title	TRACK 0 LOADER -- WD 1793, 2793; HDC-1001 

;-------------------------------- 
; author  Marcus G. Calescibetta
; date    April 23, 1984
; version 2.5
;--------------------------------
	
	.z80				; Zilog mneumonics used

;-------------------------
; HDC-1001 PORT ADDRESSES
;-------------------------

hbase	equ	0e0h			; base port address of hdc-1001
hdata	equ	hbase+0			; data register
herror	equ	hbase+1			; error register
hwrtpre	equ	hbase+1			; write pre-compensation register
hseccnt	equ	hbase+2			; sector count register
hsec	equ	hbase+3			; sector number register
hcyllow	equ	hbase+4			; cylinder low register
hcylhi	equ	hbase+5			; cylinder high register
hsdh	equ	hbase+6			; size - drive - head register
hstatus	equ	hbase+7			; status register 
hcmd	equ	hbase+7			; command register 

;-------------------
; HDC-1001 COMMANDS
;-------------------

cmdrst1	equ	01eh			; restore soft sector drive
cmdrst2	equ	01fh			; restore hard sector drive
cmdrd	equ	020h			; read sector command
cmdwrt	equ	030h			; write sector command		

;-----------------------------
; STATUS REGISTER BIT TESTERS
;-----------------------------

bsybit	equ	080h			; busy bit
rdybit	equ	040h			; data request bit
errbit	equ	001h			; error bit	

;-----------------------------
; FLOPPY CONTROLLER REGISTERS
;-----------------------------

fbase	equ	0ch			; base port addr of wd-1793 or wd-27
fcmd	equ	fbase+0			; command register		
fstat	equ	fbase+0			; status register
ftrk	equ	fbase+1			; track register
fsec	equ	fbase+2			; sector register
fdata	equ	fbase+3			; data register
fwait	equ	014h			; wait register
fdsd	equ	014h			; density - size - drive register

;----------------------------
; FLOPPY CONTROLLER COMMANDS 
;----------------------------

fstp	equ	001h

frst	equ	00ch + fstp		; fpy restore, head load, verify
fsek	equ	01ch + fstp		; fpy seek, head load, verify
frda	equ	0c4h			; fpy read addr
fwrt	equ	0a4h			; fpy write sec
frd	equ	084h			; fpy read sec
fint	equ	0d0h			; fpy int 

;---------------------
; FILE CONTROLL BLOCK
;---------------------

fcb	equ	00005Ch			; fcb base addr
fcbcr	equ	fcb+32			; fcb current record addr
buf	equ	00900h			; buffer for track 0 loader
boot	equ	00000h			; jump to warm boot addr
bdos	equ	00005h			; jump to bdos addr
coni	equ	01h			; bdos console input  function no.
cono	equ	02h			; bdos console output function no.
cr	equ	0dh			; ascii value for carriage return
lf	equ	0ah			; ascii value for line feed

;------------------
; START OF PROGRAM
;------------------

start:
	ld	sp,stack		; initalize stack pointer
	ld	hl,signon		; load hl w addr of signon msg
	call	outmsg			; display signon msg on console

;--------------------------------
; CHECK FOR FILE IN COMMAND LINE
;--------------------------------

ckf:
	ld	a,(fcb+1)		; load a w. first letter of cmd tail
	cp	' '			; check if its blank
	jp	z,getldr		; jump if no command tail

;-----------
; OPEN FILE 
;-----------

opf:
	ld	de,fcb			; load de w fcb addr for bdos call
	call	open			; try and oper file given if cmd line
	inc	a			; bdos returns a 255 if file not found
	jp	z,fnf 			; jump if no file

