AMRPT.ASM

	TITLE	'AMRAD PACKET REPEATER V1.0'
;
;  ASSEMBLED 26 NOV 1981
;
;  PROGRAM TO RUN IN THE VADCG TERMINAL NODE CONTROLLER AND
;  REPEAT PACKETS RECIEVED WHICH HAVE THE FOLLOWING ADDRESSES:
;
;  10XXXXXX
;
;  WHERE THE MSB IS THE "REQUEST FOR REPEAT" BIT, THE NEXT
;  BIT IS THE "REPEATED" BIT AND THE REMAINING BITS ARE THE
;  UNIQUE USER ADDRESS.
;
;  J. R. BLOOM KE3Z  - 26 NOV 1981
;

	MACLIB	LIB85	; 8085 MACRO LIBRARY

;  DELAY PARAMETERS - SET "DELAY" TO 1 TO ASSEMBLE THE
;  TX TURN ON DELAY.  MAKE "DLYVAL" EQUAL TO THE DELAY
;  TIME.
;  SET "CBDLY" TO 1 TO ASSEMBLE THE CHANNEL BUSY
;  DELAY.  SET "CBDLYV" TO THE DELAY VALUE.
;  SET "IDTIME" TO THE NUMBER OF SECONDS BETWEEN ID'S.

DELAY	EQU	1
DLYVAL	EQU	4000H
CBDLY	EQU	1
CBDLYV	EQU	1500H
IDTIME	EQU	480	;ID DELAY IN SECONDS
SECOND	EQU	22306	; # CWCHEKS IN SECOND

;  CONFIGURATION EQUATES

BUFSIZ	EQU	128	;MAXIMUM PACKET SIZE
MAXPKT	EQU	7	;MAXIMUM # PACKETS TO BUFFER

;  RAM MEMORY EQUATES

LORAM	EQU	1000H	;BOTTOM OF MEMORY
HIRAM	EQU	1FFFH	;TOP OF MEMORY

;  PROCESSING STATUS ("PROCST") BIT EQUATES

TXBUSY	EQU	01H	;TRANSMITTER BUSY
TXOCUR	EQU	02H	;TRANSMISSION OCCURRED SINCE ID
CWIP	EQU	04H	;CW ID IN PROGRESS
ACTDET	EQU	08H	;CHANNEL ACTIVITY DETECTED
	PAGE
;  CW ID TIMING EQUATES

CW96	EQU	64
CW48	EQU	32
CW24	EQU	16
CW12	EQU	8
CW06	EQU	4
CW03	EQU	2
CW015	EQU	1
CW007	EQU	1

;  SET CW ID TIMER FOR BAUD RATE USED

IDNUM	EQU	CW12

;  8273 PORT EQUATES

STAT73	EQU	10H	;STATUS REG
COMM73	EQU	10H	;COMMAND REG
PARM73	EQU	11H	;PARAMETER REG
RESL73	EQU	11H	;RESULT REG
TXIR73	EQU	12H	;TX INTERRUPT RESULT REG
RXIR73	EQU	13H	;RX INTERRUPT RESULR REG
TXDATA	EQU	18H	;OUTPUT DATA REG
RXDATA	EQU	20H	;INPUT DATA REG

;  8273 REGISTER EQUATES

CPBF	EQU	20H	;STATUS REG PARM BUF FULL
CRBF	EQU	10H	;STATUS REG RESULT BUF FULL
RINT	EQU	08H	;RX INT PENDING
TINT	EQU	04H	;TX INT PENDING
RXIRA	EQU	02H	;RX INT RESULT AVAILABLE
TXIRA	EQU	01H	;TX INT RESULT AVAILABLE
CD	EQU	02H	;PORT A CARRIER DETECT
	PAGE
;  INTERRUPT VECTORS AT BOTTOM OF MEMORY

