin+02h]
1417	call LVM_GetDriveLetter
1418
1419	; Save the status for later use
1420	pushf
1421
1422	; See if the drive-letter feature is active.
1423	; If active, we force the drive-letter from the user.
1424	test byte ptr [si+LocIPT_Flags], Flags_DriveLetter
1425
1426	; Nope, it's not so we don't force the boot-drive-letter
1427	; using field 25h.
1428	jz PSP_NoLogicalSupport
1429
1430	; Partition index in BX
1431	mov bl,BootPartNo ; EntryNumber is straight view
1432	mov bh,0
1433
1434	; Pointer to the user specified boot-drive
1435	; Get it and convert to ASCII letter
1436	mov al, bptr [DriveLetters+bx]
1437	sub al,3dh ; Convert BIOS notation to ASCII drive-letter
1438
1439
1440
1441	PSP_NoLogicalSupport:
1442
1443	; Drive letter is LVM obtained or user-forced.
1444	; Save it in AH.
1445	mov ah,al
1446
1447
1448	; Restore the status whether an LVM drive-letter could be obtained
1449	popf
1450
1451
1452	;
1453	; No valid LVM-info if no info found or drive-letter is zero.
1454	;
1455	jnc no_valid_lvm_info
1456	test al,al
1457	jz no_valid_lvm_info
1458
1459
1460	;
1461	; We have found a valid drive-letter in the LVM-info.
1462	;
1463
1464	; Convert to BIOS notation ('C'+3dh=80h, 'D'->81h, etc.)
1465	add al,3dh
1466
1467
1468	;
1469	; OS/2 uses this field to indicate the boot-drive-letter for the system.
1470	; It is in BIOS notation where 80h='C', 81h='D' ... 97h='Z'.
1471	; This is the field that get's forced to a specific value when the
1472	; drive-letter feature of AiR-BOOT is used.
1473	; Also, this field is the culprit of AiR-BOOT v1.07 not handling it
1474	; correctly when the system uses HPFS and this byte is zero.
1475	; This mostly involved booting older eCS versions on HPFS.
1476	; See issues #3067 and #3119 on http://bugs.ecomstation.nl
1477	;
1478
1479
1480	; Fix the boot-drive-letter field in the BPB
1481	mov bx,PhysDiskBpbIndex
1482	; Advance to field for drive-letter in BIOS notation (OS/2 - eCS)
1483	inc bx
1484	mov es:[di+bx],al
1485
1486
1487	jmp bdl_ok
1488
1489
1490	no_valid_lvm_info:
1491	; HERE SHOULD COME AN ERROR POP-UP ABOUT NO BOOT-DRIVE OR NO LVM-INFO.
1492	; WE CONTINUE BOOTING BUT OS/2 - eCS WILL MOST PROBABLY FAIL TO BOOT.
1493
1494	;mov ah,07h
1495	;mov si,offset CheckID_MBR
1496	;call VideoIO_Print
1497
1498	hang:
1499	;jmp hang
1500
1501
1502	;
1503	; Boot DriveLetter OK.
1504	;
1505	bdl_ok:
1506
1507
1508	;
1509	; If the partition getting booted is a JFS partition then write-back
1510	; the modified PBR to the disk.
1511	; Note that it's not the in-memory PBR that get's written back, but
1512	; a copy of the original where only the phys-disk and boot-drive-letter
1513	; are adjusted.
1514	;
1515	pusha
1516	mov al,[FSType]
1517	cmp al,04h ; JFS
1518	jnz no_jfs_pbr
1519
1520	; Save IPT pointer
1521	push si
1522
1523	; Copy the boot-drive and boot-drive-letter fields.
1524	mov si,offset PartitionSector
1525	mov di,offset JfsPBR
1526	mov al,[si+24h]
1527	mov [di+24h],al
1528	mov al,[si+25h]
1529	mov [di+25h],al
1530
1531	; Restore IPT pointer
1532	pop si
1533
1534	; Setup the registers for the partition location.
1535	mov ax, wptr [si+LocIPT_AbsoluteBegin+0]
1536	mov bx, wptr [si+LocIPT_AbsoluteBegin+2]
1537	mov cx, [si+LocIPT_LocationBegin+1]
1538	mov dh, [si+LocIPT_LocationBegin+0]
1539	mov dl, [si+LocIPT_Drive]
1540
1541	; Write the adjusted JFS PBR to disk.
