init.asm

与MS-DOS兼容的DOS操作系统

;    File              : $Workfile$
;
;    Description       :
;
;    Original Author   : DIGITAL RESEARCH
;
;    Last Edited By    : $CALDERA$
;
;-----------------------------------------------------------------------;
;    Copyright Work of Caldera, Inc. All Rights Reserved.
;      
;    THIS WORK IS A COPYRIGHT WORK AND CONTAINS CONFIDENTIAL,
;    PROPRIETARY AND TRADE SECRET INFORMATION OF CALDERA, INC.
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;-----------------------------------------------------------------------;
;
;    *** Current Edit History ***
;    *** End of Current Edit History ***
;
;    $Log$
;    INIT.ASM 1.25 93/12/07 15:51:27
;    Move int13pointer to offset 0B4h as some app expects it there
;    INIT.ASM 1.24 93/11/18 18:57:20
;    Increase amount reserved for COMMAND.COM by 256 bytes
;    INIT.ASM 1.23 93/11/17 19:29:26
;    Change default DEBLOCK seg to FFFF for performance reasons
;    INIT.ASM 1.19 93/07/22 19:43:59 
;    switch over to REQUEST.EQU
;    ENDLOG


	include BIOSGRPS.EQU
	include	DRMACROS.EQU
	include	IBMROS.EQU
	include MSDOS.EQU
	include	REQUEST.EQU		; request header equates
	include	BPB.EQU
	include	UDSC.EQU
	include	DRIVER.EQU

; IBM AT Hardware equates

COMPRESSED	equ	TRUE		; enables compressed changes.

; a little macro to help locate things
; it warns us when the ORG get trampled on
orgabs	MACRO	address
	local	was,is
	was = offset $
	org address
	is = offset $
	if was GT is
	if2
		%OUT ERROR - absolute data overwritten !! moving it
	endif
	org	was
endif
ENDM

jmpfar	MACRO	address, fixup
	db	0EAh		; jmpf opcode
	dw	CG:address	; offset of destination
fixup	dw	0EDCh		; segment of destination
ENDM

callfar	MACRO	address, fixup
	db	09Ah		; callf opcode
	dw	CG:address	; offset of destination
fixup	dw	0EDCh		; segment of destination
ENDM

F5KEY		equ	3F00h
F8KEY		equ	4200h
	
IVECT	segment	at 0000h

		org	0000h*4
i0off		dw	?
i0seg		dw	?

		org	0001h*4
i1off		dw	?
i1seg		dw	?

		org	0003h*4
i3off		dw	?
i3seg		dw	?

		org	0004h*4
i4off		dw	?
i4seg		dw	?

		org	0015h*4
i15off		dw	?
i15seg		dw	?

		org	0019h*4
i19off		dw	?
i19seg		dw	?

		org	001Eh*4
i1Eptr		label	dword
i1Eoff		dw	?
i1Eseg		dw	?

		org	002Fh*4
i2Fptr		label	dword
i2Foff		dw	?
i2Fseg		dw	?

		org	006Ch*4
i6Cptr		label	dword
i6Coff		dw	?
i6Cseg		dw	?

IVECT	ends


CGROUP	group	CODE, RCODE, ICODE

CG	equ	offset CGROUP

CODE	segment 'CODE'

	Assume	CS:CGROUP, DS:Nothing, ES:Nothing, SS:Nothing

	public	strat

	extrn	ConsoleTable:word
	extrn	ClockTable:word
	extrn	SerParCommonTable:word
	extrn	DiskTable:near
	extrn	Int13Deblock:near
	extrn	Int13Unsure:near
	extrn	Int2FHandler:near
	extrn	ResumeHandler:near

	extrn	biosinit_end:byte	; End of the BIOS Init Code and Data
	extrn	biosinit:near
	
	extrn	boot_options:word
	extrn	rcode_fixups:word
	extrn	rcode_seg:word
	extrn	rcode_offset:word
	extrn	rcode_len:word
	extrn	icode_len:word
	extrn	current_dos:word
	extrn	device_root:dword
	extrn	mem_size:word
	extrn	ext_mem_size:word
	extrn	init_buf:byte
	extrn	init_drv:byte
	extrn	init_runit:byte
	extrn	comspec_drv:byte
	extrn	init_flags:word


include	biosmsgs.def			; Include TFT Header File

	Public	A20Enable
A20Enable proc near
;========
; This location is fixed up at run time to be a RET
; If the BIOS is relocated to the HMA then it is fixed up again to be
; CALLF IBMDOS:A20Enable; RET
; Calling this location at run time will ensure that the HMA is mapped
; in so we can access the HMA code.
;
A20Enable endp

init	proc	near			; this is at BIOSCODE:0000h
ifndef COPYPROT
	jmp	init0			; jump to reusable init space
else
	extrn	protect:near		; Jump to Copy protection code
	jmp	protect			; which will return control to
endif					; INIT0 on completion
init	endp

compflg	label	word
ifdef COPYPROT
	dw	'  '			; stops any compression working
else
	dw	offset CGROUP:INITDATA	; compresses from INITDATA onwards
endif					; this word set to 0 when compressed

	orgabs	06h
    db  'COMPAQCompatible'  

	dw	offset CGROUP:RCODE	; lets find offset of RCODE
MemFixup dw	0			;  and its relocated segment	


