[avrcpm.git] / avrcpm / cpm / bios.asm

;    CP/M BIOS for avrcpm
;    Copyright (C) 2010 Sprite_tm
;
;    This program is free software: you can redistribute it and/or modify
;    it under the terms of the GNU General Public License as published by
;    the Free Software Foundation, either version 3 of the License, or
;    (at your option) any later version.
;
;    This program is distributed in the hope that it will be useful,
;    but WITHOUT ANY WARRANTY; without even the implied warranty of
;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;    GNU General Public License for more details.
;
;    You should have received a copy of the GNU General Public License
;    along with this program.  If not, see <http://www.gnu.org/licenses/>.
;
;    $Id$
;

msize:	equ	62	;size of available RAM in k

bias:	equ	(msize-20) * 1024 
ccp:	equ	3400h+bias	;base of cpm ccp
bdos:	equ	ccp+806h	;base of bdos
bios:	equ	ccp+1600h	;base of bios
cdisk:	equ	0004h		;current disk number (0 ... 15)
iobyte:	equ	0003h		;intel iobyte
buff:	equ	0080h		;default buffer address
retry:	equ	3		;max retries on disk i/o before error

cr:	equ	13
lf:	equ	10

READ_FUNC:  equ	7
WRITE_FUNC: equ	6
BOOT_FUNC:  equ 5
HOME_FUNC:  equ 4

	org	bios
nsects:	equ	($-ccp)/128	;warm start sector count
	
	jp boot
wboote:	
	jp wboot
	jp const
	jp conin
	jp conout
	jp list
	jp punch
	jp reader
	jp home
	jp seldsk
	jp settrk
	jp setsec
	jp setdma
	jp read
	jp write
	jp listst
	jp sectran

signon:
	db	cr,lf
	db	msize/10+'0'
	db	msize - (msize/10)*10 + '0'	;modulo doesn't work?
	db	"k cp/m vers 2.2"
msgnl:	db	cr,lf,0

const:
	in a,(0)
	ret

conin:
	in a,(0)
	cp 0ffh
	jp nz,conin

	in a,(1)
	ret

conout:
	ld a,c
	out (2),a
	ret

list:
	ret

listst:
	ld a,0
	ret

punch:
	ret

reader:
	ld a,01Fh
	ret

prmsg:
	ld	a,(hl)
	or	a
	ret	z
	push	hl
	ld	c,a
	call	conout
	pop	hl
	inc	hl
	jp	prmsg
	
prhex:
	ld	a,c
	push	af
	rra	
	rra	
	rra	
	rra	
	call	prhexdigit
	pop	af
	;	fall thru

prhexdigit:
	and	00fh
	cp	10
	jp	c,prd1
	add	a,7
prd1:
	add	a,'0'
	ld	c,a
	jp	conout


boot:
	ld	sp,buff
	ld	hl,signon
	call	prmsg
	
	xor	a
	ld	(bootdsk),a
	ld	a,(dpb)
	ld	(bootspt),a
	
	ld	c,'I'-'A'
	call	seldsk
	ld	a,h
	or	l
	jp	z,boot1

	ld	de,10
	add	hl,de
	ld	e,(hl)
	inc	hl
	ld	d,(hl)		;de = dpb of first ram disk
	
	ld	hl,7
	add	hl,de
	ld	a,(hl)		;get drm
	inc	a
	and	0fch
	rrca			;4 dir entries per sector
	rrca			;Number of sectors to init
	push	af
	
	ld	bc,6
	add	hl,bc
	ld	c,(hl)		;Start track
	push	bc		;Save track
	
; Check, if we have reserved tracks.
	ld	a,c
	or	a
	jp	z,boot0		;Skip if not.