1542	mov si, offset JfsPBR
1543	call DriveIO_SaveSector
1544
1545	no_jfs_pbr:
1546	popa
1547
1548
1549	;xor ax,ax
1550	;int 16h
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568	; ----------------------------------------------- LOGICAL PARTITION SUPPORT
1569
1570
1571
1572	; AiR-BOOT now works around it by using the LVM-info (DLAT) of
1573	; the partiton if present.
1574	; Note however that if the drive-letter feature is active,
1575	; this will override AB's automatic fixing.
1576	;
1577	; Test if the drive-letter feature is active for this partition.
1578	; If so, then the drive that the user defined will be placed at
1579	; byte 25h (37d) of the in-ram PartitionSector (BPB).
1580	; (BIOS 80h notation: 80h=C, 81h=D, etc.)
1581	; This is a remedy for when the corresponding field (25h) in the BPB on
1582	; disk is zero.
1583	;
1584
1585
1586
1587	;
1588	; Control is transferred to this point if we are booting IBM-BM.
1589	; IBM-BM does not need the BPB fixes.
1590	; It does require a other special stuff, which is already taken care of.
1591	;
1592	chainload_ibm_bm:
1593
1594	;
1595	; Control is transferred to this point if we are booting a floppy.
1596	; Booting from floppy skips all the harddisk related stuff.
1597	; This is a dirty hack to fix the boot from floppy feature.
1598	;
1599	boot_from_floppy:
1600
1601	;
1602	; Here we copy the prepared partition boot-record to 0000:7C00h
1603	; to give it control later on.
1604	;
1605	push es
1606	push si
1607	mov ax, StartBaseSeg
1608	mov es, ax
1609	mov cx, 256
1610	mov si, offset PartitionSector
1611	mov di, StartBasePtr
1612	cld
1613	rep movsw
1614	pop si
1615	pop es
1616
1617	; --------------------------------------------------- NOW START BOOT-RECORD
1618
1619
1620
1621
1622	IFDEF AUX_DEBUG
1623	call DEBUG_Dump2
1624	call DEBUG_DumpBSSSectors
1625	ENDIF
1626
1627
1628
1629	;
1630	; ################################## BYE BYE ##################################
1631	;
1632
1633	; Skip wait-for-key
1634	jmp start_pbr
1635
1636	;
1637	; Wait for keypress
1638	;
1639	xor ax, ax
1640	int 16h
1641
1642	; Is escape-key ?
1643	cmp al, 1bh
1644
1645	; Nope, Go activate PBR loader
1646	jne start_pbr
1647
1648	;xor ax,ax
1649	;mov [CurPartition_Location+00],ax
1650	;mov [CurPartition_Location+02],ax
1651	;mov [CurPartition_Location+04],ax
1652	;mov [CurPartition_Location+06],ax
1653
1654	;pusha
1655	;xor al,al
1656	;mov di,si
1657	;add di,LocIPT_Name
1658	;mov cx,12
1659	;cld
1660	;rep stosb
1661	;popa
1662
1663
1664	;push ds
1665	;pop es
1666
1667	; Yep, Reenter bootmenu
1668	jmp MBR_Main_ReEnterBootMenuPre
1669
1670
1671
1672	;
1673	; Transfer control to the PBR
1674	;
1675	start_pbr:
1676
1677	; Debug display index
1678	;pusha
1679	;mov al, cs:[si+LocIPT_Drive] ; Drive Physical No
1680	;mov ah, cs:[si+LocIPT_SystemID] ; SystemID
1681	;call VideoIO_PrintHexWord
1682	;xor ax, ax
1683	;int 16h
1684	;popa
1685
1686	;~ jmp skip_delay
1687
1688
1689	;
1690	; Show "wait dots"
1691	;
1692	pusha
1693	; Color white on black
1694	mov ch,7
1695	mov cl,0
1696	call VideoIO_Color
1697	; Locate cursor for output of debug-info
1698	mov ch,8
1699	mov cl,1
1700	call VideoIO_Locate
1701
1702	; Print dots with interval.
1703	mov cx,10
1704	print_next_dot:
1705	mov al,'.'
1706	call VideoIO_PrintSingleChar
1707	; Value 30 is about 1.5 seconds
1708	mov al,1
1709	call TIMER_WaitTicCount
1710	loop print_next_dot
1711	popa
1712
1713	;
1714	; Enter here to skip delay.
