Diff of /trunk/mkinitrd-magellan/isolinux/isolinux.asm

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	revision 1132 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 1133 by niro, Thu Aug 19 09:50:43 2010 UTC
#	Line 1	Line 1
1	; -*- fundamental -*- (asm-mode sucks)	; -*- fundamental -*- (asm-mode sucks)
	; $Id: isolinux.asm,v 1.1 2007-09-01 22:44:04 niro Exp $
2	; ****************************************************************************	; ****************************************************************************
3	;	;
4	;  isolinux.asm	;  isolinux.asm
#	Line 9	Line 8
8	;  available.  It is based on the SYSLINUX boot loader for MS-DOS	;  available.  It is based on the SYSLINUX boot loader for MS-DOS
9	;  floppies.	;  floppies.
10	;	;
11	;   Copyright (C) 1994-2005  H. Peter Anvin	;   Copyright 1994-2009 H. Peter Anvin - All Rights Reserved
12		;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
13	;	;
14	;  This program is free software; you can redistribute it and/or modify	;  This program is free software; you can redistribute it and/or modify
15	;  it under the terms of the GNU General Public License as published by	;  it under the terms of the GNU General Public License as published by
#	Line 20	Line 20
20	; ****************************************************************************	; ****************************************************************************
21
22	%define IS_ISOLINUX 1	%define IS_ISOLINUX 1
23	%include "macros.inc"	%include "head.inc"
	%include "config.inc"
	%include "kernel.inc"
	%include "bios.inc"
	%include "tracers.inc"
	%include "layout.inc"
24
25	;	;
26	; Some semi-configurable constants... change on your own risk.	; Some semi-configurable constants... change on your own risk.
#	Line 42  MAX_OPEN equ (1 << MAX_OPEN_LG2)	Line 37  MAX_OPEN equ (1 << MAX_OPEN_LG2)
37	SECTOR_SHIFT equ 11 ; 2048 bytes/sector (El Torito requirement)	SECTOR_SHIFT equ 11 ; 2048 bytes/sector (El Torito requirement)
38	SECTOR_SIZE equ (1 << SECTOR_SHIFT)	SECTOR_SIZE equ (1 << SECTOR_SHIFT)
39
40	;	ROOT_DIR_WORD equ 0x002F
	; This is what we need to do when idle
	;
	%macro RESET_IDLE 0
	; Nothing
	%endmacro
	%macro DO_IDLE 0
	; Nothing
	%endmacro
41
42	;	;
43	; The following structure is used for "virtual kernels"; i.e. LILO-style	; The following structure is used for "virtual kernels"; i.e. LILO-style
44	; option labels.  The options we permit here are `kernel' and `append	; option labels.  The options we permit here are `kernel' and `append
45	; Since there is no room in the bottom 64K for all of these, we	; Since there is no room in the bottom 64K for all of these, we
46	; stick them at vk_seg:0000 and copy them down before we need them.	; stick them in high memory and copy them down before we need them.
47	;	;
48	struc vkernel	struc vkernel
49	vk_vname: resb FILENAME_MAX ; Virtual name **MUST BE FIRST!**	vk_vname: resb FILENAME_MAX ; Virtual name **MUST BE FIRST!**
50	vk_rname: resb FILENAME_MAX ; Real name	vk_rname: resb FILENAME_MAX ; Real name
51	vk_appendlen: resw 1	vk_appendlen: resw 1
52		vk_type: resb 1 ; Type of file
53	alignb 4	alignb 4
54	vk_append: resb max_cmd_len+1 ; Command line	vk_append: resb max_cmd_len+1 ; Command line
55	alignb 4	alignb 4
#	Line 69  vk_end: equ $ ; Should be <= vk_size	Line 57  vk_end: equ $ ; Should be <= vk_size
57	endstruc	endstruc
58
59	;	;
	; Segment assignments in the bottom 640K
	; 0000h - main code/data segment (and BIOS segment)
	;
	real_mode_seg equ 3000h
	vk_seg          equ 2000h ; Virtual kernels
	xfer_buf_seg equ 1000h ; Bounce buffer for I/O to high mem
	comboot_seg equ real_mode_seg ; COMBOOT image loading zone
	;
60	; File structure.  This holds the information for each currently open file.	; File structure.  This holds the information for each currently open file.
61	;	;
62	struc open_file_t	struc open_file_t
63	file_sector resd 1 ; Sector pointer (0 = structure free)	file_sector resd 1 ; Sector pointer (0 = structure free)
64		file_bytesleft resd 1 ; Number of bytes left
65	file_left resd 1 ; Number of sectors left	file_left resd 1 ; Number of sectors left
66		resd 1 ; Unused
67	endstruc	endstruc
68
69	%ifndef DEPEND	%ifndef DEPEND
#	Line 107  dir_clust resd 1 ; Length in clusters	Line 88  dir_clust resd 1 ; Length in clusters
88	section .earlybss	section .earlybss
89	trackbufsize equ 8192	trackbufsize equ 8192
90	trackbuf resb trackbufsize ; Track buffer goes here	trackbuf resb trackbufsize ; Track buffer goes here
91	getcbuf resb trackbufsize	; ends at 2800h
	; ends at 4800h
92
93	section .bss	; Some of these are touched before the whole image
94		; is loaded.  DO NOT move this to .uibss.
95		section .bss2
96	alignb 4	alignb 4
97	ISOFileName resb 64 ; ISO filename canonicalization buffer	ISOFileName resb 64 ; ISO filename canonicalization buffer
98	ISOFileNameEnd equ $	ISOFileNameEnd equ $
99	CurDir resb dir_t_size ; Current directory	CurrentDir resb dir_t_size ; Current directory
100	RootDir resb dir_t_size ; Root directory	RootDir resb dir_t_size ; Root directory
101	FirstSecSum resd 1 ; Checksum of bytes 64-2048	FirstSecSum resd 1 ; Checksum of bytes 64-2048
102	ImageDwords resd 1 ; isolinux.bin size, dwords	ImageDwords resd 1 ; isolinux.bin size, dwords
103	InitStack resd 1 ; Initial stack pointer (SS:SP)	InitStack resd 1 ; Initial stack pointer (SS:SP)
104	DiskSys resw 1 ; Last INT 13h call	DiskSys resw 1 ; Last INT 13h call
105	ImageSectors resw 1 ; isolinux.bin size, sectors	ImageSectors resw 1 ; isolinux.bin size, sectors
106		; These following two are accessed as a single dword...
107		GetlinsecPtr resw 1 ; The sector-read pointer
108		BIOSName resw 1 ; Display string for BIOS type
109		%define HAVE_BIOSNAME 1
110		BIOSType resw 1
111	DiskError resb 1 ; Error code for disk I/O	DiskError resb 1 ; Error code for disk I/O
112	DriveNo resb 1 ; CD-ROM BIOS drive number	DriveNumber resb 1 ; CD-ROM BIOS drive number
113	ISOFlags resb 1 ; Flags for ISO directory search	ISOFlags resb 1 ; Flags for ISO directory search
114	RetryCount      resb 1 ; Used for disk access retries	RetryCount      resb 1 ; Used for disk access retries
115
116	_spec_start equ $	alignb 8
117		bsHidden resq 1 ; Used in hybrid mode
118		bsSecPerTrack resw 1 ; Used in hybrid mode
119		bsHeads resw 1 ; Used in hybrid mode
120
121
122	;	;
123	; El Torito spec packet	; El Torito spec packet
124	;	;
125
126	alignb 8	alignb 8
127		_spec_start equ $
128	spec_packet: resb 1 ; Size of packet	spec_packet: resb 1 ; Size of packet
129	sp_media: resb 1 ; Media type	sp_media: resb 1 ; Media type
130	sp_drive: resb 1 ; Drive number	sp_drive: resb 1 ; Drive number
#	Line 142  sp_devspec: resw 1 ; IDE/SCSI informa	Line 134  sp_devspec: resw 1 ; IDE/SCSI informa
134	sp_buffer: resw 1 ; User-provided buffer	sp_buffer: resw 1 ; User-provided buffer
135	sp_loadseg: resw 1 ; Load segment	sp_loadseg: resw 1 ; Load segment
136	sp_sectors: resw 1 ; Sector count	sp_sectors: resw 1 ; Sector count
137	sp_chs: resb 3   ; Simulated CHS geometry	sp_chs: resb 3 ; Simulated CHS geometry
138	sp_dummy: resb 1 ; Scratch, safe to overwrite	sp_dummy: resb 1 ; Scratch, safe to overwrite
139
140	;	;
#	Line 201  _spec_len equ _spec_end - _spec_start	Line 193  _spec_len equ _spec_end - _spec_start
193	alignb open_file_t_size	alignb open_file_t_size
194	Files resb MAX_OPEN*open_file_t_size	Files resb MAX_OPEN*open_file_t_size
195
	;
	; Constants for the xfer_buf_seg
	;
	; The xfer_buf_seg is also used to store message file buffers.  We
	; need two trackbuffers (text and graphics), plus a work buffer
	; for the graphics decompressor.