; Save CPM to ram disk.

	ld	a,(de)		;sectors per track
	ld	(bootspt),a
	ld	a,'I'-'A'
	ld	(bootdsk),a
	call	home
	ld	b,nsects
	ld	c,0		;track
	ld	d,1		;sektor (0 based)
	ld	hl,ccp
store1:
	push	bc
	push	de
	push	hl
	ld	c,d
	ld	b,0
	call	setsec
	pop	bc
	push	bc
	call	setdma
	ld	c,0
	call	write
	
	pop	hl
	ld	de,128
	add	hl,de
	pop	de
	pop	bc
	dec	b
	jp	z,boot0
	
	inc	d
	ld	a,(bootspt)
	dec	a
	cp	d		;if sector >= spt then change tracks
	jp	nc,store1
	
	ld	d,0
	inc	c
	push	bc
	push	de
	push	hl
	ld	b,0
	call	settrk	
	pop	hl
	pop	de
	pop	bc
	jp	store1

; Clear directory area of ram disk.

boot0:
	pop	bc
	call	settrk
	pop	af
	ld	d,a		;d = # of sectors
	ld	e,0		;e = sector
	push	de
	ld	hl,dirbuf	;Clear dirbuf
	ld	c,128
	ld	a,0E5h
boot_cl:
	ld	(hl),a
	inc	hl
	dec	c
	jp	nz,boot_cl

	ld	bc,dirbuf
	call	setdma
	pop	de
boot_cl2:
	push	de
	ld	c,e
	ld	b,0
	call	setsec
	ld	c,0
	call	write
	pop	de
	inc	e
	dec	d
	jp	nz,boot_cl2	
	
boot1:	
	xor	a
	ld	(iobyte),a
	ld	(cdisk),a
	jp	gocpm 

wboot:	;re-load CP/M
	ld	sp,buff
	ld	a,1<<BOOT_FUNC	;init (de)blocking
	out	(22),a
	ld	a,(bootdsk)
	ld	c,a
	call	seldsk
	call	home
	ld	b,nsects
	ld	c,0		;track
	ld	d,1		;sektor (0 based)
	ld	hl,ccp
load1:
	push	bc
	push	de
	push	hl
	ld	c,d
	ld	b,0
	call	setsec
	pop	bc
	push	bc
	call	setdma
	call	read
	cp	0		;read error?
	jp	nz,wboot
	
	pop	hl
	ld	de,128
	add	hl,de
	pop	de
	pop	bc
	dec	b
	jp	z,gocpm
	
	inc	d
	ld	a,(bootspt)
	dec	a
	cp	d		;if sector >= spt then change tracks
	jp	nc,load1
	
	ld	d,0
	inc	c
	push	bc
	push	de
	push	hl
	ld	b,0
	call	settrk	
	pop	hl
	pop	de
	pop	bc
	jp	load1
	
gocpm:
	ld	a,0c3h
	ld	(0),a
	ld	hl,wboote
	ld	(1),hl
	ld	(5),a
	ld	hl,bdos
	ld	(6),hl
		
	ld	bc,buff
	call	setdma
	ld	a,(cdisk)
	ld	c,a
	jp	ccp
	
seldsk:
	ld	hl,dphtab
	ld	b,0
	add	hl,bc
	add	hl,bc
	ld	a,(hl)		;get table entry for selected disk
	inc	hl
	ld	h,(hl)
	ld	l,a		
	or	h		;no entry, no disk
	ret	z		;

	ld	a,c
	out	(15),a
	in	a,(15)		;querry, if disk exists
	or	a		;0 = disk is ok
	ret	z
	ld	hl,0		;error return code
	ret

home:
	ld a,1<<HOME_FUNC
	out (22),a
	
	ld bc,0			; same as seek to track 0
settrk:
	ld a,c
	out (16),a
	ld a,b
	out (17),a
	ret

setsec:
	ld a,c
	out (18),a
	ret

setdma:
	ld a,c
	out (20),a
	ld a,b
	out (21),a
	ret

read:
	ld a,1<<READ_FUNC
	out (22),a
	in a,(22)
	and 1
	ret

write:
	ld	a,c
	and	3		;mask write  type
	or	1<<WRITE_FUNC
	out	(22),a
	in a,(22)
	and 1
	ret

sectran:
	;translate sector bc using table at de, res into hl
	ld h,b
	ld l,c
	ld a,d
	or e
	ret z
	ex de,hl
	add hl,bc
	ld l,(hl)
	ld h,0
	ret

dphtab:
	dw	dpe0
	dw	dpe1
	dw	dpe2
	dw	dpe3
	dw	0	
	dw	0	
	dw	0	
	dw	0	
	dw	dperd0
	dw	0	
	dw	0	
	dw	0	
	dw	0	
	dw	0	
	dw	0	
	dw	0	

