drivers/char/ser_a2232fw.ax - kernel/msm-4.19 - Gitiles

 ;.lib "axm"
 ;
 ;begin
 ;title "A2232 serial board driver"
 ;
 ;set modules "2232"
 ;set executable "2232.bin"
 ;
 ;;;;set nolink
 ;
 ;set temporary directory "t:"
 ;
 ;set assembly options "-m6502 -l60:t:list"
 ;set link options "bin"; loadadr"
 ;;;bin2c 2232.bin msc6502.h msc6502code
 ;end
 ;
 ;
 ; ### Commodore A2232 serial board driver for NetBSD by JM v1.3 ###
 ;
 ; - Created 950501 by JM -
 ;
 ;
 ; Serial board driver software.
 ;
 ;
 % Copyright (c) 1995 Jukka Marin <jmarin@jmp.fi>.
 % All rights reserved.
 %
 % Redistribution and use in source and binary forms, with or without
 % modification, are permitted provided that the following conditions
 % are met:
 % 1. Redistributions of source code must retain the above copyright
 %    notice, and the entire permission notice in its entirety,
 %    including the disclaimer of warranties.
 % 2. Redistributions in binary form must reproduce the above copyright
 %    notice, this list of conditions and the following disclaimer in the
 %    documentation and/or other materials provided with the distribution.
 % 3. The name of the author may not be used to endorse or promote
 %    products derived from this software without specific prior
 %    written permission.
 %
 % ALTERNATIVELY, this product may be distributed under the terms of
 % the GNU General Public License, in which case the provisions of the
 % GPL are required INSTEAD OF the above restrictions.  (This clause is
 % necessary due to a potential bad interaction between the GPL and
 % the restrictions contained in a BSD-style copyright.)
 %
 % THIS SOFTWARE IS PROVIDED `AS IS'' AND ANY EXPRESS OR IMPLIED
 % WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 % OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 % DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 % INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 % (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 % SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 % HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 % STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 % ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 % OF THE POSSIBILITY OF SUCH DAMAGE.
 ;
 ;
 ; Bugs:
 ;
 ; - Can't send a break yet
 ;
 ;
 ;
 ; Edited:
 ;
 ; - 950501 by JM -> v0.1	- Created this file.
 ; - 951029 by JM -> v1.3	- Carrier Detect events now queued in a separate
 ;				  queue.
 ;
 ;


 CODE		equ	$3800		; start address for program code


 CTL_CHAR	equ	$00		; byte in ibuf is a character
 CTL_EVENT	equ	$01		; byte in ibuf is an event

 EVENT_BREAK	equ	$01
 EVENT_CDON	equ	$02
 EVENT_CDOFF	equ	$03
 EVENT_SYNC	equ	$04

 XON		equ	$11
 XOFF		equ	$13


 VARBASE		macro	*starting_address	; was VARINIT
 _varbase	set	\1
 		endm

 VARDEF		macro	*name space_needs
 \1		equ	_varbase
 _varbase	set	_varbase+\2
 		endm


 stz		macro	* address
 		 db	$64,\1
 		endm

 stzax		macro	* address
 		 db	$9e,<\1,>\1
 		endm


 biti		macro	* immediate value
 		db	$89,\1
 		endm

 smb0		macro	* address
 		db	$87,\1
 		endm
 smb1		macro	* address
 		db	$97,\1
 		endm
 smb2		macro	* address
 		db	$a7,\1
 		endm
 smb3		macro	* address
 		db	$b7,\1
 		endm
 smb4		macro	* address
 		db	$c7,\1
 		endm
 smb5		macro	* address
 		db	$d7,\1
 		endm
 smb6		macro	* address
 		db	$e7,\1
 		endm
 smb7		macro	* address
 		db	$f7,\1
 		endm


