;------------------------------------------------------------------------------
;
;				 "zasmb"
;
;			  (C) P.F.Ridler 1985
;
;
;  This program assembles a file of "Zilog" mnemonic source code and produces
;  from it an excuteable .COM file or an "Intel" Hex format file.
;
;  The command line for execution is
;    
;		  zasmb [d:]name[.ext] [hex]
;
;
;  Free use is granted for educational and private, non-commercial purposes
;  only.
;
;  Copies of the program may be made for backup purposes and for private
;  exchange so long as this notice remains within the program,
;  but the program may not be circulated by way of trade nor be entered
;  into a communications network.
;
;  Enquiries about other uses should be addressed to:
;
;			P.F.Ridler,
;			4, Lewisam Ave.,
;			Chisipite,
;			ZIMBABWE.
;
;-----------------------------------------------------------------------------
;
;			Z80 assembler
;
;	latest change		22 Jan 86
;
;	"phase" error checking introduced
;	"org" error message improved		22 Jan 86
;	origin for .HEX changed to 0000H	22 Jan 86
;2.0	Intel "Hex" output			25 Dec 85
;1.5	"include" nested			24 Nov 85
;1.4	hasher changed to just adding ASCII	21 Sep 85
;	going mad on " l       "		27 Jul 85
;1.3	return to editor			27 Jul 85
;	"ld a, " fixed				27 Jul 85		
;	abort if "include" missing in pass 1	 9 Jul 85
;	push sp,  ld sp,de fixed		30 Apr 85
;	precedence in "xprshn"			18 Feb 85
;	"db 'aaaa',"				10 Feb 85
;	variable length operator table		 8 Feb 85
;1.2	conditional assembly			 8 Feb 85
;	"ld	(hl),' '" gives value error	26 Dec 84
;	"<no label>  equ N"   fixed		11 Dec 84
;	"read" fixed				10 Nov 84
;	"read" files				29 Oct 84
;	"arop a, "  fixed			26 Oct 84
;	delete .COM file if errors		26 Oct 84
;1.1	hash symbol table search		20 Oct 84
;	string search and length modified	19 Oct 84
;	multiple definition check added		13 Oct 84
;1.0	started					 8 Sep 84
;
;------------------------------------------------------------------------------
;
wboot	equ	0000H
cdrive	equ	0004H
bdos 	equ	0005H
dffcb	equ	005CH
;
bel	equ	 7
tab	equ	 9
lf	equ	10
cr	equ	13
eof	equ	26
esc	equ	27
;
true	equ	1
false	equ	0
;
debugs	equ	false
;
notype	equ	0		;expression types
numtyp	equ	1
namtyp	equ	2
strtyp	equ	3
pctype	equ	4
onebyt	equ	5
twobyt	equ	6
izreg	equ	7
regtyp	equ	8
;
pseudop	equ	14
;
codtyp	equ	11H		;line types
comtyp	equ	12H
dstyp	equ	13H
dbtyp	equ	14H
equtyp	equ	15H
orgtyp	equ	16H
;
addhl	equ	 86H		;some necessary opcodes
adchl	equ	 8EH
sbchl	equ	 9EH
jpopc	equ	0C3H
;
creg	equ	11H		;single registers
areg	equ	17H
bcreg	equ	20H		;register pairs
dereg	equ	21H
hlreg	equ	22H
spreg	equ	23H
ixreg	equ	24H
iyreg	equ	25H
afreg	equ	26H
ireg	equ	18H
rreg	equ	19H
;
rmask	equ	10H		;register masks
rpmask	equ	20H
;
maxnch	equ	7		;max. no. of characters in name
ovrhds	equ	5		;link, address and flag bytes
;
bffsiz	equ	512		;no. of bytes in source buffers
maxlvl	equ	4		;max. level for "include"'s
edit	equ	true		;set this false if editor interaction
				; not possible
;
;
	org	100H
;
	jp	zasmb
;
ccp	ds	2
z80ext 	db	'Z80'		;source file extension
comext 	db	'COM'		;object  "	"
hexext	db	'HEX'		;"Hex"   "      "
lstext	db	'LST'		;list	 "	"

;
nstnt	dw	0		;no. of symtab entries
nstsr	dw	0		;no. of symtab searches
taddr	ds	2		;^transfer ("dma") address
fcb	ds	2		;^fcb to be used
;
;
;	next group of storage must be contiguous
;
errflg 	db	' '		;error character for this line
lnnobf	db	'     '		;holds (5) digits of line number
	db	'  '
pcbuff	db	'    '		;holds (4) digits of "pc"
	db	'  '
codbff	db	'        '	;holds digits of code
	db	'  '
;
linbff 	ds     80H		;holds source line
lnbptr 	ds	2		;points to next char in line buffer
;
lintyp	ds	1		;type of line to display
pc 	ds	2		;current program counter
pcstart	dw	100H
pchex	ds	2		;auxiliary pc for "Hex"
length 	ds	2		;length of current instruction or data
datfas	ds	2
inst
datbff 	ds     80		;current instruction (or data from db)
passno 	ds	1		;current pass.  pass 1=0, pass 2=-1
namlth	ds	1		;char count in "nambff"
nambff 	ds     16		;holds current name
datlft	ds	1		;no of bytes of data left to display
regflg	ds	1		;flags if expression is name
endflg 	ds	1		;end of program flag
				; (to allow printing of end line)
havlbl	ds	1		;true if line has label
opcode 	ds	2		;current opcode from symbol table
reg1	ds	1		;register code, arg 1
reg2	ds	1		;register code, arg 2
savval 	ds	2		;saved contents of "xprval"
lstflg 	ds	1		;listing flag
lstcls	ds	1		;list file close flag
temp 	ds	2		;temp 2 byte area
mult 	ds	2		;radix of number system
stfas 	ds	2		;address of next symbol table entry
stend	ds	2		;last available space for symtab
udfflg 	ds	1		;undefined flag from "xprshn",
udfptr	ds	2		;pointer to error col
nerrs	ds	2		;no. of errors
lnndx	ds	2		;index to "lineno" for display
nlines	ds	2		;line number in current segment
totlns	ds	2		;total no. of lines
switch	ds	1		;flag to show if i/p file changed
hexflg	ds	1		;generate "Hex" if true
;
;
	include	d:zasmb.z81
;
;
getnam	push	hl		;collect name and put it into "nambff"
	push	de
	push	bc
	ld	hl,nambff
	ld	a,' '		;nambff='               '
	ld	(hl),a
	ld	de,nambff+1
	ld	bc,15
	ldir
	ld	hl,nambff
	ld	b,1		;length
	call	readch		;get next non-space char
gtnm1	cp	a,'a'		;allow "a".."z","0".."9","_","@"
	jp	c,gtnm2
	cp	a,'z'+1
	jp	c,gtnm3
gtnm2	cp	a,'@'
	jr	z,gtnm3
gtnm21	cp	a,'_'
	jr	z,gtnm3
	cp	a,'@'
	jr	z,gtnm3
	cp	a,'0'
	jr	c,gtnm9		;<"0"
	cp	a,'9'+1
	jr	nc,gtnm9	;>"9"
gtnm3 	ld	(hl),a		;put l/c char into "nambff"
	inc	hl
	inc	b
	push	hl
	ld	hl,(lnbptr)	;get next char from line buffer
	ld	a,(hl)
	call	uctolc
	inc	hl
	ld	(lnbptr),hl
	pop	hl
	jp	gtnm1
	;
gtnm9	ld	a,b
	ld	(namlth),a	;length, including count
	call	backup
 	pop	bc
	pop	de
	pop	hl
	ret
;
;
numptr	ds	2
;
numarg	push	hl		;convert digits to value
	push	de		;hex, binary and decimal allowed
	push	bc
	ld	hl,(lnbptr)	;save pointer to start of number
	ld	(numptr),hl
	ld	b,0		;length counter
numg1	ld	a,(hl)
	inc	hl
	call	uctolc
	cp	a,'0'
	jr	c,numg2
	cp	a,'9'+1
	jr	c,numg11
	cp	a,'a'
	jr	c,numg2
	cp	'f'+1
	jr	nc,numg2
numg11	inc	b
	jp	numg1
	;
numg2	cp	a,'h'		;radix?