	Public	cleanup
cleanup	PROC	far			; BIOSINIT will call here later
	ret
cleanup	endp

;	Local single character buffer for Ctrl-Break handling
	public	serparFlag, serparChar

serparFlag	db	4 dup (FALSE)	; we haven't got any yet
serparChar	db	4 dup (?)	; will store one character


;	Device driver headers for serial/parallel devices

con_drvr	dw	CG:aux_drvr, 0	; link to next device driver
		dw	DA_CHARDEV+DA_SPECIAL+DA_ISCOT+DA_ISCIN+DA_IOCTL
		dw	CG:strat, CG:IntCon
		db	'CON     '

aux_drvr	dw	CG:prn_drvr, 0		; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntCOM1
		db	'AUX     '

prn_drvr	dw	CG:clock_drvr, 0	; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntLPT1
		db	'PRN     '

clock_drvr	dw	disk_drvr, 0		; link to next device driver
		dw	DA_CHARDEV+DA_ISCLK
		dw	CG:strat, CG:IntClock
		db	'CLOCK$  '

com1_drvr	dw	CG:lpt1_drvr, 0		; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntCOM1
		db	'COM1    '

com2_drvr	dw	CG:com3_drvr, 0		; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntCOM2
		db	'COM2    '

com3_drvr	dw	CG:com4_drvr, 0		; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntCOM3
		db	'COM3    '

IFDEF EMBEDDED
	extrn	rdisk_drvr:near
com4_drvr	dw	CG:rdisk_drvr, 0	; link to next device driver
ELSE		
com4_drvr	dw	-1, -1			; link to next device driver
ENDIF	
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntCOM4
		db	'COM4    '


	orgabs	0b4h			; save address at fixed location
					;  for dirty apps

	Public	i13pointer, i13off_save, i13seg_save

i13pointer	label	dword		; address of ROS Int 13h entry
i13off_save	dw	?
i13seg_save	dw	?


	orgabs	0b8h			; REQ_HDR

	public	req_ptr, req_off, req_seg

req_ptr	label	dword
req_off	dw	0			;** fixed location **
req_seg	dw	0			;** fixed location **

strat	proc	far
	mov	cs:req_off,bx
	mov	cs:req_seg,es
	ret
strat	endp

lpt1_drvr	dw	CG:lpt2_drvr, 0		; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntLPT1
		db	'LPT1    '


lpt2_drvr	dw	CG:lpt3_drvr, 0		; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntLPT2
		db	'LPT2    '

lpt3_drvr	dw	CG:com2_drvr, 0		; link to next device driver
		dw	DA_CHARDEV
		dw	CG:strat, CG:IntLPT3
		db	'LPT3    '

	orgabs	100h			; save vectors at fixed location
					;  for dirty apps

	Public	orgInt13

NUM_SAVED_VECS	equ	5

vecSave		db	10h
		dw	0,0
		db	13h
orgInt13	dw	0,0
		db	15h
		dw	0,0
		db	19h
		dw	0,0
		db	1Bh
		dw	0,0
	
Int19Trap:
	cld
	cli				; be sure...
	push	cs
	pop	ds
	lea	si,vecSave
	mov	cx,NUM_SAVED_VECS	; restore this many vectors
Int19Trap10:
	xor	ax,ax			; zero AH for lodsb
	mov	es,ax			; ES -> interrupt vectors
	lodsb				; AX = vector to restore
	shl	ax,1
	shl	ax,1			; point at address
	xchg	ax,di			; ES:DI -> location to restore
	movsw
	movsw				; restore this vector
	loop	Int19Trap10		; go and do another
	int	19h			; and go to original int 19...


	orgabs	16ch			; PRN:/AUX: the device number

devno	db	0,0			;** fixed location **

	Public	NumDiskUnits, DeblockSeg

disk_drvr	dw	CG:com1_drvr, 0	; link to next driver
		dw	DA_NONIBM+DA_GETSET+DA_REMOVE+DA_BIGDRV
		dw	CG:strat, CG:IntDisk
NumDiskUnits	db	5, 7 dup (?)
		dw	0EDCh		; checked by DRIVER.SYS
		dw	0		; was allocate UDSC
DeblockSeg	dw	0A000h		; segment we start deblocking


IntLPT1:				; LPT1
	call	DeviceDriver
	dw	0
	
IntLPT2:				; LPT2
	call	DeviceDriver
	dw	1

IntLPT3:				; LPT3
	call	DeviceDriver
	dw	2

IntCOM1:				; AUX = COM1
	call	DeviceDriver
	dw	3

IntCOM2:				; COM2
	call	DeviceDriver
	dw	4

IntCOM3:				; COM3
	call	DeviceDriver
	dw	5

IntCOM4:				; COM4
	call	DeviceDriver
	dw	6

IntCon:
	call	DeviceDriver
	dw	offset CGROUP:ConsoleTable

IntClock:
	call	DeviceDriver
	dw	offset CGROUP:ClockTable

	Public	IntDiskTable
IntDisk:
	call	DeviceDriver
IntDiskTable:
	dw	offset CGROUP:DiskTable