1715	;
1716	skip_delay:
1717
1718
1719
1720	;
1721	; BYE BYE
1722	;
1723	xor ax, ax
1724	xor bx, bx
1725	xor cx, cx
1726	mov ds, ax
1727	mov es, ax
1728	xor dh, dh
1729	mov dl, cs:[si+LocIPT_Drive] ; Drive Physical No
1730
1731
1732
1733	;
1734	; JUMP TO PBR loader
1735	;
1736	IFDEF ReleaseCode
1737	db 0EAh
1738	dw StartBasePtr
1739	dw StartBaseSeg
1740	ENDIF
1741
1742
1743	PART_StartPartition EndP
1744
1745
1746	;
1747	; ######################################
1748	; # Is this a primary partition or not #
1749	; ######################################
1750	;
1751	; In
1752	; --
1753	; DL = Physical Disk
1754	; BX:CX = LBA sector
1755	;
1756	; Out
1757	; ---
1758	; AX = Index in PT if found, otherwise -1
1759	; CY = Set if Primary, clear if not
1760	;
1761	PART_IsPrimaryPartition Proc Near Uses bx cx dx si di ds es
1762	; Push LBA address of partition
1763	push bx
1764	push cx
1765
1766	; Load LBA sector 0 from the disk specified in DL
1767	xor bx,bx
1768	xor cx,cx
1769	mov di,ds
1770	mov si,offset [TmpSector]
1771	call DriveIO_LoadSectorLBA
1772
1773	; Restore partitions LBA address to DI:SI
1774	pop si
1775	pop di
1776
1777	; Return with index -1 and CY clear if there was an
1778	; error loading the sector.
1779	mov ax,-1
1780	cmc
1781	jnc PART_IsPrimaryPartition_exit
1782
1783	; Compare the partition address with each entry in the P-table
1784	mov cx,4 ; Nr. of PT-entries
1785	mov dx,offset [TmpSector]
1786	add dx,01beh+08h ; Point DX to 1st partition address
1787
1788	next_pe:
1789	; Computer pointer to PE
1790	mov bx,dx ; Point BX to 1st partition address
1791	mov ax,cx ; Get PE-index
1792	dec ax ; Index is zero based so adjust it
1793	shl ax,4 ; PE's are 16 bytes in size
1794	add bx,ax ; Make BX point to the PE
1795
1796	; Compare LBA address
1797	push si
1798	push di
1799	xor si,[bx+00h] ; Will put 0 in SI if the same
1800	xor di,[bx+02h] ; Will put 0 in DI if the same
1801	or si,di ; Wil set ZF if both zero
1802	pop di
1803	pop si
1804	loopnz next_pe ; Try next entry if non-zero
1805
1806	; Partition found or counter exhausted
1807	mov ax,-1
1808	clc
1809	; Not found, so exit with NC and invalid index
1810	jnz PART_IsPrimaryPartition_exit
1811
1812	; Partition is Primary, set CY and return index
1813	mov ax,cx
1814	stc
1815
1816	PART_IsPrimaryPartition_exit:
1817	ret
1818	PART_IsPrimaryPartition Endp
1819
1820
1821
1822	;
1823	; #############################
1824	; # Is this an HPFS partition #
1825	; #############################
1826	;
1827	; In
1828	; --
1829	; DL = Physical Disk
1830	; BX:CX = LBA sector
1831	;
1832	; Out
1833	; ---
1834	; CY = Set if HPFS partition, clear if not
1835	;
1836	PART_IsHPFS Proc Near Uses ax bx cx dx si di ds es
1837
1838	; Load specified LBA sector (BX:CX) from the disk in DL
1839	mov di,ds
1840	mov si,offset [TmpSector]
1841	call DriveIO_LoadSectorLBA
1842
1843	; Point to location of 'HPFS ' identifier.
1844	add si,36h
1845
1846	; DL holds equality status
1847	xor dl,dl
1848	cld
1849
1850	; Load letter into AL, xor with letter will result 0 if the same.
1851	; Then or to DL.
1852	; If at the end of the sequence DL is zero, the signature is present.