	jp	nz,numg21
	ld	de,16		; radix 16
	jp	numg31
	;
numg21	dec	hl
	dec	hl
	ld	a,(hl)
	call	uctolc
	cp	a,'b'		;binary?
	jp	nz,numg22
	dec	b
	ld	de,2		;radix 2
	jr	numg3
numg22	cp	a,'d'
	jr	nz,numg23
	dec	b
	ld	de,10
	jr	numg3
numg23	ld	de,10		;default radix
	;
numg3	inc	hl
numg31	ld	(lnbptr),hl
	ld	(mult),de
	ld	de,0		;value=0
	;
numg5	ld	hl,(numptr)
	ld	a,(hl)
	inc	hl
	ld	(numptr),hl
	call	uctolc
	cp	a,'a'
	jp	c,numg51
	add	a,9		;for "a"-"f"
numg51	and	a,0FH
	push	bc		;save counter
	push	af		;get binary value of this digit
	ld	hl,(mult)
	call	mltply
	pop	af
	ld	e,a
	ld	d,0
	add	hl,de		;add in new digit
	ex	de,hl
	pop	bc		;restore counter
	dec	b
	jp	nz,numg5	;loop if more
	;
	ld	(tval),de	;save value
	pop	bc
	pop	de
	pop	hl
	ret
;
;
strlth	ds	2
;
gtstrg	push	hl		;get a string in single quotes
	push	de		;mustn't use "readch" to avoid case conversion
	ld	bc,00
	ld	(strlth),bc
	ld	hl,(lnbptr)
	ld	de,(datfas)
gtst1 	ld	a,(strlth)	;if (string_length>=80)
	cp	a,80		;  error
	jr	z,gtst5
	ld	a,(hl)		;get next character
	inc	hl
	cp	a,cr		;if (ch==cr)
	jr	z,gtst5		;  error
	cp	a,''''		;if (ch=="'")
	jr	nz,gtst2
	ld	a,(hl)		;  get character.  no "uctolc" here
	inc	hl
	cp	a,''''		;  if (ch<>"'")
	jr	nz,gtst6	;    end of string
gtst2	ld	(de),a		;string[length]=ch
	inc	de
	ld	bc,(strlth)	;length=length+1
	inc	bc
	ld	(strlth),bc
	jr	gtst1
gtst5	call	aerror
gtst6	ld	bc,(strlth)	;if (string_length=0)
	ld	a,b
	or	a,c
	jr	nz,gtst61
	inc	bc		;  string_length=1
	ld	(strlth),bc
	xor	a,a		;  string[1]=<nul>
	ld	(de),a
	inc	de
gtst61	ld	(datfas),de
	dec	hl		;put last char back
	ld	(lnbptr),hl
	pop	de
	pop	hl
	ret
;
;
namarg	call	getnam		;argument is a name
	call	stsrch
	jp	nz,namg1	;if undefined
	ld	a,(hl)		;  keep address
	ld	(tval),a
	inc	hl
	ld	a,(hl)
	ld	(tval+1),a
	inc	hl
	ld	a,(hl)		;  save register flags
	ld	(regflg),a
	jr	namg2
	;
namg1	ld	hl,0		;process undefined name
	ld	(tval),hl	;set value to 0000
	ld	a,(udfflg)
	or	a,1
	ld	(udfflg),a	;set undefined flag
	ld	hl,(lnbptr)
	ld	(udfptr),hl
namg2	ret
;
;
;  expression evaluator  (returns expression value in "xprval")
;
;  valid operators are: +, -, *, / , \ (mod), & (and), | (or) and ~ (not)
;  elements are: names, numbers, and '$' for pc
;
fcttyp	ds	1
fctval	ds	2
;
factor	push	hl
	push	de
	ld	hl,00
	ld	(fctval),hl
	ld	a,notype
	ld	(fcttyp),a
	call	readch		;readch
	if	debugs
	call	dspnxt
	db	' >factor ch=',0
	call	dspall
	endif
	cp	a,'a'		;if (ch in [a..z,'@'])
	jr	nc,fctr0
	cp	a,'@'
	jr	nz,fctr1
	jr	fctr01
fctr0	cp	a,'z'+1
	jr	nc,fctr1
fctr01	call	backup
	call	namarg		;  name
	ld	a,(regflg)
	or	a,a
	jr	nz,fctr02
	ld	a,twobyt
	ld	(fcttyp),a
	ld	hl,(tval)
	ld	(fctval),hl
	jp	fctr6
fctr02	cp	a,izreg
	ld	hl,00
	ld	(fctval),hl
	jr	nz,fctr03
	ld	a,twobyt
	ld	(fcttyp),a
	jp	fctr6
fctr03	ld	a,regtyp
	ld	(fcttyp),a
	jp	fctr6
fctr1	cp	a,'0'		;elseif (ch in [0..9])
	jr	c,fctr2
	cp	'9'+1
	jr	nc,fctr2
	call	backup
	call	numarg		;  number
	ld	a,h
	cp	a,0
	jr	z,fct11
	cp	a,0FFH
	jr	nz,fct12
fct11	ld	a,onebyt
	jr	fct13
fct12	ld	a,twobyt
fct13	ld	(fcttyp),a
	ld	hl,(tval)
	ld	(fctval),hl
	jp	fctr6
fctr2	cp	a,'['		;elseif (ch=="[")
	jr	nz,fctr3
	call	arxprn		;  arxprn
	ld	hl,(axpval)
	ld	(fctval),hl
	call	readch		;  readch
	cp	a,']'		;  if not(ch==']')
	call	nz,serror	;    serror
	jr	fctr6
fctr3	cp	a,'$'		;elseif (ch=='$')
	jr	nz,fctr4
	ld	hl,(pc)
	ld	(fctval),hl
	ld	a,twobyt
	ld	(fcttyp),a
	jr	fctr6
fctr4	cp	a,''''		;elseif (ch=="'")
	jr	nz,fctr5
	call	gtstrg		;  getstring	
	ld	a,(strlth)
	cp	a,1		;  if (length(string)<>1) error
	call	nz,serror
	ld	hl,(datfas)	;  datfas=datfas-1
	dec	hl
	ld	(datfas),hl
	ld	a,(hl)		;  factval=datfas
	ld	(fctval),a
	ld	a,onebyt	;  facttyp=onebyte
	ld	(fcttyp),a
	jr	fctr6
fctr5	call	backup		;else
	ld	hl,00		;  put ch back
	ld	(fctval),hl
fctr6	if	debugs
	call	dspnxt