	
;Disk Parameter Header
dpbase:	
dpe0:	dw 0		;XLT: No sector translation table
	dw 0		;000: Scratchpad
	dw 0		;000: Scratchpad
	dw 0 		;000: Scratchpad
	dw dirbuf 	;DIRBUF: Address of a dirbuff scratchpad
	dw dpb		;DPB: Address of a disk parameter block
	dw chk0		;CSV: Address of scratchpad area for changed disks
	dw all0		;ALV: Address of an allocation info sratchpad
dpe1:	dw 0		;XLT: No sector translation table
	dw 0		;000: Scratchpad
	dw 0		;000: Scratchpad
	dw 0 		;000: Scratchpad
	dw dirbuf 	;DIRBUF: Address of a dirbuff scratchpad
	dw dpb		;DPB: Address of a disk parameter block
	dw chk1		;CSV: Address of scratchpad area for changed disks
	dw all1		;ALV: Address of an allocation info sratchpad
dpe2:	dw 0		;XLT: No sector translation table
	dw 0		;000: Scratchpad
	dw 0		;000: Scratchpad
	dw 0 		;000: Scratchpad
	dw dirbuf 	;DIRBUF: Address of a dirbuff scratchpad
	dw dpb		;DPB: Address of a disk parameter block
	dw chk2		;CSV: Address of scratchpad area for changed disks
	dw all2		;ALV: Address of an allocation info sratchpad
dpe3:	dw 0		;XLT: No sector translation table
	dw 0		;000: Scratchpad
	dw 0		;000: Scratchpad
	dw 0 		;000: Scratchpad
	dw dirbuf 	;DIRBUF: Address of a dirbuff scratchpad
	dw dpb		;DPB: Address of a disk parameter block
	dw chk3		;CSV: Address of scratchpad area for changed disks
	dw all3		;ALV: Address of an allocation info sratchpad

dperd0:	dw 0		;XLT: No sector translation table
	dw 0		;000: Scratchpad
	dw 0		;000: Scratchpad
	dw 0 		;000: Scratchpad
	dw dirbuf 	;DIRBUF: Address of a dirbuff scratchpad
	dw dpbrd	;DPB: Address of a disk parameter block
	dw chkrd0	;CSV: Address of scratchpad area for changed disks
	dw allrd0	;ALV: Address of an allocation info sratchpad


dpb:	dw 26		;SPT: sectors per track
	db 3		;BSH: data allocation block shift factor
	db 7		;BLM: Data Allocation Mask
	db 0		;Extent mask
	dw 242		;DSM: Disk storage capacity
	dw 63		;DRM, no of directory entries
	db 192		;AL0
	db 0		;AL1
	dw 16		;CKS, size of dir check vector
	dw 2		;OFF, no of reserved tracks
	
dpbrd:	dw 32		;SPT: sectors per track
	db 3		;BSH: data allocation block shift factor
	db 7		;BLM: Data Allocation Mask
	db 0		;Extent mask
	dw 55		;DSM: Disk storage capacity
	dw 31		;DRM, no of directory entries
	db 128		;AL0
	db 0		;AL1
	dw 0		;CKS, size of dir check vector
	dw 2		;OFF, no of reserved tracks
	
bootdsk:ds	1
bootspt:ds	1

dirbuf:
	ds 128

chk0:	ds 16
all0:	ds 31
chk1:	ds 16
all1:	ds 31
chk2:	ds 16
all2:	ds 31
chk3:	ds 16
all3:	ds 31
chkrd0:	ds 0
allrd0:	ds 7