;-----------
; READ FILE 
;-----------

rdf:
	xor	a			; clear a register
	ld	(fcbcr),a		; set current record to zero 

	ld	de,buf			; this is where the file is read into
rdflp:
	push	de			; save buffer addres so can update
	call	dma			; tell bdos to read file into buffer

	ld	de,fcb			; set up for bdos read 
	call	dread			; read one logical record

	pop	de			; recall current buffer address 
	or	a			; check if read successful
	jr	nz,putldr		; assume EOF if error on read

	ld	hl,080h			; load hl w size of logical record
	add	hl,de			; add in curr bf addr so hl is new addr
	ex	de,hl			; put new bf add in de for dma call
	jr	rdflp			; read in next logical record

;------------------------------
; GET SYSTEM FROM SOURCE DRIVE
;------------------------------

getldr:
	ld	hl,stypmsg
	call	crmsg
	call	getcc
	ld	(drvtyp),a

	cp	cr
	jp	z,putldr
	cp	'H'
	jr	z,gethrd
	cp	'F'
	jr	nz,getldr

getfpy:
	ld	hl,smsg
	call	getdrv
	ld	(sdrv),a

	ld	a,(sdrv)
	call	setden
	call	frdtrk
	jp	putldr
gethrd:
	ld	hl,smsg
	call	getdrv
	ld	(sdrv),a

	ld	a,(sdrv)
	call	hrdtrk
	jp	putldr

;---------------------------------
; PUT SYSTEM ON DESTINATION DRIVE 
;---------------------------------

putldr:
	ld	a,(drvtyp)
	and	a
	jr	z,getdtyp
	cp	0dh
	jr	nz,putjmp
getdtyp:
	ld	hl,dtypmsg
	call	crmsg
	call	getcc

	cp	cr
	jp	z,reboot

putjmp:
	cp	'H'
	jp	z,puthd
	cp	'F'
	jr	nz,putldr

putfpy:
	ld	hl,dmsg
	call	getdrv
	ld	(ddrv),a

	ld	a,(ddrv)
	call	setden
	ld	a,(ddrv)
	call	patchden
	ld	a,(ddrv)
	call	setden
	call	fwrttrk
	jp	reboot
puthd:
	ld	hl,dmsg
	call	getdrv
	ld	(ddrv),a

	ld	a,(ddrv)
	call	hwrttrk
	jp	reboot

;--------------------------
; SET DISK DENSITY TRK 000
;--------------------------

setden:
tst5dd:
	ld 	(drv),a
	ld	b,018h
	or	b
	out	(fwait),a
	ld	(dsd),a
	ld	d,04
	ld	a,d
	ld	(buf+07eh),a
	ld	hl,tst8sd
	jr	frestore

tst8sd:
	ld	a,(drv)
	out	(fwait),a
	ld	(dsd),a
	ld	hl,tst8dd
	ld	d,026d
	ld	a,d
	ld	(buf+07eh),a
	jr	frestore

tst8dd:
	ld	a,(drv)
	ld	b,08h
	or	b
	out	(fwait),a
	ld	(dsd),a
	ld	hl,trk0err
	ld	d,04
	ld	a,d
	ld	(buf+07eh),a
	jò	frestore

trk0err:
	ld	hl,tk0rder
	call	crmsg
	jp	0

frestore:
	call	tstrdy
	
	ld	a,frst
	out	(fcmd),a
	call	delay
	in	a,(fwait)

	in	a,(fcmd)
	and	018h
	ret	z
	jp	(hl)

;-----------------------------------------------------
; GET DISK DENSITY OF TRK 001 AND PATCH TO LOC. buf+07fh
;-----------------------------------------------------

patchden:
chk5dd:
	ld 	(drv),a
	ld	b,018h
	or	b
	out	(fwait),a
	ld	(dsd),a
	ld	a,0e6h
	ld	(buf+07fh),a
	ld	hl,chk8sd
	jr	fseek

chk8sd:
	ld	a,(drv)
	out	(fwait),a
	ld	(dsd),a
	ld	a,0e5h
	ld	(buf+07fh),a
	ld	hl,chk8dd
	jr	fseek

chk8dd:
	ld	a,(drv)
	ld	b,08h
	or	b
	out	(fwait),a
	ld	(dsd),a
	ld	a,0e6h
	ld	(buf+07fh),a
	ld	hl,sekerr
	jò	fseek