DeviceDriver	proc	near
	call	A20Enable		; make sure A20 is on
	jmpfar	DriverFunction, DriverFunctionFixup
DeviceDriver	endp

	extrn	i13_AX:word

	Public	Int13Trap

Int13Trap	proc	far
;--------
; The Int 13 code is in low memory for speed, with unusual conditions
; having the overhead of A20Enable calls
;
	cmp	ah,ROS_FORMAT		; ROS format function?
	 je	Int13TrapFormat
Int13Trap10:
	mov	cs:i13_AX,ax		; save Op/Count in case of error
	clc
	pushf				; fake an Int
	call	cs:i13pointer		; call the ROM BIOS
	 jc	Int13Trap20		; check for error
	ret	2			; none, so return to caller
Int13Trap20:
	cmp	ah,9			; it it a DMA error ?
	 je	Int13TrapDMA		;  then deblock it
	call	Int13TrapUnsure		; else declare floppy drive unsure
	stc				; restore error flag
	ret	2			; return to user

Int13TrapFormat:
	call	Int13TrapUnsure		; mark media as unsure
	jmps	Int13Trap10		;  and resume

Int13TrapDMA:
	call	A20Enable		; make sure A20 is on
	jmpfar	Int13Deblock, Int13DeblockFixup

Int13TrapUnsure proc near
	call	A20Enable		; make sure A20 is on
	callfar	Int13Unsure, Int13UnsureFixup
	ret
Int13TrapUnsure	endp

Int13Trap	endp


	Public	Int2FTrap

Int2FTrap	proc	far
;--------
	jmpfar	Int2FHandler, Int2FFixup
Int2FTrap	endp


Resume	proc	far
;-----
	call	A20Enable		; make sure A20 is on
	jmpfar	ResumeHandler, ResumeFixup
Resume	endp

Int0Trap proc	far
;-------
	call	A20Enable		; make sure A20 is on
	jmpfar	Int0Handler, Int0Fixup
Int0Trap endp

	Public	FastConsole

FastConsole  proc   far
;----------
; RAM entry to ensure INT29 vector is below INT20 vector
; We keep the normal path low to maxmimise performance, but on backspace we
; take the A20Enable hit and call high for greater TPA.
;
	pushx	<ax, bx, si, di, bp>	; old ROS corrupts these
	cmp	al,8			; back space character
	 je	Fastcon30		; special case
Fastcon10:
	mov	ah,0Eh			; use ROS TTY-like output function
	mov	bx,7			; use the normal attribute
	int	VIDEO_INT		; output the character in AL
Fastcon20:
	popx	<bp, di, si, bx, ax>
	iret

Fastcon30:
	call	A20Enable		; make sure A20 is on
	jmpfar	OutputBS, OutputBSFixup	; call up to the HMA

FastConsole endp

	Public	ControlBreak

ControlBreak	proc	far
;-----------
	mov	cs:word ptr local_char,'C'-40h + (256*TRUE)
;;	mov	local_char,'C'-40h	; force ^C into local buffer
;;	mov	local_flag,TRUE		; indicate buffer not empty
Int1Trap:
Int3Trap:
Int4Trap:
	iret
ControlBreak	endp

	public	daycount
daycount	dw	0



; More Disk Data

	public	local_buffer,local_id,local_pt

local_buffer	db	512 dup (?)	; local deblocking buffer
SECSIZE		equ	512
IDOFF		equ	SECSIZE-2	; last word in boot sector is ID
PTOFF		equ	IDOFF-40h	; 4*16 bytes for partition def's
local_id	equ	word ptr local_buffer + IDOFF
local_pt	equ	word ptr local_buffer + PTOFF

	public	bpbs,bpb160,bpb360,bpb720,NBPBS

;	List of BPBs that we usually support

bpb160		BPB	<512,1,1,2, 64, 40*1*8,0FEh,1, 8,1,0,0>
bpb180		BPB	<512,1,1,2, 64, 40*1*9,0FCh,2, 9,1,0,0>
bpb320		BPB	<512,2,1,2,112, 40*2*8,0FFh,1, 8,2,0,0>
bpb360		BPB	<512,2,1,2,112, 40*2*9,0FDh,2, 9,2,0,0>
bpb1200		BPB	<512,1,1,2,224,80*2*15,0F9h,7,15,2,0,0>
bpb720		BPB	<512,2,1,2,112, 80*2*9,0F9h,3, 9,2,0,0>
bpb1440		BPB	<512,1,1,2,224,80*2*18,0F0h,9,18,2,0,0>
bpb2880		BPB	<512,2,1,2,240,80*2*36,0F0h,9,36,2,0,0>
NBPBS		equ	8

;	The following is a template, that gets overwritten
;	with the real parameters and is used while formatting

	public	local_parms,parms_spt,parms_gpl
	public	layout_table,bpbtbl

local_parms	db	11011111b	; step rate