 ;-----------------------------------------------------------------------;
 ;									;
 ; stuff common for all ports, non-critical (run once / loop)		;
 ;									;
 DO_SLOW		macro	* port_number					;
 		.local			;				;
 		lda	CIA+C_PA	; check all CD inputs		;
 		cmp	CommonCDo	; changed from previous accptd?	;
 		beq	=over		; nope, do nothing else here	;
 					;				;
 		cmp	CommonCDb	; bouncing?			;
 		beq	=nobounce	; nope ->			;
 					;				;
 		sta	CommonCDb	; save current state		;
 		lda	#64		; reinitialize counter		;
 		sta	CommonCDc	;				;
 		jmp	=over		; skip CD save			;
 					;				;
 =nobounce	dec	CommonCDc	; no, decrement bounce counter	;
 		bpl	=over		; not done yet, so skip CD save	;
 					;				;
 =saveCD		ldx	CDHead		; get write index		;
 		sta	cdbuf,x		; save status in buffer		;
 		inx			;				;
 		cpx	CDTail		; buffer full?			;
 		.if	ne		; no: preserve status:		;
 		 stx	CDHead		; update index in RAM		;
 		 sta	CommonCDo	; save state for the next check	;
 		.end			;				;
 =over		.end	local						;
 		endm							;
 									;
 ;-----------------------------------------------------------------------;


 ; port specific stuff (no data transfer)

 DO_PORT		macro	* port_number
 		.local			;				;
 		lda	SetUp\1		; reconfiguration request?	;
 		.if	ne		; yes:				;
 		 lda	SoftFlow\1	; get XON/XOFF flag		;
 		 sta	XonOff\1	; save it			;
 		 lda	Param\1		; get parameter			;
 		 ora	#%00010000	; use baud generator for Rx	;
 		 sta	ACIA\1+A_CTRL	; store in control register	;
 		 stz	OutDisable\1	; enable transmit output	;
 		 stz	SetUp\1		; no reconfiguration no more	;
 		.end			;				;
 					;				;
 		lda	InHead\1	; get write index		;
 		sbc	InTail\1	; buffer full soon?		;
 		cmp	#200		; 200 chars or more in buffer?	;
 		lda	Command\1	; get Command reg value		;
 		and	#%11110011	; turn RTS OFF by default	;
 		.if	cc		; still room in buffer:		;
 		 ora	#%00001000	; turn RTS ON			;
 		.end			;				;
 		sta	ACIA\1+A_CMD	; set/clear RTS			;
 					;				;
 		lda	OutFlush\1	; request to flush output buffer;
 		.if	ne		; yessh!			;
 		 lda	OutHead\1	; get head			;
 		 sta	OutTail\1	; save as tail			;
 		 stz	OutDisable\1	; enable transmit output	;
 		 stz	OutFlush\1	; clear request			;
 		.end
 		.end	local
 		endm


 DO_DATA		macro	* port number
 		.local
 		lda	ACIA\1+A_SR	; read ACIA status register	;
 		biti	[1<<3]		; something received?		;
 		.if	ne		; yes:				;
 		 biti	[1<<1]		; framing error?		;
 		 .if	ne		; yes:				;
 		  lda	ACIA\1+A_DATA	; read received character	;
 		  bne	=SEND		; not break -> ignore it	;
 		  ldx	InHead\1	; get write pointer		;
 		  lda	#CTL_EVENT	; get type of byte		;
 		  sta	ictl\1,x	; save it in InCtl buffer	;
 		  lda	#EVENT_BREAK	; event code			;
 		  sta	ibuf\1,x	; save it as well		;
 		  inx			;				;
 		  cpx	InTail\1	; still room in buffer?		;
 		  .if	ne		; absolutely:			;
 		   stx	InHead\1	; update index in memory	;
 		  .end			;				;
 		  jmp	=SEND		; go check if anything to send	;
 		 .end			;				;
 		 			; normal char received:		;
 		 ldx	InHead\1	; get write index		;
 		 lda	ACIA\1+A_DATA	; read received character	;
 		 sta	ibuf\1,x	; save char in buffer		;
 		 stzax	ictl\1		; set type to CTL_CHAR		;
 		 inx			;				;
 		 cpx	InTail\1	; buffer full?			;
 		 .if	ne		; no: preserve character:	;
 		  stx	InHead\1	; update index in RAM		;
 		 .end			;				;
 		 and	#$7f		; mask off parity if any	;
 		 cmp	#XOFF		; XOFF from remote host?	;
 		 .if	eq		; yes:				;
 		  lda	XonOff\1	; if XON/XOFF handshaking..	;
 		  sta	OutDisable\1	; ..disable transmitter		;
 		 .end			;				;
 		.end			;				;
 					;				;
 					; BUFFER FULL CHECK WAS HERE	;
 					;				;
 =SEND		lda	ACIA\1+A_SR	; transmit register empty?	;
 		and	#[1<<4]		;				;
 		.if	ne		; yes:				;
 		 ldx	OutCtrl\1	; sending out XON/XOFF?		;
 		 .if	ne		; yes:				;
 		  lda	CIA+C_PB	; check CTS signal		;
 		  and	#[1<<\1]	; (for this port only)		;
 		  bne	=DONE		; not allowed to send -> done	;
 		  stx	ACIA\1+A_DATA	; transmit control char		;
 		  stz	OutCtrl\1	; clear flag			;
 		  jmp	=DONE		; and we're done		;
 		 .end			;				;
 					;				;
 		 ldx	OutTail\1	; anything to transmit?		;
 		 cpx	OutHead\1	;				;
 		 .if	ne		; yes:				;
 		  lda	OutDisable\1	; allowed to transmit?		;
 		  .if	eq		; yes:				;
 		   lda	CIA+C_PB	; check CTS signal		;
 		   and	#[1<<\1]	; (for this port only)		;
 		   bne	=DONE		; not allowed to send -> done	;
 		   lda	obuf\1,x	; get a char from buffer	;
 		   sta	ACIA\1+A_DATA	; send it away			;
 		   inc	OutTail\1	; update read index		;
 		  .end			;				;
 		 .end			;				;
 		.end			;				;
 =DONE		.end	local
 		endm