sekerr:
	ld	hl,sekmsg
	call	crmsg
	jp	0

fseek:
	call	tstrdy
	ld	a,1
	out	(fdata),a
	ld	a,fsek
	out	(fcmd),a
	call	delay
	in	a,(fwait)
	in	a,(fcmd)
	and	018h
	jr	z,chkds
	jp	(hl)

chkds:
	ld	a,(buf+07fh)
	and	0e5h
	ret	z

	ld	a,(dsd)
	set	2,a
	out	(fwait),a
	
;	call	tstrdy
	
	di
	ld	c,fdata
	ld	hl,trkid

	ld	a,frda
	out	(fcmd),a
	call	delay
frdalp:
	in	a,(fwait)
	or	a
	jp	p,frdax
	ini
	jr	frdalp
frdax:
	in	a,(fcmd)
	and	018h
	ret	nz

	ld	a,(sideno)
	and	a
	ret	z

	ld	a,0e7h
	ld	(buf+07fh),a
	ret

;--------------------
; FLOPPY WRITE TRACK
;--------------------

fwrttrk:
	call	tstrdy

	in	a,(fstat)
	bit	6,a
	jr	z,nwrtpro

	ld	hl,wrpmsg
	call	crmsg
	call	getcc
	cp	3
	jp	z,reboot
	jp	fwrttrk

nwrtpro:
	ld	e,1
	ld	c,fdata
	ld	hl,buf
nextsec:
	di

	ld	a,e
	out	(fsec),a
	xor	a
	out	(ftrk),a
	ld	a,fwrt
	out	(fcmd),a
fwrtlp:
	in	a,(fwait)
	or	a
	jp	p,fwrtout
	outi
	jr	fwrtlp
fwrtout:
	ei
	ld	a,d
	cp	e
	jp	z,reboot
	inc	e
	jr	nextsec

;-----------------
; HARD READ TRACK 
;-----------------

hrdtrk:
	ld	(drv),a

	ld	de,0512d		; bytes per sector
	ld	b,020h			; sdh reg sec. size setting
	ld	c,016d			; sector per track
	call	settsk
	ld	a,cmdrst1
	out	(hcmd),a
	call	polbsy
	ld	a,cmdrd
	out	(hcmd),a
	call	polbsy
	jr	z,hrdsec

	ld	hl,dmard
	call	crmsg
	call	getcc
	cp	'C'
	jp	z,cartrd

fixrd:
	ld	de,0256
	ld	b,2			;*
	ld	c,32d
	call	settsk
	ld	a,cmdrst2
	out	(hcmd),a
	call	polbsy
	ld	a,cmdrd
	out	(hcmd),a
	call	polbsy
	jr	z,hrdsec

cartrd:
	ld	de,0256
	ld	b,0			;*
	ld	c,32d
	call	settsk
	ld	a,cmdrst2
	out	(hcmd),a
	call	polbsy
	ld	a,cmdrd
	out	(hcmd),a
	call	polbsy
	jr	z,hrdsec

hrderr:
	ld	hl,tk0rder
	call	crmsg
	jp	0

hrdsec:
	ld	(bps),de
	ld	de,0
	ld	hl,buf
hrdnx:
	ld	a,d
	out	(hsec),a
	ld	a,cmdrd
	out	(hcmd),a
	call	polbsy
	call	rxdata
	call	polbsy	
	jp	nz,hrderr

	inc	d
	ld	a,c
	cp	d
	jp	nz,hrdnx	
	ret

;------------------
; HARD WRITE TRACK
;------------------

hwrttrk:
	ld	(drv),a
	
	ld	a,020h
	ld	(buf+07eh),a

	ld	de,0512d		; bytes per sector
	ld	b,020h			; sdh reg sec. size setting
	ld	c,016d			; sector per track
	call	settsk
	ld	a,cmdrst1
	out	(hcmd),a
	call	polbsy
	ld	a,cmdrd
	out	(hcmd),a
	call	polbsy
	jr	z,hwrtsec

