;	M4XFER/ASM
;
;	FILE ROUTINES
;
;	Output the characters in a packet
;
PTCHR	LD	HL,PUTFILE
	CALL	DECODE
	JP	Z,RSKP
	RET
;
;	Get a packets worth of data
;
GTCHR	LD	A,(EOFLAG)	;Check for EOF
	OR	A		;Set or reset Z
	RET	NZ		;Return if EOF occured
	CALL	GETPKT		;Get a packets worth
	JP	RSKP		;Return saying that something is there
;
;	Put a character to a file
;
PUTFILE	LD	DE,(RFIDCB)	;Get the DCB address
	CALL	XPUT		;Output the character
	RET	Z		;Return if no error
	CALL	XERROR0		;Print an error message
	LD	A,'X'		;Set EOT flag
	LD	(CZSEEN),A
	RET			;Return to caller
;
;	Put a character to the buffer
;
PUTDATA	PUSH	HL		;Save the pointer
	LD	HL,(RMTPTR)	;Get the pointer to the start
	LD	(HL),A		;Store the character
	INC	HL		;Point to next
	LD	(HL),0		;Terminate the string
	LD	(RMTPTR),HL	;Save the new pointer
	POP	HL		;Restore the pointer
	CP	A		;Set Z status
	RET			;Return
;
;	Get a character from the packet, doing all necessary decoding
;
GETDATA	PUSH	HL		;Save HL
	LD	(RMTPTR),HL	;Store as the place to but the data
	LD	HL,PUTDATA	;Get the address of the routine
	CALL	DECODE		;Decode it
	POP	HL		;Restore HL
	RET			;Return to caller
;
;	Call this address to call the address in HL
;
CALLHL	JP	(HL)
	RET
;
;	Get the next file name pointed to by MFNPTR and put it in FCB.
;	If no more names are available, then the Carry Flag will be
;	set apon return.  Otherwise, NC will exist, and FCB will
;	contain a valid TRSDOS filename.
;
MFNAME	PUSH	BC		;Save the registers
	PUSH	DE
	PUSH	HL
	LD	B,32		;Blank the FCB
	LD	HL,MFREQ
	PUSH	HL
	LD	A,32
MFN0A	LD	(HL),A
	INC	HL
	DJNZ	MFN0A
	LD	HL,(MFNPTR)	;Get the start of the next name
	POP	DE		;Get the destination
	CALL	XFSPEC		;Move and convert
	LD	(MFNPTR),HL	;Save start of next name
	PUSH	AF		;Save the returned flags
	LD	HL,MFREQ	;Get the source
	PUSH	HL		;Make a copy
	LD	DE,TFILNAM	;Get the destination
	LD	BC,32		;Get the byte count
	LDIR			;Move them
	LD	HL,TFILNAM	;Terminate the string with EOS
	LD	A,3		;Find the ETX
	LD	BC,32		;Only look this far
	CPIR			;Find it
	DEC	HL		;Back up to the ETX
	LD	(HL),EOS	;Put in an ETX
	POP	HL		;Restore the source address
	LD	DE,FCB		;Get the FCB destination
	CALL	XFSPEC		;Move a copy into FCB
	POP	AF		;Restore the return flags
	SCF			;Set initial return flag
	JR	NZ,MFFIX1	;Abort on error
	CCF			;Reset Carry to return valid name
MFFIX1	POP	HL		;Restore the registers
	POP	DE
	POP	BC
	RET			;Return to the caller
;
;	Open the filename in FCB for output
;
GETFIL	LD	A,0FFH
	LD	(FILFLG),A	;No file open
	XOR	A		;Get zero
	LD	(EOFLAG),A	;Not the end of file
	LD	(LSTCHR),A	;No previous character
	PUSH	HL
	LD	DE,FCB		;Get the FCB
	LD	HL,BUFF		;Get the data buffer
	LD	B,0		;Select LRL=256
	CALL	XOPEN		;Open the file (at least try)
	POP	HL		;Restore old HL
	JR	Z,GETFIL1	;Return if normal open
;
;	The following code handles files with LRL's different then
;	256.  The LRL open fault can be ignored in this case.