end
Commit	Line	Data
fdcfcd44 L	1	; CP/M BIOS for avrcpm
	2	; Copyright (C) 2010 Sprite_tm
	3	;
	4	; This program is free software: you can redistribute it and/or modify
	5	; it under the terms of the GNU General Public License as published by
	6	; the Free Software Foundation, either version 3 of the License, or
	7	; (at your option) any later version.
	8	;
	9	; This program is distributed in the hope that it will be useful,
	10	; but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	; GNU General Public License for more details.
	13	;
	14	; You should have received a copy of the GNU General Public License
	15	; along with this program. If not, see <http://www.gnu.org/licenses/>.
53327777 L	16	;
	17	; $Id$
	18	;
fdcfcd44	19
701f0287	20	msize: equ 62 ;size of available RAM in k
fdcfcd44	21
701f0287	22	bias: equ (msize-20) * 1024
14d4e184 L	23	ccp: equ 3400h+bias ;base of cpm ccp
	24	bdos: equ ccp+806h ;base of bdos
	25	bios: equ ccp+1600h ;base of bios
	26	cdisk: equ 0004h ;current disk number (0 ... 15)
	27	iobyte: equ 0003h ;intel iobyte
	28	buff: equ 0080h ;default buffer address
701f0287 L	29	retry: equ 3 ;max retries on disk i/o before error
	30
	31	cr: equ 13
	32	lf: equ 10
	33
db568140 L	34	READ_FUNC: equ 7
	35	WRITE_FUNC: equ 6
	36	BOOT_FUNC: equ 5
	37	HOME_FUNC: equ 4
	38
701f0287 L	39	org bios
	40	nsects: equ ($-ccp)/128 ;warm start sector count
	41
fdcfcd44	42	jp boot
701f0287	43	wboote:
fdcfcd44 L	44	jp wboot
	45	jp const
	46	jp conin
	47	jp conout
	48	jp list
	49	jp punch
	50	jp reader
	51	jp home
	52	jp seldsk
	53	jp settrk
	54	jp setsec
	55	jp setdma
	56	jp read
	57	jp write
	58	jp listst
	59	jp sectran
	60
701f0287 L	61	signon:
	62	db cr,lf
	63	db msize/10+'0'
	64	db msize - (msize/10)*10 + '0' ;modulo doesn't work?
	65	db "k cp/m vers 2.2"
a54e22b7 L	66	msgnl: db cr,lf,0
	67
	68	const:
	69	in a,(0)
	70	ret
	71
	72	conin:
	73	in a,(0)
14d4e184	74	cp 0ffh
a54e22b7 L	75	jp nz,conin
	76
	77	in a,(1)
	78	ret
	79
	80	conout:
	81	ld a,c
	82	out (2),a
	83	ret
	84
	85	list:
	86	ret
	87
	88	listst:
	89	ld a,0
	90	ret
	91
	92	punch:
	93	ret
	94
	95	reader:
14d4e184	96	ld a,01Fh
a54e22b7 L	97	ret
	98
	99	prmsg:
	100	ld a,(hl)
	101	or a
	102	ret z
	103	push hl
	104	ld c,a
	105	call conout
	106	pop hl
	107	inc hl
	108	jp prmsg
	109
	110	prhex:
	111	ld a,c
	112	push af
	113	rra
	114	rra
	115	rra
	116	rra
	117	call prhexdigit
	118	pop af
	119	; fall thru
	120
	121	prhexdigit:
14d4e184	122	and 00fh
a54e22b7 L	123	cp 10
a54e22b7 L	124	jp c,prd1
14d4e184	125	add a,7
a54e22b7	126	prd1:
14d4e184	127	add a,'0'
a54e22b7 L	128	ld c,a
	129	jp conout
	130
fdcfcd44	131