	db	' <factor: fctval=',0
	call	dsp4hex
	endif
	pop	de
	pop	hl
	ret
;
;
op 	ds	1		;current operator for "xprshn"
trmtyp	ds	1		;type of term
tval
trmval	ds	2
;
;
term	push	hl
	push	de
	if	debugs
	call	dspnxt
	db	' >term ',0
	endif
	call	factor
term1	call	readch		;readch
	cp	a,'*'		;case ch of
	jr	nz,term11
	ld	hl,(fctval)	;  '*' :
	push	hl		;    push(factval)
	call	factor		;    factor
	ld	de,(fctval)	
	pop	hl		;    pop(fact1val)
	call	mltply		;    factval=fact1val*factval
	jr	term14
term11	cp	a,'/'
	jr	nz,term12	
	ld	hl,(fctval)	;  '/' :
	push	hl
	call	factor
	ld	de,(fctval)
	pop	hl
	call	div16		;    factval=fact1val/factval
	jp	term14	
term12	cp	a,'\'
	jr	nz,term13	
	ld	hl,(fctval)
	push	hl
	call	factor
	ld	de,(fctval)
	pop	hl
	call	div16		;    factval=fact1val mod factval
	ex	de,hl
	jp	term14
term13	cp	a,'&'		;  '&'
	jr	nz,term5
	ld	hl,(fctval)
	push	hl
	call	factor
	ld	de,(fctval)
	pop	hl
	ld	a,h		;    factval=fact1val & factval
	and	a,d
	ld	h,a
	ld	a,l
	and	a,e
	ld	l,a
	;
term14	ld	(fctval),hl
	jp	term1
term5	call	backup
term6	ld	a,(fcttyp)
	ld	(trmtyp),a
	ld	hl,(fctval)
	ld	(trmval),hl
	if	debugs
	call	dspnxt
	db	' <term: trmval=',0
	call	dsp4hex
	endif
	pop	de
	pop	hl
	ret
;
;
axptyp	ds	1
axpval	ds	2
aop0	ds	1
;
arxprn	push	hl
	push	de
	call	readch
	if	debugs
	call	dspnxt
	db	' >arxprn ch=',0
	call	dspall
	endif
	cp	a,'+'		;aop0=monadic operator
	jr	z,arxp0
	cp	a,'-'
	jr	z,arxp0
	cp	a,'~'
	jr	z,arxp0
	call	backup
	ld	a,'+'
arxp0	ld	(aop0),a
	call	term
	ld	a,(aop0)	;case aop0 of
	cp	a,'+'		;  '=' :do nothing
	jr	z,arxp1
	cp	a,'-'
	jr	nz,arxp01
	ld	hl,00		;  '-' :
	ld	de,(trmval)
	or	a,a
	sbc	hl,de
	ld	(trmval),hl
	jp	arxp1
arxp01	cp	a,'~'
	jr	nz,arxp02
				;  '~' :


arxp02				;  else :do nothing
	;
arxp1	call	readch		;while (ch in ["+","-","~","|"])
	cp	a,'+'		;  case ch of
	jr	nz,arxp11
	ld	hl,(trmval)	;    '+' :
	push	hl		;      push(termval)
	ld	a,(regflg)
	push	af
	call	term		;      term
	pop	af
	ld	(regflg),a
	ld	de,(trmval)	;      pop(term1val)
	pop	hl		;      termval=term1val+termval
	add	hl,de	
	jr	arxp19
arxp11	cp	a,'-'
	jr	nz,arxp12
	ld	hl,(trmval)	;    '-' :
	push	hl
	ld	a,(regflg)
	push	af
	call	term
	pop	af
	ld	(regflg),a
	ld	de,(trmval)
	pop	hl
	or	a,a
	sbc	hl,de	
	jr	arxp19
arxp12	cp	a,'~'
	jr	nz,arxp13
	ld	hl,(trmval)	;    '~' :
	push	hl
	call	term
	ld	de,(trmval)
	pop	hl
	ld	a,h
	xor	a,d
	ld	h,a
	ld	a,l
	xor	a,e
	ld	l,a
	jr	arxp19
arxp13	cp	a,'|'
	jr	nz,arxp2
	ld	hl,(trmval)	;    '|' :
	push	hl
	call	term
	ld	de,(trmval)
	pop	hl
	ld	a,h
	or	a,d
	ld	h,a
	ld	a,l
	or	a,e
	ld	l,a
	;
arxp19	ld	(trmval),hl
	jp	arxp1
arxp2	call	backup

arxp3	ld	a,(trmtyp)
	ld	(axptyp),a
	ld	hl,(trmval)	;axpval=termval
	ld	(axpval),hl
	if	debugs
	call	dspnxt
	db	' <arxprn: axpval=',0
	call	dsp4hex
	endif
	pop	de
	pop	hl
	ret
;
;
xprtyp	ds	1
xprval	ds	2
;
xprshn	push	hl
	push	de
;
	if	debugs
	call	dspnxt
	db	cr,lf,' >xprshn ',0
	endif
;
	xor	a,a
	ld	(op),a		;op=nop
	ld	(regflg),a	;regflg=0
	ld	a,notype
	ld	(xprtyp),a
	ld	hl,0
	ld	(xprval),hl	;value=0
 	call	readch		;readch
	cp	a,'a'
	jr	nc,xprn0	;if (ch in letters)
	cp	a,''
	jr	nz,xprn1
	jr	xprn01
xprn0	cp	a,'z'+1
	jr	nc,xprn1
xprn01	call	backup
	call	arxprn
	ld	a,(axptyp)
	ld	(xprtyp),a
	ld	hl,(axpval)
	ld	(xprval),hl
	jp	xprn9
xprn1	cp	a,''''		;elseif (ch=="'")
	jr	nz,xprn2
	call	gtstrg		;  getstring
	ld	a,(strlth)	;  if (string_length>1)
	cp	a,2
	jr	c,xprn11
	ld	e,(hl)		;    exprnvalue=
	inc	hl
	ld	d,(hl)
	ld	(xprval),de
	ld	a,strtyp	;    exprntype=string
	ld	(xprtyp),a
	jp	xprn9
xprn11	ld	hl,(datfas)	;  else		#have string[1]
	dec	hl
	ld	(datfas),hl	;    datfas=datfas-1
	ld	a,(hl)
	push	af		;    push(ch)
	call	arxprn		;    arithexprn
	pop	af		;    pop(ch)
	ld	hl,(axpval)	;    exprnval=arexpval+ch
	ld	d,0
	ld	e,a
	add	hl,de
	ld	(xprval),hl
	ld	a,onebyt	;    exprtype=onebyte