;
	CP	42		;Check for different LRL ERROR
	JP	NZ,ERRORD	;If not, then error
GETFIL1	JP	RSKP		;Ignore LRL open fault
;
;	PACKET ROUTINES
;
;	Send a packet out the comm port
;
;	This routine assembles a packet from the arguments given and
;	sends it out the communications port
;
;	Arguments:
;
;	A	 - TYPE OF PACKET (D,Y,N,S,R,E,F,Z,T)
;	ARGBLK	 - PACKET SEQUENCE NUMBER
;	ARGBLK+1 - NUMBER OF DATA CHARACTERS
;
SPACK	LD	(ARGBLK+2),A	;Save data for resend to use
	LD	HL,PACKET	;GET ADDRESS OF THE SEND PACKET.
	LD	A,(SSOHCH)	;GET THE START OF HEADER CHAR.
	PUTHL	A		;PUT IN THE PACKET.
	LD	A,(CURCHK)	;GET CURRENT CHECKSUM TYPE
	SUB	'1'		;DETERMINE EXTRA LENGTH OF CHECKSUM
	LD	B,A		;COPY LENGTH
	LD	A,(ARGBLK+1)	;GET THE NUMBER OF DATA CHARS.
	ADD	A,' '+3		;Real packet length made printable
	ADD	A,B		;DETERMINE OVERALL LENGTH
	PUTHL	A		;Put in the packet
	LD	B,0		;ZERO THE CHECKSUM AC.
	LD	C,A		;START THE CHECKSUM.
	LD	A,(ARGBLK)	;GET THE PACKET NUMBER.
	TOCHAR			;ADD A SPACE SO THE NUMBER IS PRINTABLE.
	PUTHL	A		;Put in the packet
	CALL	NXTSUM		;Get next checksum value
	LD	A,(ARGBLK+2)	;GET THE PACKET TYPE.
	PUTHL	A		;Put in the packet
	CALL	NXTSUM
SPACK2	LD	A,(ARGBLK+1)	;GET THE PACKET SIZE.
	IFZ	SPACK3
	DEC	A		;DECREMENT THE CHAR COUNT.
	LD	(ARGBLK+1),A	;PUT IT BACK.
	LD	A,(HL)		;GET THE NEXT CHAR.
	INC	HL		;POINT TO NEXT CHAR.
	CALL	NXTSUM		;Compute next checksum
	JR	SPACK2		;GO TRY AGAIN.
SPACK3	LD	A,(CURCHK)	;GET THE CURRENT CHECKSUM TYPE
	IFA	'2',SPACK4
	JR	NC,SPACK5	;Go do CRC if '3'
	LD	A,C		;GET THE CHARACTER TOTAL.
	AND	0C0H		;TURN OFF ALL BUT THE TWO HIGH ORDER BITS
	RLCA			;TWO LEFT ROTATES SAME AS 6 RIGHTS
	RLCA			;.  .	.
	ADD	A,C		;ADD IT TO THE OLD BITS.
	AND	3FH		;TURN OFF THE TWO HIGH ORDER BITS.
	TOCHAR			;ADD A SPACE SO THE NUMBER IS PRINTABLE.
	PUTHL	A		;Put in the packet
	JP	SPACK7		;GO STORE EOL CHARACTER
;
;HERE FOR 3 CHARACTER CRC-CCITT
;
SPACK5	LD	(HL),0		;STORE A NULL FOR CURRENT END
	PUSH	HL		;SAVE H
	LD	HL,PACKET+1	;POINT TO FIRST CHECKSUMED CHARACTER
	CALL	CRCCLC		;CALCULATE THE CRC
	POP	HL		;RESTORE THE POINTER
	LD	C,E		;GET LOW ORDER HALF FOR LATER
	LD	B,D		;COPY THE HIGH ORDER
	LD	A,D		;GET THE HIGH ORDER PORTION
	RLCA			;SHIFT OFF LOW 4 BITS
	RLCA			;.  .	.
	RLCA			;.  .	.
	RLCA			;.  .	.
	AND	0FH		;KEEP ONLY LOW 4 BITS
	TOCHAR			;PUT INTO PRINTING RANGE
	LD	(HL),A		;STORE THE CHARACTER
	INC	HL		;POINT TO NEXT POSITION
;
;HERE FOR TWO CHARACTER CHECKSUM
;
SPACK4	LD	A,B		;GET HIGH ORDER PORTION
	AND	0FH		;ONLY KEEP LAST FOUR BITS
	RLCA			;SHIFT UP TWO BITS
	RLCA			;. .  .