	ORG	0
RESTRT: JMP	REPEAT
	ORG	08H
	RET		;NO RST 1
	ORG	10H
	RET		;NO RST 2
	ORG	18H
	RET		;NO RST 3
	ORG	20H
	RET		;NO RST 4
	ORG	24H
	RET		;NO TRAP
	ORG	28H
	RET		;NO RST 5
	ORG	2CH
	RET		;NO RST 5.5 (8250)
	ORG	30H
	RET		;NO RST 6
	ORG	34H
	JMP	TXINT	; 8273 TX INTERRUPT
	ORG	38H
	RET		;NO RST 7
	ORG	3CH
	JMP	RXINT	; 8273 RX INTERRUPT

;  ID STRING - BITS OF CW ID

IDSTR:	DB	0EH,0B8H,0EEH,0EAH,3BH,8EH,0E3H
	DB	0BBH,8EH,0AEH,8BH,0A0H
IDBYTS	EQU	$-IDSTR ;SIZE OF ID STRING
IDLTH	EQU	IDBYTS*IDNUM*8

;  8273 COMMAND STRINGS = PARM COUNT, COMMAND, PARMS

DATTRN: DB	1,97H,1 ;DATA TRANSPARENT MODE
OPMODE: DB	1,91H,0BH ;NO HDLC ABT, NO EOP, EARLY TX INT,
			  ;UNBUFFERED, SYNC, FLAG IDLE
SERIO:	DB	1,0A0H,1 ;NRZI MODE
DTRON:	DB	1,0A3H,4 ;DATA TERMINAL READY ON
SETRTS: DB	1,0A3H,1 ;RTS ON (TRANSMITTING)
RESRTS: DB	1,63H,0FEH ;RTS OFF (STOP TRANSMITTING)
RXGEN:	DB	2,0C0H,BUFSIZ+2,0 ;GENERAL RECEIVE
RDPA:	DB	0,22H	;READ PORT A BITS
RXDIS:	DB	0,0C5H	;DISABLE RECEIVER
TXCWID: DB	2,0C9H	;TX CW ID
	DW	IDLTH
CWOPMD: DB	1,60H,0F8H ;NO PRE-FRAME SYNC
CWSIO:	DB	1,51H,9 ;NRZL
	PAGE
;  BEACON DATA - CREATE UP TO MAXPKT PACKET
;  STRINGS AND ENTER THE STRING ADDR AND LENGTH
;  IN BCNTAB.  DON'T FORGET THE ADDRESS AND CONTROL

BCN1:	DB	0FFH,3,'   DE K8MMO/R',0DH,0AH
LBCN1	EQU	$-BCN1
BCN2:	DB	0FFH,3,'   HDLC PACKET REPEATER',0DH,0AH
LBCN2	EQU	$-BCN2
BCN3:	DB	0FFH,3,'   AMRAD',0DH,0AH
LBCN3	EQU	$-BCN3

;  BEACON PACKET TABLE

BCNTAB:
	DW	BCN1
	DB	LBCN1
	DW	BCN2
	DB	LBCN2
	DW	BCN3
	DB	LBCN3
NUMBCN	EQU	($-BCNTAB)/3
	PAGE
REPEAT:
	DI		;NO INT YET PLEASE

;  ZERO RAM

	LXI	D,HIRAM ;END OF RAM (STOP ADDRESS)
	LXI	H,LORAM ;BEGINNING OF RAM (START ADDRESS)
RPT010:
	MVI	M,0	;ZERO NEXT BYTE OF RAM
	INX	H
	MOV	A,D	;HIGH BYTE EQUAL?
	CMP	H
	JNZ	RPT010	;NO, KEEP ZEROING
	MOV	A,E	;LOW BYTE EQUAL?
	CMP	L
	JNZ	RPT010	;NO, KEEP ZEROING
	LXI	SP,STACK ;INIT SYSTEM STACK

;  SET UP 8273

	LXI	H,DATTRN
	CALL	COMMAND
	LXI	H,OPMODE
	CALL	COMMAND
	LXI	H,SERIO
	CALL	COMMAND
	LXI	H,DTRON
	CALL	COMMAND
	MVI	A,19H	;ENABLE RST 6.5 AND 7.5
	SIM
	EI		;OK FOR INTERRUPTS