	;
	xbs_textbuf equ 0 ; Also hard-coded, do not change
	xbs_vgabuf equ trackbufsize
	xbs_vgatmpbuf equ 2*trackbufsize
196	section .text	section .text
197	;;	;;
198	;; Primary entry point.  Because BIOSes are buggy, we only load the first	;; Primary entry point.  Because BIOSes are buggy, we only load the first
199	;; CD-ROM sector (2K) of the file, so the number one priority is actually	;; CD-ROM sector (2K) of the file, so the number one priority is actually
200	;; loading the rest.	;; loading the rest.
201	;;	;;
202	StackBuf equ $	StackBuf equ STACK_TOP-44 ; 44 bytes needed for
203		; the bootsector chainloading
204		; code!
205		OrigESDI equ StackBuf-4          ; The high dword on the stack
206
207	bootsec equ $	bootsec equ $
208
#	Line 236  bi_file: dd 0 ; LBA of boot file	Line 220  bi_file: dd 0 ; LBA of boot file
220	bi_length: dd 0xdeadbeef ; Length of boot file	bi_length: dd 0xdeadbeef ; Length of boot file
221	bi_csum: dd 0xdeadbeef ; Checksum of boot file	bi_csum: dd 0xdeadbeef ; Checksum of boot file
222	bi_reserved: times 10 dd 0xdeadbeef ; Reserved	bi_reserved: times 10 dd 0xdeadbeef ; Reserved
223		bi_end:
224
225	_start1: mov [cs:InitStack],sp ; Save initial stack pointer	; Custom entry point for the hybrid-mode disk.
226		; The following values will have been pushed onto the
227		; entry stack:
228		; - partition offset (qword)
229		; - ES
230		; - DI
231		; - DX (including drive number)
232		; - CBIOS Heads
233		; - CBIOS Sectors
234		; - EBIOS flag
235		;       (top of stack)
236		;
237		; If we had an old isohybrid, the partition offset will
238		; be missing; we can check for that with sp >= 0x7c00.
239		; Serious hack alert.
240		%ifndef DEBUG_MESSAGES
241		_hybrid_signature:
242		dd 0x7078c0fb ; An arbitrary number...
243
244		_start_hybrid:
245		pop cx ; EBIOS flag
246		pop word [cs:bsSecPerTrack]
247		pop word [cs:bsHeads]
248		pop dx
249		pop di
250		pop es
251		xor eax,eax
252		xor ebx,ebx
253		cmp sp,7C00h
254		jae .nooffset
255		pop eax
256		pop ebx
257		.nooffset:
258		mov [cs:bsHidden],eax
259		mov [cs:bsHidden+4],ebx
260
261		mov si,bios_cbios
262		jcxz _start_common
263		mov si,bios_ebios
264		jmp _start_common
265		%endif
266
267		_start1:
268		mov si,bios_cdrom
269		_start_common:
270		mov [cs:InitStack],sp ; Save initial stack pointer
271	mov [cs:InitStack+2],ss	mov [cs:InitStack+2],ss
272	xor ax,ax	xor ax,ax
273	mov ss,ax	mov ss,ax
274	mov sp,StackBuf ; Set up stack	mov sp,StackBuf ; Set up stack
275		push es ; Save initial ES:DI -> $PnP pointer
276		push di
277	mov ds,ax	mov ds,ax
278	mov es,ax	mov es,ax
279	mov fs,ax	mov fs,ax
280	mov gs,ax	mov gs,ax
281	sti	sti
282	cld	cld
283
284		mov [BIOSType],si
285		mov eax,[si]
286		mov [GetlinsecPtr],eax
287
288	; Show signs of life	; Show signs of life
289	mov si,syslinux_banner	mov si,syslinux_banner
290	call writestr	call writestr_early
291	%ifdef DEBUG_MESSAGES	%ifdef DEBUG_MESSAGES
292	mov si,copyright_str	mov si,copyright_str
293	call writestr	%else
294		mov si,[BIOSName]
295	%endif	%endif
296		call writestr_early
297
298	;	;
299	; Before modifying any memory, get the checksum of bytes	; Before modifying any memory, get the checksum of bytes
300	; 64-2048	; 64-2048
301	;	;
302	initial_csum: xor edi,edi	initial_csum: xor edi,edi
303	mov si,_start1	mov si,bi_end
304	mov cx,(SECTOR_SIZE-64) >> 2	mov cx,(SECTOR_SIZE-64) >> 2
305	.loop: lodsd	.loop: lodsd
306	add edi,eax	add edi,eax
307	loop .loop	loop .loop
308	mov [FirstSecSum],edi	mov [FirstSecSum],edi
309
310	mov [DriveNo],dl	mov [DriveNumber],dl
311	%ifdef DEBUG_MESSAGES	%ifdef DEBUG_MESSAGES
312	mov si,startup_msg	mov si,startup_msg
313	call writemsg	call writemsg
#	Line 294  initial_csum: xor edi,edi	Line 332  initial_csum: xor edi,edi
332	; Other nonzero fields	; Other nonzero fields
333	inc word [dsp_sectors]	inc word [dsp_sectors]
334
335		; Are we just pretending to be a CD-ROM?
336		cmp word [BIOSType],bios_cdrom
337		jne found_drive ; If so, no spec packet...
338
339	; Now figure out what we're actually doing	; Now figure out what we're actually doing
340	; Note: use passed-in DL value rather than 7Fh because	; Note: use passed-in DL value rather than 7Fh because
341	; at least some BIOSes will get the wrong value otherwise	; at least some BIOSes will get the wrong value otherwise
342	mov ax,4B01h ; Get disk emulation status	mov ax,4B01h ; Get disk emulation status
343	mov dl,[DriveNo]	mov dl,[DriveNumber]
344	mov si,spec_packet	mov si,spec_packet
345	int 13h	call int13
346	jc award_hack ; changed for BrokenAwardHack	jc award_hack ; changed for BrokenAwardHack
347	mov dl,[DriveNo]	mov dl,[DriveNumber]
348	cmp [sp_drive],dl ; Should contain the drive number	cmp [sp_drive],dl ; Should contain the drive number
349	jne spec_query_failed	jne spec_query_failed
350
#	Line 330  found_drive:	Line 372  found_drive:
372	mov si,noinfotable_msg	mov si,noinfotable_msg
373	call writemsg	call writemsg
374	%endif	%endif
375
376	; No such luck.  See if the the spec packet contained one.	; No such luck.  See if the spec packet contained one.
377	mov eax,[sp_lba]	mov eax,[sp_lba]
378	and eax,eax	and eax,eax
379	jz set_file ; Good enough	jz set_file ; Good enough
#	Line 340  found_drive:	Line 382  found_drive:
382	mov si,noinfoinspec_msg	mov si,noinfoinspec_msg
383	call writemsg	call writemsg
384	%endif	%endif
385
386	; No such luck.  Get the Boot Record Volume, assuming single	; No such luck.  Get the Boot Record Volume, assuming single
387	; session disk, and that we're the first entry in the chain	; session disk, and that we're the first entry in the chain.
388	mov eax,17 ; Assumed address of BRV	mov eax,17 ; Assumed address of BRV
389	mov bx,trackbuf	mov bx,trackbuf
390	call getonesec	call getonesec
#	Line 354  found_drive:	Line 396  found_drive:
396	mov eax,[trackbuf+28h] ; First boot entry	mov eax,[trackbuf+28h] ; First boot entry
397	; And hope and pray this is us...	; And hope and pray this is us...
398
399	; Some BIOSes apparently have limitations on the size	; Some BIOSes apparently have limitations on the size
400	; that may be loaded (despite the El Torito spec being very	; that may be loaded (despite the El Torito spec being very
401	; clear on the fact that it must all be loaded.)  Therefore,	; clear on the fact that it must all be loaded.)  Therefore,
402	; we load it ourselves, and *bleep* the BIOS.	; we load it ourselves, and *bleep* the BIOS.