 PORTVAR		macro	* port number
 		VARDEF	InHead\1 1
 		VARDEF	InTail\1 1
 		VARDEF	OutDisable\1 1
 		VARDEF	OutHead\1 1
 		VARDEF	OutTail\1 1
 		VARDEF	OutCtrl\1 1
 		VARDEF	OutFlush\1 1
 		VARDEF	SetUp\1 1
 		VARDEF	Param\1 1
 		VARDEF	Command\1 1
 		VARDEF	SoftFlow\1 1
 		; private:
 		VARDEF	XonOff\1 1
 		endm


  VARBASE 0	; start variables at address $0000
  PORTVAR 0	; define variables for port 0
  PORTVAR 1	; define variables for port 1
  PORTVAR 2	; define variables for port 2
  PORTVAR 3	; define variables for port 3
  PORTVAR 4	; define variables for port 4
  PORTVAR 5	; define variables for port 5
  PORTVAR 6	; define variables for port 6


  VARDEF	Crystal	1	; 0 = unknown, 1 = normal, 2 = turbo
  VARDEF	Pad_a	1
  VARDEF	TimerH	1
  VARDEF	TimerL	1
  VARDEF	CDHead	1
  VARDEF	CDTail	1
  VARDEF	CDStatus 1
  VARDEF	Pad_b	1

  VARDEF	CommonCDo 1	; for carrier detect optimization
  VARDEF	CommonCDc 1	; for carrier detect debouncing
  VARDEF	CommonCDb 1	; for carrier detect debouncing


  VARBASE $0200
  VARDEF	obuf0 256	; output data (characters only)
  VARDEF	obuf1 256
  VARDEF	obuf2 256
  VARDEF	obuf3 256
  VARDEF	obuf4 256
  VARDEF	obuf5 256
  VARDEF	obuf6 256

  VARDEF	ibuf0 256	; input data (characters, events etc - see ictl)
  VARDEF	ibuf1 256
  VARDEF	ibuf2 256
  VARDEF	ibuf3 256
  VARDEF	ibuf4 256
  VARDEF	ibuf5 256
  VARDEF	ibuf6 256

  VARDEF	ictl0 256	; input control information (type of data in ibuf)
  VARDEF	ictl1 256
  VARDEF	ictl2 256
  VARDEF	ictl3 256
  VARDEF	ictl4 256
  VARDEF	ictl5 256
  VARDEF	ictl6 256

  VARDEF	cdbuf 256	; CD event queue


 ACIA0		equ	$4400
 ACIA1		equ	$4c00
 ACIA2		equ	$5400
 ACIA3		equ	$5c00
 ACIA4		equ	$6400
 ACIA5		equ	$6c00
 ACIA6		equ	$7400

 A_DATA		equ	$00
 A_SR		equ	$02
 A_CMD		equ	$04
 A_CTRL		equ	$06
 ;  00	write transmit data	read received data
 ;  02	reset ACIA		read status register
 ;  04	write command register	read command register
 ;  06	write control register	read control register