	LD	B,A		;COPY BACK INTO SAFE PLACE
	LD	A,C		;GET LOW ORDER HALF
	RLCA			;SHIFT HIGH TWO BITS
	RLCA			;TO LOW TWO BITS
	AND	03H		;KEEP ONLY TWO LOW BITS
	OR	B		;GET HIGH ORDER PORTION IN
	TOCHAR			;CONVERT TO PRINTING CHARACTER RANGE
	PUTHL	A		;Store the character
	LD	A,C		;GET LOW ORDER PORTION
	AND	3FH		;KEEP ONLY SIX BITS
	TOCHAR			;CONVERT TO PRINTING RANGE
	PUTHL	A		;Store the character
SPACK7	LD	A,(SEOL)	;GET THE EOL THE OTHER HOST WANTS.
	PUTHL	A		;Store the character
	PUTHL	0		;End with a NULL
	LD	A,(DBFLG)
	OR	A
	JR	Z,SPACK8	;debug is off
	PUTHL	EOS		;Add terminator
SPACK8	CALL	OUTPKT		;CALL THE SYSTEM DEPENDENT ROUTINE.
	JP	QUIT
	JP	RSKP
;
;	WRITE OUT A PACKET.
;
OUTPKT	LD	A,(SPAD)	;GET THE NUMBER OF PADDING CHARS.
	LD	B,A
OUTPK2	DEC	B
	JP	M,OUTPK4
	LD	A,(SPADCH)	;GET THE PADDING CHAR.
	LD	E,A		;PUT THE CHAR IN RIGHT AC.
	CALL	OUTCHR		;OUTPUT IT.
	JR	OUTPK2
OUTPK4	LD	A,(DBFLG)
	IFZ	OUTPK5		;If not on, then check for logfile
	STROUT	SPPOS		;Print the SPACK=> message
	STROUT	PACKET+1	;Print the data
OUTPK5	LD	A,(DEBLOG)	;See if logging in effect
	IFZ	OUTPK7		;If not, then finish up
	LD	DE,DFCB		;Get the debug FCB
	TRLOG	SPPOS,OUTPK6	;Log the SPACK=> message
	TRLOG	PACKET,OUTPK6	;Log the packet data
	JR	OUTPK7
OUTPK6	XOR	A
	LD	(DEBLOG),A
	LD	DE,DFCB
	CALL	XCLOSE
OUTPK7	LD	HL,PACKET	;POINT TO THE PACKET.
OUTPK10	LD	A,(HL)		;GET THE NEXT CHARACTER.
	IFZ	OUTPK11		;Return success if EOS found
	LD	E,A		;PUT THE CHAR IN RIGHT AC.
	CALL	OUTCHR		;OUTPUT THE CHARACTER.
	INC	HL		;INCREMENT THE CHAR POINTER.
	JR	OUTPK10
OUTPK11	LD	A,(STURN)	;Is turn around needed?
	IFZ	OUTPK12		JUMP IF NOT NEEDED
	LD	E,A		;Get the character
	CALL	OUTCHR		;Output it
OUTPK12	JP	RSKP		;Return no error
;
;	Compute next checksum
;
NXTSUM	ADD	A,C
	LD	C,A
	LD	A,0		;Must use load to preserve Carry flag
	ADC	A,B
	LD	B,A
	RET
;
;THIS ROUTINE WAITS FOR A PACKET TO ARRIVE FROM THE HOST. IT READS
;CHARACTERS UNTIL IT FINDS THE SOH. IT THEN READS THE PACKET INTO PACKET.
;
;RETURNS +1 FAILURE (IF THE CHECKSUM IS WRONG OR THE PACKET TRASHED)
;	+3 SUCCESS WITH A		- MESSAGE TYPE
;			ARGBLK - MESSAGE NUMBER
;			ARGBLK+1 - LENGTH OF DATA
;
RPACK	LD	A,(RTIME)	;Get the timeout value
	LD	HL,0
	IFZ	RPACK1		;If zero, then no timeout
	LD	L,A		;Get the value as 16 bits
	LD	C,30		;Get the factor to extend it by
	CALL	XMUL16		;Do the multiplication
	LD	H,L		;Slide the 24 bit result down
	LD	L,A
RPACK1	LD	(SVTIMER),HL	;Save it as the timer value
RPACK2	CALL	STARTTIMER	;Start the timer for receive timeout
	CALL	INPKT		;READ UP TO A CARRIAGE RETURN.