#	Line 365  set_file:	Line 407  set_file:
407	found_file:	found_file:
408	; Set up boot file sizes	; Set up boot file sizes
409	mov eax,[bi_length]	mov eax,[bi_length]
410	sub eax,SECTOR_SIZE-3	sub eax,SECTOR_SIZE-3 ; ... minus sector loaded
411	shr eax,2 ; bytes->dwords	shr eax,2 ; bytes->dwords
412	mov [ImageDwords],eax ; boot file dwords	mov [ImageDwords],eax ; boot file dwords
413	add eax,(2047 >> 2)	add eax,(2047 >> 2)
#	Line 442  integrity_ok:	Line 484  integrity_ok:
484	;; Start of BrokenAwardHack --- 10-nov-2002           Knut_Petersen@t-online.de	;; Start of BrokenAwardHack --- 10-nov-2002           Knut_Petersen@t-online.de
485	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
486	;;	;;
487	;; There is a problem with certain versions of the AWARD BIOS ...	;; There is a problem with certain versions of the AWARD BIOS ...
488	;; the boot sector will be loaded and executed correctly, but, because the	;; the boot sector will be loaded and executed correctly, but, because the
489	;; int 13 vector points to the wrong code in the BIOS, every attempt to	;; int 13 vector points to the wrong code in the BIOS, every attempt to
490	;; load the spec packet will fail. We scan for the equivalent of	;; load the spec packet will fail. We scan for the equivalent of
#	Line 459  integrity_ok:	Line 501  integrity_ok:
501	;; for anybody to change it now or in the future. There are no opcodes	;; for anybody to change it now or in the future. There are no opcodes
502	;; that use encodings relativ to IP, so scanning is easy. If we find the	;; that use encodings relativ to IP, so scanning is easy. If we find the
503	;; code above in the BIOS code we can be pretty sure to run on a machine	;; code above in the BIOS code we can be pretty sure to run on a machine
504	;; with an broken AWARD BIOS ...	;; with an broken AWARD BIOS ...
505	;;	;;
506	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
507	;;	;;
#	Line 478  award_oldint13 dd 0     ;;	Line 520  award_oldint13 dd 0     ;;
520	award_string db 0b8h,1,2,0bbh,0,7ch,0b9h,6,0,0bah,80h,1,09ch,09ah    ;;	award_string db 0b8h,1,2,0bbh,0,7ch,0b9h,6,0,0bah,80h,1,09ch,09ah    ;;
521	;;	;;
522	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
523	award_hack: mov si,spec_err_msg ; Moved to this place from	award_hack: mov si,spec_err_msg ; Moved to this place from
524	call writemsg ; spec_query_faild	call writemsg ; spec_query_faild
525	;	;
526	%ifdef DEBUG_MESSAGES ;	%ifdef DEBUG_MESSAGES ;
527	;	;
#	Line 494  award_hack: mov si,spec_err_msg ; Move	Line 536  award_hack: mov si,spec_err_msg ; Move
536	%ifdef DEBUG_MESSAGES ;	%ifdef DEBUG_MESSAGES ;
537	;	;
538	call writehex8 ;	call writehex8 ;
539	mov si,award_not_crlf ;	mov si,award_not_crlf ;
540	call writestr ;	call writestr_early ;
541	%endif ;	%endif ;
542	push es ; save ES	push es ; save ES
543	mov ax,0f000h ; ES = BIOS Seg	mov ax,0f000h ; ES = BIOS Seg
544	mov es,ax ;	mov es,ax ;
545	cld ;	cld ;
546	xor di,di ; start at ES:DI = f000:0	xor di,di ; start at ES:DI = f000:0
547	award_loop: push di ; save DI	award_loop: push di ; save DI
548	mov si,award_string ; scan for award_string	mov si,award_string ; scan for award_string
549	mov cx,7 ; length of award_string = 7dw	mov cx,7 ; length of award_string = 7dw
550	repz cmpsw ; compare	repz cmpsw ; compare
551	pop di ; restore DI	pop di ; restore DI
552	jcxz award_found ; jmp if found	jcxz award_found ; jmp if found
553	inc di ; not found, inc di	inc di ; not found, inc di
554	jno award_loop ;	jno award_loop ;
555	;	;
556	award_failed: pop es ; No, not this way :-((	award_failed: pop es ; No, not this way :-((
557	award_fail2: ;	award_fail2: ;
#	Line 535  award_found: mov eax,[es:di+0eh] ; load	Line 577  award_found: mov eax,[es:di+0eh] ; load
577	;	;
578	%ifdef DEBUG_MESSAGES ;	%ifdef DEBUG_MESSAGES ;
579	;	;
580	push eax ; display message and	push eax ; display message and
581	mov si,award_not_new ; new vector address	mov si,award_not_new ; new vector address
582	call writemsg ;	call writemsg ;
583	pop eax ;	pop eax ;
584	call writehex8 ;	call writehex8 ;
585	mov si,award_not_crlf ;	mov si,award_not_crlf ;
586	call writestr ;	call writestr_early ;
587	%endif ;	%endif ;
588	mov ax,4B01h ; try to read the spec packet	mov ax,4B01h ; try to read the spec packet
589	mov dl,[DriveNo] ; now ... it should not fail	mov dl,[DriveNumber] ; now ... it should not fail
590	mov si,spec_packet ; any longer	mov si,spec_packet ; any longer
591	int 13h ;	int 13h ;
592	jc award_fail2 ;	jc award_fail2 ;
593	;	;
594	%ifdef DEBUG_MESSAGES ;	%ifdef DEBUG_MESSAGES ;
#	Line 572  spec_query_failed:	Line 614  spec_query_failed:
614	.test_loop: pusha	.test_loop: pusha
615	mov ax,4B01h	mov ax,4B01h
616	mov si,spec_packet	mov si,spec_packet
617	mov byte [si],13 ; Size of buffer	mov byte [si],13h ; Size of buffer
618	int 13h	call int13
619	popa	popa
620	jc .still_broken	jc .still_broken
621
#	Line 589  spec_query_failed:	Line 631  spec_query_failed:
631	; Okay, good enough...	; Okay, good enough...
632	mov si,alright_msg	mov si,alright_msg
633	call writemsg	call writemsg
634	mov [DriveNo],dl	.found_drive0: mov [DriveNumber],dl
635	.found_drive: jmp found_drive	.found_drive: jmp found_drive
636
637	; Award BIOS 4.51 apparently passes garbage in sp_drive,	; Award BIOS 4.51 apparently passes garbage in sp_drive,
638	; but if this was the drive number originally passed in	; but if this was the drive number originally passed in
639	; DL then consider it "good enough"	; DL then consider it "good enough"
640	.maybe_broken:	.maybe_broken:
641	cmp byte [DriveNo],dl	mov al,[DriveNumber]
642		cmp al,dl
643	je .found_drive	je .found_drive
644
645		; Intel Classic R+ computer with Adaptec 1542CP BIOS 1.02
646		; passes garbage in sp_drive, and the drive number originally
647		; passed in DL does not have 80h bit set.
648		or al,80h
649		cmp al,dl
650		je .found_drive0
651
652	.still_broken: dec dx	.still_broken: dec dx
653	cmp dl, 80h	cmp dl, 80h
654	jnb .test_loop	jnb .test_loop
#	Line 608  spec_query_failed:	Line 658  spec_query_failed:
658	; 4B01h, so we can't query a spec packet no matter	; 4B01h, so we can't query a spec packet no matter
659	; what.  If we got a drive number in DL, then try to	; what.  If we got a drive number in DL, then try to
660	; use it, and if it works, then well...	; use it, and if it works, then well...
661	mov dl,[DriveNo]	mov dl,[DriveNumber]
662	cmp dl,81h ; Should be 81-FF at least	cmp dl,81h ; Should be 81-FF at least
663	jb fatal_error ; If not, it's hopeless	jb fatal_error ; If not, it's hopeless
664
#	Line 634  fatal_error:	Line 684  fatal_error:
684	writemsg: push ax	writemsg: push ax
685	push si	push si
686	mov si,isolinux_str	mov si,isolinux_str
687	call writestr	call writestr_early
688	pop si	pop si
689	call writestr	call writestr_early
690	pop ax	pop ax
691	ret	ret
692
693	;	;
#	Line 660  writechr_simple:	Line 710  writechr_simple:
710	ret	ret
711
712	;	;
713		; int13: save all the segment registers and call INT 13h.