 CIA		equ	$7c00		; 8520 CIA
 C_PA		equ	$00		; port A data register
 C_PB		equ	$02		; port B data register
 C_DDRA		equ	$04		; data direction register for port A
 C_DDRB		equ	$06		; data direction register for port B
 C_TAL		equ	$08		; timer A
 C_TAH		equ	$0a
 C_TBL		equ	$0c		; timer B
 C_TBH		equ	$0e
 C_TODL		equ	$10		; TOD LSB
 C_TODM		equ	$12		; TOD middle byte
 C_TODH		equ	$14		; TOD MSB
 C_DATA		equ	$18		; serial data register
 C_INTCTRL	equ	$1a		; interrupt control register
 C_CTRLA		equ	$1c		; control register A
 C_CTRLB		equ	$1e		; control register B


 		section	main,code,CODE-2

 		db	>CODE,<CODE

 ;-----------------------------------------------------------------------;
 ; here's the initialization code:					;
 ;									;
 R_RESET		ldx	#$ff						;
 		txs			; initialize stack pointer	;
 		cld			; in case a 6502 is used...	;
 		ldx	#0		;				;
 		lda	#0		;				;
 		ldy	#Crystal	; this many bytes to clear	;
 clr_loop	sta	0,x		; clear zero page variables	;
 		inx			;				;
 		dey			;				;
 		bne	clr_loop	;				;
 					;				;
 		stz	CommonCDo	; force CD test at boot		;
 		stz	CommonCDb	;				;
 		stz	CDHead		; clear queue			;
 		stz	CDTail		;				;
 					;				;
 		lda	#0		;				;
 		sta	Pad_a		;				;
 		lda	#170		; test cmp			;
 		cmp	#100		;				;
 		.if	cs		;				;
 		 inc	Pad_a		; C was set			;
 		.end			;				;
 									;
 ;-----------------------------------------------------------------------;
 ; Speed check								;
 ;-----------------------------------------------------------------------;
 									;
 		lda	Crystal		; speed already set?		;
 		beq	DoSpeedy	;				;
 		jmp	LOOP		; yes, skip speed test		;
 					;				;
 DoSpeedy	lda	#%10011000	; 8N1, 1200/2400 bps		;
 		sta	ACIA0+A_CTRL	;				;
 		lda	#%00001011	; enable DTR			;
 		sta	ACIA0+A_CMD	;				;
 		lda	ACIA0+A_SR	; read status register		;
 					;				;
 		lda	#%10000000	; disable all ints (unnecessary);
 		sta	CIA+C_INTCTRL	;				;
 		lda	#255		; program the timer		;
 		sta	CIA+C_TAL	;				;
 		sta	CIA+C_TAH	;				;
 					;				;
 		ldx	#0		;				;
 		stx	ACIA0+A_DATA	; transmit a zero		;
 		nop			;				;
 		nop			;				;
 		lda	ACIA0+A_SR	; read status			;
 		nop			;				;
 		nop			;				;
 		stx	ACIA0+A_DATA	; transmit a zero		;
 Speedy1		lda	ACIA0+A_SR	; read status			;
 		and	#[1<<4]		; transmit data reg empty?	;
 		beq	Speedy1		; not yet, wait more		;
 					;				;
 		lda	#%00010001	; load & start the timer	;
 		stx	ACIA0+A_DATA	; transmit one more zero	;
 		sta	CIA+C_CTRLA	;				;
 Speedy2		lda	ACIA0+A_SR	; read status			;
 		and	#[1<<4]		; transmit data reg empty?	;
 		beq	Speedy2		; not yet, wait more		;
 		stx	CIA+C_CTRLA	; stop the timer		;
 					;				;
 		lda	CIA+C_TAL	; copy timer value for 68k	;
 		sta	TimerL		;				;
 		lda	CIA+C_TAH	;				;
 		sta	TimerH		;				;
 		cmp	#$d0		; turbo or normal?		;
 		.if	cs		;				;
 		 lda	#2		; turbo! :-)			;
 		.else			;				;
 		 lda	#1		; normal :-(			;
 		.end			;				;
 		sta	Crystal		;				;
 		lda	#0		;				;
 		sta	ACIA0+A_SR	;				;
 		sta	ACIA0+A_CTRL	; reset UART			;
 		sta	ACIA0+A_CMD	;				;
 									;
 		jmp	LOOP						;
 									;
 ;									;
 ;-----------------------------------------------------------------------;
 ;									;
 ; The Real Thing:							;
 ;									;
 LOOP		DO_SLOW			; do non-critical things	;
 		jsr	do_input	; check for received data
 		DO_PORT	0
 		jsr	do_input
 		DO_PORT	1
 		jsr	do_input
 		DO_PORT	2
 		jsr	do_input
 		DO_PORT	3
 		jsr	do_input
 		DO_PORT	4
 		jsr	do_input
 		DO_PORT	5
 		jsr	do_input
 		DO_PORT	6
 		jsr	do_input
 		jmp	LOOP


