; MOS for BBC BASIC on Acorn Atom
;
; J.G Harston code
; modified to assemble online using asm80.com
; and functions given more informative names.
;
	ASCII_ACK   equ 6
    ASCII_BEL   equ 7
    ASCII_LF    equ $0A
	ASCII_CR	equ	$0D
	ASCII_NAK   equ $15
	ASCII_ESC	equ	$1B
	ASCII_SP	equ	$20
    ASCII_0     equ $30
	ATOM_SP	equ	$40

; I/O Addresses

if	1;		Atom:

    lowest_memory	equ	$0800
    highest_memory	equ	$4000
    screen_RAM	equ	$4000
	ATOM_PPI	equ	$7000
	ATOM_VIA	equ	$7800	
			org	$F000
endif

if 0 ; W65C02SXB
;
; This board has no 8255 PPI
; and you won't find one that runs at 14 MHz
; but since the port directions are fixed for Atom use 
; you could simply use TTL chips.
; If you don't need to scan a keyboard, 
; tape, or a 6847 then you could do without it altogether.
;
;
;	ATOM_PPI	equ	$7000
	ATOM_VIA	equ	$7fc0	
endif

ATOM_PPI_PORT_A		equ	ATOM_PPI+0	; D7-4 to 6847, D3-0 to keyboard column decoder
ATOM_PPI_PORT_B		equ	ATOM_PPI+1	; D7-0 from keyboard rows
ATOM_PPI_PORT_C		equ	ATOM_PPI+2	; D7-0 inputs
ATOM_PPI_CTRL		equ	ATOM_PPI+3

ATOM_VIA_IOBB		equ	ATOM_VIA+0
ATOM_VIA_IOA		equ	ATOM_VIA+1
ATOM_VIA_DDRB		equ	ATOM_VIA+2
ATOM_VIA_DDRA		equ	ATOM_VIA+3
ATOM_VIA_T1CL		equ	ATOM_VIA+4
ATOM_VIA_T1CH		equ	ATOM_VIA+5
ATOM_VIA_T1LL		equ	ATOM_VIA+6
ATOM_VIA_T1LH		equ	ATOM_VIA+7
ATOM_VIA_T2CL		equ	ATOM_VIA+8
ATOM_VIA_T2CH		equ	ATOM_VIA+9
ATOM_VIA_SR		equ	ATOM_VIA+$a
ATOM_VIA_ACR		equ	ATOM_VIA+$b
ATOM_VIA_PCR		equ	ATOM_VIA+$c
ATOM_VIA_IFR		equ	ATOM_VIA+$d
ATOM_VIA_IER		equ	ATOM_VIA+$e
ATOM_VIA_ORA_IRA	equ	ATOM_VIA+$f



	
; > BBCMOS1/SRC
; Source for Atom MOS interface for BBC BASIC
; Source recreation by J.G.Harston
;	
	
;	SYS "OS_GetEnv" TO A$
;	A$=A$+" "
;	A$=MID$(A$,1+INSTR(A$," ",1+INSTR(A$," ",1+INSTR(A$," "))))
;;	A%=INSTR(A$+" "," ")
;	outfile$=LEFT$(A$,A%-1)
;	A$=MID$(A$,A%+1)
;	IF outfile$=""
;	outfile$="outfile"
;;	A%=INSTR(A$+" "," ")
;	version$=LEFT$(A$,A%-1)
;	A$=MID$(A$,A%+1)
;	IF version$=""
;	version$="1"
;;	A%=INSTR(A$+" "," ")
;	bugfix$ =LEFT$(A$,A%-1)
;	A$=MID$(A$,A%+1)
;	IF bugfix$ =""
;	bugfix$ ="0"
;;	IF outfile$=""
;	ERROR 220,"Syntax
;		B6502 -quit BBCMOS/src <outfile> <version> <bugfix>"
;	END
;;
;	PRINT "Assembling
;		Atom BBC MOS version ";version$
;	PRINT "Bugfix level
;		";bugfix$
;	PRINT "Outfile
;		";outfile$
;	ON ERROR REPORT
;	PRINT " at line ";ERL
;	END
;
;
; Note
;	There are many bugs in this code.
;	There is overlap between BBC memory locations and Atom memory locations,
;	eg
;	$FE is BBC FAULT pointer and Atom NoPrint character
;	Error messages all have wrong error number.
;	Unsupported calls bomb out instead of returning cleanly.
;	Some implemented calls don't return correct results.
;
; Memory Map
; ----------
; $00-&8F - BBC BASIC zero page workspace
;
IRQ_A_store	equ	$98
IRQ_X_store	equ	$99
; $9A
CLI_A_store	equ	$9B

CLI_line_pointer	equ	$9C	; word
; $9E/F - pointer to control block or memory

OSWRCH_A_store	equ	$9E
OSWRCH_X_store	equ	$9f
OSWRCH_Y_store	equ	$A0

pointer_control_block	equ	$9e
pointer_to_memory   	equ	$9e     ; an alias

pointer_YX          equ $9f

; $A1

OSWORD_0_control_block    equ $A2
OSWORD_0_text_address    equ $A4
OSWORD_0_maximum_length    equ $A6
OSWORD_0_lowest_character    equ $A7
OSWORD_0_highest_character    equ $A8
;
screen_map          equ $B3 ;   0-4
start_of_screen   equ $B4

;
; $C9/A - OSCLI dispatch address
;
; $DD	- Y store in OSCLI

current_line    equ $DE
; $DE/F - Address of start of current line
; $E0	- b7=VDU disabled
; $E1
vector_0xE2 equ $E2
; $E4/5 - X/Y store in VDU code
; $E8/9 - inline text pointer
inline_text_ptr equ $E8
; $EA
;
;
ESC_flag    equ $FF
;
; $0300-4 - TIME
; $0305-E	VDU queue
;	$305 - $01	$11	$12	$13	$16	$17	$1F
;	$306 - char colour mode	log	mode char	x
;	$307 -		colour phy	b1	y
;	$308 -			red	b2
;	$309 -			grn	b3
;	$30A -			blu	b4
;	$30B -				b5
;	$30C -				b6
;	$30D -				b7
;	$30E -				b8
; $030F

PLOT_vector     equ $0313   ; word
; $0315
VDU_queue_length    equ $316
sound_duration  equ $317   ; word
sound_pitch     equ $319    ; word
; $0319/A - SOUND pitch - copied to 6522 T2 at ATOM_VIA_T2CL on Timer1
; $031B/C - INKEY delay
; $031D-F - b16-b39 of INKEY delay
; $0320-4 - now+delay for INKEY
;
; $032A	- MODE
;
; $0400-&07FF - BBC BASIC workspace
;
	
	
; MOS entry addresses
; -------------------
;	OS_CLI	equ	$FFF7
;	OSBYTE	equ	$FFF4
;	OSWORD	equ	$FFF1
;	OSWRCH	equ	$FFEE
;	OSWRCR	equ	$FFEC
;	OSNEWL	equ	$FFE7
;	OSASCI	equ	$FFE3
;	OSRDCH	equ	$FFE0
	
	
; Vectors
; -------
	userv	equ	$200
	brkv	equ	$202
	irq1v	equ	$204
	irq2v	equ	$206
	cliv	equ	$208
	bytev	equ	$20A
	wordv	equ	$20C
	wrchv	equ	$20E
	rdchv	equ	$210
	filev	equ	$212
	argsv	equ	$214
	bgetv	equ	$216
	bputv	equ	$218
	gbpbv	equ	$21A
	findv	equ	$21C
	fscv	equ	$21E
	evntv	equ	$220
	uptv	equ	$222
	netv	equ	$224
	vduv	equ	$226
	keyv	equ	$228
	insv	equ	$22A
	remv	equ	$22C
	cnpv	equ	$22E
	ind1v	equ	$230
	ind2v	equ	$232
	ind3v	equ	$234
	
	

	
;	BUGFIX%=VALbugfix$
;	DIM mcode% $1100
;	load%	equ	$F000
;	FOR opt%=4 TO 7 STEP 3
;	P%=load%
;	O%=mcode%
;	[OPT opt%
; ==============
; OSWORD HANDLER
; ==============
; On entry, A =function
;		XY=>control block
; On exit,	A,X,Y preserved if not OSWORD 0
;		control block updated
;
OSWORD_handler:
	CMP #$00
	BEQ OSWORD_0_READ_INPUT_LINE	; Jump with read input line
	CMP #$01
	BEQ LF013	; Jump with =TIME
	CMP #$02
	BEQ OSWORD_2_TIME_set	; Jump with TIME=
	CMP #$07
	BEQ LF016	; Jump with SOUND
if	1	;	OPT FNif(BUGFIX%<1)
		JMP LF0E6		; Otherwise, generate error - BAD, should just return
else
		RTS			; Unrecognised OSWORD, return
endif
;
LF013:
	JMP OSWORD_1_TIME		; Pass on to do =TIME
LF016:
	JMP OSWORD_7_SOUND_chn_vol_pitch_dur		; Pass on to do SOUND


; OSWORD 0 - READ INPUT LINE
; ========================== 
; Bugs
	
;	If line length becomes:	127 chars, DEL/Ctrl-U mess up
;	Escape is printed then checked for, it shouldn't be printed

OSWORD_0_READ_INPUT_LINE:
	STX OSWORD_0_control_block
	STY $A3
	LDY #4
loop_F01F:
	LDA (OSWORD_0_control_block),Y
	STA $00A4,Y ; Copy control block
	DEY
	BPL loop_F01F
loop_F027:
	LDY #0		; Line length=0
loop_F029:
	JSR OSRDCH		; Wait for character
	
				; Should check for Escape
	CMP #ASCII_ESC
	BNE LF03E	; Not Ctrl-U
loop_F030:
	DEY
	BMI loop_F027		; Dec. length, restart if <0
	
				; *BUG* is line length>128, fails
	LDA #$7F
	JSR OSWRCH	; VDU 127
	JMP loop_F030		; Loop back until all done

LF03B:
	JMP loop_F027		; Nothing calls this
		
LF03E:
	CMP #$7F
	BNE not_DELETE	; Not DELETE
	DEY
	BMI loop_F027		; Dec. length, restart if <0
	
				; *BUG* is line length>128, fails
	JSR OSWRCH		; VDU 127
	JMP loop_F029		; Loop back for another character
		
not_DELETE:
	JSR OSWRCH		; Print this character
	CMP #ASCII_CR
	BEQ ASCII_CR_pressed	; If <CR>, finish
	CMP #ASCII_ESC
	BEQ ASCII_ESC_pressed	; If <Esc>, finish - shouldn't have printed this
	CMP OSWORD_0_lowest_character
	BCC loop_F029	; If <charlo, loop for another character
	CMP OSWORD_0_highest_character
	BEQ store_character	; If =charmax, store this character
	BCS loop_F029		; If:	charmax, loop for another character
store_character:
	STA (OSWORD_0_text_address),Y
	INY		; Store character, increment pointer
	CPY OSWORD_0_maximum_length
	BCC loop_F029	; If <lenmax, loop for another character
	LDA #$7F
	JSR OSWRCH	; Otherwise, delete this character
	
				; *BUG* if last character was nonprinting, this will fail
	DEY
	JMP loop_F029		; Dec. pointer and loop back

; <cr> pressed
; ------------
ASCII_CR_pressed:
	STA (OSWORD_0_text_address),Y
	JSR OSNEWL	; Store <cr> and print newline
	LDX #0		; X=$00 - Ok
	CLC			; CLC=ok
	RTS	

; <esc> pressed
; -------------
ASCII_ESC_pressed:
	SEC			; SEC=Escape
	LDX #$FF		; X=$FF - Escape
	STX ESC_flag			; Also set ESCFLAG
	RTS	


OSWORD_2_TIME_set:
	STX pointer_control_block
	STY pointer_control_block+1
	LDY #4		; Copy 5 bytes of control block
loop_F085:
	LDA (pointer_control_block),Y
	STA $0300,Y ; Copy to TIME at $0300-&0304
	DEY
	BPL loop_F085		
	LDY pointer_control_block+1
	RTS		; Restore Y and return

OSWORD_1_TIME:
	STX pointer_control_block
	STY pointer_control_block+1
	LDY #4			; Copy 5 bytes of control block
loop_F096:
	LDA $0300,Y
	STA (pointer_control_block),Y ; Copy from TIME at $0300-&0304
	DEY
	BPL loop_F096
	LDY pointer_control_block+1
	RTS		; Restore Y and return


OSWORD_7_SOUND_chn_vol_pitch_dur:
	STX pointer_control_block
	STY pointer_control_block+1
	LDY #$04		; Point to pitch
	LDA (pointer_control_block),Y
	STA sound_pitch	; $319/A=pitch
	INY
	LDA (pointer_control_block),Y
	STA sound_pitch+1
	INY
	LDA (pointer_control_block),Y
	STA sound_duration	; $317/8=duration
	INY
	LDA (pointer_control_block),Y
	STA sound_duration+1
	LDA sound_pitch
	STA ATOM_VIA_T2CL	; Store pitch.lo to 6522 T2.lo
	LDA sound_pitch+1
	STA ATOM_VIA_T2CH	; Store pitch.hi to 6522 T2.hi
	LDA #$A0
	STA ATOM_VIA_IER	; Enable 6522 T2 IRQs to toggle Speaker 
	LDY pointer_control_block+1
	RTS		; Restore Y and return


; ==============
; OSBYTE HANDLER
; ==============
; On entry, A =function
;		XY=parameters
; On exit,	A =preserved (memory calls may return a value)
;		XY=return values
;		Cy=may contain a return value
LF0D2:
OSBYTE_handler:
	CMP #$83
	BEQ OSBYTE_0x83_Read_bottom_of_memory	; Jump with read bottom of memory
	CMP #$84
	BEQ OSBYTE_0x84_Read_top_of_memory	; Jump with read top of memory
	CMP #$81
	BEQ OSBYTE_0x81_INKEY	; Jump with INKEY
	CMP #$7E
	BEQ OSBYTE_0x7E_Escape_Acknowledge	; Jump with Escape Acknowledge
	CMP #$82
	BEQ OSBYTE_0x82_Read_address_high_word	; Jump with address high word
LF0E6:
if	0	;	OPT FNif(BUGFIX%<1)
		BRK
endif
	db 254
	db "NOT IMPLEMENTED"
	db 0
if	0
; *BUG* - should just return
else
		RTS
endif