714		; Some CD-ROM BIOSes have been found to corrupt segment registers
715		; and/or disable interrupts.
716		;
717		int13:
718		pushf
719		push bp
720		push ds
721		push es
722		push fs
723		push gs
724		int 13h
725		mov bp,sp
726		setc [bp+10] ; Propagate CF to the caller
727		pop gs
728		pop fs
729		pop es
730		pop ds
731		pop bp
732		popf
733		ret
734
735		;
736	; Get one sector.  Convenience entry point.	; Get one sector.  Convenience entry point.
737	;	;
738	getonesec:	getonesec:
#	Line 669  getonesec:	Line 742  getonesec:
742	;	;
743	; Get linear sectors - EBIOS LBA addressing, 2048-byte sectors.	; Get linear sectors - EBIOS LBA addressing, 2048-byte sectors.
744	;	;
	; Note that we can't always do this as a single request, because at least
	; Phoenix BIOSes has a 127-sector limit.  To be on the safe side, stick
	; to 32 sectors (64K) per request.
	;
745	; Input:	; Input:
746	; EAX - Linear sector number	; EAX - Linear sector number
747	; ES:BX - Target buffer	; ES:BX - Target buffer
748	; BP - Sector count	; BP - Sector count
749	;	;
750	getlinsec:	getlinsec: jmp word [cs:GetlinsecPtr]
751
752		%ifndef DEBUG_MESSAGES
753
754		;
755		; First, the variants that we use when actually loading off a disk
756		; (hybrid mode.)  These are adapted versions of the equivalent routines
757		; in ldlinux.asm.
758		;
759
760		;
761		; getlinsec_ebios:
762		;
763		; getlinsec implementation for floppy/HDD EBIOS (EDD)
764		;
765		getlinsec_ebios:
766		xor edx,edx
767		shld edx,eax,2
768		shl eax,2 ; Convert to HDD sectors
769		add eax,[bsHidden]
770		adc edx,[bsHidden+4]
771		shl bp,2
772
773		.loop:
774		push bp                         ; Sectors left
775		.retry2:
776		call maxtrans ; Enforce maximum transfer size
777		movzx edi,bp ; Sectors we are about to read
778		mov cx,retry_count
779		.retry:
780
781		; Form DAPA on stack
782		push edx
783		push eax
784		push es
785		push bx
786		push di
787		push word 16
788		mov si,sp
789		pushad
790		mov dl,[DriveNumber]
791		push ds
792		push ss
793		pop ds ; DS <- SS
794		mov ah,42h ; Extended Read
795		call int13
796		pop ds
797		popad
798		lea sp,[si+16] ; Remove DAPA
799		jc .error
800		pop bp
801		add eax,edi ; Advance sector pointer
802		adc edx,0
803		sub bp,di ; Sectors left
804		shl di,9 ; 512-byte sectors
805		add bx,di ; Advance buffer pointer
806		and bp,bp
807		jnz .loop
808
809		ret
810
811		.error:
812		; Some systems seem to get "stuck" in an error state when
813		; using EBIOS.  Doesn't happen when using CBIOS, which is
814		; good, since some other systems get timeout failures
815		; waiting for the floppy disk to spin up.
816
817		pushad ; Try resetting the device
818		xor ax,ax
819		mov dl,[DriveNumber]
820		call int13
821		popad
822		loop .retry ; CX-- and jump if not zero
823
824		;shr word [MaxTransfer],1 ; Reduce the transfer size
825		;jnz .retry2
826
827		; Total failure.  Try falling back to CBIOS.
828		mov word [GetlinsecPtr], getlinsec_cbios
829		;mov byte [MaxTransfer],63 ; Max possibe CBIOS transfer
830
831		pop bp
832		jmp getlinsec_cbios.loop
833
834		;
835		; getlinsec_cbios:
836		;
837		; getlinsec implementation for legacy CBIOS
838		;
839		getlinsec_cbios:
840		xor edx,edx
841		shl eax,2 ; Convert to HDD sectors
842		add eax,[bsHidden]
843		shl bp,2
844
845		.loop:
846		push edx
847		push eax
848		push bp
849		push bx
850
851		movzx esi,word [bsSecPerTrack]
852		movzx edi,word [bsHeads]
853		;
854		; Dividing by sectors to get (track,sector): we may have
855		; up to 2^18 tracks, so we need to use 32-bit arithmetric.
856		;
857		div esi
858		xor cx,cx
859		xchg cx,dx ; CX <- sector index (0-based)
860		; EDX <- 0
861		; eax = track #
862		div edi ; Convert track to head/cyl
863
864		; We should test this, but it doesn't fit...
865		; cmp eax,1023
866		; ja .error
867
868		;
869		; Now we have AX = cyl, DX = head, CX = sector (0-based),
870		; BP = sectors to transfer, SI = bsSecPerTrack,
871		; ES:BX = data target
872		;
873
874		call maxtrans ; Enforce maximum transfer size
875
876		; Must not cross track boundaries, so BP <= SI-CX
877		sub si,cx
878		cmp bp,si
879		jna .bp_ok
880		mov bp,si
881		.bp_ok:
882
883		shl ah,6 ; Because IBM was STOOPID
884		; and thought 8 bits were enough
885		; then thought 10 bits were enough...
886		inc cx ; Sector numbers are 1-based, sigh
887		or cl,ah
888		mov ch,al
889		mov dh,dl
890		mov dl,[DriveNumber]
891		xchg ax,bp ; Sector to transfer count
892		mov ah,02h ; Read sectors
893		mov bp,retry_count
894		.retry:
895		pushad
896		call int13
897		popad
898		jc .error
899		.resume:
900		movzx ecx,al ; ECX <- sectors transferred
901		shl ax,9 ; Convert sectors in AL to bytes in AX
902		pop bx
903		add bx,ax
904		pop bp
905		pop eax
906		pop edx
907		add eax,ecx
908		sub bp,cx
909		jnz .loop
910		ret
911
912		.error:
913		dec bp
914		jnz .retry
915
916		xchg ax,bp ; Sectors transferred <- 0
917		shr word [MaxTransfer],1
918		jnz .resume
919		jmp disk_error
920
921		;
922		; Truncate BP to MaxTransfer
923		;
924		maxtrans:
925		cmp bp,[MaxTransfer]
926		jna .ok
927		mov bp,[MaxTransfer]
928		.ok: ret
929
930		%endif
931
932		;
933		; This is the variant we use for real CD-ROMs:
934		; LBA, 2K sectors, some special error handling.
935		;
936		getlinsec_cdrom:
937	mov si,dapa ; Load up the DAPA	mov si,dapa ; Load up the DAPA
938	mov [si+4],bx	mov [si+4],bx
939	mov bx,es	mov [si+6],es
	mov [si+6],bx
940	mov [si+8],eax	mov [si+8],eax
941	.loop:	.loop:
942	push bp ; Sectors left	push bp ; Sectors left
943	cmp bp,[MaxTransfer]	cmp bp,[MaxTransferCD]
944	jbe .bp_ok	jbe .bp_ok
945	mov bp,[MaxTransfer]	mov bp,[MaxTransferCD]
946	.bp_ok:	.bp_ok:
947	mov [si+2],bp	mov [si+2],bp
948	push si	push si
949	mov dl,[DriveNo]	mov dl,[DriveNumber]
950	mov ah,42h ; Extended Read	mov ah,42h ; Extended Read
951	call xint13	call xint13
952	pop si	pop si
#	Line 710  getlinsec:	Line 964  getlinsec:
964	; INT 13h with retry	; INT 13h with retry
965	xint13: mov byte [RetryCount],retry_count	xint13: mov byte [RetryCount],retry_count
966	.try: pushad	.try: pushad
967	int 13h	call int13
968	jc .error	jc .error
969	add sp,byte 8*4 ; Clean up stack	add sp,byte 8*4 ; Clean up stack
970	ret	ret
#	Line 733  xint13: mov byte [RetryCount],retry_cou	Line 987  xint13: mov byte [RetryCount],retry_cou
987	shr ah,1 ; Otherwise, try to reduce	shr ah,1 ; Otherwise, try to reduce
988	adc ah,0 ; the max transfer size, but not to 0	adc ah,0 ; the max transfer size, but not to 0
989	.setsize:	.setsize:
990	mov [MaxTransfer],ah	mov [MaxTransferCD],ah
991	mov [dapa+2],ah	mov [dapa+2],ah
992	.again:	.again:
993	pop ax	pop ax
#	Line 744  xint13: mov byte [RetryCount],retry_cou	Line 998  xint13: mov byte [RetryCount],retry_cou
998	mov al,[DiskError]	mov al,[DiskError]
999	call writehex2	call writehex2
1000	mov si,oncall_str	mov si,oncall_str
1001	call writestr	call writestr_early
1002	mov ax,[DiskSys]	mov ax,[DiskSys]
1003	call writehex4	call writehex4
1004	mov si,ondrive_str	mov si,ondrive_str
1005	call writestr	call writestr_early
1006	mov al,dl	mov al,dl
1007	call writehex2	call writehex2
1008	call crlf	call crlf
#	Line 758  xint13: mov byte [RetryCount],retry_cou	Line 1012  xint13: mov byte [RetryCount],retry_cou
1012	; kaboom: write a message and bail out.  Wait for a user keypress,	; kaboom: write a message and bail out.  Wait for a user keypress,
1013	;  then do a hard reboot.	;  then do a hard reboot.