 do_input	DO_DATA	0
 		DO_DATA	1
 		DO_DATA	2
 		DO_DATA	3
 		DO_DATA	4
 		DO_DATA	5
 		DO_DATA	6
 		rts


 ;-----------------------------------------------------------------------;
 		section	vectors,data,$3ffa
 		dw	$d0d0
 		dw	R_RESET
 		dw	$c0ce
 ;-----------------------------------------------------------------------;


 		end
	;.lib "axm"
	;
	;begin
	;title "A2232 serial board driver"
	;
	;set modules "2232"
	;set executable "2232.bin"
	;
	;;;;set nolink
	;
	;set temporary directory "t:"
	;
	;set assembly options "-m6502 -l60:t:list"
	;set link options "bin"; loadadr"
	;;;bin2c 2232.bin msc6502.h msc6502code
	;end
	;
	;
	; ### Commodore A2232 serial board driver for NetBSD by JM v1.3 ###
	;
	; - Created 950501 by JM -
	;
	;
	; Serial board driver software.
	;
	;
	% Copyright (c) 1995 Jukka Marin <jmarin@jmp.fi>.
	% All rights reserved.
	%
	% Redistribution and use in source and binary forms, with or without
	% modification, are permitted provided that the following conditions
	% are met:
	% 1. Redistributions of source code must retain the above copyright
	% notice, and the entire permission notice in its entirety,
	% including the disclaimer of warranties.
	% 2. Redistributions in binary form must reproduce the above copyright
	% notice, this list of conditions and the following disclaimer in the
	% documentation and/or other materials provided with the distribution.
	% 3. The name of the author may not be used to endorse or promote
	% products derived from this software without specific prior
	% written permission.
	%
	% ALTERNATIVELY, this product may be distributed under the terms of
	% the GNU General Public License, in which case the provisions of the
	% GPL are required INSTEAD OF the above restrictions. (This clause is
	% necessary due to a potential bad interaction between the GPL and
	% the restrictions contained in a BSD-style copyright.)
	%
	% THIS SOFTWARE IS PROVIDED `AS IS'' AND ANY EXPRESS OR IMPLIED
	% WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	% OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	% DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
	% INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	% (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	% SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	% HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	% STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
	% OF THE POSSIBILITY OF SUCH DAMAGE.
	;
	;
	; Bugs:
	;
	; - Can't send a break yet
	;
	;
	;
	; Edited:
	;
	; - 950501 by JM -> v0.1 - Created this file.
	; - 951029 by JM -> v1.3 - Carrier Detect events now queued in a separate
	; queue.
	;
	;


	CODE equ $3800 ; start address for program code


	CTL_CHAR equ $00 ; byte in ibuf is a character
	CTL_EVENT equ $01 ; byte in ibuf is an event

	EVENT_BREAK equ $01
	EVENT_CDON equ $02
	EVENT_CDOFF equ $03
	EVENT_SYNC equ $04

	XON equ $11
	XOFF equ $13


	VARBASE macro *starting_address ; was VARINIT
	_varbase set \1
	endm

	VARDEF macro *name space_needs
	\1 equ _varbase
	_varbase set _varbase+\2
	endm


	stz macro * address
	db $64,\1
	endm

	stzax macro * address
	db $9e,<\1,>\1
	endm


	biti macro * immediate value
	db $89,\1
	endm

	smb0 macro * address
	db $87,\1
	endm
	smb1 macro * address
	db $97,\1
	endm
	smb2 macro * address
	db $a7,\1
	endm
	smb3 macro * address
	db $b7,\1
	endm
	smb4 macro * address
	db $c7,\1
	endm
	smb5 macro * address
	db $d7,\1
	endm
	smb6 macro * address
	db $e7,\1
	endm
	smb7 macro * address
	db $f7,\1
	endm