	ld	hl,dmawrt
	call	crmsg
	call	getcc
	cp	'C'
	jp	z,cartwrt

fixwrt:
	ld	de,0256
	ld	b,2
	ld	c,32d
	call	settsk
	ld	a,cmdrst2
	out	(hcmd),a
	call	polbsy
	ld	a,cmdrd
	out	(hcmd),a
	call	polbsy
	jr	z,hwrtsec

cartwrt:
	ld	de,0256
	ld	b,0
	ld	c,32d
	call	settsk
	ld	a,cmdrst2
	out	(hcmd),a
	call	polbsy
	ld	a,cmdrd
	out	(hcmd),a
	call	polbsy
	jr	z,hwrtsec

hwrterr:
	ld	hl,tk0wrer
	call	crmsg
	jp	0

hwrtsec:
	ld	(bps),de
	ld	de,0
	ld	hl,buf
hwrtnx:
	ld	a,d
	out	(hsec),a

	ld	a,cmdwrt
	out	(hcmd),a
	call	polbsy
	call	snddata
	call	polbsy	
	jp	nz,hwrterr

	inc	d
	ld	a,c
	cp	d
	jp	nz,hwrtnx	
	ret

;------------------------------
; HARD DISK SET TASK REGISTERS
;------------------------------

settsk:
	ld	a,(drv)
	sla	a
	sla	a
	sla	a
	or	b
	out	(hsdh),a
	out	(hsdh),a

	xor	a
	out	(hcylhi),a
	out	(hcyllow),a
	out	(hsec),a

	ret

;-----------
; POLL BUSY
;-----------

polbsy:
	in	a,(hstatus)
	and	a
	jp	m,polbsy

	call	delay
	call	delay

polskc:
	in	a,(hstatus)
	and	010h
	jr	z,polskc
	
	in	a,(hstatus)
	and	1
	ret

;--------------
; RECIEVE DATA
;--------------

rxdata:
	push	bc

	ld	a,(bps)
	ld	b,a
	ld	c,hdata
	inir

	ld	a,(bps+1)
	and	2
	jp	z,rxx
	inir
rxx:
	pop	bc
	ret

;-----------
; SEND DATA
;-----------

snddata:
	push	bc

	ld	a,(bps)
	ld	b,a
	ld	c,hdata
	otir
	
	ld	a,(bps+1)
	and	2
	jp	z,sndx
	otir
sndx:
	pop	bc
	ret	

;--------------------
; FLOPPY READ TRACK
;--------------------

frdtrk:
	call	tstrdy
	ld	e,1
	ld	c,fdata
	ld	hl,buf
rdsec:
	di
	ld	a,e
	out	(fsec),a
	xor	a
	out	(ftrk),a
	ld	a,frd
	out	(fcmd),a
frdlp:
	in	a,(fwait)
	or	a
	jp	p,frdout
	ini
	jr	frdlp
frdout:
	ei
	ld	a,d
	cp	e
	ret	z
	inc	e
	jr	rdsec

;--------------------------------
; GET SOURCE - DESTINATION DRIVE
;--------------------------------

getdrv:
	push	hl
	call	crmsg
	call	getc
	pop	hl

	cp	cr
	jð	z,reboot	
	cp	'0' 
	jp	c,getdrv
	cp	'4' 
	jp	nc,getdrv

	and	00fh	
	ret

;-------------------------------
; TEST IF FLOPPY DRIVE IS READY
;-------------------------------

tstrdy:
	push	hl
	push	de
	push	bc
	push	af
tststart:	
	ld	a,fint
	out	(fcmd),a
	call	delay
	ld	de,0ffffh

	ld	hl,tstnidx
tstnidx:
	in	a,(fstat)
	bit	1,a
	jr	nz,decde

	ld	hl,tstidx
tstidx:
	in	a,(fstat)
	bit	1,a
	jr	z,decde	

	ld	hl,tstrdx
tstrdx:
	in	a,(fstat)
	bit	7,a
	jr	z,tstx

decde:
	dec	de
	ld	a,d
	or	e

	jr	z,notready

	jp	(hl)