OSBYTE_0x82_Read_address_high_word:
	RTS			; Return XY unchanged

OSBYTE_0x7E_Escape_Acknowledge:
	JMP loop_until_no_ESC

OSBYTE_0x83_Read_bottom_of_memory:
	LDX #$00
	LDY #$08
	RTS	; Return $0800

		
OSBYTE_0x84_Read_top_of_memory:
	PHA
	LDA #<lowest_memory
	STA pointer_to_memory
	LDA #>lowest_memory
	STA pointer_to_memory+1	; $9E/F=>&0800, lowest available location
	LDY #$00
scanning_loop:
	LDA (pointer_to_memory),Y
	EOR #$FF
	STA (pointer_to_memory),Y	; Complement byte in memory
	CMP (pointer_to_memory),Y
	BNE LF125		; Doesn't match, end of RAM
	EOR #$FF
	STA (pointer_to_memory),Y		; Complement it back to restore it
	INY
	BNE scanning_loop			; Loop for 256 bytes
	INC pointer_to_memory+1
	LDA pointer_to_memory+1
	CMP #>highest_memory
	BCC scanning_loop ; Scan up to $4000
LF125:
	TYA
	TAX
	LDY pointer_to_memory+1				; X=low byte, Y=high byte
	PLA
	RTS				; A.b7=1, indicates <&10000

OSBYTE_0x81_INKEY:
	STX $031B
	STY $031C			; Store INKEY countdown time
	LDX #0
	STX $031F
	STX $031E
	STX $031D			; Set b16-b39 of INKEY delay to zero
LF13C:
	LDY #$04
	CLC				; Five bytes to add
LF13F:
	LDA $0300,X
	ADC $031B,X
	STA $0320,X ; $320-4 = TIME+INKEY delay
	INX
	DEY
	BPL LF13F
LF14C:
	JSR LFE4A
	BCC LF162			; Test keyboard, jump if key pressed
	LDX #$04			; Compare five bytes
LF153:
	LDA $0320,X
	CMP $0300,X			; Compare TIME with INKEY timeout
	BMI LF16A			; Timed out, jump to exit
	BNE LF14C			; Not the same, loop back
	DEX
	BPL LF153			; Loop to test all five bytes
	BMI LF16A			; All bytes same, timed out
	
	
; Key pressed
; -----------
LF162:
	JSR LF16E	; Convert keypress
	TAX		; X=keypress
	LDY #$00	; Y = $00 - Ok
	CLC
	RTS		; CLC=Ok, and return

LF16A:
	LDY #ESC_flag
	SEC
	RTS		 ; Y = $FF, SEC = Timed out
		
LF16E:
	PHP
	JMP LFE8A	; Push flags, jump to convert keypress

		
OSBYTE_0x7E_Escape_Acknowledge_:
if	0	;	OPT FNif(BUGFIX%>0)
		LDX ESC_flag		; X=old Escape state
endif

loop_until_no_ESC:
	LDA ESC_flag
	BPL LF17C	; No pending Escape, exit
	JSR LF17D
	JMP loop_until_no_ESC	; Update Escape state, loop until no Escape
LF17C:
	RTS			; **BUG** Should return previous Escape state in X

; Update Escape state by checking for Escape key pressed
; ------------------------------------------------------
LF17D:
	LDA ATOM_PPI_PORT_A
	PHA			; Get keyboard column
	AND #$F0
	STA ATOM_PPI_PORT_A		; Select keyboard column 0
	LDA ATOM_PPI_PORT_B
	AND #$20
	BEQ LF191	; Read keyboard row, jump if Escape pressed
	LDA #$00
	BPL LF1A0		; Set 'No Escape'

; Escape pressed
LF191:
	LDA #$20
	STA ATOM_VIA_IER		; Disable VIA T2 IRQs - stop toggling speaker
	LDA #$00
	STA sound_duration
	STA sound_duration+1	; Clear SOUND duration to cancel sound
	LDA #$FF			; Set 'Escape pending'
LF1A0:
	STA ESC_flag			; Set Escape state
	PLA
	STA ATOM_PPI_PORT_A
	RTS		; Restore keyboard column


; 6522 INTERUPT
; =============
ATOM_VIA_INTERRUPT:
	AND #$40
	BNE LF1C2		; Jump if Timer1 interupt

; 6522 Timer2 Interupt
; -------------------- 
	LDA ATOM_PPI_PORT_C
	EOR #$04
	STA ATOM_PPI_PORT_C ; Toggle Speaker bit
	LDA sound_pitch
	STA ATOM_VIA_T2CL		; Copy SOUND pitch to T2 latches
	LDA sound_pitch+1
	STA ATOM_VIA_T2CH		; 
	LDA IRQ_A_store
	RTI			; Restore A and return

; 6522 Timer1 Interupt - 100Hz timer
; ----------------------------------
LF1C2:
	STX IRQ_X_store
	JSR LF17D		; Update Escape state
	LDA sound_duration
	ORA sound_duration+1
	BEQ LF1E7 ; If SOUND duration is zero, jump to continue
	LDA sound_duration
	BNE LF1D7
	DEC sound_duration+1 ; Decrement SOUND duration
LF1D7:
	DEC sound_duration
	LDA sound_duration
	ORA sound_duration+1
	BNE LF1E7 ; If SOUND duration not zero, jump to continue
	LDA #$20
	STA ATOM_VIA_IER		; Disable 6522 T2 IRQs, stop toggling Speaker
LF1E7:
	LDX #$00			; Increment 5-byte TIME
LF1E9:
	INC $0300,X
	INX
	CPX #$05
	BEQ LF1F6
	LDA $02FF,X
	BEQ LF1E9
LF1F6:
	LDX IRQ_X_store
	LDA ATOM_VIA_T1CL		; Reset 6522 T1.lo counter
	LDA IRQ_A_store
	RTI			; Restore A and return
		
LF1FE:
	LDX #$03	; F1FE= A2 03	".
LF200:
	LDA $030F,X	; F200= BD 0F 03	=..
	STA screen_map,X	; F203= 95 B3		3
	DEX		; F205= CA		J
	BPL LF200	; F206= 10 F8		x
	LDA $030E	; F208= AD 0E 03	-..
	AND #$04	; F20B= 29 04	).
	BNE LF222	; F20D= D0 13	P.
	LDX #$02	; F20F= A2 02	".
LF211:
	CLC		; F211= 18		
	LDA $BB,X	; F212= B5 BB	5;
	ADC screen_map,X	; F214= 75 B3	u3
	STA $BB,X	; F216= 95 BB		;
	LDA $BC,X	; F218= B5 BC	5<
	ADC start_of_screen,X	; F21A= 75 B4	u4
	STA $BC,X	; F21C= 95 BC		<
	DEX		; F21E= CA		J
	DEX		; F21F= CA		J
	BPL LF211	; F220= 10 EF		o
LF222:
	LDX #$03	; F222= A2 03	".
LF224:
	LDA $BB,X	; F224= B5 BB	5;
	STA $030F,X	; F226= 9D 0F 03	...
	DEX		; F229= CA		J
	BPL LF224	; F22A= 10 F8		x
	LDA $030E	; F22C= AD 0E 03	-..
	AND #$03	; F22F= 29 03	).
	BEQ LF23F	; F231= F0 0C	p.
	STA $BF		; F233= 85 BF		?
	LDA $030E	; F235= AD 0E 03	-..
	AND #$08	; F238= 29 08	).
	BEQ LF240	; F23A= F0 04	p.
	JSR LF301	; F23C= 20 01 F3	s
LF23F:
	RTS		; F23F= 60		`
		
LF240:
	LDX #$02	; F240= A2 02	".
LF242:
	SEC		; F242= 38		8
	LDA $BB,X	; F243= B5 BB	5;
	SBC screen_map,X	; F245= F5 B3	u3
	LDY screen_map,X	; F247= B4 B3	43
	STY $BB,X	; F249= 94 BB		;
	STA screen_map,X	; F24B= 95 B3		3
	LDY start_of_screen,X	; F24D= B4 B4	44
	LDA $BC,X	; F24F= B5 BC	5<
	SBC start_of_screen,X	; F251= F5 B4	u4
	STY $BC,X	; F253= 94 BC		<
	STA start_of_screen,X	; F255= 95 B4		4
	STA $B7,X	; F257= 95 B7		7
	BPL LF268	; F259= 10 0D		
	LDA #$00	; F25B= A9 00	).
	SEC		; F25D= 38		8
	SBC screen_map,X	; F25E= F5 B3	u3
	STA screen_map,X	; F260= 95 B3		3
	LDA #$00	; F262= A9 00	).
	SBC start_of_screen,X	; F264= F5 B4	u4
	STA start_of_screen,X	; F266= 95 B4		4
LF268:
	DEX		; F268= CA		J
	DEX		; F269= CA		J
	BPL LF242	; F26A= 10 D6		V
	LDA start_of_screen+1		; F26C= A5 B5	%5
	CMP screen_map		; F26E= C5 B3	E3
	LDA $B6		; F270= A5 B6	%6
	SBC start_of_screen		; F272= E5 B4	e4
	BCC LF2A5	; F274= 90 2F		/
	LDA #$00	; F276= A9 00	).
	SBC start_of_screen+1		; F278= E5 B5	e5
	STA $B8		; F27A= 85 B8		8
	LDA #$00	; F27C= A9 00	).
	SBC $B6		; F27E= E5 B6	e6
	SEC		; F280= 38		8
	ROR A		; F281= 6A		j
	STA $BA		; F282= 85 BA		
	
	ROR $B8		; F284= 66 B8	f8
LF286:
	JSR LF301	; F286= 20 01 F3	s
	LDA $BD		; F289= A5 BD	%=
	CMP $0311	; F28B= CD 11 03	M..
	BNE LF298	; F28E= D0 08	P.
	LDA $BE		; F290= A5 BE	%>
	CMP $0312	; F292= CD 12 03	M..
	BNE LF298	; F295= D0 01	P.
LF297:
	RTS		; F297= 60		`
		
LF298:
	JSR LF2DE	; F298= 20 DE F2	^r
	LDA $BA		; F29B= A5 BA	%
	
	BMI LF286	; F29D= 30 E7	0g
	JSR LF2CD	; F29F= 20 CD F2	Mr
	JMP LF286	; F2A2= 4C 86 F2	L.r
		
LF2A5:
	LDA start_of_screen		; F2A5= A5 B4	%4
	LSR A		; F2A7= 4A		J
	STA $BA		; F2A8= 85 BA		
	
	LDA screen_map		; F2AA= A5 B3	%3
	ROR A		; F2AC= 6A		j
	STA $B8		; F2AD= 85 B8		8
LF2AF:
	JSR LF301	; F2AF= 20 01 F3	s
	LDA $BB		; F2B2= A5 BB	%;
	CMP $030F	; F2B4= CD 0F 03	M..
	BNE LF2C0	; F2B7= D0 07	P.
	LDA $BC		; F2B9= A5 BC	%<
	CMP $0310	; F2BB= CD 10 03	M..
	BEQ LF297	; F2BE= F0 D7	pW
LF2C0:
	JSR LF2CD	; F2C0= 20 CD F2	Mr
	LDA $BA		; F2C3= A5 BA	%
	
	BPL LF2AF	; F2C5= 10 E8		h
	JSR LF2DE	; F2C7= 20 DE F2	^r
	JMP LF2AF	; F2CA= 4C AF F2	L/r
		
LF2CD:
	SEC		; F2CD= 38		8
	LDA $B8		; F2CE= A5 B8	%8
	SBC start_of_screen+1		; F2D0= E5 B5	e5
	STA $B8		; F2D2= 85 B8		8
	LDA $BA		; F2D4= A5 BA	%
	
	SBC $B6		; F2D6= E5 B6	e6
	STA $BA		; F2D8= 85 BA		
	
	LDX #$00	; F2DA= A2 00	".
	BEQ LF2ED	; F2DC= F0 0F	p.
LF2DE:
	CLC		; F2DE= 18		
	LDA $B8		; F2DF= A5 B8	%8
	ADC screen_map		; F2E1= 65 B3	e3
	STA $B8		; F2E3= 85 B8		8
	LDA $BA		; F2E5= A5 BA	%
	
	ADC start_of_screen		; F2E7= 65 B4	e4
	STA $BA		; F2E9= 85 BA		
	
	LDX #$02	; F2EB= A2 02	".
LF2ED:
	LDA $B7,X	; F2ED= B5 B7	57
	BPL LF2FA	; F2EF= 10 09		
	LDA $BB,X	; F2F1= B5 BB	5;
	BNE LF2F7	; F2F3= D0 02	P.
	DEC $BC,X	; F2F5= D6 BC	V<
LF2F7:
	DEC $BB,X	; F2F7= D6 BB	V;
LF2F9:
	RTS		; F2F9= 60		`
		
LF2FA:
	INC $BB,X	; F2FA= F6 BB	v;
	BNE LF2F9	; F2FC= D0 FB	P{
	INC $BC,X	; F2FE= F6 BC	v<
	RTS		; F300= 60		`
		
; Call the plot subroutine for the current screen mode
LF301:
	JMP (PLOT_vector)	; F301= 6C 13 03	l..