	ld	(xprtyp),a
	jp	xprn9
	;
xprn2	call	backup		;else
	call	arxprn
	ld	a,(axptyp)
	cp	a,notype
	jr	nz,xprn21
	call	serror
	jr	xprn9
xprn21	ld	(xprtyp),a
	ld	hl,(axpval)
	ld	(xprval),hl
	;
xprn9	if	debugs
	call	dspnxt
	db	' <xprshn: xprval=',0
	call	dsp4hex
	call	dspnxt
	db	' xprtyp=',0
	ld	a,(xprtyp)
	call	dsp2hex
	endif
	pop	de
	pop	hl
	ret
;
;
clspar	push	af		;check for closing ')'
	call	readch
	cp	a,')'
	call	nz,serror
	pop	af
	ret
;
;
setup	call	clrscr		;display title
	ld	h,6
	ld	l,20
	call	curpos
	call	dspnxt
 	db	'Zimsoft Z-80 assembler 2.0',0
	ld	h,9
	ld	l,23
	call	curpos
	call	dspnxt
	db	'(C) P.F.Ridler  1985'
	db	esc,'N',cr,lf,0		;for printer
	ld	h,12
	ld	l,0
	call	curpos
	;
	ld	hl,(0001H)	;get base of CCP
	ld	de,1603H	;for standard CP/M !!!!!!!
	or	a,a
	sbc	hl,de
	ld	(ccp),hl
	ld	hl,dffcb	;move drive and name from default fcb to
	ld	de,srcfcb	;  source fcb
	ld	bc,9
	ldir
	ld	hl,z80ext	;source type is "Z80"
	ld	bc,3
	ldir
	ld	hl,srcfcb
	ld	bc,12
	add	hl,bc
	ld	(hl),0
	inc	de
	ld	bc,20
	ldir
	ld	hl,dffcb	;move drive and name from default fcb to
	ld	de,objfcb	;  object fcb
	ld	bc,9
	ldir
	ld	a,(6DH)		;if ({6CH}=='H')
	cp	a,'H'
	ld	a,false
	jr	nz,setup00
	ld	a,true		;  hexflag=true
	ld	hl,wrhex	;  set output write routine to "wrhex"
	ld	(ndst55+1),hl	;    instead of "wrbyte"
setup00	ld	(hexflg),a
	jr	nz,setup01
	ld	hl,00		;  pcstart=0000H
	ld	(pcstart),hl
	ld	hl,hexext	;  extn='HEX'
	jr	setup02		;else
setup01	ld	hl,comext	;  extn='COM'
setup02	ld	bc,3
	ldir
	ld	hl,objfcb	;set up list file
	ld	bc,12		;drive and name same as source
	add	hl,bc
	ld	(hl),0
	inc	de
	ld	bc,20
	ldir
	ld	hl,dffcb	;move drive and name from default fcb to
	ld	de,lstfcb	;  list fcb
	ld	bc,9
	ldir
	ld	hl,lstext	;extension="LST"
	ld	bc,3
	ldir
	ld	hl,lstfcb	;zero rest of list fcb
	ld	bc,12
	add	hl,bc
	ld	(hl),0
	inc	de
	ld	bc,20
	ldir
	;
	ld	de,srcfcb	;try to open source file
	ld	(fcb),de
	call	opnfil
	jr	nz,setup1	;if source file not found
 	call	dspnxt
 	db	cr,lf,'Source (.Z80) file not found.',0
	call	press
	jp	abort
setup1	ld	de,objfcb	;delete any output file of same name
	ld	(fcb),de
	call	delfil
	ld	de,objfcb	;create a new output file
	ld	(fcb),de
	call	crtfil
	jr	nz,setp11	;if unable to create
	call	dspnxt
 	db	cr,lf,'Unable to create/open object (.COM) file.',0
	call	press
	jp	abort
setp11	ld	de,lstfcb	;delete any list file of same name
	ld	(fcb),de
	call	delfil
	ld	de,lstfcb	;create a new list file
	ld	(fcb),de
	call	crtfil
	jr	nz,setup2	;if unable to create
	call	dspnxt
 	db	cr,lf,'Unable to create/open list (.LST) file.',0
	call	press
	jp	abort
setup2	xor	a,a		
	ld	(objfas),a	;reset output buffer pointer
	ld	(lstfas),a	;	list	"	"
	ld	(symtab),a	;symbol table terminator
	ld	hl,symtab	;point to first available space in "symtab"
	ld	(stfas),hl
	ld	hl,(0006)	;set top of symtab
	ld	de,07
	or	a,a
	sbc	hl,de
	ld	(stend),hl	;set top of symtab
	ld	bc,512		;zero 512-byte hash table
	ld	hl,hshtbl
setup3	ld	(hl),0
	inc	hl
	dec	bc
	ld	a,b
	or	a,c
	jr	nz,setup3
	ld	hl,regtbl	;hash registers into symbol table
	ld	b,16
setup4	push	bc
	ld	de,stbuff
	ld	a,(hl)		;length
	add	a,ovrhds
	ld	c,a
	ld	b,0
	ldir			;move entry to "stbuff"
	push	hl
	call	ptn2st		;put into "symtab"
	pop	hl
	pop	bc
	djnz	setup4
	ld	hl,00		;no. of symtab entries excluding registers
	ld	(nstnt),hl
	call	dspnxt
	db	'Pass 1  ',cr,lf,0
	ld	a,8
	ld	(ndots),a
	ld	hl,srcfcb
	call	dspfnm
	ret
;
;
getlin	ld	hl,(nlines)	;get next input line
	inc	hl		;fill buffer until <lf> or <eof> found
	ld	(nlines),hl
	call	dspdot
 	ld	hl,linbff	;reset line buffer pointer
	ld	(lnbptr),hl
gtln1 	call	getbyt		;get a byte from disc buffer
	cp	a,eof
	ret	z		;if <eof> return
gtln2	ld	(hl),a
	inc	hl
	cp	a,lf
	jr	nz,gtln1	;else loop until <lf> found
	ret
;
;
backup 	push	hl		;put character back into line buffer