1853	lodsb
1854	xor al,'H'
1855	or dl,al
1856	lodsb
1857	xor al,'P'
1858	or dl,al
1859	lodsb
1860	xor al,'F'
1861	or dl,al
1862	lodsb
1863	xor al,'S'
1864	or dl,al
1865	lodsb
1866	xor al,' '
1867	or dl,al
1868	lodsb
1869	xor al,' '
1870	or dl,al
1871	lodsb
1872	xor al,' '
1873	or dl,al
1874	lodsb
1875	xor al,' '
1876	or dl,al
1877
1878	; Assume not present
1879	clc
1880	jnz PART_IsHPFS_exit
1881
1882	; JFS signature found
1883	stc
1884
1885	PART_IsHPFS_exit:
1886	ret
1887	PART_IsHPFS Endp
1888
1889
1890	;
1891	; ###########################
1892	; # Is this a JFS partition #
1893	; ###########################
1894	;
1895	; In
1896	; --
1897	; DL = Physical Disk
1898	; BX:CX = LBA sector
1899	;
1900	; Out
1901	; ---
1902	; CY = Set if JFS partition, clear if not
1903	;
1904	PART_IsJFS Proc Near Uses ax bx cx dx si di ds es
1905
1906	; Load specified LBA sector (BX:CX) from the disk in DL
1907	mov di,ds
1908	mov si,offset [TmpSector]
1909	call DriveIO_LoadSectorLBA
1910
1911	; Point to location of 'JFS ' identifier.
1912	add si,36h
1913
1914	; DL holds equality status
1915	xor dl,dl
1916	cld
1917
1918	; Load letter into AL, xor with letter will result 0 if the same.
1919	; Then or to DL.
1920	; If at the end of the sequence DL is zero, the signature is present.
1921	lodsb
1922	xor al,'J'
1923	or dl,al
1924	lodsb
1925	xor al,'F'
1926	or dl,al
1927	lodsb
1928	xor al,'S'
1929	or dl,al
1930	lodsb
1931	xor al,' '
1932	or dl,al
1933	lodsb
1934	xor al,' '
1935	or dl,al
1936	lodsb
1937	xor al,' '
1938	or dl,al
1939	lodsb
1940	xor al,' '
1941	or dl,al
1942	lodsb
1943	xor al,' '
1944	or dl,al
1945
1946	; Assume not present
1947	clc
1948	jnz PART_IsJFS_exit
1949
1950	; JFS signature found
1951	stc
1952
1953	PART_IsJFS_exit:
1954	ret
1955	PART_IsJFS Endp
1956
1957
1958
1959	;
1960	; ######################################
1961	; # Is this a FAT12 or FAT16 partition #
1962	; ######################################
1963	;
1964	; In
1965	; --
1966	; DL = Physical Disk
1967	; BX:CX = LBA sector
1968	;
1969	; Out
1970	; ---
1971	; CY = Set if FAT12 or FAT16 partition, clear if not
1972	;
1973	; This can be a FAT12 or FAT16 partition.
1974	; When OS/2 formats volume with FAT it does not use the FAT16 identifier,
1975	; but uses the FAT identifier.
1976	;
1977	PART_IsFAT Proc Near Uses ax bx cx dx si di ds es
1978
1979	; First see if this is a FAT32 partition.
1980	; If it is, exit with NC indicating not FAT12 or FAT16.
1981	call PART_IsFAT32
1982	cmc
1983	jnc PART_IsFAT_exit
1984
1985	; Load specified LBA sector (BX:CX) from the disk in DL
1986	mov di,ds
1987	mov si,offset [TmpSector]
1988	call DriveIO_LoadSectorLBA
1989
1990	; Point to location of 'FAT ' identifier.
1991	add si,36h
1992
1993	; DL holds equality status
1994	xor dl,dl
1995	cld
1996
1997	; Load letter into AL, xor with letter will result 0 if the same.
1998	; Then or to DL.
1999	; If at the end of the sequence DL is zero, the signature is present.
2000	lodsb
2001	xor al,'F'
2002	or dl,al
2003	lodsb
2004	xor al,'A'
2005	or dl,al
2006	lodsb
2007	xor al,'T'
2008	or dl,al
2009	lodsb
2010
2011	; Since OS/2 formats FAT volumes with an identifier of 'FAT ',
2012	; and others with 'FAT16 ', we skip two bytes for comparison.
2013	; The rest must be spaces however.
2014	; xor al,' '
2015	; or dl,al
2016	lodsb
2017	; xor al,' '
2018	; or dl,al
2019
2020	lodsb
2021	xor al,' '
2022	or dl,al
2023	lodsb
2024	xor al,' '
2025	or dl,al
2026	lodsb
2027	xor al,' '
2028	or dl,al
2029
2030	; Assume not present
2031	clc
2032	jnz PART_IsFAT_exit
2033
2034	; FAT signature found
2035	stc
2036
2037	PART_IsFAT_exit:
2038	ret
2039	PART_IsFAT Endp
2040
2041
2042	;
2043	; #############################
2044	; # Is this a FAT32 partition #
2045	; #############################
2046	;
2047	; In
2048	; --
2049	; DL = Physical Disk
2050	; BX:CX = LBA sector
2051	;
2052	; Out
2053	; ---
2054	; CY = Set if FAT32 partition, clear if not
2055	;
2056	PART_IsFAT32 Proc Near Uses ax bx cx dx si di ds es
2057
2058	; Load specified LBA sector (BX:CX) from the disk in DL
2059	mov di,ds
2060	mov si,offset [TmpSector]
2061	call DriveIO_LoadSectorLBA
2062
2063	; Point to location of 'FAT32 ' identifier.