; Set up screen mode
; ==================
; Note, VDU driver only supports MODE 7
; 
LF304:
	LDY #$00
	LDA #$07
	AND screen_map
	STA screen_map	; Ensure MODE is 0-7
	STA $032A
	LDA #$07
	SEC
	SBC screen_map	; A=7-MODE
	BEQ LF34A			; Jump with MODE 7
	CMP #$05
	BMI LF31C	; Jump with 
	LDA #$04
LF31C:
	LDX #$40		; X = $40xx, start of screen memory
	STX start_of_screen+1
	STY start_of_screen
	STA screen_map
	TAX
	LDA LF357-1,X	; Get address of screen memory for this screen map
	TAX		; X=end of screen memory
	TYA		; Y=0
LF32A:
	STA (start_of_screen),Y
	DEY	; Clear video memory
	BNE LF32A		; Loop for 256 bytes
	INC start_of_screen+1		; Step to next 256 bytes
	CPX start_of_screen+1
	BNE LF32A	; Loop to end of video memory

; Set up PLOT and 6847
; --------------------
LF335:
	LDY screen_map		; Get MODE *BUG* in MODE 7 this is 7
	LDA LF360,Y
	STA PLOT_vector+1 ; Set up PLOT vector
	LDA LF35B,Y
	STA PLOT_vector
	LDA LF365,Y
	STA ATOM_PPI_PORT_A ; Set screen geometry
	RTS

; Set up MODE 7
; -------------
LF34A:
	LDA #ATOM_SP
LF34C:
	STA screen_RAM,Y	; Store in 512-byte screen RAM
	STA screen_RAM+$100,Y
	DEY
	BNE LF34C	; Loop to clear memory
	BEQ LF335	; Jump back to set VDU variables

; Address of end of screen memory
; -------------------------------
LF357:
	db $44	; MODE 6	- screen_RAM-&4400
	db $46	; MODE 5	- screen_RAM-&4600
	db $4C	; MODE 4	- screen_RAM-&4C00
	db $58	; MODE 3-0 - screen_RAM-&5800

; PLOT vector table
; -----------------
LF35B:
	db <LF36A ; 255 ; MODE 6
	db <LF3C3 ; AND 255 ; MODE 5
	db <LF3DC ; AND 255 ; MODE 4
	db <LF3F5 ; AND 255
	db <LF432 ; AND 255

LF360:
	db >LF36A ; DIV 256
	db >LF3C3 ; DIV 256
	db >LF3DC ; DIV 256
	db >LF3F5 ; DIV 256
	db >LF432 ; DIV 256

; 6847 screen geometry settings
; -----------------------------
LF365:
	db $00
	db $30
	db $70
	db $B0
	db $F0

; MODE 7 - select screen type 0 (text)
; ====================================
LF36A:
	LDA $BC		; F36A= A5 BC	%<
	ORA $BE		; F36C= 05 BE		>
	BNE LF3C2	; F36E= D0 52	PR
	LDA $BB		; F370= A5 BB	%;
	CMP #$40	; F372= C9 40	I@
	BCS LF3C2	; F374= B0 4C	0L
	LSR A		; F376= 4A		J
	STA $C0		; F377= 85 C0		@
	LDA #$2F	; F379= A9 2F	)/
	SEC		; F37B= 38		8
	SBC $BD		; F37C= E5 BD	e=
	CMP #$30	; F37E= C9 30	I0
	BCS LF3C2	; F380= B0 40	0@
	LDX #$FF	; F382= A2 FF	".
	SEC		; F384= 38		8
LF385:
	INX		; F385= E8		h
	SBC #$03	; F386= E9 03	i.
	BCS LF385	; F388= B0 FB	0{
	ADC #$03	; F38A= 69 03	i.
	STA $C2		; F38C= 85 C2		B
	TXA		; F38E= 8A		
	ASL A		; F38F= 0A		
	ASL A		; F390= 0A		
	ASL A		; F391= 0A		
	ASL A		; F392= 0A		
	ASL A		; F393= 0A		
	ORA $C0		; F394= 05 C0		@
	STA $C0		; F396= 85 C0		@
	LDA #$40	; F398= A9 40	)@
	ADC #$00	; F39A= 69 00	i.
	STA $C1		; F39C= 85 C1		A
	LDA $BB		; F39E= A5 BB	%;
	LSR A		; F3A0= 4A		J
	LDA $C2		; F3A1= A5 C2	%B
	ROL A		; F3A3= 2A		*
	TAY		; F3A4= A8		(
	LDA LF453,Y	; F3A5= B9 53 F4	9St
LF3A8:
	LDY #$00	; F3A8= A0 00		
	LDX $BF		; F3AA= A6 BF	$?
	DEX		; F3AC= CA		J
	BEQ LF3BE	; F3AD= F0 0F	p.
	DEX		; F3AF= CA		J
	BEQ LF3B9	; F3B0= F0 07	p.
	EOR #$FF	; F3B2= 49 FF	I.
	AND ($C0),Y	; F3B4= 31 C0	1@
	STA ($C0),Y	; F3B6= 91 C0		@
	RTS		; F3B8= 60		`
		
LF3B9:
	EOR ($C0),Y	; F3B9= 51 C0	Q@
	STA ($C0),Y	; F3BB= 91 C0		@
	RTS		; F3BD= 60		`
		
LF3BE:
	ORA ($C0),Y	; F3BE= 11 C0		@
	STA ($C0),Y	; F3C0= 91 C0		@
LF3C2:
	RTS		; F3C2= 60		`

; MODE 6 - select screen type 1
; =============================
LF3C3:
	LDA $BC		; F3C3= A5 BC	%<
	ORA $BE		; F3C5= 05 BE		>
	BNE LF3C2	; F3C7= D0 F9	Py
	LDA $BB		; F3C9= A5 BB	%;
	BMI LF3C2	; F3CB= 30 F5	0u
	LSR A		; F3CD= 4A		J
	LSR A		; F3CE= 4A		J
	LSR A		; F3CF= 4A		J
	STA $C0		; F3D0= 85 C0		@
	LDA #$3F	; F3D2= A9 3F	)?
	SEC		; F3D4= 38		8
	SBC $BD		; F3D5= E5 BD	e=
	CMP #$40	; F3D7= C9 40	I@
	BCC LF40D	; F3D9= 90 32		2
	RTS		; F3DB= 60		`

; MODE 5 - select screen type 2
; =============================
LF3DC:
	LDA $BC		; F3DC= A5 BC	%<
	ORA $BE		; F3DE= 05 BE		>
	BNE LF3C2	; F3E0= D0 E0	P`
	LDA $BB		; F3E2= A5 BB	%;
	BMI LF3C2	; F3E4= 30 DC	0\
	LSR A		; F3E6= 4A		J
	LSR A		; F3E7= 4A		J
	LSR A		; F3E8= 4A		J
	STA $C0		; F3E9= 85 C0		@
	LDA #$5F	; F3EB= A9 5F	)_
	SEC		; F3ED= 38		8
	SBC $BD		; F3EE= E5 BD	e=
	CMP #$60	; F3F0= C9 60	I`
	BCC LF40D	; F3F2= 90 19		
LF3F4:
	RTS		; F3F4= 60		`

; MODE 4 - select screen type 3
; =============================
LF3F5:
	LDA $BC		; F3F5= A5 BC	%<
	ORA $BE		; F3F7= 05 BE		>
	BNE LF3C2	; F3F9= D0 C7	PG
	LDA $BB		; F3FB= A5 BB	%;
	BMI LF3C2	; F3FD= 30 C3	0C
	LSR A		; F3FF= 4A		J
	LSR A		; F400= 4A		J
	LSR A		; F401= 4A		J
	STA $C0		; F402= 85 C0		@
	LDA #$BF	; F404= A9 BF	)?
	SEC		; F406= 38		8
	SBC $BD		; F407= E5 BD	e=
	CMP #$C0	; F409= C9 C0	I@
	BCS LF3C2	; F40B= B0 B5	05
LF40D:
	LDY #$00	; F40D= A0 00		
	STY $C1		; F40F= 84 C1		A
LF411:
	ASL A		; F411= 0A		
	ROL $C1		; F412= 26 C1	$A
	ASL A		; F414= 0A		
	ROL $C1		; F415= 26 C1	$A
	ASL A		; F417= 0A		
	ROL $C1		; F418= 26 C1	$A
	ASL A		; F41A= 0A		
	ROL $C1		; F41B= 26 C1	$A
	ADC $C0		; F41D= 65 C0	e@
	STA $C0		; F41F= 85 C0		@
	LDA $C1		; F421= A5 C1	%A
	ADC #$40	; F423= 69 40	i@
	STA $C1		; F425= 85 C1		A
	LDA $BB		; F427= A5 BB	%;
	AND #$07	; F429= 29 07	).
	TAY		; F42B= A8		(
	LDA LF451,Y	; F42C= B9 51 F4	9Qt
	JMP LF3A8	; F42F= 4C A8 F3	L(s

; MODE 0-3 - select screen type 4
; ===============================
LF432:
	LDA $BC		; F432= A5 BC	%<
	ORA $BE		; F434= 05 BE		>
	BNE LF3F4	; F436= D0 BC	P<
	LDA $BB		; F438= A5 BB	%;
	LSR A		; F43A= 4A		J
	LSR A		; F43B= 4A		J
	LSR A		; F43C= 4A		J
	STA $C0		; F43D= 85 C0		@
	LDA #$BF	; F43F= A9 BF	)?
	SEC		; F441= 38		8
	SBC $BD		; F442= E5 BD	e=
	CMP #$C0	; F444= C9 C0	I@
	BCS LF3F4	; F446= B0 AC	0,
	LDY #$00	; F448= A0 00		
	STY $C1		; F44A= 84 C1		A
	ASL A		; F44C= 0A		
	ROL $C1		; F44D= 26 C1	$A
	BPL LF411	; F44F= 10 C0		@

; Bitmap table
; ============
LF451:
	db $80
	db $40
LF453:
	db $20
	db $10
	db $08
	db $04
	db $02
	db $01

; ONLY CALLED FROM UNREACHABLE CODE

LF459:
	AND #$03	; F459= 29 03		
	TAY		; F45B= A8		(
	LDA LF49D,Y	; F45C= B9 9D F4	9.t
	STA $0315	; F45F= 8D 15 03	...
	LDA ATOM_PPI_PORT_A
	AND #$F0	; F465= 29 F0	)p
	CMP #$70	; F467= C9 70	Ip
	BNE LF477	; F469= D0 0C	P.
	LDA #$00	; F46B= A9 00	).
	TAY		; F46D= A8		(
LF46E:
	STA $4600,Y	; F46E= 99 00 46	..F
	STA $4700,Y	; F471= 99 00 47	..G
	DEY		; F474= 88		
	BNE LF46E	; F475= D0 F7	Pw
LF477:
	LDA ATOM_PPI_PORT_A
	AND #$DF	; F47A= 29 DF	)_
	STA ATOM_PPI_PORT_A
	ROL A		; 
	ROL A		;
	ROL A		; 
	AND #$03	; 
	TAY		; 
	LDA LF491,Y	; 
	STA PLOT_vector	; 
	LDA LF495,Y	; 
	STA PLOT_vector+1	; 

; TODO BAD STUFF HAPPENS HERE !!!
LF491:
	db <LF4A1 ; AND 255
	db <LF4BF ; AND 255
	db <LF4D7 ; AND 255
	db <LF506 ; AND 255

LF495:
	db >LF4A1 ; DIV 256
	db >LF4BF ; DIV 256
	db >LF4D7 ; DIV 256
	db >LF506 ; DIV 256

LF499:
	db $3F	; F499= 3F		
	db $CF	; F49A= CF		
	db $F3	; F49B= F3		
	db $FC	; F49C= FC		

LF49D:
	db $00	; F49D= 00		
	db $55	; F49E= 55		
	db $AA	; F49E= AA		
	db $FF	; F4A0= FF		

LF4A1:
	LDA $BC		; F4A1= A5 BC	
	ORA $BE		; F4A3= 05 BE	
	BNE LF4EE	; F4A5= D0 47	
	LDA $BB		; F4A7= A5 BB	
	CMP #$40	; F4A9= C9 40	
	BCS LF4EE	; F4AB= B0 41	
	LSR A		; F4AD= 4A	
	LSR A		; F4AE= 4A	
	STA $C0		; F4AF= 85 C0	
	LDY #$00	; F4B1= A0 00		
	STY $C1		; F4B3= 84 C1	
	LDA #$3F	; F4B5= A9 3F	
	SEC		; F4B7= 38	
	SBC $BD		; F4B8= E5 BD	
	CMP #$40	; F4BA= C9 40	I@
	BCC LF524	; F4BC= 90 66		f
	RTS		; F4BE= 60		`

LF4BF:	
	LDA $BC		; F4BF= A5 BC	%<
	ORA $BE		; F4C1= 05 BE		>
	BNE LF4EE	; F4C3= D0 29	P)
	LDA $BB		; F4C5= A5 BB	%;
	BMI LF4EE	; F4C7= 30 25	0%
	LSR A		; F4C9= 4A		J
	LSR A		; F4CA= 4A		J
	STA $C0		; F4CB= 85 C0		@
	LDA #$3F	; F4CD= A9 3F	)?
	SEC		; F4CF= 38		8
	SBC $BD		; F4D0= E5 BD	e=
	CMP #$40	; F4D2= C9 40	I@
	BCC LF51D	; F4D4= 90 47		G
	RTS		; F4D6= 60		`

LF4D7:	
	LDA $BC		; F4D7= A5 BC	%<
	ORA $BE		; F4D9= 05 BE		>
	BNE LF4EE	; F4DB= D0 11	P.
	LDA $BB		; F4DD= A5 BB	%;
	BMI LF4EE	; F4DF= 30 0D	0.
	LSR A		; F4E1= 4A		J
	LSR A		; F4E2= 4A		J
	STA $C0		; F4E3= 85 C0		@
	LDA #$5F	; F4E5= A9 5F	)_
	SEC		; F4E7= 38		8
	SBC $BD		; F4E8= E5 BD	e=
	CMP #$60	; F4EA= C9 60	I`
	BCC LF51D	; F4EC= 90 2F		/
LF4EE:
	RTS		; F4EE= 60		`
		
LF4EF:
	EOR #$FF	; F4EF= 49 FF	I.
	EOR ($C0),Y	; F4F1= 51 C0	Q@
	STA ($C0),Y	; F4F3= 91 C0		@
	RTS		; F4F5= 60		`
		
LF4F6:
	TAX		; F4F6= AA		*
	AND ($C0),Y	; F4F7= 31 C0	1@
	STA ($C0),Y	; F4F9= 91 C0		@
	TXA		; F4FB= 8A		
	EOR #$FF	; F4FC= 49 FF	I.
	AND $0315	; F4FE= 2D 15 03	-..
	ORA ($C0),Y	; F501= 11 C0		@
	STA ($C0),Y	; F503= 91 C0		@
	RTS		; F505= 60		`