1014	;	;
1015		disk_error:
1016	kaboom:	kaboom:
1017	lss sp,[cs:StackPtr]	RESET_STACK_AND_SEGS AX
	mov ax,cs
	mov ds,ax
	mov es,ax
	mov fs,ax
	mov gs,ax
	sti
1018	mov si,err_bootfailed	mov si,err_bootfailed
1019	call cwritestr	call writestr
1020	call getchar	call getchar
1021	cli	cli
1022	mov word [BIOS_magic],0 ; Cold reboot	mov word [BIOS_magic],0 ; Cold reboot
#	Line 778  kaboom:	Line 1027  kaboom:
1027	; -----------------------------------------------------------------------------	; -----------------------------------------------------------------------------
1028
1029	%include "writestr.inc" ; String output	%include "writestr.inc" ; String output
1030	writestr equ cwritestr	writestr_early equ writestr
1031	%include "writehex.inc" ; Hexadecimal output	%include "writehex.inc" ; Hexadecimal output
1032
1033	; -----------------------------------------------------------------------------	; -----------------------------------------------------------------------------
1034	; Data that needs to be in the first sector	; Data that needs to be in the first sector
1035	; -----------------------------------------------------------------------------	; -----------------------------------------------------------------------------
1036
1037	syslinux_banner db CR, LF, 'ISOLINUX ', version_str, ' ', date, ' ', 0	syslinux_banner db CR, LF, MY_NAME, ' ', VERSION_STR, ' ', DATE_STR, ' ', 0
1038	copyright_str   db ' Copyright (C) 1994-', year, ' H. Peter Anvin'	copyright_str   db ' Copyright (C) 1994-'
1039	db CR, LF, 0	asciidec YEAR
1040		db ' H. Peter Anvin et al', CR, LF, 0
1041	isolinux_str db 'isolinux: ', 0	isolinux_str db 'isolinux: ', 0
1042	%ifdef DEBUG_MESSAGES	%ifdef DEBUG_MESSAGES
1043	startup_msg: db 'Starting up, DL = ', 0	startup_msg: db 'Starting up, DL = ', 0
1044	spec_ok_msg: db 'Loaded spec packet OK, drive = ', 0	spec_ok_msg: db 'Loaded spec packet OK, drive = ', 0
1045	secsize_msg: db 'Sector size appears to be ', 0	secsize_msg: db 'Sector size ', 0
1046	offset_msg: db 'Loading main image from LBA = ', 0	offset_msg: db 'Main image LBA = ', 0
1047	size_msg: db 'Sectors to load = ', 0	size_msg: db 'Sectors to load = ', 0
1048	loaded_msg: db 'Loaded boot image, verifying...', CR, LF, 0	loaded_msg: db 'Loaded boot image, verifying...', CR, LF, 0
1049	verify_msg: db 'Image checksum verified.', CR, LF, 0	verify_msg: db 'Image checksum verified.', CR, LF, 0
#	Line 803  noinfotable_msg db 'No boot info table,	Line 1053  noinfotable_msg db 'No boot info table,
1053	noinfoinspec_msg db 'Spec packet missing LBA information, trying to wing it...', CR, LF, 0	noinfoinspec_msg db 'Spec packet missing LBA information, trying to wing it...', CR, LF, 0
1054	spec_err_msg: db 'Loading spec packet failed, trying to wing it...', CR, LF, 0	spec_err_msg: db 'Loading spec packet failed, trying to wing it...', CR, LF, 0
1055	maybe_msg: db 'Found something at drive = ', 0	maybe_msg: db 'Found something at drive = ', 0
1056	alright_msg: db 'Looks like it might be right, continuing...', CR, LF, 0	alright_msg: db 'Looks reasonable, continuing...', CR, LF, 0
1057	nospec_msg db 'Extremely broken BIOS detected, last ditch attempt with drive = ', 0	nospec_msg db 'Extremely broken BIOS detected, last attempt with drive = ', 0
1058	nothing_msg: db 'Failed to locate CD-ROM device; boot failed.', CR, LF	nothing_msg: db 'Failed to locate CD-ROM device; boot failed.', CR, LF
1059	trysbm_msg db 'See http://syslinux.zytor.com/sbm for more information.', CR, LF, 0	trysbm_msg db 'See http://syslinux.zytor.com/sbm for more information.', CR, LF, 0
1060	diskerr_msg: db 'Disk error ', 0	diskerr_msg: db 'Disk error ', 0
#	Line 817  bailmsg equ err_bootfailed	Line 1067  bailmsg equ err_bootfailed
1067	crlf_msg db CR, LF	crlf_msg db CR, LF
1068	null_msg db 0	null_msg db 0
1069
1070	alignb 4, db 0	bios_cdrom_str db 'ETCD', 0
1071	StackPtr dw StackBuf, 0 ; SS:SP for stack reset	%ifndef DEBUG_MESSAGES
1072	MaxTransfer dw 32 ; Max sectors per transfer	bios_cbios_str db 'CHDD', 0
1073		bios_ebios_str db 'EHDD' ,0
1074		%endif
1075
1076		alignz 4
1077		bios_cdrom: dw getlinsec_cdrom, bios_cdrom_str
1078		%ifndef DEBUG_MESSAGES
1079		bios_cbios: dw getlinsec_cbios, bios_cbios_str
1080		bios_ebios: dw getlinsec_ebios, bios_ebios_str
1081		%endif
1082
1083		; Maximum transfer size
1084		MaxTransfer dw 127 ; Hard disk modes
1085		MaxTransferCD dw 32 ; CD mode
1086
1087	rl_checkpt equ $ ; Must be <= 800h	rl_checkpt equ $ ; Must be <= 800h
1088
1089	rl_checkpt_off equ ($-$$)	; This pads to the end of sector 0 and errors out on
1090	;%ifndef DEPEND	; overflow.
1091	;%if rl_checkpt_off > 0x800	times 2048-($-$$) db 0
	;%error "Sector 0 overflow"
	;%endif
	;%endif
1092
1093	; ----------------------------------------------------------------------------	; ----------------------------------------------------------------------------
1094	;  End of code and data that have to be in the first sector	;  End of code and data that have to be in the first sector
1095	; ----------------------------------------------------------------------------	; ----------------------------------------------------------------------------
1096
1097	all_read:	all_read:
	;
	; Initialize screen (if we're using one)
	;
	; Now set up screen parameters
	call adjust_screen
	; Wipe the F-key area
	mov al,NULLFILE
	mov di,FKeyName
	mov cx,10*(1 << FILENAME_MAX_LG2)
	rep stosb
	; Patch the writechr routine to point to the full code
	mov word [writechr+1], writechr_full-(writechr+3)
	; Tell the user we got this far...
	%ifndef DEBUG_MESSAGES ; Gets messy with debugging on
	mov si,copyright_str
	call writestr
	%endif
1098
1099	; Test tracers	; Test tracers
1100	TRACER 'T'	TRACER 'T'
#	Line 866  all_read:	Line 1106  all_read:
1106	%include "init.inc"	%include "init.inc"
1107	%include "cpuinit.inc"	%include "cpuinit.inc"
1108
1109		; Patch the writechr routine to point to the full code
1110		mov word [writechr+1], writechr_full-(writechr+3)
1111
1112		; Tell the user we got this far...