	JP	QUIT		;RETURN BAD.
	CALL	STOPTIMER	;Stop the timeout countdown
RPACK3	CALL	GETCHR		;GET A CHARACTER.
	JP	RPACK2		;HIT A CR;NULL LINE; JUST START OVER.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JR	NZ,RPACK3	;NO, GO UNTIL IT IS.
RPACK4	CALL	GETCHR		;GET A CHARACTER.
	JP	QUIT		;HIT THE CARRIAGE RETURN, RETURN BAD.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JR	Z,RPACK4	;YES, THEN GO START OVER.
	LD	(PACKET+1),A	;STORE IN PACKET ALSO
	LD	C,A		;START THE CHECKSUM.
	LD	A,(CURCHK)	;GET BLOCK CHECK TYPE
	SUB	'1'		;DETERMINE EXTRA LENGTH OF BLOCK CHECK
	LD	B,A		;GET A COPY
	LD	A,C		;GET BACK LENGTH CHARACTER
	SUB	' '+3		;GET THE REAL DATA COUNT.
	SUB	B		;GET TOTAL LENGTH
	LD	(ARGBLK+1),A
	LD	B,0		;CLEAR HIGH ORDER HALF OF CHECKSUM
	CALL	GETCHR		;GET A CHARACTER.
	JP	QUIT		;HIT THE CARRIAGE RETURN, RETURN BAD.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JR	Z,RPACK4	;YES, THEN GO START OVER.
	LD	(ARGBLK),A
	LD	(PACKET+2),A	;SAVE ALSO IN PACKET
	CALL	NXTSUM		;ADD THE CHARACTER TO THE CHECKSUM
	LD	A,(ARGBLK)
	SUB	' '		;GET THE REAL PACKET NUMBER.
	LD	(ARGBLK),A
	CALL	GETCHR		;GET A CHARACTER.
	JP	QUIT		;HIT THE CARRIAGE RETURN, RETURN BAD.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JR	Z,RPACK4	;YES, THEN GO START OVER.
	LD	(TEMP1),A	;SAVE THE MESSAGE TYPE.
	LD	(PACKET+3),A	;SAVE IN PACKET
	LD	(RECTYP),A
	CALL	NXTSUM		;ADD THE CHARACTER TO THE CHECKSUM.
	LD	A,(ARGBLK+1)	;GET THE NUMBER OF DATA CHARACTERS.
	LD	(TEMP2),A
	LD	HL,DATA		;POINT TO THE DATA BUFFER.
	LD	(DATPTR),HL
RPACK5	LD	A,(TEMP2)
	DEC	A		;ANY DATA CHARACTERS?
	JP	M,RPACK6	;IF NOT GO GET THE CHECKSUM.
	LD	(TEMP2),A
	CALL	GETCHR		;GET A CHARACTER.
	JP	QUIT		;HIT THE END-OF-LINE, RETURN BAD.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JR	Z,RPACK4	;YES, THEN GO START OVER.
	LD	HL,(DATPTR)
	PUTHL	A		;Store the character
	LD	(DATPTR),HL
	CALL	NXTSUM		;ADD THE CHARACTER TO THE CHECKSUM.
	JR	RPACK5		;GO GET ANOTHER.
RPACK6	CALL	CHKECHO		;See if only echo of previous
	JP	RPACK3		;Yes, restart
	CALL	GETCHR		;Get a character
	JP	QUIT		;HIT THE CARRIAGE RETURN, RETURN BAD.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JP	Z,RPACK4	;YES, THEN GO START OVER.
	SUB	' '		;TURN THE CHAR BACK INTO A NUMBER.
	LD	(TEMP3),A
;DETERMINE TYPE OF CHECKSUM
	LD	A,(CURCHK)	;GET THE CURRENT CHECKSUM TYPE
	IFA	'2',RPACK9	;Jump if 2 character
	JR	NC,RPACK8	;Jump if 3 character
;
;	1 character checksum
;
	LD	A,C		;Get the character count
	AND	0C0H		;Keep 2 MSB's
	RLCA			;Move them to 2 LSB's
	RLCA
	ADD	A,C		;Add the 2 low bits to bottom
	AND	3FH		;Remove 2 high bits after add
	LD	B,A
	LD	A,(TEMP3)	;GET THE REAL RECEIVED CHECKSUM.