	;-----------------------------------------------------------------------;
	; ;
	; stuff common for all ports, non-critical (run once / loop) ;
	; ;
	DO_SLOW macro * port_number ;
	.local ; ;
	lda CIA+C_PA ; check all CD inputs ;
	cmp CommonCDo ; changed from previous accptd? ;
	beq =over ; nope, do nothing else here ;
	; ;
	cmp CommonCDb ; bouncing? ;
	beq =nobounce ; nope -> ;
	; ;
	sta CommonCDb ; save current state ;
	lda #64 ; reinitialize counter ;
	sta CommonCDc ; ;
	jmp =over ; skip CD save ;
	; ;
	=nobounce dec CommonCDc ; no, decrement bounce counter ;
	bpl =over ; not done yet, so skip CD save ;
	; ;
	=saveCD ldx CDHead ; get write index ;
	sta cdbuf,x ; save status in buffer ;
	inx ; ;
	cpx CDTail ; buffer full? ;
	.if ne ; no: preserve status: ;
	stx CDHead ; update index in RAM ;
	sta CommonCDo ; save state for the next check ;
	.end ; ;
	=over .end local ;
	endm ;
	;
	;-----------------------------------------------------------------------;


	; port specific stuff (no data transfer)

	DO_PORT macro * port_number
	.local ; ;
	lda SetUp\1 ; reconfiguration request? ;
	.if ne ; yes: ;
	lda SoftFlow\1 ; get XON/XOFF flag ;
	sta XonOff\1 ; save it ;
	lda Param\1 ; get parameter ;
	ora #%00010000 ; use baud generator for Rx ;
	sta ACIA\1+A_CTRL ; store in control register ;
	stz OutDisable\1 ; enable transmit output ;
	stz SetUp\1 ; no reconfiguration no more ;
	.end ; ;
	; ;
	lda InHead\1 ; get write index ;
	sbc InTail\1 ; buffer full soon? ;
	cmp #200 ; 200 chars or more in buffer? ;
	lda Command\1 ; get Command reg value ;
	and #%11110011 ; turn RTS OFF by default ;
	.if cc ; still room in buffer: ;
	ora #%00001000 ; turn RTS ON ;
	.end ; ;
	sta ACIA\1+A_CMD ; set/clear RTS ;
	; ;
	lda OutFlush\1 ; request to flush output buffer;
	.if ne ; yessh! ;
	lda OutHead\1 ; get head ;
	sta OutTail\1 ; save as tail ;
	stz OutDisable\1 ; enable transmit output ;
	stz OutFlush\1 ; clear request ;
	.end
	.end local
	endm


	DO_DATA macro * port number
	.local
	lda ACIA\1+A_SR ; read ACIA status register ;
	biti [1<<3] ; something received? ;
	.if ne ; yes: ;
	biti [1<<1] ; framing error? ;
	.if ne ; yes: ;
	lda ACIA\1+A_DATA ; read received character ;
	bne =SEND ; not break -> ignore it ;
	ldx InHead\1 ; get write pointer ;
	lda #CTL_EVENT ; get type of byte ;
	sta ictl\1,x ; save it in InCtl buffer ;
	lda #EVENT_BREAK ; event code ;
	sta ibuf\1,x ; save it as well ;
	inx ; ;
	cpx InTail\1 ; still room in buffer? ;
	.if ne ; absolutely: ;
	stx InHead\1 ; update index in memory ;
	.end ; ;
	jmp =SEND ; go check if anything to send ;
	.end ; ;
	; normal char received: ;
	ldx InHead\1 ; get write index ;
	lda ACIA\1+A_DATA ; read received character ;
	sta ibuf\1,x ; save char in buffer ;
	stzax ictl\1 ; set type to CTL_CHAR ;
	inx ; ;
	cpx InTail\1 ; buffer full? ;
	.if ne ; no: preserve character: ;
	stx InHead\1 ; update index in RAM ;
	.end ; ;
	and #$7f ; mask off parity if any ;
	cmp #XOFF ; XOFF from remote host? ;
	.if eq ; yes: ;
	lda XonOff\1 ; if XON/XOFF handshaking.. ;
	sta OutDisable\1 ; ..disable transmitter ;
	.end ; ;
	.end ; ;
	; ;
	; BUFFER FULL CHECK WAS HERE ;
	; ;
	=SEND lda ACIA\1+A_SR ; transmit register empty? ;
	and #[1<<4] ; ;
	.if ne ; yes: ;
	ldx OutCtrl\1 ; sending out XON/XOFF? ;
	.if ne ; yes: ;
	lda CIA+C_PB ; check CTS signal ;
	and #[1<<\1] ; (for this port only) ;
	bne =DONE ; not allowed to send -> done ;
	stx ACIA\1+A_DATA ; transmit control char ;
	stz OutCtrl\1 ; clear flag ;
	jmp =DONE ; and we're done ;
	.end ; ;
	; ;
	ldx OutTail\1 ; anything to transmit? ;
	cpx OutHead\1 ; ;
	.if ne ; yes: ;
	lda OutDisable\1 ; allowed to transmit? ;
	.if eq ; yes: ;
	lda CIA+C_PB ; check CTS signal ;
	and #[1<<\1] ; (for this port only) ;
	bne =DONE ; not allowed to send -> done ;
	lda obuf\1,x ; get a char from buffer ;
	sta ACIA\1+A_DATA ; send it away ;
	inc OutTail\1 ; update read index ;
	.end ; ;
	.end ; ;
	.end ; ;
	=DONE .end local
	endm