1113		%ifndef DEBUG_MESSAGES ; Gets messy with debugging on
1114		mov si,copyright_str
1115		call writestr_early
1116		%endif
1117
1118	;	;
1119	; Now we're all set to start with our *real* business. First load the	; Now we're all set to start with our *real* business. First load the
1120	; configuration file (if any) and parse it.	; configuration file (if any) and parse it.
#	Line 885  all_read:	Line 1134  all_read:
1134	; mkisofs gave us a pointer to the primary volume descriptor	; mkisofs gave us a pointer to the primary volume descriptor
1135	; (which will be at 16 only for a single-session disk!); from the PVD	; (which will be at 16 only for a single-session disk!); from the PVD
1136	; we should be able to find the rest of what we need to know.	; we should be able to find the rest of what we need to know.
1137	;	;
1138	get_fs_structures:	get_fs_structures:
1139	mov eax,[bi_pvd]	mov eax,[bi_pvd]
1140	mov bx,trackbuf	mov bx,trackbuf
#	Line 893  get_fs_structures:	Line 1142  get_fs_structures:
1142
1143	mov eax,[trackbuf+156+2]	mov eax,[trackbuf+156+2]
1144	mov [RootDir+dir_lba],eax	mov [RootDir+dir_lba],eax
1145	mov [CurDir+dir_lba],eax	mov [CurrentDir+dir_lba],eax
1146	%ifdef DEBUG_MESSAGES	%ifdef DEBUG_MESSAGES
1147	mov si,dbg_rootdir_msg	mov si,dbg_rootdir_msg
1148	call writemsg	call writemsg
#	Line 901  get_fs_structures:	Line 1150  get_fs_structures:
1150	call crlf	call crlf
1151	%endif	%endif
1152	mov eax,[trackbuf+156+10]	mov eax,[trackbuf+156+10]
1153	mov [RootDir+dir_len],eax	mov [RootDir+dir_len],eax
1154	mov [CurDir+dir_len],eax	mov [CurrentDir+dir_len],eax
1155	add eax,SECTOR_SIZE-1	add eax,SECTOR_SIZE-1
1156	shr eax,SECTOR_SHIFT	shr eax,SECTOR_SHIFT
1157	mov [RootDir+dir_clust],eax	mov [RootDir+dir_clust],eax
1158	mov [CurDir+dir_clust],eax	mov [CurrentDir+dir_clust],eax
1159
1160	; Look for an isolinux directory, and if found,	; Look for an isolinux directory, and if found,
1161	; make it the current directory instead of the root	; make it the current directory instead of the root
1162	; directory.	; directory.
1163		; Also copy the name of the directory to CurrentDirName
1164		mov word [CurrentDirName],ROOT_DIR_WORD ; Write '/',0 to the CurrentDirName
1165	mov di,boot_dir ; Search for /boot/isolinux	mov di,boot_dir ; Search for /boot/isolinux
1166	mov al,02h	mov al,02h
1167		push di
1168	call searchdir_iso	call searchdir_iso
1169		pop di
1170	jnz .found_dir	jnz .found_dir
1171	mov di,isolinux_dir	mov di,isolinux_dir
1172	mov al,02h ; Search for /isolinux	mov al,02h ; Search for /isolinux
1173		push di
1174	call searchdir_iso	call searchdir_iso
1175		pop di
1176	jz .no_isolinux_dir	jz .no_isolinux_dir
1177	.found_dir:	.found_dir:
1178	mov [CurDir+dir_len],eax	; Copy current directory name to CurrentDirName
1179		push si
1180		push di
1181		mov si,di
1182		mov di,CurrentDirName
1183		call strcpy
1184		mov byte [di],0 ;done in case it's not word aligned
1185		dec di
1186		mov byte [di],'/'
1187		pop di
1188		pop si
1189
1190		mov [CurrentDir+dir_len],eax
1191	mov eax,[si+file_left]	mov eax,[si+file_left]
1192	mov [CurDir+dir_clust],eax	mov [CurrentDir+dir_clust],eax
1193	xor eax,eax ; Free this file pointer entry	xor eax,eax ; Free this file pointer entry
1194	xchg eax,[si+file_sector]	xchg eax,[si+file_sector]
1195	mov [CurDir+dir_lba],eax	mov [CurrentDir+dir_lba],eax
1196	%ifdef DEBUG_MESSAGES	%ifdef DEBUG_MESSAGES
1197	push si	push si
1198	mov si,dbg_isodir_msg	mov si,dbg_isodir_msg
#	Line 945  load_config:	Line 1212  load_config:
1212	call writemsg	call writemsg
1213	%endif	%endif
1214
1215	mov di,isolinux_cfg	mov si,config_name
1216		mov di,ConfigName
1217		call strcpy
1218
1219		mov di,ConfigName
1220	call open	call open
1221	jz no_config_file ; Not found or empty	jz no_config_file ; Not found or empty
1222
#	Line 961  load_config:	Line 1232  load_config:
1232	%include "ui.inc"	%include "ui.inc"
1233
1234	;	;
1235	; Linux kernel loading code is common.	; Enable disk emulation.  The kind of disk we emulate is dependent on the
1236	;	; size of the file: 1200K, 1440K or 2880K floppy, otherwise harddisk.
	%include "runkernel.inc"
	;
	; COMBOOT-loading code
	;
	%include "comboot.inc"
	%include "com32.inc"
	%include "cmdline.inc"
	;
	; Boot sector loading code
	;
	%include "bootsect.inc"
	;
	; Enable disk emulation.  The kind of disk we emulate is dependent on the size of
	; the file: 1200K, 1440K or 2880K floppy, otherwise harddisk.
1237	;	;
1238	is_disk_image:	is_disk_image:
1239	TRACER CR	TRACER CR
#	Line 987  is_disk_image:	Line 1241  is_disk_image:
1241	TRACER 'D'	TRACER 'D'
1242	TRACER ':'	TRACER ':'
1243
1244	shl edx,16	mov edx,eax ; File size
	mov dx,ax ; Set EDX <- file size
1245	mov di,img_table	mov di,img_table
1246	mov cx,img_table_count	mov cx,img_table_count
1247	mov eax,[si+file_sector] ; Starting LBA of file	mov eax,[si+file_sector] ; Starting LBA of file
#	Line 1012  is_disk_image:	Line 1265  is_disk_image:
1265	mov bx,trackbuf	mov bx,trackbuf
1266	mov cx,1 ; Load 1 sector	mov cx,1 ; Load 1 sector
1267	call getfssec	call getfssec
1268
1269	cmp word [trackbuf+510],0aa55h ; Boot signature	cmp word [trackbuf+510],0aa55h ; Boot signature
1270	jne .bad_image ; Image not bootable	jne .bad_image ; Image not bootable
1271
#	Line 1031  is_disk_image:	Line 1284  is_disk_image:
1284	.part_loop:	.part_loop:
1285	add di,byte 16	add di,byte 16
1286	loop .part_scan	loop .part_scan
1287
1288	push eax ; H/S	push eax ; H/S
1289	push edx ; File size	push edx ; File size
1290	mov bl,ah	mov bl,ah
#	Line 1080  is_disk_image:	Line 1333  is_disk_image:
1333
1334	mov ax,4C00h ; Enable emulation and boot	mov ax,4C00h ; Enable emulation and boot
1335	mov si,dspec_packet	mov si,dspec_packet
1336	mov dl,[DriveNo]	mov dl,[DriveNumber]
1337	lss sp,[InitStack]	lss sp,[InitStack]
1338	TRACER 'X'	TRACER 'X'
1339
1340	int 13h	call int13
1341
1342	; If this returns, we have problems	; If this returns, we have problems
1343	.bad_image:	.bad_image:
1344	mov si,err_disk_image	mov si,err_disk_image
1345	call cwritestr	call writestr
1346	jmp enter_command	jmp enter_command
1347
1348	;	;
#	Line 1109  is_disk_image:	Line 1362  is_disk_image:
1362	.done_sector: ret	.done_sector: ret
1363
1364	;	;
1365	; Boot a specified local disk.  AX specifies the BIOS disk number; or	; close_file:
1366	; 0xFFFF in case we should execute INT 18h ("next device.")	;     Deallocates a file structure (pointer in SI)
1367		;     Assumes CS == DS.