	IFA	B,RPACK10	;Jump checksum OK
RPACK7	CALL	UPDRTR		;If checksum bad, update retries
	RET			;Return error
;
;	Here for three character CRC-CCITT
;
RPACK8	LD	HL,(DATPTR)	;GET THE ADDRESS OF THE DATA
	LD	(HL),0		;Store a zero in the buffer as terminator
	LD	HL,PACKET+1	;POINT AT START OF CHECKSUMMED REGION
	CALL	CRCCLC		;CALCULATE THE CRC
	LD	C,E		;SAVE LOW ORDER HALF FOR LATER
	LD	B,D		;ALSO COPY HIGH ORDER
	LD	A,D		;GET HIGH BYTE
	RLCA			;WANT HIGH FOUR BITS
	RLCA			;.  .	.
	RLCA			;AND SHIFT TWO MORE
	RLCA			;.  .	.
	AND	0FH		;KEEP ONLY 4 BITS
	LD	D,A		;BACK INTO D
	LD	A,(TEMP3)	;GET FIRST VALUE BACK
	IFANOT	D,RPACK7	;Jump if not correct
	CALL	GETCHR		;GET A CHARACTER.
	JP	QUIT		;HIT THE CARRIAGE RETURN, RETURN BAD.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JP	Z,RPACK4	;YES, THEN GO START OVER.
	SUB	' '		;REMOVE SPACE OFFSET
	LD	(TEMP3),A	;STORE FOR LATER CHECK
;
;	Here for a two character checksum and last two characters of CRC
;
RPACK9	LD	A,B		;GET HIGH ORDER PORTION
	AND	0FH		;ONLY FOUR BITS
	RLCA			;Shift up 2 bits
	RLCA
	LD	B,A		;Save back into B
	LD	A,C		;Get low order byte
	RLCA			;Move the 2 MSB's to 2 LSB's
	RLCA
	AND	03H		;Save only low 2 bits
	OR	B		;Get other 4 bits
	LD	B,A		;Save back into B
	LD	A,(TEMP3)	;Get this portion of the checksum
	IFANOT	B,RPACK7	;If wrong, then give up
	CALL	GETCHR		;GET A CHARACTER.
	JP	QUIT		;HIT THE CARRIAGE RETURN, RETURN BAD.
	CALL	CPRSOH		;IS THE CHAR THE START OF HEADER CHAR?
	JP	Z,RPACK4	;YES, THEN GO START OVER.
	SUB	' '		;REMOVE SPACE OFFSET
	LD	B,A		;SAVE IN SAFE PLACE
	LD	A,C		;GET LOW 8 BITS OF CHECKSUM
	AND	3FH		;KEEP ONLY 6 BITS
	IFANOT	B,RPACK7	;Jump if bad value
RPACK10	LD	HL,(DATPTR)
	PUTHL	0		;End with a NULL
	LD	A,(TEMP1)	;GET THE TYPE.
	JP	RSKP
;
;	Input a packet
;
INPKT	LD	HL,RECPKT	;POINT TO THE BEGINNING OF THE PACKET.
	LD	(PKTPTR),HL
INPKT2	CALL	INCHR		;GET A CHARACTER.
	JP	INPKT7		;Skip out if key typed that is valid
	LD	HL,(PKTPTR)	;Get the packet position
	PUTHL	A		;Store the character
	LD	(PKTPTR),HL	;Save the pointer
	CALL	CPREOL		;IS IT THE EOL CHARACTER?
	JR	NZ,INPKT2
	PUTHL	EOS		;Put in the terminator
	LD	A,(DBFLG)
	IFZ	INPKT3		;Jump if debug off
	STROUT	RPPOS		;Output RPACK=> message
	STROUT	RECPKT+1	;Print the received packet
INPKT3	LD	A,(DEBLOG)	;See if debug log in on
	IFZ	INPKT6		;Jump if not enabled
	LD	DE,DFCB		;Get the FCB
	TRLOG	RPPOS,OUTPK6	;Log the RPACK=> message
	TRLOG	RECPKT+1,OUTPK6	;Log the packet
INPKT6	LD	HL,RECPKT
	LD	(PKTPTR),HL	;SAVE THE PACKET POINTER.