;  HERE WHEN WAITING TO RECEIVE PACKETS

RPT050:
	LXI	H,BUFFER ;INIT TO FIRST BUFFER
	SHLD	BUFPTR
	CALL	RXSET	;SET UP AND ISSUE RX COMMAND

;  WAITING FOR PACKET TO ARRIVE

RPT060:
	CALL	CWCHEK	;CHECK IF ID NEEDED
	LDA	NUMPKT	;GET # PACKETS RECEIVED
	ORA	A	;NO PACKET YET?
	JZ	RPT060	;NOT YET, KEEP WAITING
	PAGE
;  PACKET(S) RECEIVED - WAIT FOR CARRIER TO GO AWAY

RPT070:
	CALL	CHKBSY	;SEE IF CHANNEL BUSY
	JNZ	RPT060	;YES, WAIT FOR IT TO CLEAR
	IF	CBDLY
	LXI	H,CBDLYV ;SET UP TIMER
	SHLD	TIME
	CALL	TIMER
	CALL	CHKBSY	;CHECK CHANNEL AGAIN
	JNZ	RPT070	;BUSY AGAIN, WAIT SOME MORE
	ENDIF

;  HERE TO SET UP FOR PACKET TRANSMISSION

	LDA	PROCST	;GET PROCESSING STATUS
	ORI	TXBUSY+TXOCUR ;SHOW TRANSMITTING
	STA	PROCST
	LXI	H,SETRTS ;TURN ON TX
	CALL	COMMAND
	IF	DELAY
	LXI	H,DLYVAL ;SETUP DELAY TIMER
	SHLD	TIME
	CALL	TIMER	;WAIT FOR TIME OUT
	ENDIF
	LXI	H,NUMPKT
	MOV	B,M	;B = PACKET COUNTER
	LXI	H,BUFFER ;INITIAL BUFFER TO SEND
	PAGE
;  PACKET SENDING LOOP - CALLS TXPKT TO DO THE WORK.
;  AFTER EACH PACKET SENT, DECREMENTS PACKET COUNT (B)
;  AND, IF NOT 0, SENDS ANOTHER PACKET.

RPT080:
	SHLD	BUFPTR	;POINTER TO CURRENT BUFFER
	CALL	TXPKT	;TRANSMIT THE PACKET
	LXI	D,BUFSIZ+3 ;INCREMENT TO NEXT BUFFER
	LHLD	BUFPTR	;CURRENT BUFFER PTR
	DAD	D
	DCR	B	;ALL PACKETS SENT YET?
	JNZ	RPT080	;NO, KEEP SENDING

;  RE-INITIALIZE NUMBER OF PACKETS TO 0 AND START OVER

RPT090:
	LDA	TXWAIT	;HAS FINAL TX INT OCCURRED?
	CPI	2
	JNZ	RPT090	;NO, WAIT FOR COMPLETION
	LXI	H,RESRTS ;STOP TRANSMITTING
	CALL	COMMAND
	LDA	PROCST	;GET PROCESSING STATUS
	ANI	0FEH	;SHOW NOT TRANSMITTING
	STA	PROCST
	XRA	A
	STA	NUMPKT
	JMP	RPT050
	PAGE
;  TRANSMISSION ROUTINES

;  TXPKT - DISABLES RECEIVER, COMMANDS 8273 TO SEND
;  A PACKET AND WAITS FOR PACKET COMPLETION

TXPKT:
	PUSH	B
	XCHG		;SAVE HL IN DE
	LXI	H,RXDIS ;DISABLE RECEIVER
	CALL	COMMAND
	LXI	H,CMDBUF ;WHERE TO BUILD COMMAND
	MVI	M,2	;TWO PARAMETERS
	INX	H
	MVI	M,0C8H	;TX FRAME COMMAND
	INX	H
	LDAX	D	;GET PACKET LENGTH
	INX	D	;POINT TO PACKET DATA
	MOV	M,A
	INX	H
	MVI	M,0	;MS BYTE OF LENGTH
	XCHG		;HL = PACKET POINTER
	MOV	A,M	;GET ADDRESS
	ORI	0C0H	;REPEATED BIT SET
	MOV	M,A
	SHLD	PKTPTR
	XRA	A	;WAIT FLAG RESET
	STA	TXWAIT
	LXI	H,CMDBUF ;COMMAND 8273 TO TRANSMIT FRAME
	CALL	COMMAND

