Title Micro_Decision Installation SubProceedure Number 2 (6_Jul_84)
;
;	Copyright 1984
;	Morrow Designs, Inc.
;	San Leandro, Ca.
;	John Zalabak
;
	.z80
	Aseg
	Org	0100h

;----------------------------------------------------------------------
; Index (6_Jul_84)
;-----------------
;
;	Isub2_Main	Main Line of Sub Installation Proceedure 2
;
;	Get_Version	Check the CP/M version
;	Install_Drives	Install the Number of Physical Drives
;
;	Read_Cpm2_Bios	Read the Cp/m 2.2 Bios
;	Write_Cpm2_Bios	Write the Cp/m 2.2 Bios
;	Setup_IX	Setup the IX and Initialize Pertinant Values
;
;	Get_Bios_Pntr	Get One of the Bios Pointers
;	Get_DE_Indr_HL	Load the DE register Pair Indirectly Through the HL
;
;	Cpm2_Bias	Figure the Memory Bias for Cpm 2.2
;	Apply_Bias_DE	Apply the Bias to the DE Pair
;
;	Report_Errors	Report an Error on the Console
;	Print_Message	Print a Message on the Console
	page		60

;----------------------------------------------------------------------
; Equates (25_Jun_84)
;--------------------
;
		;Bios/Bdos Equates
Bios_Entry	equ	0		;Bios Entry Point
Bdos_Entry	equ	5		;Bdos:	Entry Vector Location
Bdos_PString	equ	9		;	Print a Sting on the Console
Bdos_Ret_Ver	equ	12		;       Return CP/M version

		; Cp/m 2.2 Bios Jump Table Offsets
Bios_Offset	equ	200h		;Offset: Bios Start from Start Disk Buffer
Bios_Address	equ	1		;Address of Bios (Warm Boot Vector Addr)
WBoot_Offset	equ	4		;Warm Boot address (Gives base of Bios)

RdBlk_Offset	equ	37h		;Read a Block from the Floppy Disk
WrBlk_Offset	equ	3Ah		;Write a Block to the Floppy Disk

RamDatX_Offset	equ	40h		;Pointer to RamDatX Area
RamDatY_Offset	equ	42h		;Pointer to RamDatY Area
Mtab_Offset	equ	44h		;Pointer to Mtabs

		; RamDatX Area Definitions
HstDsk		equ	0		;Host Level Disk
HstTrk		equ	1		; "     "   Track
HstSec		equ	2		; "     "   Sector
SecCnt		equ	3		;Sector Count (1 to n)
Retry		equ	4		;Error Retry Count
HstBuf		equ	5		;Host Buffer
ErFlag		equ	7		;Error Flag

		; Error String Codes
Error_Opening	equ	10		;Error Intro
Error_Version	equ	11		;Wrong Version of CP/M
Sys_Read_Err	equ	12		;Unable to read System from the Disk
Sys_Write_Err	equ	13		;Unable to Write System to the Disk

		;Non Printing Ascii Equates
Control_C	equ	03h		;Control C (Force CPM Warm Boot)
Tab		equ	09h		;Tab
Lf		equ	0Ah		;Line Feed
Cr		equ	0Dh		;Carriage Return

		;Other Definitions
Disk_Buffer	equ	2000h		;Start of Disk Buffer (must be above Rom)
Mtab_Leng	equ	9		;Length of an Mtab
Tot_Mtab	equ	5		;Total Number of Mtabs
		page

;======================================================================
; Main Line of Sub Installation Proceedure 2 (6_Jul_84)
;======================================================
;
Isub2_Main:
	call	Get_Version		;If (this is NOT Version 2.x)
	jr	nz,ImErr		;	Goto Report Error

	call	Read_Cpm2_Bios		;Read the Bios
	or	a			;If (there was an error)
	jr	nz,ImErr		;	Goto Report Error

	call	Install_Drives		;Install the Drives

	call	Write_Cpm2_Bios		;Write the Bios
	or	a			;If (There was an Error)
	jr	z,ImDone		;	Goto Report Error

ImErr:	call	Report_Errors		;Report the Error
ImDone:	jp	Bios_Entry		;Return


;======================================================================
; Check the CP/M version (5_Jul_84)
;==================================
;	1) This routine checks the CP/M version. It returns with the
;	   Z flag = 1 if CP/M 2.
;
Get_Version:
	ld	c,Bdos_Ret_Ver		;Return version Bdos call
	call	Bdos_Entry
	ld	a,0F0h
	and	l
	cp	20h			;If (this is NOT CP/M 2.x)
	ld	a,Error_Version		;	A:= Version Error
	ret	nz			;	Return

	ld	a,0			;Else	A:= No Error
	ret				;	Return
	page

;======================================================================
; Install the Number of Physical Drives (6_Jul_84)
;=================================================
;	1) This routine Updates the Bios Image of Vnum, copies the resident
;	   system's Mtabs into the Memory image and then resets the current
;	   track values in the memory image to De:Calibrated (0FFh).
;
Install_Drives:
	call	Cpm2_Bias		;Figure the Bias values