2064	add si,52h
2065
2066	; DL holds equality status
2067	xor dl,dl
2068	cld
2069
2070	; Load letter into AL, xor with letter will result 0 if the same.
2071	; Then or to DL.
2072	; If at the end of the sequence DL is zero, the signature is present.
2073	lodsb
2074	xor al,'F'
2075	or dl,al
2076	lodsb
2077	xor al,'A'
2078	or dl,al
2079	lodsb
2080	xor al,'T'
2081	or dl,al
2082	lodsb
2083	xor al,'3'
2084	or dl,al
2085	lodsb
2086	xor al,'2'
2087	or dl,al
2088	lodsb
2089	xor al,' '
2090	or dl,al
2091	lodsb
2092	xor al,' '
2093	or dl,al
2094	lodsb
2095	xor al,' '
2096	or dl,al
2097
2098	; Assume not present
2099	clc
2100	jnz PART_IsFAT32_exit
2101
2102	; FAT32 signature found
2103	stc
2104
2105	PART_IsFAT32_exit:
2106	ret
2107	PART_IsFAT32 Endp
2108
2109
2110
2111	;
2112	; ##############################################################
2113	; # Does this partition have the Windows BootManager installed #
2114	; ##############################################################
2115	;
2116	; In
2117	; --
2118	; DL = Physical Disk
2119	; BX:CX = LBA sector
2120	;
2121	; Out
2122	; ---
2123	; CY = Set if BOOTMGR found, clear if not
2124	;
2125	;PART_IsWinBMGR Proc Near Uses ax bx cx dx si di ds es
2126	;
2127	; ; Load specified LBA sector (BX:CX) from the disk in DL
2128	; mov di,ds
2129	; mov si,offset [TmpSector]
2130	; call DriveIO_LoadSectorLBA
2131
2132	; ; Point to location of 'BOOTMGR' signature.
2133	; add si,169h
2134
2135	; ; DL holds equality status
2136	; xor dl,dl
2137	; cld
2138
2139	; ; Load letter into AL, xor with letter will result 0 if the same.
2140	; ; Then or to DL.
2141	; ; If at the end of the sequence DL is zero, the signature is present.
2142	; lodsb
2143	; xor al,'B'
2144	; or dl,al
2145	; lodsb
2146	; xor al,'O'
2147	; or dl,al
2148	; lodsb
2149	; xor al,'O'
2150	; or dl,al
2151	; lodsb
2152	; xor al,'T'
2153	; or dl,al
2154	; lodsb
2155	; xor al,'M'
2156	; or dl,al
2157	; lodsb
2158	; xor al,'G'
2159	; or dl,al
2160	; lodsb
2161	; xor al,'R'
2162	; or dl,al
2163
2164	; ; Assume not present
2165	; clc
2166	; jnz PART_IsWinBMGR_exit
2167
2168	; ; BOOTMGR signature found
2169	; stc
2170
2171	; PART_IsWinBMGR_exit:
2172	; ret
2173	;PART_IsWinBMGR Endp
2174
2175
2176	;
2177	; ##########################################################
2178	; # Get the offset of the phys-disk field in the PBR (BPB) #
2179	; ##########################################################
2180	;
2181	; In
2182	; --
2183	; DS:SI = IPT
2184	;
2185	; Out
2186	; ---
2187	; AX = Index in PBR for phys-disk field
2188	;
2189	PART_GetFieldIndex Proc Near uses bx cx dx
2190	; Check for FAT32 partition
2191	mov dl,bptr [si+LocIPT_Drive]
2192	mov cx,[si+LocIPT_AbsoluteBegin+00h]
2193	mov bx,[si+LocIPT_AbsoluteBegin+02h]
2194	call PART_IsFAT32
2195	mov ax,24h ; Offset in old-style BPB
2196	jnc PART_GetFieldIndex_exit
2197	mov ax,40h ; Offset in FAT32 BPB
2198	PART_GetFieldIndex_exit:
2199	ret
2200	PART_GetFieldIndex EndP

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