1368	;	;
1369	local_boot:	close_file:
1370	call vgaclearmode	and si,si
1371	lss sp,[cs:Stack] ; Restore stack pointer	jz .closed
1372	xor dx,dx	mov dword [si],0 ; First dword == file_left
1373	mov ds,dx	xor si,si
1374	mov es,dx	.closed: ret
	mov fs,dx
	mov gs,dx
	mov si,localboot_msg
	call writestr
	cmp ax,-1
	je .int18
	; Load boot sector from the specified BIOS device and jump to it.
	mov dl,al
	xor dh,dh
	push dx
	xor ax,ax ; Reset drive
	call xint13
	mov ax,0201h ; Read one sector
	mov cx,0001h ; C/H/S = 0/0/1 (first sector)
	mov bx,trackbuf
	call xint13
	pop dx
	cli ; Abandon hope, ye who enter here
	mov si,trackbuf
	mov di,07C00h
	mov cx,512 ; Probably overkill, but should be safe
	rep movsd
	lss sp,[cs:InitStack]
	jmp 0:07C00h ; Jump to new boot sector
	.int18:
	int 18h ; Hope this does the right thing...
	jmp kaboom ; If we returned, oh boy...
	;
	; Abort loading code
	;
	%include "abort.inc"
1375
1376	;	;
1377	; searchdir:	; searchdir:
#	Line 1163  local_boot:	Line 1383  local_boot:
1383	;     If successful:	;     If successful:
1384	; ZF clear	; ZF clear
1385	; SI = file pointer	; SI = file pointer
1386	; DX:AX or EAX = file length in bytes	; EAX = file length in bytes
1387	;     If unsuccessful	;     If unsuccessful
1388	; ZF set	; ZF set
1389	;	;
#	Line 1187  searchdir_iso:	Line 1407  searchdir_iso:
1407	push es	push es
1408	push ds	push ds
1409	pop es ; ES = DS	pop es ; ES = DS
1410	mov si,CurDir	mov si,CurrentDir
1411	cmp byte [di],'/' ; If filename begins with slash	cmp byte [di],'/' ; If filename begins with slash
1412	jne .not_rooted	jne .not_rooted
1413	inc di ; Skip leading slash	inc di ; Skip leading slash
#	Line 1195  searchdir_iso:	Line 1415  searchdir_iso:
1415	.not_rooted:	.not_rooted:
1416	mov eax,[si+dir_clust]	mov eax,[si+dir_clust]
1417	mov [bx+file_left],eax	mov [bx+file_left],eax
1418		shl eax,SECTOR_SHIFT
1419		mov [bx+file_bytesleft],eax
1420	mov eax,[si+dir_lba]	mov eax,[si+dir_lba]
1421	mov [bx+file_sector],eax	mov [bx+file_sector],eax
1422	mov edx,[si+dir_len]	mov edx,[si+dir_len]
#	Line 1275  searchdir_iso:	Line 1497  searchdir_iso:
1497	mov eax,[si+2] ; Location of extent	mov eax,[si+2] ; Location of extent
1498	mov [bx+file_sector],eax	mov [bx+file_sector],eax
1499	mov eax,[si+10] ; Data length	mov eax,[si+10] ; Data length
1500		mov [bx+file_bytesleft],eax
1501	push eax	push eax
1502	add eax,SECTOR_SIZE-1	add eax,SECTOR_SIZE-1
1503	shr eax,SECTOR_SHIFT	shr eax,SECTOR_SHIFT
1504	mov [bx+file_left],eax	mov [bx+file_left],eax
1505	pop eax	pop eax
1506	mov edx,eax	jz .failure ; Empty file?
1507	shr edx,16	; ZF = 0
	and bx,bx ; ZF = 0
1508	mov si,bx	mov si,bx
1509	pop es	pop es
1510	ret	ret
#	Line 1320  allocate_file:	Line 1542  allocate_file:
1542	ret	ret
1543
1544	;	;
1545	; iso_compare_names:	; iso_compare_names:
1546	; Compare the names DS:SI and DS:DI and report if they are	; Compare the names DS:SI and DS:DI and report if they are
1547	; equal from an ISO 9660 perspective.  SI is the name from	; equal from an ISO 9660 perspective.  SI is the name from
1548	; the filesystem; CX indicates its length, and ';' terminates.	; the filesystem; CX indicates its length, and ';' terminates.
#	Line 1373  iso_compare_names:	Line 1595  iso_compare_names:
1595	;	;
1596	; mangle_name: Mangle a filename pointed to by DS:SI into a buffer pointed	; mangle_name: Mangle a filename pointed to by DS:SI into a buffer pointed
1597	;       to by ES:DI; ends on encountering any whitespace.	;       to by ES:DI; ends on encountering any whitespace.
1598		;       DI is preserved.
1599	;	;
1600	;       This verifies that a filename is < FILENAME_MAX characters,	;       This verifies that a filename is < FILENAME_MAX characters,
1601	;       doesn't contain whitespace, zero-pads the output buffer,	;       doesn't contain whitespace, zero-pads the output buffer,
1602	;       and removes trailing dots and redundant slashes,	;       and removes trailing dots and redundant slashes,
1603	;       so "repe cmpsb" can do a compare, and the	;       so "repe cmpsb" can do a compare, and the
1604	;       path-searching routine gets a bit of an easier job.	;       path-searching routine gets a bit of an easier job.
1605	;	;
1606	mangle_name:	mangle_name:
1607		push di
1608	push bx	push bx
1609	xor ax,ax	xor ax,ax
1610	mov cx,FILENAME_MAX-1	mov cx,FILENAME_MAX-1
#	Line 1401  mangle_name:	Line 1625  mangle_name:
1625	.mn_end:	.mn_end:
1626	cmp bx,di ; At the beginning of the buffer?	cmp bx,di ; At the beginning of the buffer?
1627	jbe .mn_zero	jbe .mn_zero
1628	cmp byte [di-1],'.' ; Terminal dot?	cmp byte [es:di-1],'.' ; Terminal dot?
1629	je .mn_kill	je .mn_kill
1630	cmp byte [di-1],'/' ; Terminal slash?	cmp byte [es:di-1],'/' ; Terminal slash?
1631	jne .mn_zero	jne .mn_zero
1632	.mn_kill: dec di ; If so, remove it	.mn_kill: dec di ; If so, remove it
1633	inc cx	inc cx
#	Line 1413  mangle_name:	Line 1637  mangle_name:
1637	xor ax,ax ; Zero-fill name	xor ax,ax ; Zero-fill name
1638	rep stosb	rep stosb
1639	pop bx	pop bx
1640		pop di
1641	ret ; Done	ret ; Done
1642
1643	;	;
1644	; unmangle_name: Does the opposite of mangle_name; converts a DOS-mangled	; unmangle_name: Does the opposite of mangle_name; converts a DOS-mangled
1645	;                filename to the conventional representation.  This is needed	;                filename to the conventional representation.  This is needed
1646	;                for the BOOT_IMAGE= parameter for the kernel.	;                for the BOOT_IMAGE= parameter for the kernel.
	;                NOTE: A 13-byte buffer is mandatory, even if the string is
	;                known to be shorter.
1647	;	;
1648	;                DS:SI -> input mangled file name	;                DS:SI -> input mangled file name
1649	;                ES:DI -> output buffer	;                ES:DI -> output buffer
#	Line 1442  unmangle_name: call strcpy	Line 1665  unmangle_name: call strcpy
1665	;  On exit:	;  On exit:
1666	; SI -> File pointer (or 0 on EOF)	; SI -> File pointer (or 0 on EOF)
1667	; CF = 1 -> Hit EOF	; CF = 1 -> Hit EOF
1668		; ECX -> Bytes actually read
1669	;	;
1670	getfssec:	getfssec:
1671	TRACER 'F'	TRACER 'F'
1672	push ds	push ds
1673	push cs	push cs
1674	pop ds ; DS <- CS	pop ds ; DS <- CS
#	Line 1456  getfssec:	Line 1679  getfssec:
1679	mov ecx,[si+file_left]	mov ecx,[si+file_left]
1680	.ok_size:	.ok_size:
1681
1682	mov bp,cx	pushad
	push cx
	push si
1683	mov eax,[si+file_sector]	mov eax,[si+file_sector]
1684		mov bp,cx
1685	TRACER 'l'	TRACER 'l'
1686	call getlinsec	call getlinsec
1687	xor ecx,ecx	popad
	pop si
	pop cx
1688
1689		; ECX[31:16] == 0 here...