	ld	de,RamDatY_Offset
	call	Get_Bios_Pntr		;DE:= Pointer to Start of RamDatY
	dec	de
	dec	de			;DE:= Pointer to Vnum
	ld	a,(de)			;A:= Vnum
	call	Apply_Bias_DE		;DE:= Pointer to Memory Image of Vnum
	ld	(de),a			;Update Vnum

	ld	de,Mtab_Offset
	call	Get_Bios_Pntr		;DE:= Pointer to Start of Mtabs

	push	de
	call	Apply_Bias_DE		;DE:= Pointer to Memory Image of Mtabs
	pop	hl			;HL:= Pointer to System Mtabs
	ld	bc,Mtab_Leng * Tot_Mtab	;BC:= Counter for number of Mtabs

	push	de			;(Save pointer to start of Memory Mtabs)
	ldir				;Move the System Mtabs to Memory Image
	pop	hl
	ld	de,Mtab_Leng - 1	;DE:= Offset to Current Track in Mtab
	add	hl,de			;HL:= Pointer to Current Track (memory image)

	ld	de,Mtab_Leng		;DE:= Length of an Mtab
	ld	b,Tot_Mtab		;B:= Counter (total number of Mtabs)
IdLp1:	ld	(hl),0FFh		;Repeat	Reset the Current Track
	add	hl,de			;	HL:= HL + Mtab_Leng
	djnz	IdLp1			;Until (all current track values reset)
	ret				;Return
	page

;======================================================================
; Read the Cp/m 2.2 Bios (23_Jun_84)
;===================================
;	1) This routine reads the Bios from the system tracks into the
;	   next free memory space (next free space pointer set in Build_Tables)
;
Read_Cpm2_Bios:
	call	Setup_IX		;Set IX to RamdatX and Save the Original
	ld	de,RdBlk_Offset		;DE:= Offset to the RdBlk Address
	call	Get_Bios_Pntr

	ex	de,hl			;HL:= Vector to Read a Block Routine
	call	IR_HL			;Execute the read a block routine
	ld	a,(ix+ErFlag)
	or	a			;If (there were no errors)
	ret	z			;	Return

	ld	a,Sys_Read_Err		;Else	A:= Error Code
	ret				;	Return

IR_HL:	jp	(hl)

;======================================================================
; Write the Cp/m 2.2 Bios (25_Jun_84)
;====================================
;	1) This routine writes the Bios back to the system tracks.
;
Write_Cpm2_Bios:
	call	Setup_IX		;Set IX to RamdatX and Save the Original
	ld	de,WrBlk_Offset		;DE:= Offset to the WrBlk Address
	call	Get_Bios_Pntr

	ex	de,hl			;HL:= Vector to Read a Block Routine
	call	IW_HL			;Execute the Write a Block routine
	ld	a,(ix+ErFlag)
	or	a			;If (There were no errors)
	ret	z			;	Return

	ld	a,Sys_Write_Err		;Else	A:= Error Code
	ret				;	Return

IW_HL:	jp	(hl)
	page

;----------------------------------------------------------------------
; Setup the IX and Initialize Pertinant Values (22_Jun_84)
;---------------------------------------------------------
;	1) This routine Sets the IX register 2 pages before the start of
;	   the Bdos and then initializes the essential parameters.
;
Setup_IX:
	ld	hl,(Bdos_Entry+1)	;HL:= Pointer to Start of Bdos
	ld	l,0			;HL:= Pointer to Base of Bios
	dec	h			;HL:= Base Page of Bios - 1
	dec	h
	push	hl
	pop	ix			;IX:= Base Page of Bios - 1

	ld	(ix+HstDsk),0		;Drive:= 0
	ld	(ix+HstTrk),1		;Starting_Track:= 1
	ld	(ix+HstSec),2		;Starting_Sector:= 2
	ld	(ix+SecCnt),4		;Number_of_Sectors_to_Read:= 4
	ld	(ix+Retry),10		;Retries:= 10

	ld	(ix+HstBuf),  LOW  Disk_Buffer
	ld	(ix+HstBuf+1),HIGH Disk_Buffer
	ld	(ix+ErFlag),0		;Error_Flag:= Reset
	ret

;----------------------------------------------------------------------
; Get One of the Bios Pointers (20_Jun_84)
;-----------------------------------------
;
Get_Bios_Pntr:
	ld	hl,(Bios_Entry+1)	;HL:= Pointer to Warm Boot Entry
	ld	l,0			;HL:= Pointer to Base of Bios
	call	Get_DE_Indr_HL		;DE:= Contents of Addr Pointed to by HL
	ret				;Return

;----------------------------------------------------------------------
; Load the DE register Pair Indirectly Through the HL (20_Jun_84)
;---------------------------------------------------------------- 
;	1) This routine Loads the DE register pair Indirectly through the
;	   HL register pair after adding the entry values of the DE and HL.
;	2) Register Usage:
;		DE -> On Entry = Offset; On Exit = (HL + DE)
;		HL -> [preseved] Base Address
;
Get_DE_Indr_HL:
	add	hl,de			;HL:= Pointer to RamDatY Pointer
	ld	e,(hl)
	inc	hl
	ld	d,(hl)			;DE:= Contents of Addr Pointed to by HL
	dec	hl
	ret				;Return
	page

