title 'Character I/O handler for z80 chip based system'

; Character I/O for the Modular CP/M 3 BIOS

	public	?cinit,?ci,?co,?cist,?cost
	public	@ctbl

;	maclib Z80	; define Z80 op codes
;	maclib ports	; define port addresses
	maclib modebaud.lib	; define mode bits and baud equates

;max$devices	equ 6

	cseg

?cinit:
	ret
;	mov a,c ! cpi max$devices ! jz cent$init ; init parallel printer
;	rnc				; invalid device
;	mov l,c ! mvi h,0		; make 16 bits from device number
;	push h				; save device in stack
;	dad h ! dad h ! dad h		; *8 
;	lxi d,@ctbl+7 ! dad d ! mov l,m	; get baud rate
;	mov a,l ! cpi baud$600		; see if baud > 300
;	mvi a,44h ! jnc hi$speed	; if >= 600, use *16 mode
;	mvi a,0C4h			;    else, use *64 mode
;hi$speed:
;	sta sio$reg$4	
;	mvi h,0 ! lxi d,speed$table ! dad d	; point to counter entry
;	mov a,m ! sta speed		; get and save ctc count
;	pop h				; recover 
;	lxi d,data$ports ! dad d	; point at SIO port address
;	mov a,m ! inr a ! sta sio$port	; get and save port
;	lxi d,baud$ports-data$ports ! dad d	; offset to baud rate port
;	mov a,m ! sta ctc$port		; get and save
;	lxi h,serial$init$tbl
;	jmp stream$out
;
;cent$init:
;	lxi h,pio$init$tbl
;
;stream$out:
;	mov a,m ! ora a ! rz
;	mov b,a ! inx h ! mov c,m ! inx h
;	outir
;	jmp stream$out


?ci:		; character input
	;ld	bc,0000H	; unit 0, func 0 = CIN
	ld	c,b		; Unit number to C
	ld	b,00h		; HBIOS CIN Function
	rst	08		; do it
	ld	a,e		; put char in A
	ret			; done

;	mov a,b ! cpi 6 ! jnc null$input ; can't read from centronics
;ci1:
;	call ?cist ! jz ci1		; wait for character ready
;	dcr c ! inp a			; get data
;	ani 7Fh				; mask parity
;	ret
;
;null$input:
;	mvi a,1Ah			; return a ctl-Z for no device
;	ret

?cist:		; character input status
	;ld	bc,0200H		; unit 0, func 2 = IST
	ld	c,b			; Unit number to C
	ld	b,02h			; HBIOS IST Function
	rst	08			; do it
	or	a			; set flags
	ret	z			; return w/ ZF set if no char ready
	or	0FFH			; else signal nothing ready
	ret				; done

;	mov a,b ! cpi 6 ! jnc null$status ; can't read from centronics
;	mov l,b ! mvi h,0		; make device number 16 bits
;	lxi d,data$ports ! dad d	; make pointer to port address
;	mov c,m ! inr c			; get SIO status port
;	inp a				; read from status port
;	ani 1			; isolate RxRdy
;	rz				; return with zero
;	ori 0FFh
;	ret

;null$status:
;	xra a ! ret

?co:		; character output
	ld	e,c		; char to E
	;ld	bc,0100H	; unit 0, func 1 = COUT
	ld	c,b		; Unit number to C
	ld	b,01h		; HBIOS COUT Function
	rst	08		; do it
	ret			; done

;	mov a,b ! cpi 6 ! jz centronics$out
;	jnc null$output
;	mov a,c ! push psw		; save character from <C>
;	push b				; save device number
;co$spin:
;	call ?cost ! jz co$spin		; wait for TxEmpty
;	pop h ! mov l,h ! mvi h,0	; get device number in <HL>
;	lxi d,data$ports ! dad d	; make address of port address
;	mov c,m				; get port address
;	pop psw ! outp a		; send data
;null$output:
;	ret
;
;centronics$out:
;	in p$centstat ! ani 20h ! jnz centronics$out
;	mov a,c ! out p$centdata	; give printer data
;	in p$centstat ! ori 1 ! out p$centstat	; set strobe
;	ani 7Eh ! out p$centstat		; clear strobe
;	ret

?cost:		; character output status
	;ld	bc,0300H		; unit 0, func 3 = OST
	ld	c,b			; Unit number to C
	ld	b,03h			; HBIOS OST Function
	rst	08			; do it
	or	a			; set flags
	ret	z			; return w/ ZF set if not ready to send
	or	0FFH			; else signal nothing ready
	ret				; done


;	mov a,b ! cpi 6 ! jz cent$stat
;	jnc null$status
;	mov l,b ! mvi h,0
;	lxi d,data$ports ! dad d
;	mov c,m ! inr c 
;	inp a				; get input status
;	ani 4 ! rz			; test transmitter empty
;	ori 0FFh ! ret			; return true if ready
;
;
;cent$stat:
;	in p$centstat ! cma
;	ani 20h ! rz
;	ori 0FFh ! ret	

;baud$ports:		; CTC ports by physical device number
;	db	p$baud$con1,p$baud$lpt1,p$baud$con2,p$baud$con34
;	db	p$baud$con34,p$baud$lpt2
;
;data$ports:		; serial base ports by physical device number
;	db	p$crt$data,p$lpt$data,p$con2data,p$con3data
;	db	p$con4data,p$lpt2data


@ctbl	db	'COM0  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM1  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM2  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM3  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM4  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM5  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM6  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM7  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM8  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM9  '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM10 '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	'COM11 '
	db	mb$in$out+mb$serial+baud$none
	db	baud$none
	db	0

;@ctbl	db 'CRT   '	; device 0, CRT port 0
;	db mb$in$out+mb$serial+mb$softbaud
;	db baud$9600
;	db 'LPT   '	; device 1, LPT port 0
;	db mb$in$out+mb$serial+mb$softbaud+mb$xonxoff
;	db baud$9600
;	db 'CRT1  '	; device 2, CRT port 1
;	db mb$in$out+mb$serial+mb$softbaud
;	db baud$9600
;	db 'CRT2  '	; device 3, CRT port 2
;	db mb$in$out+mb$serial+mb$softbaud
;	db baud$9600
;	db 'CRT3  '	; device 4, CRT port 3
;	db mb$in$out+mb$serial+mb$softbaud
;	db baud$9600
;	db 'VAX   '	; device 5, LPT port 1 used for VAX interface
;	db mb$in$out+mb$serial+mb$softbaud
;	db baud$9600
;	db 'CEN   '	; device 6, Centronics parallel printer
;	db mb$output
;	db baud$none
;	db 0			; table terminator

;speed$table	db	0,255,255,255,233,208,104,208,104,69,52,35,26,17,13,7
;
;serial$init$tbl
;		db 2		; two bytes to CTC
;ctc$port	ds 1		; port address of CTC
;		db 47h		; CTC mode byte
;speed		ds 1		; baud multiplier
;		db 7		; 7 bytes to SIO
;sio$port	ds 1		; port address of SIO
;		db 18h,3,0E1h,4
;sio$reg$4	ds 1
;		db 5,0EAh 	
;		db 0		; terminator
;
;pio$init$tbl	db	2,p$zpio$2b,0Fh,07h
;		db	3,p$zpio$2a,0CFh,0F8h,07h
;		db 0

	end