LF506:
	LDA $BC		; F506= A5 BC	%<
	ORA $BE		; F508= 05 BE		>
	BNE LF4EE	; F50A= D0 E2	Pb
	LDA $BB		; F50C= A5 BB	%;
	BMI LF4EE	; F50E= 30 DE	0^
	LSR A		; F510= 4A		J
	LSR A		; F511= 4A		J
	STA $C0		; F512= 85 C0		@
	LDA #$BF	; F514= A9 BF	)?
	SEC		; F516= 38		8
	SBC $BD		; F517= E5 BD	e=
	CMP #$C0	; F519= C9 C0	I@
	BCS LF4EE	; F51B= B0 D1	0Q
LF51D:
	LDY #$00	; F51D= A0 00		
	STY $C1		; F51F= 84 C1		A
	ASL A		; F521= 0A		
	ROL $C1		; F522= 26 C1	$A
LF524:
	ASL A		; F524= 0A		
	ROL $C1		; F525= 26 C1	$A
	ASL A		; F527= 0A		
	ROL $C1		; F528= 26 C1	$A
	ASL A		; F52A= 0A		
	ROL $C1		; F52B= 26 C1	$A
	ASL A		; F52D= 0A		
	ROL $C1		; F52E= 26 C1	$A
	ADC $C0		; F530= 65 C0	e@
	STA $C0		; F532= 85 C0		@
	LDA $C1		; F534= A5 C1	%A
	ADC #$80	; F536= 69 80	i.
	STA $C1		; F538= 85 C1		A
	LDA $BB		; F53A= A5 BB	%;
	AND #$03	; F53C= 29 03	).
	TAX		; F53E= AA		*
	LDA LF499,X	; F53F= BD 99 F4	=.t
	LDX $BF		; F542= A6 BF	$?
	DEX		; F544= CA		J
	BEQ LF4F6	; F545= F0 AF	p/
	DEX		; F547= CA		J
	BEQ LF4EF	; F548= F0 A5	p%
	AND ($C0),Y	; F54A= 31 C0	1@
	STA ($C0),Y	; F54C= 91 C0		@
	RTS		; F54E= 60		`


; ==============
; OSWRCH HANDLER
; ==============
; On entry, A=character to output
; On exit,	A,X,Y preserved
;		On the BBC flags also preserved
;
OSWRCH_handler:
	STY OSWRCH_Y_store
	STX OSWRCH_X_store
	STA OSWRCH_A_store	; Save registers
	LDX VDU_queue_length
	BEQ LF57F	; Jump if VDU queue empty
	STA $0305,X
	DEX
	STX VDU_queue_length ; Store byte in VDU queue
	BNE LF578			; Queue not empty, exit
	LDA $0305			; Get VDU command
	CMP #$16
	BEQ LF5D1	; Jump with MODE
	CMP #$19
	BEQ LF575	; Jump with PLOT
	CMP #$1F
	BNE LF578	; Exit if not TAB
	JMP VDU_31_x_y_TAB			; Jump with TAB
LF575:
	JMP LF614			; Jump onwards for PLOT
LF578:
	LDY OSWRCH_Y_store
	LDX OSWRCH_X_store
	LDA OSWRCH_A_store	; Restore registers
	RTS			; and return

; VDU queue empty, must be character or first byte of command
; -----------------------------------------------------------
LF57F:
	CMP #$16
	BNE LF58E	; Jump if not VDU 22, start of MODE

; One more byte needed
; --------------------
LF583:
	LDX #$01
	STX VDU_queue_length	; One more byte needed
	STA $0305
	JMP LF578	; Save command, and exit
LF58E:
	CMP #$19
	BNE LF59D	; Jump if not VDU 25, start of PLOT
	LDX #$05
	STX VDU_queue_length	; Five more bytes needed
	STA $0305
	JMP LF578	; Save command, and exit
LF59D:
	CMP #$12
	BEQ LF583	; Jump if VDU 18, COLOUR, to collect one byte
	CMP #$1F
	BNE LF5B0	; Jump if not VDU 31, TAB
	LDX #$02
	STX VDU_queue_length	; Two more bytes needed
	STA $0305
	JMP LF578	; Save command, and exit
LF5B0:
	CMP #$10
	BNE LF5BD	; Jump if not VDU 16 - CLG
	LDA $032A
	STA $0306
	JMP LF5D1			; Continue into MODE

; All VDU command sequences checked for, must be single character
; --------------------------------------------------------------- 
LF5BD:
	LDY OSWRCH_Y_store
	LDX OSWRCH_X_store
	LDA OSWRCH_A_store	; Get registers back
	CMP #$61
	BMI LF5CE	; Not a lower-case character
	CMP #$7B
	BPL LF5CE	
	SEC
	SBC #$20		; Force lower case to upper case
LF5CE:
	JMP LFE2B			; Jump to Atom Kernel VDU code


; VDU 22,n - MODE
; =============== 
LF5D1:
	LDA $0306
	STA screen_map		; Get MODE parameter, set current MODE
	JSR LF304			; Set up VDU hardware
	LDA screen_map			; Get current MODE
	CMP #$07
	BNE LF5ED	; Not MODE 7, move graphics cursor to 0,0
	JSR LF578			; Get original registers back
	LDA #$0C
	JSR OSWRCH	; Do CLS, overwriting register store
	JSR LF578			; Get registers back from register store
	LDA #$07
	RTS		; Restore A to 7 and return

; Do MOVE 0,0 to move graphics cursor to (0,0)
; -------------------------------------------- 
LF5ED:
	JSR LF578			; Get original registers back
	PHA			; Save A
	LDA #$19
	JSR OSWRCH	; PLOT
	LDA #$04
	JSR OSWRCH	; PLOT 4 = MOVE
	LDA #$00			; Do MOVE 0,0
	JSR OSWRCH
	JSR OSWRCH	; Send X=0
	JSR OSWRCH
	JSR OSWRCH	; Send Y=0
	PLA
	RTS			; Restore A and return

		
; UNREACHABLE

	LDA $0306	; F60B= AD 06 03	-..
	JSR LF459	; F60E= 20 59 F4	Yt
	JMP LF578	; F611= 4C 78 F5	Lxu
		
LF614:
	LDA $030A	; F614= AD 0A 03	-..
	CMP #$40	; F617= C9 40	I@
	BCC LF61D	; F619= 90 02		
	SBC #$38	; F61B= E9 38	i8
LF61D:
	AND #$1F	; F61D= 29 1F	).
	STA $030E	; F61F= 8D 0E 03	...
	LDA #$00	; F622= A9 00	).
	STA $032B	; F624= 8D 2B 03	.+.
	LDA $0308	; F627= AD 08 03	-..
	BPL LF636	; F62A= 10 0A		
	LDX #$03	; F62C= A2 03	".
	JSR LF6FA	; F62E= 20 FA F6	zv
	LDA #$FF	; F631= A9 FF	).
	STA $032B	; F633= 8D 2B 03	.+.
LF636:
	LDA #$00	; F636= A9 00	).
	STA $BB		; F638= 85 BB		;
	STA $BC		; F63A= 85 BC		<
	LDA $0309	; F63C= AD 09 03	-..
LF63F:
	SEC		; F63F= 38		8
	SBC #$05	; F640= E9 05	i.
	BCS LF649	; F642= B0 05	0.
	DEC $0308	; F644= CE 08 03	N..
	BMI LF651	; F647= 30 08	0.
LF649:
	INC $BB		; F649= E6 BB	f;
	BNE LF63F	; F64B= D0 F2	Pr
	INC $BC		; F64D= E6 BC	f<
	BNE LF63F	; F64F= D0 EE	Pn
LF651:
	LDA ATOM_PPI_PORT_A	; F651= AD 00 70	-.p
	AND #$F0	; F654= 29 F0	)p
	CMP #$F0	; F656= C9 F0	Ip
	BEQ LF666	; F658= F0 0C	p.
	CMP #$20	; F65A= C9 20	I 
	BCS LF662	; F65C= B0 04	0.
	LSR $BC		; F65E= 46 BC	F<
	ROR $BB		; F660= 66 BB	f;
LF662:
	LSR $BC		; F662= 46 BC	F<
	ROR $BB		; F664= 66 BB	f;
LF666:
	LDA $032B	; F666= AD 2B 03	-+.
	BPL LF670	; F669= 10 05		
	LDX #$08	; F66B= A2 08	".
	JSR LF70C	; F66D= 20 0C F7	w
LF670:
	LDA #$00	; F670= A9 00	
	STA $032C	; F672= 8D 2C 03	
	LDA $0306	; F675= AD 06 03	
	BPL LF684	; F678= 10 0A	
	LDX #$01	; F67A= A2 01	
	JSR LF6FA	; F67C= 20 FA F6	
	LDA #$FF	; F67F= A9 FF	
	STA $032C	; F681= 8D 2C 03	
LF684:
	LDA ATOM_PPI_PORT_A	; F684= AD 00 70	-.p
	AND #$F0	; F687= 29 F0	)p
	CMP #$10	; F689= C9 10	I.
	BEQ LF695	; F68B= F0 08	p.
	CMP #$30	; F68D= C9 30	I0
	BEQ LF695	; F68F= F0 04	p.
	CMP #$50	; F691= C9 50	IP
	BNE LF6AA	; F693= D0 15	P.
LF695:
	LDA $0307	; F695= AD 07 03	-..
	STA $BD		; F698= 85 BD		=
	LDA $0306	; F69A= AD 06 03	-..
	STA $BE		; F69D= 85 BE		>
	LSR $BE		; F69F= 46 BE	F>
	ROR $BD		; F6A1= 66 BD	f=
	LSR $BE		; F6A3= 46 BE	F>
	ROR $BD		; F6A5= 66 BD	f=
	JMP LF6E2	; F6A7= 4C E2 F6	Lbv
		
LF6AA:
	LDA $0307	; F6AA= AD 07 03	-..
	ASL A		; F6AD= 0A		
	STA $BD		; F6AE= 85 BD		=
	LDA $0306	; F6B0= AD 06 03	-..
	ROL A		; F6B3= 2A		*
	STA $BE		; F6B4= 85 BE		>
	CLC		; F6B6= 18		
	LDA $BD		; F6B7= A5 BD	
	ADC $0307	; F6B9= 6D 07 03	
	STA $BD		; F6BC= 85 BD	
	LDA $BE		; F6BE= A5 BE	
	ADC $0306	; F6C0= 6D 06 03	.
	STA $BE		; F6C3= 85 BE	
	LSR $BE		; F6C5= 46 BE	
	ROR $BD		; F6C7= 66 BD	
	LSR $BE		; F6C9= 46 BE	
	ROR $BD		; F6CB= 66 BD	
	LSR $BE		; F6CD= 46 BE	
	ROR $BD		; F6CF= 66 BD	
	LSR $BE		; F6D1= 46 BE	
	ROR $BD		; F6D3= 66 BD	
	LDA ATOM_PPI_PORT_A	; F6D5= AD 00 70	-.p
	AND #$F0	; F6D8= 29 F0	)p
	CMP #$A0	; F6DA= C9 A0	I 
	BCS LF6EA	; F6DC= B0 0C	0.
	CMP #$00	; F6DE= C9 00	I.
	BNE LF6E6	; F6E0= D0 04	P.
LF6E2:
	LSR $BE		; F6E2= 46 BE	F>
	ROR $BD		; F6E4= 66 BD	f=
LF6E6:
	LSR $BE		; F6E6= 46 BE	F>
	ROR $BD		; F6E8= 66 BD	f=
LF6EA:
	LDA $032C	; F6EA= AD 2C 03	-,.
	BPL LF6F4	; F6ED= 10 05		
	LDX #$0A	; F6EF= A2 0A	".
	JSR LF70C	; F6F1= 20 0C F7	w
LF6F4:
	JSR LF1FE	; F6F4= 20 FE F1	~q
	JMP LF578	; F6F7= 4C 78 F5	Lxu
		
LF6FA:
	SEC		; F6FA= 38		8
	LDA #$00	; F6FB= A9 00	).
	SBC $0306,X	; F6FD= FD 06 03	}..
	STA $0306,X	; F700= 9D 06 03	...
	LDA #$00	; F703= A9 00	).
	SBC $0305,X	; F705= FD 05 03	}..
	STA $0305,X	; F708= 9D 05 03	...
	RTS		; F70B= 60		`
		
LF70C:
	SEC		; F70C= 38		8
	LDA #$00	; F70D= A9 00	).
	SBC screen_map,X	; F70F= F5 B3	u3
	STA screen_map,X	; F711= 95 B3		3
	LDA #$00	; F713= A9 00	).
	SBC start_of_screen,X	; F715= F5 B4	u4
	STA start_of_screen,X	; F717= 95 B4		4
	RTS		; F719= 60		`


; OSFILE HANDLER
; ==============
OSFILE_handler:
	STA OSWRCH_A_store		; F71A= 85 9E		
	STX OSWRCH_X_store		; F71C= 86 9F		
	STY OSWRCH_Y_store		; F71E= 84 A0			
	LDX #$A9	; F720= A2 A9	")
	LDY #$03	; F722= A0 03		
LF724:
	LDA (pointer_YX),Y	; F724= B1 9F	1.
	STA $00A9,Y	; F726= 99 A9 00	.).
	DEY		; F729= 88		
	BPL LF724	; F72A= 10 F8		x
	LDA OSWRCH_A_store		; F72C= A5 9E	%.
	BEQ LF74A	; F72E= F0 1A	p.
	LDA #$00	; F730= A9 00	).
	STA $AD		; F732= 85 AD		-
	LDY #$06	; F734= A0 06		
	LDA (pointer_YX),Y	; F736= B1 9F	1.
	BEQ LF740	; F738= F0 06	p.
	JSR LF945	; F73A= 20 45 F9	Ey
	JMP LF76E	; F73D= 4C 6E F7	Lnw
		
LF740:
	LDA #$FF	; F740= A9 FF	).
	STA $AD		; F742= 85 AD		-
	JSR LF945	; F744= 20 45 F9	Ey
	JMP LF76E	; F747= 4C 6E F7	Lnw
		
LF74A:
	LDY #$06	; F74A= A0 06		
	LDA (pointer_YX),Y	; F74C= B1 9F	1.
	STA $AD		; F74E= 85 AD		-
	INY		; F750= C8		H
	LDA (pointer_YX),Y	; F751= B1 9F	1.
	STA $AE		; F753= 85 AE		
	LDY #$0A	; F755= A0 0A		
	LDA (pointer_YX),Y	; F757= B1 9F	1.
	STA $AF		; F759= 85 AF		/
	INY		; F75B= C8		H
	LDA (pointer_YX),Y	; F75C= B1 9F	1.
	STA $B0		; F75E= 85 B0		0
	LDY #$0E	; F760= A0 0E		
	LDA (pointer_YX),Y	; F762= B1 9F	1.
	STA $B1		; F764= 85 B1		1
	INY		; F766= C8		H
	LDA (pointer_YX),Y	; F767= B1 9F	1.
	STA $B2		; F769= 85 B2		2
	JSR LFAB8	; F76B= 20 B8 FA	8z
LF76E:
	LDA $9E		; F76E= A5 9E	%.
	LDX OSWRCH_X_store		; F770= A6 9F	$.
	LDY OSWRCH_Y_store		; F772= A4 A0	$ 
	RTS		; F774= 60		`