701f0287 L	132	boot:
	133	ld sp,buff
	134	ld hl,signon
	135	call prmsg
a54e22b7 L	136
	137	xor a
	138	ld (bootdsk),a
	139	ld a,(dpb)
	140	ld (bootspt),a
	141
	142	ld c,'I'-'A'
	143	call seldsk
	144	ld a,h
	145	or l
	146	jp z,boot1
	147
	148	ld de,10
	149	add hl,de
	150	ld e,(hl)
	151	inc hl
	152	ld d,(hl) ;de = dpb of first ram disk
	153
	154	ld hl,7
	155	add hl,de
	156	ld a,(hl) ;get drm
	157	inc a
14d4e184	158	and 0fch
a54e22b7 L	159	rrca ;4 dir entries per sector
	160	rrca ;Number of sectors to init
	161	push af
	162
	163	ld bc,6
	164	add hl,bc
	165	ld c,(hl) ;Start track
	166	push bc ;Save track
	167
	168	; Check, if we have reserved tracks.
	169	ld a,c
	170	or a
	171	jp z,boot0 ;Skip if not.
	172
	173	; Save CPM to ram disk.
	174
	175	ld a,(de) ;sectors per track
	176	ld (bootspt),a
	177	ld a,'I'-'A'
	178	ld (bootdsk),a
	179	call home
	180	ld b,nsects
	181	ld c,0 ;track
	182	ld d,1 ;sektor (0 based)
	183	ld hl,ccp
	184	store1:
	185	push bc
	186	push de
	187	push hl
	188	ld c,d
	189	ld b,0
	190	call setsec
	191	pop bc
	192	push bc
	193	call setdma
	194	ld c,0
	195	call write
	196
	197	pop hl
	198	ld de,128
	199	add hl,de
	200	pop de
	201	pop bc
	202	dec b
	203	jp z,boot0
	204
	205	inc d
	206	ld a,(bootspt)
	207	dec a
	208	cp d ;if sector >= spt then change tracks
	209	jp nc,store1
	210
	211	ld d,0
	212	inc c
	213	push bc
	214	push de
	215	push hl
	216	ld b,0
	217	call settrk
	218	pop hl
	219	pop de
	220	pop bc
	221	jp store1
	222
223	; Clear directory area of ram disk.
224
225	boot0:
226	pop bc
227	call settrk
228	pop af
229	ld d,a ;d = # of sectors
230	ld e,0 ;e = sector
231	push de
232	ld hl,dirbuf ;Clear dirbuf
233	ld c,128
14d4e184	234	ld a,0E5h
a54e22b7 L	235	boot_cl:
	236	ld (hl),a
	237	inc hl
	238	dec c
	239	jp nz,boot_cl
	240
	241	ld bc,dirbuf
	242	call setdma
	243	pop de
	244	boot_cl2:
	245	push de
	246	ld c,e
	247	ld b,0
	248	call setsec
	249	ld c,0
	250	call write
	251	pop de
	252	inc e
	253	dec d
	254	jp nz,boot_cl2
	255
	256	boot1:
701f0287 L	257	xor a
	258	ld (iobyte),a
	259	ld (cdisk),a
	260	jp gocpm
fdcfcd44	261
701f0287 L	262	wboot: ;re-load CP/M
701f0287 L	263	ld sp,buff
a54e22b7	264	ld a,1<<BOOT_FUNC ;init (de)blocking
db568140	265	out (22),a
a54e22b7 L	266	ld a,(bootdsk)
a54e22b7 L	267	ld c,a
701f0287 L	268	call seldsk
	269	call home
	270	ld b,nsects
	271	ld c,0 ;track
	272	ld d,1 ;sektor (0 based)
	273	ld hl,ccp
	274	load1:
	275	push bc
	276	push de
	277	push hl
	278	ld c,d
db568140	279	ld b,0
701f0287 L	280	call setsec
	281	pop bc
	282	push bc
	283	call setdma
	284	call read
	285	cp 0 ;read error?
	286	jp nz,wboot
	287
	288	pop hl
	289	ld de,128