;  WAIT FOR END OF PACKET TRANSMISSION

TXP010:
	CALL	CWCHEK	;DEC CW ID TIMER
	LDA	TXWAIT	;CHECK WAIT FLAG
	ORA	A
	JZ	TXP010	;KEEP WAITING
	POP	B
	RET		;ALL DONE
	PAGE
;  TRANSMIT INTERRUPT SERVICE ROUTINE

TXINT:
	PUSH	H	;SAVE REGISTERS
	PUSH	B
	PUSH	PSW
	LDA	PROCST	;GET PROCESSING STATUS
	ANI	CWIP	;CW ID INT?
	JNZ	IDINT	;YES, PROCESS IT
	IN	STAT73	;END OF PACKET OR DATA INT?
	ANI	TXIRA
	JNZ	TXI010	;END OF PACKET - GO PROCESS
	LHLD	PKTPTR	;GET DATA POINTER
	MOV	A,M	;GET NEXT BYTE OF DATA
	INX	H
	SHLD	PKTPTR
	OUT	TXDATA	;SEND DATA BYTE TO 8273
	JMP	TXI020	;RETURN

;  END OF PACKET - SET WAIT FLAG

TXI010:
	IN	TXIR73	;GET THE STATUS
	CPI	0CH	;EARLY TX INT?
	JNZ	TXI015	;NO, FINAL INTERRUPT
	MVI	A,1	;FLAG EARLY TX INT
	JMP	TXI019
TXI015:
	MVI	A,02H
TXI019:
	STA	TXWAIT
TXI020:
	POP	PSW	;RESTORE REGS
	POP	B
	POP	H
	EI		;INTS OK AGAIN
	RET
	PAGE
;  SET UP FOR RECEIVE

RXSET:
	LHLD	BUFPTR	;POINT TO CURRENT BUFFER
	MVI	M,0	;COUNT = 0
	INX	H	;FIRST DATA BYTE
	SHLD	PKTPTR
	LXI	H,RXGEN ;COMMAND 8273 TO RECEIVE
	CALL	COMMAND
	RET
	PAGE
;  RECEIVE INTERRUPT SERVICE

RXINT:
	PUSH	H	;SAVE REGISTERS
	PUSH	B
	PUSH	PSW
	IN	STAT73	;END OF PACKET OR DATA INT?
	ANI	RXIRA
	JNZ	RXI010	;END OF PACKET - PROCESS IT
	LHLD	PKTPTR	;DATA POINTER
	IN	RXDATA	;GET NEXT DATA BYTE
	MOV	M,A	;STORE IN BUFFER
	INX	H
	SHLD	PKTPTR
	JMP	RXI030	;RETURN

;  HERE AT END OF PACKET.  GET THE INTERRUPT STATUS
;  AND THE RESULTS (RECEIVED BUFFER LENGTH).