; CLI HANDLER
; =========== 
CLI_handler:
	STA CLI_A_store
	STX CLI_line_pointer
	STY CLI_line_pointer+1
	LDY #1		; Point to second character
	
				; *BUG* This means OSCLI "fred" parses "red"
loop_until_CR:
	LDA (CLI_line_pointer),Y
	STA $00FF,Y ; Copy command line to $100+
	INY
	CMP #ASCII_CR
	BNE loop_until_CR	; Loop until <cr>
	JSR LF8C3		; Process command line
	LDY CLI_line_pointer+1
	LDX CLI_line_pointer
	LDA CLI_A_store ; Restore X/Y/A (not needed)
	RTS


; VDU 31,x,y - TAB
; ================ 
VDU_31_x_y_TAB:
	LDX $0307	; F791= AE 07 03	...
	CPX #$20	; F794= E0 20	` 
	BCS LF7B6	; F796= B0 1E	0.
	LDA $0306	; F798= AD 06 03	-..
	CMP #$10	; F79B= C9 10	I.
	BCS LF7B6	; F79D= B0 17	0.
	LDY $E0		; F79F= A4 E0	$`
	JSR cursor_off	; F7A1= 20 1D FD	}
	STX $E0		; F7A4= 86 E0		`
	LSR $DF		; F7A6= 46 DF	F_
	ASL A		; F7A8= 0A		
	ASL A		; F7A9= 0A		
	ASL A		; F7AA= 0A		
	ASL A		; F7AB= 0A		
	ASL A		; F7AC= 0A		
	STA current_line		; F7AD= 85 DE		^
	ROL $DF		; F7AF= 26 DF	$_
	LDY $E0		; F7B1= A4 E0	$`
	JSR cursor_off	; F7B3= 20 1D FD	}
LF7B6:
	JMP LF578	; F7B6= 4C 78 F5	Lxu

LF7B9:	
	db " WORK +"


Print_inline_text:
	PLA
	STA inline_text_ptr
	PLA
	STA inline_text_ptr+1
loop_F7C6:
	LDY #0
	INC inline_text_ptr
	BNE LF7CE
	INC inline_text_ptr+1	; Update address
LF7CE:
	LDA (inline_text_ptr),Y
	BMI end_of_text	; bit 7=1, end of text
	JSR OSWRCH
	JMP loop_F7C6	; Print character and loop for more
end_of_text:
	JMP (inline_text_ptr)		; Jump back to code after text


LF7DB:
	LDX #$D4	; F7DB= A2 D4	"T
	JSR LF7E0	; F7DD= 20 E0 F7	`w
LF7E0:
	LDA $01,X	; F7E0= B5 01	5.
	JSR print_hex_byte	; F7E2= 20 F1 F7	qw
	INX		; F7E5= E8		h
	INX		; F7E6= E8		h
	LDA $FE,X	; F7E7= B5 FE	5~
	JSR print_hex_byte	; F7E9= 20 F1 F7	qw
print_ASCII_space:
	LDA #ASCII_SP
	JMP OSWRCH	; F7EE= 4C EE FF	Ln.
		
print_hex_byte:
	PHA		; save for later
	LSR A
	LSR A
	LSR A
	LSR A
	JSR print_hex_digit	; F7F6= 20 FA F7	zw
	PLA		; restore
print_hex_digit:
	AND #$0F
	CMP #$A
	BCC hex_nibble_is_adjusted		
	ADC #6
hex_nibble_is_adjusted:
	ADC #ASCII_0
	JMP OSWRCH	; F804= 4C EE FF	Ln.
		
LF807:
	JSR LF863	; F807= 20 63 F8	cx
	LDX #$00	; F80A= A2 00	".
	CMP #$22	; F80C= C9 22	I"
	BEQ LF816	; F80E= F0 06	p.
	INX		; F810= E8		h
	BNE LF82E	; F811= D0 1B	P.
LF813:
	JMP LFA53	; F813= 4C 53 FA	LSz
		
LF816:
	INY		; F816= C8		H
	LDA $0100,Y	; F817= B9 00 01	9..
	CMP #ASCII_CR	; F81A= C9 0D	I.
	BEQ LF813	; F81C= F0 F5	pu
	STA $0140,X	; F81E= 9D 40 01	.@.
	INX		; F821= E8		h
	CMP #$22	; F822= C9 22	I"
	BNE LF816	; F824= D0 F0	Pp
	INY		; F826= C8		H
	LDA $0100,Y	; F827= B9 00 01	9..
	CMP #$22	; F82A= C9 22	I"
	BEQ LF816	; F82C= F0 E8	ph
LF82E:
	LDA #$0D	; F82E= A9 0D	).
	STA $013F,X	; F830= 9D 3F 01	.?.
	LDA #$40	; F833= A9 40	)@
	STA $C9		; F835= 85 C9		I
	LDA #$01	; F837= A9 01	).
	STA $CA		; F839= 85 CA		J
	LDX #$C9	; F83B= A2 C9	"I
	RTS		; F83D= 60		`
		
LF83E:
	LDY #$00	; F83E= A0 00		
LF840:
	LDA $00,X	; F840= B5 00	5.
	STA $00C9,Y	; F842= 99 C9 00	.I.
	INX		; F845= E8		h
	INY		; F846= C8		H
	CPY #$0A	; F847= C0 0A	@.
	BCC LF840	; F849= 90 F5		u
	LDY #$FF	; F84B= A0 FF		
	LDA #$0D	; F84D= A9 0D	).
LF84F:
	INY		; F84F= C8		H
	CPY #$0E	; F850= C0 0E	@.
	BCS LF85B	; F852= B0 07	0.
	CMP ($C9),Y	; F854= D1 C9	QI
	BNE LF84F	; F856= D0 F7	Pw
	CPY #0	; F858= C0 00	@.
	RTS
		
LF85B:
	BRK
	db 254
	db "NAME"
	BRK
; *BUG* Error number wrong, should be 221

loop_F862:
	INY		; F862= C8		H
LF863:
	LDA $0100,Y	; F863= B9 00 01	9..
	CMP #ASCII_SP
	BEQ loop_F862	; F868= F0 F8	px
	RTS
		
LF86B:
	CMP #ASCII_0
	BCC SEC_and_RTS
	CMP #ASCII_0+10
	BCC LF87B
	SBC #7
	BCC SEC_and_RTS
	CMP #$40
	BCS RTS_F87D
LF87B:
	AND #$0F
RTS_F87D:
	RTS
		
SEC_and_RTS:
	SEC		; F87E= 38		8
	RTS		; F87F= 60		`
		
LF880:
	LDA #0	; F880= A9 00	).
	STA $0,X	; F882= 95 00		
	STA $1,X	; F884= 95 01		
	STA $2,X	; F886= 95 02		
	JSR LF863	; F888= 20 63 F8	cx
LF88B:
	LDA $0100,Y	; F88B= B9 00 01	9..
	JSR LF86B	; F88E= 20 6B F8	kx
	BCS LF8A8	; F891= B0 15	0.
	ASL A		; F893= 0A		
	ASL A		; F894= 0A		
	ASL A		; F895= 0A		
	ASL A		; F896= 0A		
	STY $02,X	; F897= 94 02		
	LDY #$04	; F899= A0 04		
LF89B:
	ASL A		; F89B= 0A		
	ROL $00,X	; F89C= 36 00	6.
	ROL $01,X	; F89E= 36 01	6.
	DEY		; F8A0= 88		
	BNE LF89B	; F8A1= D0 F8	Px
	LDY $02,X	; F8A3= B4 02	4.
	INY		; F8A5= C8		H
	BNE LF88B	; F8A6= D0 E3	Pc
LF8A8:
	LDA $02,X	; F8A8= B5 02	5.
	RTS		; F8AA= 60		`

; Command table
; -------------
LF8AB:
	db "CAT" 
	db >STAR_CAT ; DIV 256
	db <STAR_CAT ; AND 255
	db "LOAD"
	db >LF932 ; DIV 256
	db <LF932 ; AND 255
	db "SAVE"
	db >LFA91 ; DIV 256
	db <LFA91 ; AND 255
	db "RUN" 
	db >LF9F6 ; DIV 256
	db <LF9F6 ; AND 255
	db ""	
	db >LF8FA ; DIV 256
	db <LF8FA ; AND 255

; Process command line at $100+
; -----------------------------
LF8C3:
	LDX #$FF	; F8C3= A2 FF	
	CLD		; F8C5= D8		
LF8C6:
	LDY #$00	; F8C6= A0 00		
	STY $DD		; F8C8= 84 DD		
	JSR LF863	; F8CA= 20 63 F8	
	DEY		; F8CD= 88		
LF8CE:
	INY		; F8CE= C8		
	INX		; F8CF= E8		
LF8D0:
	LDA LF8AB,X	; F8D0= BD AB F8	
	BMI LF8ED	; F8D3= 30 18	
	CMP $0100,Y	; F8D5= D9 00 01	
	BEQ LF8CE	; F8D8= F0 F4	
	DEX		; F8DA= CA		
LF8DB:
	INX		; F8DB= E8		
	LDA LF8AB,X	; F8DC= BD AB F8	
	BPL LF8DB	; F8DF= 10 FA		z
	INX		; F8E1= E8		
	LDA $0100,Y	; F8E2= B9 00 01	
	CMP #$2E	; F8E5= C9 2E	
	BNE LF8C6	; F8E7= D0 DD	
	INY		; F8E9= C8		
	DEX		; F8EA= CA		
	BCS LF8D0	; F8EB= B0 E3	
LF8ED:
	STA $CA		; F8ED= 85 CA		
	LDA LF8AB+1,X	; F8EF= BD AC F8	
	STA $C9		; F8F2= 85 C9		
	CLC		; F8F4= 18		
	LDX #$00	; F8F5= A2 00	
	JMP ($00C9)	; Jump to routine with X = $00, CLC

LF8FA:
	BRK
	db 254
	db "BAD COMMAND"
	BRK


; OSARGS HANDLER
; ==============
OSARGS_handler:
	BRK		; **BANG!**

LF909:
	JSR LFB61	; F909= 20 61 FB	a{
	BVC OSARGS_handler	; F90C= 50 FA	Pz
	BEQ LF909	; F90E= F0 F9	py
	JSR LFBFE	; F910= 20 FE FB	~{
	LDY #$00	; F913= A0 00		
LF915:
	JSR OSBGET	; F915= 20 D7 FF	W.
	STA ($CB),Y	; F918= 91 CB		K
	INC $CB		; F91A= E6 CB	fK
	BNE LF920	; F91C= D0 02	P.
	INC $CC		; F91E= E6 CC	fL
LF920:
	LDX #$D4	; F920= A2 D4	"T
	JSR LF9DE	; F922= 20 DE F9	^y
	BNE LF915	; F925= D0 EE	Pn
	SEC		; F927= 38		8
LF928:
	ROR $DD		; F928= 66 DD	f]
	CLC		; F92A= 18		
	ROR $DD		; F92B= 66 DD	f]
	PLP		; F92D= 28		(
	RTS		; F92E= 60		`
		
; UNREACHABLE
	SEC		; F92F= 38		8
	ROR $DD		; F930= 66 DD	f]


; *LOAD <name> (<addr>)
; =====================
LF932:
	JSR LF807	; F932= 20 07 F8	x
	LDX #$CB	; F935= A2 CB	"K
	JSR LF880	; F937= 20 80 F8	x
	BEQ LF940	; F93A= F0 04	p.
	LDA #$FF	; F93C= A9 FF	).
	STA $CD		; F93E= 85 CD		M
LF940:
	JSR LFA4C	; F940= 20 4C FA	Lz
	LDX #$C9	; F943= A2 C9	"I
LF945:
	PHP		; F945= 08		
	SEI		; F946= 78		x
	JSR LF83E	; F947= 20 3E F8	>x
	PHP		; F94A= 08		
	JSR LFC13	; F94B= 20 13 FC	|
	PLP		; F94E= 28		(
	BEQ LF909	; F94F= F0 B8	p8
	LDA #$00	; F951= A9 00	).
	STA $D0		; F953= 85 D0		P
	STA $D1		; F955= 85 D1		Q
LF957:
	JSR LF979	; F957= 20 79 F9	yy
	BCC LF928	; F95A= 90 CC		L
	INC $D0		; F95C= E6 D0	fP
	INC $CC		; F95E= E6 CC	fL
	BNE LF957	; F960= D0 F5	Pu
	CLC		; F962= 18		
	BCC LF928	; F963= 90 C3		C
LF965:
	JSR OSWRCH	; F965= 20 EE FF	n.
	INY		; F968= C8
LF969:
	LDA $00ED,Y	; F969= B9 ED 00	9m.
	CMP #ASCII_CR	; F96C= C9 0D	I.
	BNE LF965	; F96E= D0 F5	Pu
LF970:
	INY		; F970= C8		H
	JSR print_ASCII_space	; F971= 20 EC F7	lw
	CPY #$0E	; F974= C0 0E	@.
	BCC LF970	; F976= 90 F8		x
	RTS		; F978= 60		`
		