	PORTVAR macro * port number
	VARDEF InHead\1 1
	VARDEF InTail\1 1
	VARDEF OutDisable\1 1
	VARDEF OutHead\1 1
	VARDEF OutTail\1 1
	VARDEF OutCtrl\1 1
	VARDEF OutFlush\1 1
	VARDEF SetUp\1 1
	VARDEF Param\1 1
	VARDEF Command\1 1
	VARDEF SoftFlow\1 1
	; private:
	VARDEF XonOff\1 1
	endm


	VARBASE 0 ; start variables at address $0000
	PORTVAR 0 ; define variables for port 0
	PORTVAR 1 ; define variables for port 1
	PORTVAR 2 ; define variables for port 2
	PORTVAR 3 ; define variables for port 3
	PORTVAR 4 ; define variables for port 4
	PORTVAR 5 ; define variables for port 5
	PORTVAR 6 ; define variables for port 6



	VARDEF Crystal 1 ; 0 = unknown, 1 = normal, 2 = turbo
	VARDEF Pad_a 1
	VARDEF TimerH 1
	VARDEF TimerL 1
	VARDEF CDHead 1
	VARDEF CDTail 1
	VARDEF CDStatus 1
	VARDEF Pad_b 1

	VARDEF CommonCDo 1 ; for carrier detect optimization
	VARDEF CommonCDc 1 ; for carrier detect debouncing
	VARDEF CommonCDb 1 ; for carrier detect debouncing


	VARBASE $0200
	VARDEF obuf0 256 ; output data (characters only)
	VARDEF obuf1 256
	VARDEF obuf2 256
	VARDEF obuf3 256
	VARDEF obuf4 256
	VARDEF obuf5 256
	VARDEF obuf6 256

	VARDEF ibuf0 256 ; input data (characters, events etc - see ictl)
	VARDEF ibuf1 256
	VARDEF ibuf2 256
	VARDEF ibuf3 256
	VARDEF ibuf4 256
	VARDEF ibuf5 256
	VARDEF ibuf6 256

	VARDEF ictl0 256 ; input control information (type of data in ibuf)
	VARDEF ictl1 256
	VARDEF ictl2 256
	VARDEF ictl3 256
	VARDEF ictl4 256
	VARDEF ictl5 256
	VARDEF ictl6 256

	VARDEF cdbuf 256 ; CD event queue


	ACIA0 equ $4400
	ACIA1 equ $4c00
	ACIA2 equ $5400
	ACIA3 equ $5c00
	ACIA4 equ $6400
	ACIA5 equ $6c00
	ACIA6 equ $7400

	A_DATA equ $00
	A_SR equ $02
	A_CMD equ $04
	A_CTRL equ $06
	; 00 write transmit data read received data
	; 02 reset ACIA read status register
	; 04 write command register read command register
	; 06 write control register read control register