	290	add hl,de
	291	pop de
	292	pop bc
	293	dec b
	294	jp z,gocpm
	295
	296	inc d
a54e22b7 L	297	ld a,(bootspt)
	298	dec a
	299	cp d ;if sector >= spt then change tracks
	300	jp nc,load1
fdcfcd44	301
701f0287 L	302	ld d,0
	303	inc c
	304	push bc
	305	push de
	306	push hl
db568140	307	ld b,0
701f0287 L	308	call settrk
	309	pop hl
	310	pop de
	311	pop bc
	312	jp load1
	313
	314	gocpm:
	315	ld a,0c3h
	316	ld (0),a
	317	ld hl,wboote
	318	ld (1),hl
	319	ld (5),a
	320	ld hl,bdos
	321	ld (6),hl
	322
	323	ld bc,buff
	324	call setdma
	325	ld a,(cdisk)
	326	ld c,a
	327	jp ccp
66faee4c	328
a54e22b7 L	329	seldsk:
	330	ld hl,dphtab
	331	ld b,0
	332	add hl,bc
	333	add hl,bc
	334	ld a,(hl) ;get table entry for selected disk
	335	inc hl
	336	ld h,(hl)
	337	ld l,a
	338	or h ;no entry, no disk
	339	ret z ;
	340
	341	ld a,c
	342	out (15),a
	343	in a,(15) ;querry, if disk exists
	344	or a ;0 = disk is ok
	345	ret z
	346	ld hl,0 ;error return code
fdcfcd44 L	347	ret
fdcfcd44 L	348
db568140 L	349	home:
	350	ld a,1<<HOME_FUNC
	351	out (22),a
	352
	353	ld bc,0 ; same as seek to track 0
fdcfcd44	354	settrk:
fdcfcd44 L	355	ld a,c
fdcfcd44 L	356	out (16),a
db568140 L	357	ld a,b
db568140 L	358	out (17),a
fdcfcd44 L	359	ret
	360
	361	setsec:
fdcfcd44 L	362	ld a,c
fdcfcd44 L	363	out (18),a
fdcfcd44 L	364	ret
	365
	366	setdma:
fdcfcd44 L	367	ld a,c
	368	out (20),a
	369	ld a,b
	370	out (21),a
fdcfcd44 L	371	ret
	372
	373	read:
db568140	374	ld a,1<<READ_FUNC
fdcfcd44	375	out (22),a
a54e22b7 L	376	in a,(22)
a54e22b7 L	377	and 1
fdcfcd44 L	378	ret
	379
	380	write:
a54e22b7 L	381	ld a,c
	382	and 3 ;mask write type
	383	or 1<<WRITE_FUNC
db568140	384	out (22),a
a54e22b7 L	385	in a,(22)
a54e22b7 L	386	and 1
fdcfcd44 L	387	ret
fdcfcd44 L	388
fdcfcd44 L	389	sectran:
fdcfcd44 L	390	;translate sector bc using table at de, res into hl
fdcfcd44 L	391	ld h,b
fdcfcd44 L	392	ld l,c
db568140 L	393	ld a,d
	394	or e
	395	ret z
	396	ex de,hl
	397	add hl,bc
	398	ld l,(hl)
	399	ld h,0
fdcfcd44 L	400	ret
fdcfcd44 L	401
a54e22b7 L	402	dphtab:
	403	dw dpe0
	404	dw dpe1
	405	dw dpe2
	406	dw dpe3
	407	dw 0
	408	dw 0
	409	dw 0
	410	dw 0
	411	dw dperd0
	412	dw 0
	413	dw 0
	414	dw 0
	415	dw 0
	416	dw 0
	417	dw 0
	418	dw 0
	419
701f0287	420
fdcfcd44 L	421
fdcfcd44 L	422	;Disk Parameter Header
66faee4c L	423	dpbase:
	424	dpe0: dw 0 ;XLT: No sector translation table
	425	dw 0 ;000: Scratchpad
	426	dw 0 ;000: Scratchpad
	427	dw 0 ;000: Scratchpad
	428	dw dirbuf ;DIRBUF: Address of a dirbuff scratchpad
	429	dw dpb ;DPB: Address of a disk parameter block
	430	dw chk0 ;CSV: Address of scratchpad area for changed disks