	ld	hl,(lnbptr)	;after look ahead
	dec	hl
	ld	(lnbptr),hl
	pop	hl
	ret
;
;
dsfill	push	af		;fill "ds" space with <nul>s
	push	hl
	ld	a,(passno)	;if (pass2)
	or	a,a
	jr	z,dsfl2
	ld	a,(dsflag)	;  if (dsflag)
	or	a,a
	jr	z,dsfl11
	ld	hl,(dslgth)	;    for i=1 upto dslgth
dsfl1	ld	a,h
	or	a,l
	jr	z,dsfl11
	xor	a,a		;      writebyte(0)
	call	wrbyte
	dec	hl
	jr	dsfl1
dsfl11	xor	a,a		;  dsflag=false
	ld	(dsflag),a
	ld	hl,00		;  dslgth=0
	ld	(dslgth),hl
dsfl2	pop	hl
	pop	af
	ret
;
;
;	set error flags
;
aerror	push	af
	ld	a,'A'		;argument error
	jr	error
;
berror	push	af
	ld	a,'B'
	jr	error
;
ferror	push	af
	ld	a,'F'		;"include" file not found 
	jr	error
;
lerror	push	af
	ld	a,'L'		;lable too long
	jr	error
;
merror	push	af
	ld	a,'M'		;multiple definition
	jr	error
;
oerror	push	af
	ld	a,'O'		;op-code
	jr	error
;
rerror	push	af
	ld	a,'R'		;range error
	jr	error
;
serror	push	af
	ld	a,'S'		;syntax error
	jr	error
;
uerror	push	af
	ld	a,'U'		;undefined variable
	jr	error
;
verror	push	af
	ld	a,'V'		;value error
	jr	error
;
xerror	push	af
	ld	a,'X'		;extra character on line
	jr	error
;
error	ld	(errflg),a	;set error flag
	push	hl
	ld	hl,(lnbptr)
	ld	(errptr),hl
	pop	hl
	pop	af
	ret
;
;
stbuff	ds	15		;buffer for symbol table entry
symadr	ds	2		;^address of address in last "ptn2st"
;
;
	ds	128		;just the usual stack
stack	equ	$
;
;
;
zasmb	ld	sp,stack
	call	setup		;display heading and initialise
	xor	a,a
	ld	(passno),a	;indicate pass 1
	;
pass2	xor	a,a
	ld	(dsflag),a	;ds_flag=false
	ld	(lstcls),a	;list_close=false
	ld	(lstflg),a	;list_flag=off
	ld	a,'.'
	ld	(chdsp),a
	ld	hl,-1
	ld	(nlines),hl	;nlines=-1
	inc	hl
	ld	(level),hl	;include_level=0
	ld	(totlns),hl	;total_lines=0
	ld	(nerrs),hl	;nerrors=0
	ld	(nstsr),hl
	ld	(dslgth),hl	;ds_length=0
	ld	hl,(pcstart)
	ld	(pc),hl		;pc=pcstart  (100H for .COM, 0000H for .HEX)
	ld	(pchex),hl
	ld	hl,srcbff	;set up to read from source file
	ld	(ipbuff),hl
	ld	hl,srcend
	ld	(ipbndx),hl
	ld	(ipbend),hl
	ld	hl,srcfcb
	ld	(pipfcb),hl
;
;
;	main loop - read a source line
;			process label and opcode
;			print line (unless option=n)
;			output hex (if necessary)
;			back to main loop for next line
;
;
next	ld	sp,stack
	ld	hl,00
	ld	(xprval),hl
	ld	(length),hl
	ld	hl,datbff
	ld	(datfas),hl
	ld	a,false
	ld	(udfflg),a
	ld	(endflg),a
	ld	(switch),a	;i/p file switched=false
	ld	(havlbl),a
	ld	a,' '
	ld	(errflg),a
	ld	a,codtyp
	ld	(lintyp),a
	call	getlin		;get next line
	cp	a,eof
	jr	nz,next0
	ld	a,(level)	;if (level==0)
	or	a,a
	jp	z,endop1	;  jump to endop1
	ld	a,true		;else
	ld	(switch),a	;  sitch=true
next0	ld	a,(linbff)	;get char in col 0
	cp	a,tab
	jp	z,next2		;tab, so no label
	cp	a,cr
	jp	z,ndstmt	;null line
	cp	a,' '
	jp	z,next2		;no label
	cp	a,';'
	jr	nz,next1
	ld	a,comtyp
	ld	(lintyp),a
	jp	ndstmt
next1	ld	a,true
	ld	(havlbl),a
	call	getnam		;get label
	call	readch
	cp	a,':'		;ignore ":"
	call	nz,backup	;  calculate length of label and build entry
	ld	b,1		;length
	ld	hl,nambff
	ld	de,stbuff+1
next11	ld	a,(hl)		;collect label
	cp	a,' '
	jr	z,next12
	ld	(de),a
	inc	hl
	inc	de
	inc	b
	jr	next11
next12	ld	a,b		;check name length
	cp	a,maxnch+2	;allow for length byte
	jr	c,next13
	call	lerror
	jp	ndstmt		;else label error
next13	ld	(stbuff),a	;  length
	ex	de,hl
	xor	a,a		;  link=00
	inc	hl
	ld	(hl),a
	inc	hl
	ld	(hl),a
	ld	a,(pc)
	ld	(hl),a
	inc	hl		;  address=pc
	ld	a,(pc+1)
	ld	(hl),a
	inc	hl
	ld	(hl),0		;  type=0
	ld	a,(passno)
	or	a,a		;if pass=0
	jr	nz,next15
	call	stsrch		;  stsrch
	jr	nz,next14	;  if found
	ld	hl,(flgadd)	;    flag as multiply defined
	ld	a,(hl)
	or	a,80H
	ld	(hl),a
	jr	next2		;else
next14	call	ptn2st		;  enter symbol into table
	ld	(symadr),hl	;  save address for "equ"
	jr	next2
next15	call	stsrch		;elseif (pass=2)    #check phase error!!!