LF979:
	LDA #$00	; F979= A9 00	).
	STA $DC		; F97B= 85 DC		\
	JSR LFB61	; F97D= 20 61 FB	a{
	BVC LF979+1	; **BANG!**
	BNE LF979	; F982= D0 F5	Pu
	JSR LFB9C	; F984= 20 9C FB	{
	PHP		; F987= 08		
	JSR LFBB5	; F988= 20 B5 FB	5{
	PLP		; F98B= 28		(
	BEQ LF99E	; F98C= F0 10	p.
	LDA $DB		; F98E= A5 DB	%[
	AND #$20	; F990= 29 20	) 
	ORA $EA		; F992= 05 EA		j
	BNE LF979	; F994= D0 E3	Pc
	JSR LF969	; F996= 20 69 F9	iy
	JSR OSNEWL	; F999= 20 E7 FF	g.
	BNE LF979	; F99C= D0 DB	P[
LF99E:
	LDX #$02	; F99E= A2 02	".
	LDA $DD		; F9A0= A5 DD	%]
	BMI LF9B7	; F9A2= 30 13	0.
LF9A4:
	LDA $CF,X	; F9A4= B5 CF	5O
	CMP $D8,X	; F9A6= D5 D8	UX
	BCS LF9B2	; F9A8= B0 08	0.
	LDA #$05	; F9AA= A9 05	).
	JSR LFC15	; F9AC= 20 15 FC	|
	JSR LFC13	; F9AF= 20 13 FC	|
LF9B2:
	BNE LF979	; F9B2= D0 C5	PE
	DEX		; F9B4= CA		J
	BNE LF9A4	; F9B5= D0 ED	Pm
LF9B7:
	JSR LFBFE	; F9B7= 20 FE FB	~{
	BIT $DB		; F9BA= 24 DB	$[
	BVC LF9C9	; F9BC= 50 0B	P.
	DEY		; F9BE= 88		
LF9BF:
	INY		; F9BF= C8		H
	JSR OSBGET	; F9C0= 20 D7 FF	W.
	STA ($CB),Y	; F9C3= 91 CB		K
	CPY $D8		; F9C5= C4 D8	DX
	BNE LF9BF	; F9C7= D0 F6	Pv
LF9C9:
	LDA $DC		; F9C9= A5 DC	%\
	STA $CE		; F9CB= 85 CE		N
	JSR OSBGET	; F9CD= 20 D7 FF	W.
	CMP $CE		; F9D0= C5 CE	EN
	BEQ LF9DB	; F9D2= F0 07	p.
	BRK
	db 254
	db "SUM?"
	BRK
; *BUG* Error number wrong, should be 216

LF9DB:
	ROL $DB		; F9DB= 26 DB	$[
	RTS		; F9DD= 60		`
		
LF9DE:
	INC $00,X	; F9DE= F6 00	v.
	BNE LF9E4	; F9E0= D0 02	P.
	INC $01,X	; F9E2= F6 01	v.
LF9E4:
	LDA $00,X	; F9E4= B5 00	5.
	CMP $02,X	; F9E6= D5 02	U.
	BNE LF9EE	; F9E8= D0 04	P.
	LDA $01,X	; F9EA= B5 01	5.
	CMP $03,X	; F9EC= D5 03	U.
LF9EE:
	RTS		; F9EE= 60		`

; UNREACHABLE

	DEX		; F9EF= CA		J
	JSR LFA4C	; F9F0= 20 4C FA	Lz
	STX $EA		; F9F3= 86 EA		j
LF9F5:
	RTS		; F9F5= 60		`
		
LF9F6:
	JSR LF932	; F9F6= 20 32 F9	2y
	BIT $DD		; F9F9= 24 DD	$]
	BVS LFA49	; F9FB= 70 4C	pL
	JMP ($00D6)	; F9FD= 6C D6 00	lV.


; *CAT
; ====
STAR_CAT:
	PHP		; FA00= 08		
	JSR LFA4C	; FA01= 20 4C FA	Lz
	JSR LFC13	; FA04= 20 13 FC	|
LFA07:
	JSR LFB61	; FA07= 20 61 FB	a{
	BVS LFA0E	; FA0A= 70 02	p.
	PLP		; FA0C= 28		(
	RTS		; FA0D= 60		`
		
LFA0E:
	BEQ LFA1A	; FA0E= F0 0A	p.
	LDY #$00	; FA10= A0 00		
	JSR LF970	; FA12= 20 70 F9	py
	JSR LF7DB	; FA15= 20 DB F7	[w
	BNE LFA33	; FA18= D0 19	P.
LFA1A:
	JSR LFB9C	; FA1A= 20 9C FB	{
	JSR LFBB5	; FA1D= 20 B5 FB	5{
	JSR LF969	; FA20= 20 69 F9	iy
	JSR LF7DB	; FA23= 20 DB F7	[w
	ROL $DB		; FA26= 26 DB	$[
	BPL LFA33	; FA28= 10 09		
	INX		; FA2A= E8		h
	JSR LF7E0	; FA2B= 20 E0 F7	`w
	LDA $FD,X	; FA2E= B5 FD	5}
	JSR print_hex_byte	; FA30= 20 F1 F7	qw
LFA33:
	JSR OSNEWL	; FA33= 20 E7 FF	g.
	BNE LFA07	; FA36= D0 CF	PO
	JMP OSNEWL	; FA38= 4C E7 FF	Lg.
		
LFA3B:
	JSR LF880	; FA3B= 20 80 F8	x
	BEQ LFA53	; FA3E= F0 13	p.
	RTS		; FA40= 60		`
		
	LDX #$CB	; FA41= A2 CB	"K
	JSR LFA3B	; FA43= 20 3B FA	;z
	JSR LFA4C	; FA46= 20 4C FA	Lz
LFA49:
	JMP ($00CB)	; FA49= 6C CB 00	lK.
		
LFA4C:
	JSR LF863	; FA4C= 20 63 F8	
	CMP #ASCII_CR	; FA4F= C9 0D	
	BEQ LF9F5	; FA51= F0 A2	
LFA53:
	BRK
	db 254
	db "SYNTAX"
	BRK
; *BUG* error number wrong, should be 220

LFA5C:
	SEC		; FA5C= 38		8
	LDA $D1		; FA5D= A5 D1	%Q
	SBC $CF		; FA5F= E5 CF	eO
	PHA		; FA61= 48		H
	LDA $D2		; FA62= A5 D2	%R
	SBC $D0		; FA64= E5 D0	eP
	TAY		; FA66= A8		(
	PLA		; FA67= 68		h
	CLC		; FA68= 18		
	ADC $CB		; FA69= 65 CB	eK
	STA $CD		; FA6B= 85 CD		M
	TYA		; FA6D= 98		
	ADC $CC		; FA6E= 65 CC	eL
	STA $CE		; FA70= 85 CE		N
	LDY #$04	; FA72= A0 04		
LFA74:
	LDA $00CA,Y	; FA74= B9 CA 00	9J.
	JSR OSBPUT	; FA77= 20 D4 FF	T.
	DEY		; FA7A= 88		
	BNE LFA74	; FA7B= D0 F7	Pw
LFA7D:
	LDA ($CF),Y	; FA7D= B1 CF	1O
	JSR OSBPUT	; FA7F= 20 D4 FF	T.
	INC $CF		; FA82= E6 CF	fO
	BNE LFA88	; FA84= D0 02	P.
	INC $D0		; FA86= E6 D0	fP
LFA88:
	LDX #$CB	; FA88= A2 CB	"K
	JSR LF9DE	; FA8A= 20 DE F9	^y
	BNE LFA7D	; FA8D= D0 EE	Pn
	PLP		; FA8F= 28		(
	RTS		; FA90= 60		`

LFA91:	
	JSR LF807	; FA91= 20 07 F8	x
	LDX #$CB	; FA94= A2 CB	"K
	JSR LFA3B	; FA96= 20 3B FA	;z
	LDX #$D1	; FA99= A2 D1	"Q
	JSR LFA3B	; FA9B= 20 3B FA	;z
	LDX #$CD	; FA9E= A2 CD	"M
	JSR LF880	; FAA0= 20 80 F8	x
	PHP		; FAA3= 08		
	LDA $CB		; FAA4= A5 CB	%K
	LDX $CC		; FAA6= A6 CC	$L
	PLP		; FAA8= 28		(
	BNE LFAAF	; FAA9= D0 04	P.
	STA $CD		; FAAB= 85 CD		M
	STX $CE		; FAAD= 86 CE		N
LFAAF:
	STA $CF		; FAAF= 85 CF		O
	STX $D0		; FAB1= 86 D0		P
	JSR LFA4C	; FAB3= 20 4C FA	Lz
	LDX #$C9	; FAB6= A2 C9	"I
LFAB8:
	PHP		; FAB8= 08		
	SEI		; FAB9= 78		x
	JSR LF83E	; FABA= 20 3E F8	>x
	PHP		; FABD= 08		
	LDA #$06	; FABE= A9 06	).
	JSR LFC15	; FAC0= 20 15 FC	|
	LDX #$07	; FAC3= A2 07	".
	JSR LFB4D	; FAC5= 20 4D FB	M{
	PLP		; FAC8= 28		(
	BEQ LFA5C	; FAC9= F0 91	p.
	LDX #$04	; FACB= A2 04	".
LFACD:
	LDA $CE,X	; FACD= B5 CE	5N
	STA $D2,X	; FACF= 95 D2		R
	DEX		; FAD1= CA		J
	BNE LFACD	; FAD2= D0 F9	Py
	STX $D0		; FAD4= 86 D0		P
	STX $D1		; FAD6= 86 D1		Q
	LDA $D5		; FAD8= A5 D5	%U
	BNE LFADE	; FADA= D0 02	P.
	DEC $D6		; FADC= C6 D6	FV
LFADE:
	DEC $D5		; FADE= C6 D5	FU
	CLC		; FAE0= 18		
LFAE1:
	ROR $D2		; FAE1= 66 D2	fR
	SEC		; FAE3= 38		8
	LDX #$FF	; FAE4= A2 FF	".
	LDA $D5		; FAE6= A5 D5	%U
	SBC $D3		; FAE8= E5 D3	eS
	STA $CF		; FAEA= 85 CF		O
	LDA $D6		; FAEC= A5 D6	%V
	SBC $D4		; FAEE= E5 D4	eT
	PHP		; FAF0= 08		
	ROR $D2		; FAF1= 66 D2	fR
	PLP		; FAF3= 28		(
	BCC LFAFC	; FAF4= 90 06		
	CLC		; FAF6= 18		
	BEQ LFAFC	; FAF7= F0 03	p.
	STX $CF		; FAF9= 86 CF		O
	SEC		; FAFB= 38		8
LFAFC:
	ROR $D2		; FAFC= 66 D2	fR
	INX		; FAFE= E8		h
	JSR LFB0E	; FAFF= 20 0E FB	{
	INC $D0		; FB02= E6 D0	fP
	INC $D4		; FB04= E6 D4	fT
	INC $CC		; FB06= E6 CC	fL
	ROL $D2		; FB08= 26 D2	$R
	BCS LFAE1	; FB0A= B0 D5	0U
	PLP		; FB0C= 28		(
	RTS		; FB0D= 60		`
		
LFB0E:
	LDX #$07	; FB0E= A2 07	".
	JSR LFB4D	; FB10= 20 4D FB	M{
	STX $DC		; FB13= 86 DC		\
	LDY #$04	; FB15= A0 04		
LFB17:
	LDA #$2A	; FB17= A9 2A	)*
	JSR OSBPUT	; FB19= 20 D4 FF	T.
	DEY		; FB1C= 88		
	BNE LFB17	; FB1D= D0 F8	Px
LFB1F:
	LDA ($C9),Y	; FB1F= B1 C9	1I
	JSR OSBPUT	; FB21= 20 D4 FF	T.
	INY		; FB24= C8		H
	CMP #ASCII_CR	; FB25= C9 0D	I.
	BNE LFB1F	; FB27= D0 F6	Pv
	LDY #$08	; FB29= A0 08		
LFB2B:
	LDA $00CA,Y	; FB2B= B9 CA 00	9J.
	JSR OSBPUT	; FB2E= 20 D4 FF	T.
	DEY		; FB31= 88		
	BNE LFB2B	; FB32= D0 F7	Pw
	JSR LFB54	; FB34= 20 54 FB	T{
	BIT $D2		; FB37= 24 D2	$R
	BVC LFB46	; FB39= 50 0B	P.
	DEY		; FB3B= 88		
LFB3C:
	INY		; FB3C= C8		H
	LDA ($D3),Y	; FB3D= B1 D3	1S
	JSR OSBPUT	; FB3F= 20 D4 FF	T.
	CPY $CF		; FB42= C4 CF	DO
	BNE LFB3C	; FB44= D0 F6	Pv
LFB46:
	LDA $DC		; FB46= A5 DC	%\
	JSR OSBPUT	; FB48= 20 D4 FF	T.
	LDX #$04	; FB4B= A2 04	".
LFB4D:
	STX ATOM_PPI_PORT_C	; FB4D= 8E 02 70	..p
	LDX #$78	; FB50= A2 78	"x
	BNE LFB56	; FB52= D0 02	P.
LFB54:
	LDX #$1E	; FB54= A2 1E	".
LFB56:
	JSR Wait_until_no_VSync	; FB56= 20 3F FE	?~
	DEX		; FB59= CA		J
	BNE LFB56	; FB5A= D0 FA	Pz
	RTS		; FB5C= 60		`
		
LFB5D:
	LDX #$06	; FB5D= A2 06	".
	BNE LFB56	; FB5F= D0 F5	Pu
LFB61:
	BIT ATOM_PPI_PORT_B	; FB61= 2C 01 70	,.p
	BPL LFB61	; FB64= 10 FB		{
	BVC LFB61	; FB66= 50 F9	Py
LFB68:
	LDY #$00	; FB68= A0 00		
	STA $C3		; FB6A= 85 C3		C
	LDA #$10	; FB6C= A9 10	).
	STA $C2		; FB6E= 85 C2		B
LFB70:
	BIT ATOM_PPI_PORT_B	; FB70= 2C 01 70	,.p
	BPL LFB84	; FB73= 10 0F		
	BVC LFB84	; FB75= 50 0D	P.
	JSR LFC92	; FB77= 20 92 FC	|
	BCS LFB68	; FB7A= B0 EC	0l
	DEC $C3		; FB7C= C6 C3	FC
	BNE LFB70	; FB7E= D0 F0	Pp
	DEC $C2		; FB80= C6 C2	FB
	BNE LFB70	; FB82= D0 EC	Pl
LFB84:
	BVS LFB87	; FB84= 70 01	p.
	RTS		; FB86= 60		`
		
LFB87:
	LDY #$04	; FB87= A0 04		
	PHP		; FB89= 08		
	JSR LFBB7	; FB8A= 20 B7 FB	7{
	PLP		; FB8D= 28		(
	LDY #$04	; FB8E= A0 04		
	LDA #$2A	; FB90= A9 2A	)*
LFB92:
	CMP $00D3,Y	; FB92= D9 D3 00	YS.
	BNE LFB9A	; FB95= D0 03	P.
	DEY		; FB97= 88		
	BNE LFB92	; FB98= D0 F8	Px
LFB9A:
	RTS		; FB9A= 60		`
		