RXI010:
	IN	RXIR73	;GET INT RESULTS
	MOV	C,A	;SAVE THE RESULT STATUS
RXI015:
	IN	STAT73	;RX INT STILL PENDING?
	ANI	RINT
	JZ	RXI017	;NO, GO CHECK INT RESULT
	IN	STAT73	;CHECK FOR INT RES AVAIL. AGAIN
	ANI	RXIRA	;INT RESULT AVAIL. AGAIN?
	JZ	RXI015	;NO, KEEP WAITING
	IN	RXIR73	;GET LOW BYTE OF COUNT
	LHLD	BUFPTR
	MOV	M,A	;STORE COUNT
RXI016:
	IN	STAT73	;STILL PENDING?
	ANI	RINT
	JZ	RXI017	;NO, GO CHECK STATUS
	IN	STAT73	;RESULT AVAILABLE?
	ANI	RXIRA
	JZ	RXI016	;NO, KEEP WAITING
	IN	RXIR73	;GET (AND IGNORE) RESULT BYTE
	JMP	RXI016
	PAGE
;  CHECK THE RX STATUS.	 IF IT SHOWS A GOOD FRAME,
;  CHECK FOR VALID ADDRESS (10XXXXXX) AND, IF SO,
;  UPDATE THE BUFFER POINTER AND NUMBER OF PACKETS
;  COUNT.

RXI017:
	MOV	A,C	;RESTORE RESULTS
	CPI	0E0H	;GOOD STATUS?
	JC	RXI020	;NO, RESCHEDULE RX
	LDA	PROCST	;GET PROCESSING STATUS
	ORI	ACTDET	;SHOW CHANNEL ACTIVITY
	STA	PROCST
	LHLD	BUFPTR	;GET BUFFER POINTER
	INX	H	;POINT TO ADDRESS BYTE
	MOV	A,M
	DCX	H
	ANI	0C0H	;MASK OFF ALL BUT RPT BITS
	CPI	080H	;WANTS RPT BUT NOT FROM RPTR?
	JNZ	RXI020	;NO, IGNORE THE PACKET
	LXI	B,BUFSIZ+3
	DAD	B
	SHLD	BUFPTR
	LXI	H,NUMPKT ;ANOTHER PACKET AVAILABLE
	INR	M

;  HERE TO RE-SCHEDULE RECEPTION.  IF "MAXPKT"
;  PACKETS HAVE BEEN RECEIVED, DISABLE THE RECEIVER.
;  OTHERWISE, COMMAND THE 8273 TO RECEIVE AGAIN.

RXI020:
	LDA	NUMPKT
	CPI	MAXPKT	;MAXIMUM # PACKETS IN YET?
	JC	RXI025	;NO, RX ANOTHER
	LXI	H,RXDIS ;STOP RECEIVING
	CALL	COMMAND
	JMP	RXI030
RXI025:
	CALL	RXSET
RXI030:
	POP	PSW	;RESTORE REGS
	POP	B
	POP	H
	EI
	RET
	PAGE
;  SUBROUTINES

;  COMMAND - OUTPUT COMMAND AND PARAMETERS TO 8273

COMMAND:
	MOV	B,M	;GET # PARAMETERS
	INX	H
CMD010:
	IN	STAT73	;CAN WE COMMAND?
	RLC
	JC	CMD010	;NO, KEEP WAITING
	MOV	A,M	;GET COMMAND
	OUT	COMM73
CMD020:
	MOV	A,B	;ANY PARAMETERS?
	ANA	A
	RZ		;NO, RETURN
	INX	H	;POINT TO NEXT PARM
	DCR	B
CMD030:
	IN	STAT73	;OK TO STUFF PARM INTO 8273?
	ANI	CPBF
	JNZ	CMD030	;NO, KEEP WAITING
	MOV	A,M	;GET PARM
	OUT	PARM73
	JMP	CMD020

;  RESULT ROUTINE - RETURNS 8273 RESULT REG

RESULT:
	IN	STAT73	;OK TO READ RESULT REG?
	ANI	CRBF
	JZ	RESULT
	IN	RESL73
	RET
	PAGE
;  TIMING SUBROUTINES

;  TIMER - COUNTS DOWN TIME VALUE IN "TIME"

TIMER:
	CALL	TIMER1	;WAIT ONE COUNT
	JNZ	TIMER	;GO AGAIN IF NOT TIMED OUT
	RET
TIMER1:
	LHLD	TIME	;GET TIMER VALUE
	DCX	H	;COUNT DOWN ONCE
	SHLD	TIME
	MOV	A,H	;CHECK FOR ZERO VALUE
	ORA	L
	RET