	jr	nz,next16	;  stsrch           #must be found!!!
	ld	hl,(flgadd)	;  if found
	ld	a,(hl)
	and	a,80H		;    if bit 7 set
	jr	z,next2
	call	merror		;      set "multiply defined" flag
	jr	next2		;  else
next16	ld	a,1		;    set "undefined" flag
	ld	(udfflg),a
	ld	hl,(lnbptr)
	ld	(udfptr),hl
next2	call	getnam		;process opcode
	ld	a,(nambff)
	cp	a,' '
	jp	z,ndstmt	;if no opcode must be comment
	call	opsrch		;search op-code table
	jr	z,next21
	call	oerror		;op-code error
	jp	ndstmt
next21	ld	a,(hl)
	ld	(opcode),a
	inc	hl
	ld	a,(hl)
	ld	(opcode+1),a	;save opcode
	inc	hl
	ld	a,(hl)		;get type byte
	cp	a,pseudop
	call	c,dsfill
	dec	a
	add	a,a		;-1 and double for table index
	ld	e,a
	ld	d,0
	ld	hl,typtbl
	add	hl,de
	ld	e,(hl)
	inc	hl
	ld	d,(hl)
	ex	de,hl
	jp	(hl)		;dispatch to proper instruction type
;
;
	include	d:zasmb.z82	;pseudo ops
;
;
;	e n d   o f   s t a t e m e n t   p r o c e s s i n g
;
;
chkend	push	af		;check that there is nothing else on line
	call	readch
	cp	a,';'		;???
	jr	z,chnd1
	cp	a,cr
	jr	z,chnd1
	cp	a,lf
	jr	z,chnd1
	cp	a,' '
	jp	p,chnd0
	add	a,40H
chnd0	ld	(xch),a
	call	xerror		;extra character(s) on line
chnd1	pop	af
	ret
;
;
end1	ld	(inst),a
	ld	a,1
	jp	endlth
;
;
end2	ld	(inst),hl
	ld	a,2
	jr	endlth
;
;
endahl	ld	(inst),a
	ld	(inst+1),hl
	ld	a,3
	jr	endlth
;
;
endhla	ld	(inst),hl
	ld	(inst+2),a
	ld	a,3
	jr	endlth
;
;
end4	ld	(inst),hl
	ld	(inst+2),de
	ld	a,4
	jp	endlth
;
;
endlth	ld	(length),a
;
ndstmt	ld	a,(errflg)	;if (not error)
	cp	a,' '
	call	z,chkend	;  check end
	ld	a,(nocode)	;if (nocode)
	cp	a,true
	jr	nz,ndst0
	ld	hl,00		;  length=0
	ld	(length),hl
	ld	a,comtyp	;  linetype=comment
	ld	(lintyp),a
ndst0	ld	a,(errflg)	;if (errflg=='F')
	cp	a,'F'
	jr	nz,ndst01
	call	dsplin		;  display line
	call	dsperr		;  display error
	jp	abort		;  abort
ndst01	ld	a,(passno)	;elseif (pass2)
	or	a,a
	jp	z,ndst6
	ld	a,(udfflg)	;  if (undefined)
	or	a,a
	jr	z,ndst1
	ld	hl,(udfptr)
	ld	(lnbptr),hl
	call	uerror		;    errflg='U'
ndst1	ld	a,(errflg)	;  if (errflg<>" ")
	cp	a,' '
	jr	z,ndst2
	call	dsplin		;    display line
	call	dsperr
	ld	hl,(nerrs)	;    nerrors=nerrors+1
	inc	hl
	ld	(nerrs),hl
	jr	ndst3
ndst2	ld	a,(lstflg)	;  if ((lstflg)or(errflg))
	or	a,a
	jp	z,ndst5
ndst3	call	lstlin		;    send line to .LST file
	ld	a,(errflg)	;  if (errflg<>" ")
	cp	a,' '
	jp	z,ndst5
	call	lsterr
ndst5	ld	a,(length)	;  if ((length>0)and
	ld	b,a
	or	a,a
	jr	z,ndst6
	ld	a,(lintyp)	;      (line_type<>"ds"))
	cp	a,dstyp
	jr	z,ndst6
	ld	hl,inst		;    for i=1 to length
ndst51	ld	a,(hl)
	inc	hl
ndst55	call	wrbyte		;      write_byte
	djnz	ndst51
	;
ndst6	ld	a,(switch)	;if (input switched)
	cp	a,true
	jr	nz,ndst61
	xor	a,a
	ld	(ndots),a	;  ndots=0
	ld	hl,(totlns)
	ld	de,(nlines)
	inc	de		;line numbers start from 0
	add	hl,de
	ld	(totlns),hl
	ld	hl,level	;  level=level-1
	dec	(hl)
	ld	hl,ch4dsp
	ld	de,(level)
	add	hl,de
	ld	a,(hl)
	ld	(chdsp),a
	ld	hl,buffers
	ld	de,(level)
	add	hl,de
	add	hl,de
	ld	a,(hl)
	inc	hl
	ld	h,(hl)
	ld	l,a		;HL=^index[level]
	ld	e,(hl)
	inc	hl
	ld	d,(hl)
	inc	hl
	ld	(ipbndx),de
	ld	e,(hl)
	inc	hl
	ld	d,(hl)
	inc	hl
	ld	(nlines),de
	ld	(pipfcb),hl
	ld	de,36
	add	hl,de
	ld	(ipbuff),hl
	ld	de,bffsiz
	add	hl,de
	ld	(ipbend),hl
	ld	hl,(pipfcb)
	call	dspfnm
ndst61	ld	hl,(pc)		;pc=pc+length
	ld	de,(length)
	add	hl,de
	ld	(pc),hl
	ld	a,(endflg)	;if not endflag
	or	a,a
	jp	z,next		;  go process next line
	ld	a,(passno)
	cpl			;pass=not pass
	ld	(passno),a
	cp	a,0
	jp	z,endit
	;
	xor	a,a		;reset current extent
	ld	hl,(pipfcb)
	ld	bc,12
	add	hl,bc
	ld	(hl),a
	ld	hl,(pipfcb)	;reset current record
	ld	bc,32
	add	hl,bc
	ld	(hl),a
	call	opnfil
	call	dspnxt
	db	cr,lf,lf,'Pass 2  ',cr,lf,0
	ld	a,8
	ld	(ndots),a
	ld	hl,(pipfcb)
	call	dspfnm
	xor	a,a		;reset end-line flag
	ld	(endflg),a
	jp	pass2
;
;
endit	ld	a,(hexflg)	;if (hex output)
	cp	a,true
	jr	nz,endit0
	call	wrhxbff		;  move last hex record to disc
	call	wrhxbff		;  terminator record
endit0
	ld	a,(objfas)	;if not new record
	cp	a,128
	jr	z,endit1
	ld	a,eof		;  put ^Z into write buffer 
	call	wrbyte
	ld	a,128		;  force write
endit1	ld	(objfas),a
	call	wrbyte
	ld	de,objfcb
	ld	(fcb),de
	ld	hl,(nerrs)	;if (nerrors==0)
	ld	a,h
	or	a,l
	jr	nz,endt11
	call	clsfil		;  close .COM file
	jr	nz,endit2
	call	dspnxt
	db	cr,lf,bel,'Cannot close output file. Disc full?'