LFB9B:
	INY		; FB9B= C8		H
LFB9C:
	JSR OSBGET	; FB9C= 20 D7 FF	W.
	STA $00ED,Y	; FB9F= 99 ED 00	.m.
	CMP #ASCII_CR	; FBA2= C9 0D	I.
	BNE LFB9B	; FBA4= D0 F5	Pu
	LDY #$FF	; FBA6= A0 FF		
LFBA8:
	INY		; FBA8= C8		H
	LDA ($C9),Y	; FBA9= B1 C9	1I
	CMP $00ED,Y	; FBAB= D9 ED 00	Ym.
	BNE LFB9A	; FBAE= D0 EA	Pj
	CMP #ASCII_CR	; FBB0= C9 0D	I.
	BNE LFBA8	; FBB2= D0 F4	Pt
	RTS		; FBB4= 60		`
		
LFBB5:
	LDY #$08	; FBB5= A0 08		
LFBB7:
	JSR OSBGET	; FBB7= 20 D7 FF	W.
	STA $00D3,Y	; FBBA= 99 D3 00	.S.
	DEY		; FBBD= 88		
	BNE LFBB7	; FBBE= D0 F7	Pw
	RTS		; FBC0= 60		`


; OSBGET HANDLER
; ============== 
OSBGET_handler:
	STX $EC		; FBC1= 86 EC		l
	STY $C3		; FBC3= 84 C3		C
	PHP		; FBC5= 08		
	SEI		; FBC6= 78		x
LFBC7:
	LDA #$78	; FBC7= A9 78	)x
	STA $C0		; FBC9= 85 C0		@
LFBCB:
	JSR LFC92	; FBCB= 20 92 FC	|
	BCC LFBC7	; FBCE= 90 F7		w
	INC $C0		; FBD0= E6 C0	f@
	BPL LFBCB	; FBD2= 10 F7		w
LFBD4:
	LDA #$53	; FBD4= A9 53	)S
	STA $C4		; FBD6= 85 C4		D
	LDX #$00	; FBD8= A2 00	".
	LDY ATOM_PPI_PORT_C	; FBDA= AC 02 70	,.p
LFBDD:
	JSR LFCA2	; FBDD= 20 A2 FC	"|
	BEQ LFBE2	; FBE0= F0 00	p.
LFBE2:
	BEQ LFBE5	; FBE2= F0 01	p.
	INX		; FBE4= E8		h
LFBE5:
	DEC $C4		; FBE5= C6 C4	FD
	BNE LFBDD	; FBE7= D0 F4	Pt
	CPX #$0C	; FBE9= E0 0C	`.
	ROR $C0		; FBEB= 66 C0	f@
	BCC LFBD4	; FBED= 90 E5		e
	LDA $C0		; FBEF= A5 C0	%@
	PLP		; FBF1= 28		(
	LDY $C3		; FBF2= A4 C3	$C
	LDX $EC		; FBF4= A6 EC	$l
LFBF6:
	PHA		; FBF6= 48		H
	CLC		; FBF7= 18		
	ADC $DC		; FBF8= 65 DC	e\
	STA $DC		; FBFA= 85 DC		\
	PLA		; FBFC= 68		h
	RTS		; FBFD= 60		`
		
LFBFE:
	LDA $CD		; FBFE= A5 CD	%M
	BMI LFC0A	; FC00= 30 08	0.
	LDA $D4		; FC02= A5 D4	%T
	STA $CB		; FC04= 85 CB		K
	LDA $D5		; FC06= A5 D5	%U
	STA $CC		; FC08= 85 CC		L
LFC0A:
	RTS		; FC0A= 60		`
		

; OSFIND HANDLER
; ==============
OSFIND_handler:
	CMP #$C0
	BEQ LFC13	; Jump with OPENUP
	LDA #$06
	BNE LFC15	; A = $06 for OPENIN/OPENOUT/CLOSE
LFC13:
	LDA #$04			; A = $04 for OPENUP
LFC15:
	LDX #$07
	STX ATOM_PPI_PORT_C
	BIT $EA
	BNE LFC4B
	CMP #$05
	BEQ print_REWIND_TAPE
	BCS print_RECORD_TAPE
	JSR Print_inline_text
print_PLAY_TAPE:
	db "PLAY"
	BNE print_TAPE
print_RECORD_TAPE:
	JSR Print_inline_text
	db "RECORD"
	BNE print_TAPE
print_REWIND_TAPE:
	JSR Print_inline_text
	db "REWIND"
	NOP
print_TAPE:
	JSR Print_inline_text
	db " TAPE"
	NOP	
LFC4B:
	JSR OSRDCH
	JMP OSNEWL
		

; OSBPUT HANDLER
; ==============
OSBPUT_handler:
	STX $EC		; FC51= 86 EC		l
	STY $C3		; FC53= 84 C3		C
	PHP		; FC55= 08		
	SEI		; FC56= 78		x
	PHA		; FC57= 48		H
	JSR LFBF6	; FC58= 20 F6 FB	v{
	STA $C0		; FC5B= 85 C0		@
	JSR LFCAD	; FC5D= 20 AD FC	-|
	LDA #$0A	; FC60= A9 0A	).
	STA $C1		; FC62= 85 C1		A
	CLC		; FC64= 18		
loop_FC65:
	BCC LFC71	; FC65= 90 0A		
	LDX #$07	; FC67= A2 07	".
	STX ATOM_PPI_PORT_C	; FC69= 8E 02 70	..p
	JSR LFCAF	; FC6C= 20 AF FC	/|
	BMI LFC84	; FC6F= 30 13	0.
LFC71:
	LDY #4	
loop_FC73:
	LDA #4
LFC75:
	STA ATOM_PPI_PORT_C
	JSR LFCAD
	INC ATOM_PPI_PORT_C
	JSR LFCAD
	DEY		
	BNE loop_FC73
LFC84:
	SEC		; FC84= 38		8
	ROR $C0		; FC85= 66 C0	f@
	DEC $C1		; FC87= C6 C1	FA
	BNE loop_FC65	; FC89= D0 DA	PZ
	LDY $C3		; FC8B= A4 C3	$C
	LDX $EC		; FC8D= A6 EC	$l
LFC8F:
	PLA		; FC8F= 68		h
	PLP		; FC90= 28		(
	RTS		; FC91= 60		`
		
LFC92:
	LDX #0
	LDY ATOM_PPI_PORT_C
LFC97:
	INX
	BEQ RTS_FCA1
	JSR LFCA2
	BEQ LFC97
	CPX #8
RTS_FCA1:
	RTS		; FCA1= 60		`
		
LFCA2:
	STY $C5		; FCA2= 84 C5		E
	LDA ATOM_PPI_PORT_C	; FCA4= AD 02 70	-.p
	TAY		; FCA7= A8		(
	EOR $C5		; FCA8= 45 C5	EE
	AND #$20	; FCAA= 29 20	) 
	RTS		; FCAC= 60		`
		
LFCAD:
	LDX #0
LFCAF:
	LDA #$10
loop_FCB1:
	BIT ATOM_PPI_PORT_C
	BEQ loop_FCB1
loop_FCB6:
	BIT ATOM_PPI_PORT_C
	BNE loop_FCB6
	DEX
	BPL loop_FCB1
	RTS
		
handle_characters:
	CMP #ASCII_ACK
	BEQ VDU_enable	; <ACK> - enable VDU
	CMP #ASCII_NAK
	BEQ VDU_disable	; <NAK> - disable VDU
	LDY $E0
	BMI LFCEE	; VDU is disabled
	CMP #ASCII_ESC
	BEQ VDU_enable	; <ESC> - reset VDU
	CMP #ASCII_BEL
	BEQ bell	; <BEL> - ring bell
	JSR cursor_off		; Remove cursor
	LDX #$0A
	JSR index_into_WRCH_character_translation_table
	BNE do_printable_character
	JMP do_control_character

VDU_enable:
	CLC		
	LDX #0
	STX ATOM_PPI_PORT_A	; 
	
VDU_disable:
	LDX #2
LFCE8:
	PHP		; 		
	ASL current_line,X	; 
	PLP		; 
	ROR current_line,X	; 
LFCEE:
	RTS
		
bell:
	LDA #5
	TAY
speaker_outer_loop:
	STA ATOM_PPI_CTRL
speaker_inner_loop:
	DEX	
	BNE speaker_inner_loop
	EOR #$01	; toggle speaker bit
	INY 
	BPL speaker_outer_loop
	RTS


NMI_handler:
	PHA
	JMP (userv) ; Hand on to Atom NMIV
		
; Store character in display RAM
; ------------------------------
do_printable_character:
	CMP #ASCII_SP
	BCC cursor_off	; If <' ',
	ADC #$1F		; Add $20
	BMI LFD0C
	EOR #$60	; If <&80, toggle b6/b5
LFD0C:
	JSR Wait_for_VSync		; Wait for VSync
	STA (current_line),Y		; Store in video RAM

LFD11:
	INY		; FD11= C8		H
	CPY #$20	; FD12= C0 20	@ 
	BCC LFD1B	; FD14= 90 05		
	JSR LFDC5	; FD16= 20 C5 FD	E}

LFD19:
	LDY #$00	; FD19= A0 00		
LFD1B:
	STY $E0		; FD1B= 84 E0		`
cursor_off:
	PHA		; 
	JSR Wait_for_VSync	; 
	LDA (current_line),Y	; 
	EOR $E1		; 
	STA (current_line),Y	; 
	PLA		; 
	RTS		; 
		
LFD29:
	JSR LFE0E	; FD29= 20 0E FE	~
	LDA #$20	; FD2C= A9 20	) 
	JSR Wait_for_VSync	; FD2E= 20 44 FE	D~
	STA (current_line),Y	; FD31= 91 DE		^
	BPL LFD1B	; FD33= 10 E6		f

LFD35:
	JSR LFE0E	; FD35= 20 0E FE	~
	JMP LFD1B	; FD38= 4C 1B FD	L.}

LFD3B:	
	JSR LFDC5	; FD3B= 20 C5 FD	E}
LFD3E:
	LDY $E0		; FD3E= A4 E0	$`
	BPL LFD1B	; FD40= 10 D9		Y

LFD42:
	LDY #$80	; FD42= A0 80		
	STY $E1		; FD44= 84 E1		a
	LDY #$00	; FD46= A0 00		
	STY ATOM_PPI_PORT_A	; FD48= 8C 00 70	..p
	LDA #$20	; FD4B= A9 20	) 
LFD4D:
	STA screen_RAM,Y	; FD4D= 99 00 40	..@
	STA screen_RAM+$100,Y	; FD50= 99 00 41	..A
	INY		; FD53= C8		H
	BNE LFD4D	; FD54= D0 F7	Pw

LFD56:
	LDA #$40	; FD56= A9 40	)@
	LDY #$00	; FD58= A0 00		
	STA current_line+1		; FD5A= 85 DF		_
	STY current_line		; FD5C= 84 DE		^
	BEQ LFD1B	; FD5E= F0 BB	p;

LFD60:
	JSR LFE13	; FD60= 20 13 FE	~
	JMP LFD1B	; FD63= 4C 1B FD	L.}

LFD66:	
	CLC		; FD66= 18		
	LDA #$10	; FD67= A9 10	).
	STA $E6		; FD69= 85 E6		f

LFD6B:
	LDX #$08	; FD6B= A2 08	".
	JSR LFCE8	; FD6D= 20 E8 FC	h|
	JMP cursor_off	; FD70= 4C 1D FD	L.}

LFD73:
	LDA $E7		; FD73= A5 E7	%g
	EOR #$60	; FD75= 49 60	I`
	STA $E7		; FD77= 85 E7		g
	BCS LFD84	; FD79= B0 09	0.

LFD7B:
	AND #$05	; FD7B= 29 05	).
	ROL ATOM_PPI_PORT_B	; FD7D= 2E 01 70	..p
	ROL A		; FD80= 2A		*
	JSR handle_characters	; FD81= 20 BF FC	?|
LFD84:
	JMP LFE73	; FD84= 4C 73 FE	Ls~
		
LFD87:
	LDY $E0		; FD87= A4 E0	$`
	JSR Wait_for_VSync	; FD89= 20 44 FE	D~
	LDA (current_line),Y	; FD8C= B1 DE	1^
	EOR $E1		; FD8E= 45 E1	Ea
	BMI LFD94	; FD90= 30 02	0.
	EOR #$60	; FD92= 49 60	I`
LFD94:
	SBC #$20	; FD94= E9 20	i 
	JMP LFDC2	; FD96= 4C C2 FD	LB}
		
LFD99:
	LDA #$5F	; FD99= A9 5F	)_
LFD9B:
	EOR #$20	; FD9B= 49 20	I 
	BNE LFDC2	; FD9D= D0 23	P#
LFD9F:
	EOR $E7		; FD9F= 45 E7	Eg
LFDA1:
	BIT ATOM_PPI_PORT_B	; FDA1= 2C 01 70	,.p
	BMI LFDA8	; FDA4= 30 02	0.
	EOR #$60	; FDA6= 49 60	I`
LFDA8:
	JMP LFDB8	; FDA8= 4C B8 FD	L8}
		
LFDAB:
	ADC #$39	; FDAB= 69 39	i9
	BCC LFDA1	; FDAD= 90 F2		r
LFDAF:
	EOR #$10	; FDAF= 49 10	I.