;----------------------------------------------------------------------
; Figure the Memory Bias for Cpm 2.2 (21_Jun_84)
;-----------------------------------------------
;	1) This routine Sets up the Bios Base and the Bios Bias. The Bios
;	   Base is the starting memory address of where the bios is current
;	   loaded. The bios Bias is the Starting Memory Address of where the
;	   bios is intented to be loaded.
;
Cpm2_Bias:
	ld	hl,Disk_Buffer		;HL:= Start of the Disk Buffer
	ld	de,Bios_Offset		;DE:= Offset to Bios Start
	add	hl,de			;HL:= Pointer to Start of Cpm Bios
	ld	(Bios_Base),hl		;(save the Base address of the Bios)
	ld	de,WBoot_Offset		;DE:= Offset to Warm Boot Address
	call	Get_DE_Indr_HL
	ld	e,0			;DE:= Start of Load Location of Bios
	ld	(Bios_Bias),de		;(save the Load address of the Bios)
	ret

;----------------------------------------------------------------------
; Apply the Bias to the DE Pair (21_Jun_84)
;------------------------------------------
;	1) This routine adjusts the DE pair. On entry, the DE pair is pointing
;	   to the actual load address of an object. On exit, the DE pair is
;	   pointing to the current memory location containing that object.
;	2) Register Usage:
;		DE -> Entry: Load Address; Exit: Actual Address
;		HL -> Used in figuring the offsets
;
Apply_Bias_DE:
	push	hl
	ex	de,hl			;HL:= Load Address Data Object
	ld	de,(Bios_Bias)		;DE:= Load Address Base of Bios
	or	a
	sbc	hl,de			;HL:= Offset from Bios Base
	ld	de,(Bios_Base)		;DE:= Offset to Base of Bios in Memory
	add	hl,de
	ex	de,hl			;DE:= Current Memory address
	pop	hl
	ret
	page

;======================================================================
; Report Errors (5_Jun_84)
;=========================
;	1) Report Errors on the console.
;	2) Register Usage:
;		A  -> Has Error Code on entry
;
Report_Errors:
	push	af
	ld	a,Error_Opening
	call	Print_Message		;Print the Error Opening Message
	pop	af

	call	Print_Message		;Print the Error Message
	ret

;======================================================================
; Print a Message on the Console (5_Jul_84)
;==========================================
;	1) This routine prints a message string on the console.
;	2) Register Usage:
;		A  -> Has Error Code on entry
;		B  -> Counter
;		C  -> Holds copy of Error Code
;		DE -> Pointer to Message String
;		HL -> Pointer into Message Code Table
;
Print_Message:
	push	af
	ld	de,CrLf			;DE:= Pointer to Cr/Lf String
	ld	c,Bdos_PString		;C:= Print String Function
	call	Bdos_Entry		;Print Carriage Return Line Feed
	pop	af

	ld	c,a			;C:= Error Code to Find
	ld	b,Max_Table
	ld	hl,Message_Table	;HL:= Start of the Message table
PMLp1:	ld	a,(hl)			;Repeat	A:= Table's Message Code
	inc	hl
	ld	e,(hl)
	inc	hl
	ld	d,(hl)			;	DE:= Pointer to String
	inc	hl			;	(HL equal to start next entry)
	cp	c			;	If (Code eq table)
	jr	z,PMprn			;		Goto Print
	djnz	PMLp1			;Until (the whole tables been checked)

	ld	de,NoCode		;(set pointer to 'Unrecognized Message')
PMprn:	ld	c,Bdos_PString		;
	call	Bdos_Entry		;	Print the Message
	ret
	page

;----------------------------------------------------------------------
; Message Strings (6_Jul_84)
;---------------------------
;
; Message String Lookup Table 
;-----------------------------
;
Message_Table:
	db	Error_Opening	;Error Intro
	dw	ErrOpn
	db	Error_Version	;Wrong Version of CP/M
	dw	EVmsg
	db	Sys_Read_Err	;Unable to read System from the Disk
	dw	SRmsg
	db	Sys_Write_Err	;Unable to Write System to the Disk
	dw	SWmsg
End_Table:
Max_Table	equ	( (End_Table - Message_Table)/3 ) + 1
		page

;----------------------------------------------------------------------
; Text Strings (6_Jul_84)
;------------------------
;
ErrOpn:	db	'*=> Error: $'
EVmsg:	db	'This Program only runs under CP/M 2.x $'
SRmsg:	db	'Unable to read System from the Disk $'
SWmsg:	db	'Unable to Write System to the Disk $'

CrLf:	db	Cr,Lf,'$'
NoCode:	db	'Unrecognized Message $'

;----------------------------------------------------------------------
; Local Data Area (5_Jul_84)
;---------------------------
;
Bios_Base:	dw	0		;Actual Memory Address of the Bios
Bios_Bias:	dw	0		;Intended Load Address of the Bios
		end