;  CHKBSY - CHECK TO SEE IF CHANNEL BUSY

CHKBSY:
	LXI	H,RDPA	;TELL 8273 TO READ PORT A
	CALL	COMMAND
	CALL	RESULT	;GET THE STATUS BITS
	ANI	CD	;LOOK AT CARRIER DETECT
	RET		;(Z SET IF CHANNEL FREE)
	PAGE

;  CW ID CHECKER

CWCHEK:
	LHLD	CWSEC	;GET SECOND COUNT
	MOV	A,H
	ORA	L	;COUNT = 0?
	JZ	CWC005	;YES, CHECK TIME COUNT
	DCX	H	;ANOTHER TICK GONE
	SHLD	CWSEC
	RET
CWC005:
	LHLD	CWTIME	;GET TIME COUNT
	MOV	A,H
	ORA	L	;TIME EXPIRED?
	JZ	CWC007	;YES, GO TRY ID
	DCX	H	;ANOTHER SECOND GONE
	SHLD	CWTIME
	LXI	H,SECOND ;SETUP SECOND COUNT
	SHLD	CWSEC
	RET

;  HERE TO TRY CW ID - CHECK STATUS: IF WE ARE
;  TRANSMITTING OR HAVE PACKETS TO SEND, WAIT.
;  WAIT ALSO IF CHANNEL IS BUSY

CWC007:
	LDA	PROCST	;GET PROCESSING STATUS
	ANI	TXBUSY	;TRANSMITTING?
	RNZ		;YES, WAIT
	LDA	NUMPKT	;PACKETS IN BUFFER?
	ORA	A
	RNZ		;YES, WAIT
	CALL	CHKBSY	;SEE IF CHANNEL FREE
	RNZ		;NOPE! WAIT
	LDA	PROCST
	ORI	CWIP	;SHOW CW IN PROGRESS
	STA	PROCST
	LXI	H,RXDIS ;KILL RECEIVER
	CALL	COMMAND
	LXI	H,CWOPMD ;NO PRE-FRAME SYNC
	CALL	COMMAND
	LXI	H,CWSIO ;NRZL
	CALL	COMMAND
	LXI	H,SETRTS ;TURN ON TX
	CALL	COMMAND
	MVI	A,0
	STA	CWCNT
	LXI	H,IDSTR ;ADDRESS OF ID STRING
	SHLD	CWPTR
	MVI	A,0
	STA	CWBIT
	XRA	A	;INIT WAIT FLAG
	STA	TXWAIT
	LXI	H,TXCWID ;TELL 8273 TO TX
	CALL	COMMAND
	PAGE
CWC030:
	LDA	TXWAIT	;FINISHED YET?
	CPI	2	;END OF FRAME?
	JNZ	CWC030	;NO, KEEP WAITING
	LXI	H,RESRTS ;TURN OFF TX (RTS)
	CALL	COMMAND
	LXI	H,BUFFER
	SHLD	PKTPTR	;INIT BUFFER POINTER
	LXI	H,BCNTAB ;INIT PACKET TABLE POINTER
	SHLD	BCNPTR
	MVI	C,NUMBCN ;# PACKETS TO FILL

;  FILL NEXT PACKET

CWC050:
	LHLD	BCNPTR
	MOV	E,M	;GET PACKET STRING ADDRESS
	INX	H
	MOV	D,M
	INX	H
	MOV	B,M	;GET PACKET LENGTH
	INX	H
	SHLD	BCNPTR	;UPDATE TABLE POINTER
	LHLD	PKTPTR	;GET NEXT BUFFER ADDRESS
	MOV	M,B	;STORE LENGTH
	INX	H