LFDB1:
	BIT ATOM_PPI_PORT_B	; FDB1= 2C 01 70	,.p
	BMI LFDB8	; FDB4= 30 02	0.
	EOR #$10	; FDB6= 49 10	I.
LFDB8:
	CLC		; FDB8= 18		
	ADC #$20	; FDB9= 69 20	i 

LFDBB:
	BIT ATOM_PPI_PORT_B	; FDBB= 2C 01 70	,.p
	BVS LFDC2	; FDBE= 70 02	p.
	AND #$1F	; FDC0= 29 1F	).
LFDC2:
	JMP LFE39	; FDC2= 4C 39 FE	L9~
		
LFDC5:
	LDA current_line		; FDC5= A5 DE	%^
	LDY current_line+1		; FDC7= A4 DF	$_
	CPY #$41	; FDC9= C0 41	@A
	BCC LFE05	; FDCB= 90 38		8
	CMP #$E0	; FDCD= C9 E0	I`
	BCC LFE05	; FDCF= 90 34		4
	LDY $E6		; FDD1= A4 E6	$f
	BMI LFDE1	; FDD3= 30 0C	0.
	DEY		; FDD5= 88		
	BNE LFDDF	; FDD6= D0 07	P.
LFDD8:
	JSR LFE4A	; FDD8= 20 4A FE	J~
	BCS LFDD8	; FDDB= B0 FB	0{
	LDY #$10	; FDDD= A0 10		
LFDDF:
	STY $E6		; FDDF= 84 E6		f
LFDE1:
	LDY #$20	; FDE1= A0 20		
	JSR Wait_until_no_VSync	; FDE3= 20 3F FE	?~
LFDE6:
	LDA screen_RAM,Y	; FDE6= B9 00 40	9.@
	STA $3FE0,Y	; FDE9= 99 E0 3F	.`?
	INY		; FDEC= C8		H
	BNE LFDE6	; FDED= D0 F7	Pw
	JSR Wait_for_VSync	; FDEF= 20 44 FE	D~
LFDF2:
	LDA screen_RAM+$100,Y	; FDF2= B9 00 41	9.A
	STA $40E0,Y	; FDF5= 99 E0 40	.`@
	INY		; FDF8= C8		H
	BNE LFDF2	; FDF9= D0 F7	Pw
	LDY #$1F	; FDFB= A0 1F		
	LDA #$20	; FDFD= A9 20	) 
LFDFF:
	STA (current_line),Y	; FDFF= 91 DE		^
	DEY		; FE01= 88		
	BPL LFDFF	; FE02= 10 FB		{
	RTS		; FE04= 60		`
		
LFE05:
	ADC #$20	; FE05= 69 20	i 
	STA current_line		; FE07= 85 DE		^
	BNE LFE0D	; FE09= D0 02	P.
	INC current_line+1		; FE0B= E6 DF	f_
LFE0D:
	RTS		; FE0D= 60		`
		
LFE0E:
	DEY		; FE0E= 88		
	BPL LFE2A	; FE0F= 10 19		
	LDY #$1F	; FE11= A0 1F		
LFE13:
	LDA current_line		; FE13= A5 DE	%^
	BNE LFE22	; FE15= D0 0B	P.
	LDX current_line+1		; FE17= A6 DF	$_
	CPX #$40	; FE19= E0 40	`@
	BNE LFE22	; FE1B= D0 05	P.
	PLA		; FE1D= 68		h
	PLA		; FE1E= 68		h
	JMP LFD3E	; FE1F= 4C 3E FD	L>}
		
LFE22:
	SBC #$20	; FE22= E9 20	i 
	STA current_line		; FE24= 85 DE		^
	BCS LFE2A	; FE26= B0 02	0.
	DEC current_line+1		; FE28= C6 DF	F_
LFE2A:
	RTS		; FE2A= 60		`

; Write a character to VDU
; ------------------------
LFE2B:
	JSR LFED4	; Send to printer
	PHP		; FE2E= 08		
	PHA		; FE2F= 48		H
	CLD		; FE30= D8		X
	STY $E5		; FE31= 84 E5		e
	STX $E4		; FE33= 86 E4		d
	JSR handle_characters	; FE35= 20 BF FC	?|
	PLA		; FE38= 68		h
LFE39:
	LDX $E4		; FE39= A6 E4	$d
	LDY $E5		; FE3B= A4 E5	$e
	PLP		; FE3D= 28		(
	RTS		; FE3E= 60		`
		
Wait_until_no_VSync:
	BIT ATOM_PPI_PORT_C
	BPL Wait_until_no_VSync	; Wait until no VSync
Wait_for_VSync:
	BIT ATOM_PPI_PORT_C
	BMI Wait_for_VSync	; Wait until VSync
	RTS

LFE4A:
	LDY #$3B	; FE4A= A0 3B	;
	CLC		; FE4C= 18		
	LDA #$20	; FE4D= A9 20	) 
LFE4F:
	LDX #$0A	; FE4F= A2 0A	".
LFE51:
	BIT ATOM_PPI_PORT_B	; FE51= 2C 01 70	,.p
	BEQ LFE5E	; FE54= F0 08	p.
	INC ATOM_PPI_PORT_A	; FE56= EE 00 70	n.p
	DEY		; FE59= 88		
	DEX		; FE5A= CA		J
	BNE LFE51	; FE5B= D0 F4	Pt
	LSR A		; 
LFE5E:
	PHP		;		
	PHA		;
	LDA ATOM_PPI_PORT_A
	AND #$F0	; 
	STA ATOM_PPI_PORT_A	
	PLA
	PLP
	BNE LFE4F	; FE6A= D0 E3	Pc
	RTS		; FE6C= 60		`


; OSRDCH HANDLER
; ============== 
RDCHV_handler:
	PHP		; FE6D= 08		
	CLD		; FE6E= D8		X
	STX $E4		; FE6F= 86 E4		d
	STY $E5		; FE71= 84 E5		e
LFE73:
	BIT ATOM_PPI_PORT_C	; FE73= 2C 02 70	,.p
	BVC LFE7D	; FE76= 50 05	P.
	JSR LFE4A	; FE78= 20 4A FE	J~
	BCC LFE73	; FE7B= 90 F6		v
LFE7D:
	JSR LFB5D	; FE7D= 20 5D FB	]{
LFE80:
	JSR LFE4A
	BCS LFE80
	JSR LFE4A
	BCS LFE80
LFE8A:
	TYA		; FE8A= 98		
	LDX #$17	; FE8B= A2 17	".
	JSR index_into_WRCH_character_translation_table	; FE8D= 20 9E FE	~
do_control_character:
	LDA LFEBC,X
	STA vector_0xE2
    LDA #>LFD11
	STA vector_0xE2+1
	TYA
	JMP (vector_0xE2)
		
LFE9D:
	DEX
index_into_WRCH_character_translation_table:
	CMP WRCH_character_translation_table,X
	BCC LFE9D
	RTS

WRCH_character_translation_table:
	db $00
	db $08
	db $09
	db $0A	; WRCH character translation table
	db $0B
	db $0C
	db $0D
	db $0E
	db $0F
	db $1E
	db $7F

	db $00
	db $01
	db $05
	db $06	; RDCH character translation table
	db $08
	db $0E
	db $0F
	db $10
	db $11
	db $1C
	db $20
	db $21
	db $3B

; WRCH and RDCH character translation dispatch table
; Low byte of addresses - high byte is LFD11 DIV 256
; --------------------------------------------------
LFEBC:
; WRCH translation addresses
	db <cursor_off ; AND 255 ; VDU 0
	db <LFD35 ; AND 255 ; VDU 8
	db <LFD11 ; AND 255 ; VDU 9
	db <LFD3B ; AND 255 ; VDU 10
	db <LFD60 ; AND 255 ; VDU 11
	db <LFD42 ; AND 255 ; VDU 12
	db <LFD19 ; AND 255 ; VDU 13
	db <LFD66 ; AND 255 ; VDU 14
	db <LFD6B ; AND 255 ; VDU 15
	db <LFD56 ; AND 255 ; VDU 30
	db <LFD29 ; AND 255 ; VDU 127

; RDCH translation addresses
	db <LFDB8 ; AND 255 ; 0
	db <LFDAB ; AND 255 ; 1
	db <LFD73 ; AND 255 ; 5
	db <LFD7B ; AND 255 ; 6
	db <LFDBB ; AND 255 ; 8
	db <LFD87 ; AND 255 ; 14
	db <LFD99 ; AND 255 ; 15
	db <LFDB8 ; AND 255 ; 16
	db <LFDB1 ; AND 255 ; 17
	db <LFDAF ; AND 255 ; 28
	db <LFDA1 ; AND 255 ; 32
	db <LFD9F ; AND 255 ; 33
	db <LFD9B ; AND 255 ; 49

LFED4:
	PHA
	CMP #$02
	BEQ LFF00
	CMP #$03
	BEQ LFF11
	CMP $FE
	BEQ LFF0F	; *BUG* This is Atom location, but is BBC FAULT pointer
	LDA $780C
	AND #$0E
	BEQ LFF0F
	PLA
LFEE9:
	BIT $7801	; FEE9= 2C 01 78	
	BMI LFEE9	; FEEC= 30 FB	
	STA $7801	; FEEE= 8D 01 78
	PHA		; FEF1= 48		
	LDA $780C	; FEF2= AD 0C 78	
	AND #$F0	; FEF5= 29 F0	
	ORA #$0C	; FEF7= 09 0C		
	STA $780C	; FEF9= 8D 0C 78	
	ORA #$02	; FEFC= 09 02		
	BNE LFF0C	; FEFE= D0 0C	
LFF00:
	LDA #$7F	; FF00= A9 7F	
	STA ATOM_VIA_DDRA	; FF02= 8D 03 78	
	LDA $780C	; FF05= AD 0C 78	
	AND #$F0	; FF08= 29 F0	
	ORA #$0E	; FF0A= 09 0E		
LFF0C:
	STA $780C	; FF0C= 8D 0C 78	
LFF0F:
	PLA		; FF0F= 68		h

; DEFAULT OSGBPB, IRQ2 HANDLER
; ============================
; *BUG* IRQ2V should point to RTI

IRQ2_handler:
	RTS		; FF10= 60		`
		
LFF11:
	LDA $780C	; FF11= AD 0C 78	-.x
	AND #$F0	; FF14= 29 F0	)p
	BCS LFF0C	; FF16= B0 F4	0t

RESET_handler:
	LDX #$19
LFF1A:
	LDA Default_vectors,X
	STA irq1v,X	; Set up default vectors
	DEX
	BPL LFF1A
	TXS		; Clear stack
	TXA
	INX
	STX $EA
	STX $E1
	STX $E7	; Clear some locations
	LDA #$0A
	STA $FE		; Atom PrintIgnore character
	
					; *BUG* This is BBC FAULT address
	LDA #$8A
	STA ATOM_PPI_CTRL	; Set up 8255
	LDA #$07
	STA ATOM_PPI_PORT_C
	JSR Print_inline_text
	db 6
	db 12
	db 15	; Enable VDU, clear screen, paged off
	db "BBC BASIC"
	db 10
	db 10
	db 13
;
;   Atom Clock is 
    VIA_clock_rate_Hz   equ 1000000
    VIA_IRQ_rate_Hz    equ  100
    VIA_T1_divisor  equ (VIA_clock_rate_Hz/VIA_IRQ_rate_Hz)-2
;
;
;
					; Set up 6522
	LDA #<VIA_T1_divisor
	STA ATOM_VIA_T1CL	; T1 = $270E for 100Hz IRQs
	LDA #>VIA_T1_divisor
	STA ATOM_VIA_T1CH	
;
	LDA #$40
	STA ATOM_VIA_ACR	; AuxCtrl=
	LDA #$C0
	STA ATOM_VIA_IER	; Enable T1 IRQs
	LDA #0
	LDX #4		
;
set_TIME_to_zero_loop:
	STA $0300,X
	DEX
	BPL set_TIME_to_zero_loop ; Set TIME to zero
	STA VDU_queue_length
	STA sound_duration	; Set SOUND duration to zero
	STA $FF			; Clear Escape flag
	LDA #$0E
	STA $FD		; *BUG* Should fetch from $8007
	LDA #$80
	STA $FE		; Point last error to BASIC copyright message
	LDA $C000			; Is extension ROM present?
	CMP #$AA
	BNE LFF85	; No, skip past
	JSR $C001
	CLI		; Call extension ROM
LFF85:
	JMP $8000			; Enter BASIC at $8000

; ===============
Default_vectors:
				; $200 - NMIV, initialised by DOS
				; $202 - BRKV, initialised by BASIC
	dw $8000		; $204 - IRQ1V
	dw IRQ2_handler		; $206 - IRQ2V
	dw CLI_handler		; $208 - CLIV
	dw OSBYTE_handler	; $20A - BYTEV
	dw OSWORD_handler	; $20C - WORDV
	dw OSWRCH_handler	; $20E - WRCHV
	dw RDCHV_handler	; $210 - RDCHV
	dw OSFILE_handler	; $212 - FILEV
	dw OSARGS_handler	; $214 - ARGSV
	dw OSBGET_handler	; $216 - BGETV
	dw OSBPUT_handler	; $218 - BPUTV
	dw IRQ2_handler		; $21A - GBPBV
	dw OSFIND_handler	; $21C - FINDV
				; $21E - FSCV

; ===========
IRQ_handler:
	STA IRQ_A_store
	PLA
	PHA		; Get pushed flags from stack
	AND #$10
	BNE LFFBA	; Jump if BRK occured
	LDA ATOM_VIA_IFR
	AND #$60	; Check 6522 Timer1/Timer2 interupt status
	BEQ LFFB4
	JMP ATOM_VIA_INTERRUPT	; Jump to process 6522 interupt
LFFB4:
	LDA IRQ_A_store
	PHA
	JMP (irq1v)	; Unrecognised, pass on to IRQ1V

; BRK occured, set up error pointer and pass on to BRKV
; -----------------------------------------------------
LFFBA:
	LDA IRQ_A_store
	PLP
	PLA
	SEC
	SBC #$01
	STA $FD
	PLA
	SBC #$00
	STA $FE		; $FD/E=>error

OSBRK:	JMP (brkv)	; Pass to BRKV
OSIRQ2:	JMP (irq2v)	; Pass to IRQ2V
	
	
; Filing system entry points
; --------------------------
OSFIND:	JMP (findv)
OSGBPB:	JMP (gbpbv)
OSBPUT:	JMP (bputv)
OSBGET:	JMP (bgetv)
OSARGS:	JMP (argsv)
OSFILE:	JMP (filev)
;
; MOS I/O entry points
; --------------------
OSRDCH:	JMP (rdchv)
OSASCI:	CMP #ASCII_CR
	BNE OSWRCH
OSNEWL:	JSR OSWRCH
OSWRCR:	LDA #ASCII_CR
OSWRCH:	JMP (wrchv)
OSWORD:	JMP (wordv)
OSBYTE:	JMP (bytev)
OS_CLI:	JMP (cliv)
	
	
NMI:	dw NMI_handler
RESET:	dw RESET_handler
IRQ:	dw IRQ_handler
;	]
;	NEXT
;	OSCLI"Save "+outfile$+" "+STR$~mcode%+" "+STR$~O%+" "+STR$~load%+" "+STR$~load%
;	ON ERROR ON ERROR OFF
;	END
;	*Quit
	
	
;	DEFFNif(A%)
;	IFA%
;	z%=-1
;	=opt% ELSE z%=P%
;	=opt%
;	DEFFNendif
;	IFz%=-1
;	=opt% ELSE z%=P%-z%
;	P%=P%-z%
;	O%=O%-z%
;	=opt%
;	DEFFNelse
;	IFz%=-1
;	z%=P%
;	=opt% ELSE z%=P%-z%
;	P%=P%-z%
;	O%=O%-z%
;	z%=-1
;	=opt%