	jp	abort		;else
endt11	call	delfil		;  delete .COM file
	;
endit2	ld	a,cr
	call	wrlist
	ld	a,lf
	call	wrlist
	ld	a,(lstfas)	;if not new record
	cp	a,128
	jr	z,endt21
	ld	a,eof		;  put ^Z into list buffer 
	call	wrlist
	ld	a,128		;  force write
endt21	ld	(lstfas),a
	call	wrlist
	ld	de,lstfcb
	ld	(fcb),de
	ld	a,(lstcls)	;if (list_close)
	or	a,a
	jr	z,endt22
	call	clsfil		;  close .LST file
	jr	nz,endit3
	call	dspnxt
	db	cr,lf,bel,'Cannot close output file. Disc full?'
	jp	abort		;else
endt22	call	delfil		;  delete file
	;
endit3	ld	hl,(pc)
	dec	hl
	ld	de,lstadd
	ld	a,h
	call	cnv2hex
	ld	a,l
	call	cnv2hex
	;
	call	dspnxt
 	db	cr,lf,lf,'Last address used   = '
lstadd 	db	'xxxxH',0
	;
	ld	hl,(stfas)
	ld	de,nxtadd
	ld	a,h
	call	cnv2hex
	ld	a,l
	call	cnv2hex
	call	dspnxt
	db	cr,lf,'Next symbol address = '
nxtadd	db	'xxxxH',0
	;
	ld	hl,(stfas)
	ld	de,symtab
	or	a,a
	sbc	hl,de
	ld	de,stlgth
	ld	a,h
	call	cnv2hex
	ld	a,l
	call	cnv2hex
	call	dspnxt
	db	cr,lf,'Symbol table length = '
stlgth	db	'xxxxH',0
	;
	call	dspnxt
	db	cr,lf,lf,'No. of symbol table searches = ',0
	ld	hl,(nstsr)
	ld	de,lnnobf	;errbff
	call	decval
	ld	hl,lnnobf	;errbff
	call	dspdec
	;
	call	dspnxt
	db	cr,lf,'No. of symbol table entries  = ',0
	ld	hl,(nstnt)
	ld	de,lnnobf	;errbff
	call	decval
	ld	hl,lnnobf	;errbff
	call	dspdec
	;
	call	dspnxt
 	db	bel,cr,lf,lf,'Assembly complete.  ',0
	;
	ld	hl,(nlines)	;totlns+1 to account for line 0
	ld	de,(totlns)
	add	hl,de
	inc	hl
	ld	de,lnnobf
	call	decval
	ld	hl,lnnobf
	call	dspdec
	call	dspnxt
	db	' lines, ',0
	ld	hl,(nerrs)
	ld	de,0
	call	cphlde
	jr	nz,endit5
	call	dspnxt
	db	'no errors',0
	jr	endit6
endit5	ld	hl,(nerrs)
	ld	de,lnnobf	;errbff
	call	decval		;put "nerrs" into "lineno"
	ld	hl,lnnobf	;errbff
	call	dspdec		;display "lineno"
	call	dspnxt
	db	' error',0
	ld	hl,(nerrs)
	ld	de,1
	call	cphlde
	jp	z,endit6
	ld	a,'s'
	call	dspch
endit6	ld	a,'.'
	call	dspch
	jp	wboot
;
abort	call	dspnxt
	db	bel,cr,lf,lf,'Assembly abandoned.',0
	jp	wboot
;
;
;
;			Opcode Table
;
;	Each symbol table entry is of varying length.
;
;	The first byte contains the length of the opcode mnemonic plus one.
;
;	The second byte holds the first character of the name.
;
;	Following the name are 2 bytes holding the the order code
;	and then a 1 byte type.
;
;	The table is searchec by hashing on the first character of the
;	menmonic and then scanned serially.
;
;
;			op-code table
;
;		index to alphabetical subsections
;
;
opcndx	dw	opcta,opctb,opctc,opctd,opcte,opctf,opct0
	dw	opcth,opcti,opctj,opct0,opctl,opct0,opctn
	dw	opcto,opctp,opct0,opctr,opcts,opct0,opct0
	dw	opct0,opct0,opctx,opct0,opct0
;
;			op-code table.
;
;	opcodes should be in order of frequency within sections.