1690	add [si+file_sector],ecx	add [si+file_sector],ecx
1691	sub [si+file_left],ecx	sub [si+file_left],ecx
1692	ja .not_eof ; CF = 0	shl ecx,SECTOR_SHIFT ; Convert to bytes
1693		cmp ecx,[si+file_bytesleft]
1694	xor ecx,ecx	jb .not_all
1695	mov [si+file_sector],ecx ; Mark as unused	mov ecx,[si+file_bytesleft]
1696	xor si,si	.not_all: sub [si+file_bytesleft],ecx
1697		jnz .ret ; CF = 0 in this case...
1698		push eax
1699		xor eax,eax
1700		mov [si+file_sector],eax ; Unused
1701		mov si,ax
1702		pop eax
1703	stc	stc
1704		.ret:
	.not_eof:
1705	pop ds	pop ds
1706	TRACER 'f'	TRACER 'f'
1707	ret	ret
#	Line 1486  getfssec:	Line 1712  getfssec:
1712
1713	%include "getc.inc" ; getc et al	%include "getc.inc" ; getc et al
1714	%include "conio.inc" ; Console I/O	%include "conio.inc" ; Console I/O
1715		%include "configinit.inc" ; Initialize configuration
1716	%include "parseconfig.inc" ; High-level config file handling	%include "parseconfig.inc" ; High-level config file handling
1717	%include "parsecmd.inc" ; Low-level config file handling	%include "parsecmd.inc" ; Low-level config file handling
1718	%include "bcopy32.inc" ; 32-bit bcopy	%include "bcopy32.inc" ; 32-bit bcopy
#	Line 1495  getfssec:	Line 1722  getfssec:
1722	%include "highmem.inc" ; High memory sizing	%include "highmem.inc" ; High memory sizing
1723	%include "strcpy.inc" ; strcpy()	%include "strcpy.inc" ; strcpy()
1724	%include "rawcon.inc" ; Console I/O w/o using the console functions	%include "rawcon.inc" ; Console I/O w/o using the console functions
1725		%include "idle.inc" ; Idle handling
1726		%include "adv.inc" ; Auxillary Data Vector
1727		%include "localboot.inc" ; Disk-based local boot
1728
1729	; -----------------------------------------------------------------------------	; -----------------------------------------------------------------------------
1730	;  Begin data section	;  Begin data section
#	Line 1502  getfssec:	Line 1732  getfssec:
1732
1733	section .data	section .data
1734
	boot_prompt db 'boot: ', 0
	wipe_char db BS, ' ', BS, 0
	err_notfound db 'Could not find kernel image: ',0
	err_notkernel db CR, LF, 'Invalid or corrupt kernel image.', CR, LF, 0
	err_noram db 'It appears your computer has less than '
	asciidec dosram_k
	db 'K of low ("DOS")'
	db CR, LF
	db 'RAM.  Linux needs at least this amount to boot.  If you get'
	db CR, LF
	db 'this message in error, hold down the Ctrl key while'
	db CR, LF
	db 'booting, and I will take your word for it.', CR, LF, 0
	err_badcfg      db 'Unknown keyword in config file.', CR, LF, 0
	err_noparm      db 'Missing parameter in config file.', CR, LF, 0
	err_noinitrd    db CR, LF, 'Could not find ramdisk image: ', 0
	err_nohighmem   db 'Not enough memory to load specified kernel.', CR, LF, 0
	err_highload    db CR, LF, 'Kernel transfer failure.', CR, LF, 0
	err_oldkernel   db 'Cannot load a ramdisk with an old kernel image.'
	db CR, LF, 0
	err_notdos db ': attempted DOS system call', CR, LF, 0
	err_comlarge db 'COMBOOT image too large.', CR, LF, 0
	err_bssimage db 'BSS images not supported.', CR, LF, 0
	err_a20 db CR, LF, 'A20 gate not responding!', CR, LF, 0
	notfound_msg db 'not found', CR, LF, 0
	localboot_msg db 'Booting from local disk...', CR, LF, 0
	cmdline_msg db 'Command line: ', CR, LF, 0
	ready_msg db 'Ready.', CR, LF, 0
	trying_msg db 'Trying to load: ', 0
	crlfloading_msg db CR, LF ; Fall through
	loading_msg     db 'Loading ', 0
	dotdot_msg      db '.'
	dot_msg         db '.', 0
	fourbs_msg db BS, BS, BS, BS, 0
	aborted_msg db ' aborted.', CR, LF, 0
	crff_msg db CR, FF, 0
1735	default_str db 'default', 0	default_str db 'default', 0
1736	default_len equ ($-default_str)	default_len equ ($-default_str)
1737	boot_dir db '/boot' ; /boot/isolinux	boot_dir db '/boot' ; /boot/isolinux
1738	isolinux_dir db '/isolinux', 0	isolinux_dir db '/isolinux', 0
1739	ConfigName equ $	config_name db 'isolinux.cfg', 0
	isolinux_cfg db 'isolinux.cfg', 0
1740	err_disk_image db 'Cannot load disk image (invalid file)?', CR, LF, 0	err_disk_image db 'Cannot load disk image (invalid file)?', CR, LF, 0
1741
1742	%ifdef DEBUG_MESSAGES	%ifdef DEBUG_MESSAGES
#	Line 1552  dbg_isodir_msg db 'isolinux directory at	Line 1745  dbg_isodir_msg db 'isolinux directory at
1745	dbg_config_msg db 'About to load config file...', CR, LF, 0	dbg_config_msg db 'About to load config file...', CR, LF, 0
1746	dbg_configok_msg db 'Configuration file opened...', CR, LF, 0	dbg_configok_msg db 'Configuration file opened...', CR, LF, 0
1747	%endif	%endif
	;
	; Command line options we'd like to take a look at
	;
	; mem= and vga= are handled as normal 32-bit integer values
	initrd_cmd db 'initrd='
	initrd_cmd_len equ 7
1748
1749	;	;
1750	; Config file keyword table	; Config file keyword table
#	Line 1567  initrd_cmd_len equ 7	Line 1754  initrd_cmd_len equ 7
1754	;	;
1755	; Extensions to search for (in *forward* order).	; Extensions to search for (in *forward* order).
1756	;	;
1757	align 4, db 0	alignz 4
1758	exten_table: db '.cbt' ; COMBOOT (specific)	exten_table: db '.cbt' ; COMBOOT (specific)
1759	db '.img' ; Disk image	db '.img' ; Disk image
1760	db '.bin' ; CD boot sector	db '.bin' ; CD boot sector
#	Line 1579  exten_table_end:	Line 1766  exten_table_end:
1766	;	;
1767	; Floppy image table	; Floppy image table
1768	;	;
1769	align 4, db 0	alignz 4
1770	img_table_count equ 3	img_table_count equ 3
1771	img_table:	img_table:
1772	dd 1200*1024 ; 1200K floppy	dd 1200*1024 ; 1200K floppy
#	Line 1610  img_table:	Line 1797  img_table:
1797	; **** ISOLINUX:: We may have to make this flexible, based on what the	; **** ISOLINUX:: We may have to make this flexible, based on what the
1798	; **** BIOS expects our "sector size" to be.	; **** BIOS expects our "sector size" to be.
1799	;	;
1800	alignb 4, db 0	alignz 4
1801	BufSafe dw trackbufsize/SECTOR_SIZE ; Clusters we can load into trackbuf	BufSafe dw trackbufsize/SECTOR_SIZE ; Clusters we can load into trackbuf
	BufSafeSec dw trackbufsize/SECTOR_SIZE ; = how many sectors?
1802	BufSafeBytes dw trackbufsize ; = how many bytes?	BufSafeBytes dw trackbufsize ; = how many bytes?
	EndOfGetCBuf dw getcbuf+trackbufsize ; = getcbuf+BufSafeBytes
1803	%ifndef DEPEND	%ifndef DEPEND
1804	%if ( trackbufsize % SECTOR_SIZE ) != 0	%if ( trackbufsize % SECTOR_SIZE ) != 0
1805	%error trackbufsize must be a multiple of SECTOR_SIZE	%error trackbufsize must be a multiple of SECTOR_SIZE

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