	431	dw all0 ;ALV: Address of an allocation info sratchpad
	432	dpe1: dw 0 ;XLT: No sector translation table
	433	dw 0 ;000: Scratchpad
	434	dw 0 ;000: Scratchpad
	435	dw 0 ;000: Scratchpad
	436	dw dirbuf ;DIRBUF: Address of a dirbuff scratchpad
	437	dw dpb ;DPB: Address of a disk parameter block
	438	dw chk1 ;CSV: Address of scratchpad area for changed disks
	439	dw all1 ;ALV: Address of an allocation info sratchpad
	440	dpe2: dw 0 ;XLT: No sector translation table
	441	dw 0 ;000: Scratchpad
	442	dw 0 ;000: Scratchpad
	443	dw 0 ;000: Scratchpad
	444	dw dirbuf ;DIRBUF: Address of a dirbuff scratchpad
	445	dw dpb ;DPB: Address of a disk parameter block
	446	dw chk2 ;CSV: Address of scratchpad area for changed disks
	447	dw all2 ;ALV: Address of an allocation info sratchpad
	448	dpe3: dw 0 ;XLT: No sector translation table
db568140 L	449	dw 0 ;000: Scratchpad
	450	dw 0 ;000: Scratchpad
	451	dw 0 ;000: Scratchpad
	452	dw dirbuf ;DIRBUF: Address of a dirbuff scratchpad
	453	dw dpb ;DPB: Address of a disk parameter block
66faee4c L	454	dw chk3 ;CSV: Address of scratchpad area for changed disks
66faee4c L	455	dw all3 ;ALV: Address of an allocation info sratchpad
fdcfcd44	456
a54e22b7 L	457	dperd0: dw 0 ;XLT: No sector translation table
	458	dw 0 ;000: Scratchpad
	459	dw 0 ;000: Scratchpad
	460	dw 0 ;000: Scratchpad
	461	dw dirbuf ;DIRBUF: Address of a dirbuff scratchpad
	462	dw dpbrd ;DPB: Address of a disk parameter block
	463	dw chkrd0 ;CSV: Address of scratchpad area for changed disks
	464	dw allrd0 ;ALV: Address of an allocation info sratchpad
	465
	466
	467	dpb: dw 26 ;SPT: sectors per track
db568140 L	468	db 3 ;BSH: data allocation block shift factor
	469	db 7 ;BLM: Data Allocation Mask
	470	db 0 ;Extent mask
	471	dw 242 ;DSM: Disk storage capacity
	472	dw 63 ;DRM, no of directory entries
	473	db 192 ;AL0
	474	db 0 ;AL1
	475	dw 16 ;CKS, size of dir check vector
	476	dw 2 ;OFF, no of reserved tracks
	477
a54e22b7 L	478	dpbrd: dw 32 ;SPT: sectors per track
	479	db 3 ;BSH: data allocation block shift factor
	480	db 7 ;BLM: Data Allocation Mask
	481	db 0 ;Extent mask
	482	dw 55 ;DSM: Disk storage capacity
14d4e184	483	dw 31 ;DRM, no of directory entries
a54e22b7 L	484	db 128 ;AL0
	485	db 0 ;AL1
	486	dw 0 ;CKS, size of dir check vector
	487	dw 2 ;OFF, no of reserved tracks
	488
	489	bootdsk:ds 1
	490	bootspt:ds 1
fdcfcd44 L	491
	492	dirbuf:
	493	ds 128
	494
66faee4c L	495	chk0: ds 16
	496	all0: ds 31
	497	chk1: ds 16
	498	all1: ds 31
	499	chk2: ds 16
	500	all2: ds 31
	501	chk3: ds 16
	502	all3: ds 31
a54e22b7 L	503	chkrd0: ds 0
a54e22b7 L	504	allrd0: ds 7
fdcfcd44	505
701f0287	506	end
db568140	507