tstx:
	pop	af
	pop	bc
	pop	de
	pop	hl
	ret

notready:
	ld	hl,nrdymsg
	call	crmsg
	call	getcc
	cp	3
	jp	z,reboot
	jp	tststart
	
;---------------------
; DELAY 28 US AT 6MHZ
;---------------------

delay:
	push	af
	ld	a,3
delaylp:
	ex	(sp),hl
	ex	(sp),hl
	dec	a
	jr	nz,delaylp
	pop	af
	ret

;------------------------------------------------
; GET UPPER CASE CHARACTER FROM CONSOLE KEYBOARD
;------------------------------------------------

getcc:
	ld	c,coni	
	call	bdos
	and	05fh
	ret

;-------------------------------------
; GET CHARACTER FROM CONSOLE KEYBOARD
;-------------------------------------

getc:
	ld	c,coni
	call	bdos
	ret

;------------------------------
; DISPLAY CHARACTER ON CONSOLE
;------------------------------

putc:
	ld	e,a
	ld	c,cono
	call	bdos
	ret

;--------------------------
; DISPLAY CR,LF ON CONSOLE
;--------------------------

crlf:
	ld	a,cr
	call	putc
	ld	a,lf
	call	putc
	ret

;------------------------------
; DISPLAY CR,LF,MSG ON CONSOLE
;-------------------------------

crmsg:
	push	hl			; display cr,lf, msg pointed to by hl 
	call	crlf			; until zero encountered
	pop	hl			;DROP THRU TO OUTMSG0
outmsg:
	ld	a,m
	or	a
	ret	z

	push	hl
	call	putc
	pop	hl
	inc	hl
	jp	outmsg

;-----------------------------------
; READ LOGICAL SECTOR INTO DMA ADDR
;-----------------------------------

dread:
	ld	c,014h
	jp	bdos

;-----------
; OPEN FILE
;-----------

open:
	ld	c,00fh
	jp	bdos

;-----------------
; SET DMA ADDRESS
;-----------------

dma:
	ld	c,01ah
	jp	bdos

;----------------
; FILE NOT FOUND
;----------------

fnf:
	ld	hl,nofile
	call	crmsg

	xor	a
	ld	(fcb+13),a
	ld	hl,fcb+1
	call	outmsg

;------
; EXIT
;------

reboot:
	call	crlf
	jp	boot
	
;--------------
; DATA STORAGE
;--------------

signon:
	db	'LDRGEN 2.5',cr,lf,0
nofile:
	db	'Can''nt open file: ',0
stypmsg:
	db	'Read loader from Hard or Floppy drive    (H,F) : ',0
dtypmsg:
	db	'Write loader to Hard or Floppy  drive    (H,F) : ',0
smsg:
	db	'Physical drive no. of loader source      (0-3) : ',0
dmsg:
	db	'Physical drive no. of loader destination (0-3) : ',0
dmawrt:
	db	'Write loader to cartriage or fixed       (C,F) : ',0
dmard:
	db	'Read loader from cartrige or fixed       (C,F) : ',0
nrdymsg:
	db	'Drive Not Ready : ',0
wrpmsg:
	db	'Disk Write Protected : ',0
tk0rder:
	db	'Cannot Read Track 000',0
tk0wrer:
	db	'Cannot Write Track 000',0
sekmsg:
	db	'Cannot Read Track 1',0

drvtyp:	db	0			; 'H' or 'F'
sdrv:	db	0			; source drive
ddrv:	db	0			; destination drive 
drv:	db	0			; working variable
den:	db	0			; disk density byte
dsd:	db	0			; 
bps:	dw	0			; hd bytes per sector

trkid:
trkno:	db	0
sideno:	db	0
secno:	db	0
seclen:	db	0
crc1:	db	0
crc2:	db	0

	ds	040h
stack:
	end