;  FILL NEXT BUFFER

CWC060:
	LDAX	D	;GET NEXT PACKET BYTE
	INX	D
	MOV	M,A	;PUT INTO BUFFER
	INX	H
	DCR	B
	JNZ	CWC060
	LHLD	PKTPTR
	LXI	D,BUFSIZ+3
	DAD	D	;FORM NEXT BUFFER ADDR
	SHLD	PKTPTR
	DCR	C	;LAST BEACON PACKET?
	JNZ	CWC050	;NO, KEEP GOING
	MVI	A,NUMBCN
	STA	NUMPKT	;INIT # PACKETS
	LXI	H,OPMODE
	CALL	COMMAND ;RE-SETUP 8273
	LXI	H,SERIO
	CALL	COMMAND
	LDA	PROCST	;SHOW CWID COMPLETE
	ANI	0FBH
	STA	PROCST
	LXI	H,IDTIME ;SET UP TIMER AGAIN
	SHLD	CWTIME
	RET
	PAGE
;  CW ID TX INTERRUPT SERVICE ROUTINE

IDINT:
	IN	STAT73	;RESULT OR DATA INT?
	ANI	TXIRA
	JNZ	IDI020	;RESULT, GO PROCESS IT
	LDA	CWCNT	;DONE WITH THIS BIT?
	ORA	A
	JNZ	IDI004	;NO, DO THIS BIT AGAIN
	LDA	CWDAT	;ROTATE TO NEXT BIT
	RLC
	STA	CWDAT
	LDA	CWBIT	;DONE WITH THIS BYTE
	ORA	A
	JNZ	IDI002	;NO, SKIP BYTE UPDATE
	LHLD	CWPTR	;GET ID STRING POINTER
	MOV	A,M	;GET NEXT BYTE
	INX	H	;UPDATE STRING POINTER
	SHLD	CWPTR
	STA	CWDAT
	MVI	A,8	;INIT BIT COUNT
IDI002:
	DCR	A	;NEXT BIT
	STA	CWBIT
	MVI	A,IDNUM ;INIT REPEAT COUNT
IDI004:
	DCR	A	;ANOTHER COUNT DONE
	STA	CWCNT
	LDA	CWDAT	;GET CURRENT DATA
	RLC		;MOVE CURRENT BIT TO CARRY
	MVI	A,0	;IF BIT IS ZERO
	JNC	IDI010	;BIT IS 0, SEND IT
	MVI	A,0FFH	;BIT IS 1
IDI010:
	OUT	TXDATA	;OUTPUT THE DATA BYTE
	JMP	IDI030	;RETURN

;  HERE IF RESULT INTERRUPT - SET STATUS

IDI020:
	IN	TXIR73	;GET INTERRUPT STATUS
	CPI	0CH	;EARLY INTERRUPT?
	JNZ	IDI025	;NO, FINAL INTERRUPT
	MVI	A,1	;SHOW EARLY INT
	JMP	IDI027
IDI025:
	MVI	A,2	;SHOW FINAL INT
IDI027:
	STA	TXWAIT
IDI030:
	POP	PSW
	POP	B
	POP	H
	EI		;INTS OK AGAIN
	RET
	PAGE
;  RAM ALLOCATION

	ORG	LORAM
	DS	100	;STACK AREA
STACK	EQU	$
NUMPKT: DS	1	;# PACKETS RECEIVED
CMDBUF: DS	4	;PLACE TO BUILD COMMANDS
PKTPTR: DS	2	;POINTER TO CURRENT PACKET BYTE
BUFPTR: DS	2	;POINTER TO CURRENT BUFFER
TXWAIT: DS	1	;TX WAIT FLAG
TIME:	DS	2	;TIMER VALUE
PROCST: DS	1	;PROCESSING STATUS BYTE
CWCNT:	DS	1	;CW ID BIT REPEAT COUNT
CWPTR:	DS	2	;ID STRING POINTER
CWBIT:	DS	1	;ID BYTE BIT COUNT
CWDAT:	DS	1	;ID TEMP DATA
CWSEC:	DS	2	;CW ID SECOND COUNT
CWTIME: DS	2	;CW TIMER
BCNPTR: DS	2	;PACKET BEACON POINTER
BUFFER: DS	(BUFSIZ+3)*MAXPKT

	END