;
opcta	db	3
	db	4,'add',   80H, 86H, 6
	db	4,'and',  0A0H,0A6H, 6
	db	4,'adc',   88H, 8EH, 6
opctb	db	1
	db	4,'bit',  046H,   0,12
opctc	db	8
	db	5,'call', 0CDH,0C4H, 3
	db	3,'cp',   0B8H,0BEH, 6
	db	4,'cpd',  0EDH,0A9H, 1
	db	5,'cpdr', 0EDH,0B9H, 1
	db	4,'cpi',  0EDH,0A1H, 1
	db	5,'cpir', 0EDH,0B1H, 1
	db	4,'cpl',  02FH,   0, 1
	db	4,'ccf',  03FH,   0, 1
opctd	db	10
	db	3,'db',      3,   0,14
	db	3,'ds',      2,   0,14
	db	3,'dw',      4,   0,14
	db	4,'dec',   05H, 0BH,13
	db	5,'defb',    3,   0,14
	db	5,'defs',    2,   0,14
	db	5,'defw',    4,   0,14
	db	5,'djnz',  10H,   0, 4
	db	4,'daa',   27H,   0, 1
	db	3,'di',   0F3H,   0, 1
opcte	db	6
	db	3,'ei',   0FBH,   0, 1
	db	3,'ex',   0EBH,   0,10
	db	4,'equ',     1,   0,14
	db	4,'exx',  0D9H,   0, 1
	db	4,'end',     5,   0,14
	db	6,'endif',  10,   0,14
opctf	db	1
	db	5,'forg',   11,   0,14
opcth	db	1
	db	5,'halt', 076H,   0, 1
opcti	db	11
	db	4,'inc',   04H, 03H,13
	db	3,'in',   0DBH,   0, 7
	db	4,'ind',  0EDH,0AAH, 1
	db	5,'indr', 0EDH,0BAH, 1
	db	4,'ini',  0EDH,0A2H, 1
	db	5,'inir', 0EDH,0B2H, 1
	db	8,'include', 8,   0,14 
	db	3,'if',      9,   0,14
	db	4,'im0',  0EDH, 46H, 1
	db	4,'im1',  0EDH, 56H, 1
	db	4,'im2',  0EDH, 5EH, 1
opctj	db	2
	db	3,'jr',   018H,   0, 4
	db	3,'jp',   0C3H, 0C2H,3
opctl	db	6
	db	3,'ld',      0,   0, 8
	db	4,'ldd',  0EDH,0A8H, 1
	db	5,'lddr', 0EDH,0B8H, 1
	db	4,'ldi',  0EDH,0A0H, 1
	db	5,'ldir', 0EDH,0B0H, 1
	db	5,'list',    7,   0,14
opctn	db	2
	db	4,'neg',  0EDH, 44H, 1
	db	4,'nop',  000H,   0, 1
opcto	db	7
	db	3,'or',   0B0H,0B6H, 6
	db	4,'out',  0D3H,   0, 7
	db	4,'org',     6,   0,14
	db	5,'otdr', 0EDH,0BBH, 1
	db	5,'otir', 0EDH,0B3H, 1
	db	5,'outd', 0EDH,0ABH, 1
	db	5,'outi', 0EDH,0A3H, 1
opctp	db	2
	db	4,'pop',  0C1H,   0, 9
	db	5,'push', 0C5H,   0, 9
opctr	db	17
	db	4,'ret',  0C9H,   0,11
	db	3,'rl',    10H,   0, 2
	db	4,'rla',   17H,   0, 1
	db	4,'rlc',   00H,   0, 2
	db	5,'rlca',  07H,   0, 1
	db	4,'rld',  0EDH, 6FH, 1
	db	3,'rr',    18H,   0, 2
	db	4,'rra',   1FH,   0, 1
	db	4,'rrc',   08H,   0, 2
	db	5,'rrca',  0FH,   0, 1
	db	4,'rrd',  0EDH, 67H, 1
	db	5,'read',    8,   0,14 
	db	4,'rst',  0C7H,   0, 5
	db	4,'res',  086H,   0,12
	db	5,'reti', 0EDH, 4DH, 1
	db	5,'retn', 0EDH, 45H, 1
	db	6,'reorg', 12,    0,14
opcts	db	7
	db	4,'sub',  90H,  96H, 6
	db	4,'sbc',  98H,  9EH, 6
	db	4,'scf',  37H,    0, 1
	db	4,'sla',  20H,    0, 2
	db	4,'sra',  28H,    0, 2
	db	4,'srl',  38H,    0, 2
	db	4,'set', 0C6H,    0,12
opctx	db	1
	db	4,'xor', 0A8H, 0AEH, 6
opct0	db	1
	db	1,' '
;
;
cndtbl	db	3,'nz'		;condition table
	db	2,'z '
	db	3,'nc'
	db	2,'c '
	db	3,'po'
	db	3,'pe'
	db	2,'p '
	db	2,'m '
;
;
;		registers have to be entered by hashing.
;
;
regtbl	db	2,'b',  0,0, 0,0, 10H		;registers
	db	2,'c',  0,0, 0,0, 11H
	db	2,'d',  0,0, 0,0, 12H
	db	2,'e',  0,0, 0,0, 13H
	db	2,'h',  0,0, 0,0, 14H
	db	2,'l',  0,0, 0,0, 15H
	db	2,'a',  0,0, 0,0, 17H
	db	3,'bc', 0,0, 0,0, 20H
	db	3,'de', 0,0, 0,0, 21H
	db	3,'hl', 0,0, 0,0, 22H
	db	3,'sp', 0,0, 0,0, 23H
	db	3,'ix', 0,0, 0,0, 24H
	db	3,'iy', 0,0, 0,0, 25H
	db	3,'af', 0,0, 0,0, 26H
	db	2,'i',  0,0, 0,0, 18H
	db	2,'r',  0,0, 0,0, 19H
;
;
ch4dsp	db	'.','_',',',':',';'
;
;
pipfcb	ds	2	;holds address of current input fcb
;
objfcb 	ds	1	;output file control block
	ds	35
lstfcb	ds	1	;list    "	"	"
	ds	35
;
;
buffers	dw	level0,level1,level2,level3,level4
;
level0	ds	2	;index to buffer
	ds	2	;current line no.
srcfcb	ds	36	;fcb
srcbff	ds	bffsiz	;buffer
srcend	equ	$	;end of buffer
;
level1	ds	2	;0
	ds	2	;2
	ds	36	;4
	ds	bffsiz	;40
;
level2	ds	2
	ds	2
	ds	36
	ds	bffsiz
;	
level3	ds	2
	ds	2
	ds	36
	ds	bffsiz
;
level4	ds	2
	ds	2
	ds	36
	ds	bffsiz
;
ipbndx	ds	2	;index for current input buffer (source or read)
ipbuff	ds	2	;holds address of current input buffer
ipbend	ds	2	;holds address of end of current input buffer
;
;
objfas 	ds	2	;object file buffer pointer
objbff 	ds	128	;object file buffer
lstfas	ds	2	;list file buffer pointer
lstbff	ds	128	;list file buffer
;
;
;		hash table
;
hshtbl	ds	512
;
;
;			Symbol Table
;
;	Each symbol table entry is of varying length.
;
;	The first byte contains the length of the name plus one.
;
;	The second byte holds the first character of the name.
;
;	Following the name are 2 bytes of address (or value for "equs"
;	and 1 byte of type (used in opcodes).
;
;
	db	'symtab>>'
;
symtab	ds	0	;first available space in "symtab"
;
;
	end