	CIA equ $7c00 ; 8520 CIA
	C_PA equ $00 ; port A data register
	C_PB equ $02 ; port B data register
	C_DDRA equ $04 ; data direction register for port A
	C_DDRB equ $06 ; data direction register for port B
	C_TAL equ $08 ; timer A
	C_TAH equ $0a
	C_TBL equ $0c ; timer B
	C_TBH equ $0e
	C_TODL equ $10 ; TOD LSB
	C_TODM equ $12 ; TOD middle byte
	C_TODH equ $14 ; TOD MSB
	C_DATA equ $18 ; serial data register
	C_INTCTRL equ $1a ; interrupt control register
	C_CTRLA equ $1c ; control register A
	C_CTRLB equ $1e ; control register B





	section main,code,CODE-2

	db >CODE,<CODE

	;-----------------------------------------------------------------------;
	; here's the initialization code: ;
	; ;
	R_RESET ldx #$ff ;
	txs ; initialize stack pointer ;
	cld ; in case a 6502 is used... ;
	ldx #0 ; ;
	lda #0 ; ;
	ldy #Crystal ; this many bytes to clear ;
	clr_loop sta 0,x ; clear zero page variables ;
	inx ; ;
	dey ; ;
	bne clr_loop ; ;
	; ;
	stz CommonCDo ; force CD test at boot ;
	stz CommonCDb ; ;
	stz CDHead ; clear queue ;
	stz CDTail ; ;
	; ;
	lda #0 ; ;
	sta Pad_a ; ;
	lda #170 ; test cmp ;
	cmp #100 ; ;
	.if cs ; ;
	inc Pad_a ; C was set ;
	.end ; ;
	;
	;-----------------------------------------------------------------------;
	; Speed check ;
	;-----------------------------------------------------------------------;
	;
	lda Crystal ; speed already set? ;
	beq DoSpeedy ; ;
	jmp LOOP ; yes, skip speed test ;
	; ;
	DoSpeedy lda #%10011000 ; 8N1, 1200/2400 bps ;
	sta ACIA0+A_CTRL ; ;
	lda #%00001011 ; enable DTR ;
	sta ACIA0+A_CMD ; ;
	lda ACIA0+A_SR ; read status register ;
	; ;
	lda #%10000000 ; disable all ints (unnecessary);
	sta CIA+C_INTCTRL ; ;
	lda #255 ; program the timer ;
	sta CIA+C_TAL ; ;
	sta CIA+C_TAH ; ;
	; ;
	ldx #0 ; ;
	stx ACIA0+A_DATA ; transmit a zero ;
	nop ; ;
	nop ; ;
	lda ACIA0+A_SR ; read status ;
	nop ; ;
	nop ; ;
	stx ACIA0+A_DATA ; transmit a zero ;
	Speedy1 lda ACIA0+A_SR ; read status ;
	and #[1<<4] ; transmit data reg empty? ;
	beq Speedy1 ; not yet, wait more ;
	; ;
	lda #%00010001 ; load & start the timer ;
	stx ACIA0+A_DATA ; transmit one more zero ;
	sta CIA+C_CTRLA ; ;
	Speedy2 lda ACIA0+A_SR ; read status ;
	and #[1<<4] ; transmit data reg empty? ;
	beq Speedy2 ; not yet, wait more ;
	stx CIA+C_CTRLA ; stop the timer ;
	; ;
	lda CIA+C_TAL ; copy timer value for 68k ;
	sta TimerL ; ;
	lda CIA+C_TAH ; ;
	sta TimerH ; ;
	cmp #$d0 ; turbo or normal? ;
	.if cs ; ;
	lda #2 ; turbo! :-) ;
	.else ; ;
	lda #1 ; normal :-( ;
	.end ; ;
	sta Crystal ; ;
	lda #0 ; ;
	sta ACIA0+A_SR ; ;
	sta ACIA0+A_CTRL ; reset UART ;
	sta ACIA0+A_CMD ; ;
	;
	jmp LOOP ;
	;
	; ;
	;-----------------------------------------------------------------------;
	; ;
	; The Real Thing: ;
	; ;
	LOOP DO_SLOW ; do non-critical things ;
	jsr do_input ; check for received data
	DO_PORT 0
	jsr do_input
	DO_PORT 1
	jsr do_input
	DO_PORT 2
	jsr do_input
	DO_PORT 3
	jsr do_input
	DO_PORT 4
	jsr do_input
	DO_PORT 5
	jsr do_input
	DO_PORT 6
	jsr do_input
	jmp LOOP


	do_input DO_DATA 0
	DO_DATA 1
	DO_DATA 2
	DO_DATA 3
	DO_DATA 4
	DO_DATA 5
	DO_DATA 6
	rts


	;-----------------------------------------------------------------------;
	section vectors,data,$3ffa
	dw $d0d0
	dw R_RESET
	dw $c0ce
	;-----------------------------------------------------------------------;



	end