	LD	A,(RTURN)	;Get the turn around character
	CALL	WAITT		;Go wait for it.
	JP	RSKP		;Return no error
;
;	Error return processing.  This code deals with the keystrokes
;	that are recognized in INCHR().
;
INPKT7	LD	A,(CZSEEN)
	IFANOT	'A',INPKT8	;Status
	CALL	SHOTRANS	;Show the transfer status
	JR	INPKT16
INPKT8	IFANOT	'B',INPKT9	;Cancel Batch?
	LD	A,'Z'		;Get the packet type
	LD	(CZSEEN),A
	LD	DE,CBATCH	;Get the cancel message
	CALL	CONDIS		;Print it if not doing REMOTE commands
	JP	INPKT2
INPKT9	IFANOT	'F',INPKT10	;Cancel FILE?
	LD	A,'X'		;Get the PACKET type
	LD	(CZSEEN),A
	LD	DE,CFILE	;Get the cancel message
	CALL	CONDIS		;Print it if not doing REMOTE commands
	JP	INPKT2
INPKT10	IFANOT	'E',INPKT12	;Send error, and ABORT?
	XOR	A
	LD	(CZSEEN),A	;Reset the key pressed flag
	CALL	STOPTIMER	;Stop the timer
	LD	A,ABRTMSGLEN	;Get length of message
	LD	(ARGBLK+1),A	;Save the length
	LD	HL,ABRTMSG	;Get the message
	LD	DE,DATA		;Where to put it
	LD	C,A		;Get the length in BC
	LD	B,0
	LDIR			;Move the message
	LD	A,'E'		;Get the packet type
	CALL	SPACK		;Send the error packet
	JP	ABORT		;Give up on an error
	JP	KERMIT		;Give up completely
INPKT12	IFANOT	'C',INPKT14	;Cancel transfer, immediately
	XOR	A
	LD	(CZSEEN),A	;Zap the old key pressed
	CALL	STOPTIMER	;Stop the timer
	JP	KERMIT		;Jump to restart
INPKT14	IFANOT	'D',INPKT18	;Toggle debug mode?
	LD	A,(DBFLG)	;Get the debug flag
	XOR	1		;Toggle value
	LD	(DBFLG),A	;Store it back
INPKT16	XOR	A		;Finish up handling, reset key pressed
	LD	(CZSEEN),A	;Reset the flag
	JP	INPKT2		;Get the next character
INPKT18	IFANOT	'H',INPKT20	;Help?
	STROUT	HELPMSG		;Print the message
	JR	INPKT16		;Finish up
INPKT20	XOR	A		;Otherwise, return no input to force
	LD	(CZSEEN),A	;resend to occur...
	RET			;Return no input packet
;
GETCHR	LD	HL,(PKTPTR)	;GET THE PACKET POINTER.
	LD	A,(HL)		;GET THE CHAR.
	INC	HL
	LD	(PKTPTR),HL
	CALL	CPREOL		;IS IT THE END OF LINE
	JP	NZ,RSKP		;IF NOT RETURN RETSKP.
	RET			;IF SO RETURN FAILURE.
;
;	Assorted comparison routines
;
CPSSOH	PUSH	HL
	LD	HL,SSOHCH
CPSH10	CP	(HL)
	POP	HL
	RET
CPRSOH	PUSH	HL
	LD	HL,RSOHCH
	JR	CPSH10
CPSEOL	PUSH	HL
	LD	HL,SEOL
	JR	CPSH10
CPREOL	PUSH	HL
	LD	HL,REOL
	JR	CPSH10
CPSPAD	PUSH	HL
	LD	HL,SPADCH
	JR	CPSH10
CPRPAD	PUSH	HL
	LD	HL,RPADCH
	JR	CPSH10
CPSTME	PUSH	HL
	LD	HL,STIME
	JR	CPSH10
CPRTME	PUSH	HL
	LD	HL,RTIME
	JR	CPSH10
CPSQTE	PUSH	HL
	LD	HL,SQUOTE
	JR	CPSH10
CPRQTE	PUSH	HL
	LD	HL,RQUOTE
	JR	CPSH10
;
;THIS ROUTINE WILL CALCULATE A CRC USING THE CCITT POLYNOMIAL FOR
;A STRING.
;
;USAGE
;	HL/ ADDRESS OF STRING
;	A/ LENGTH OF STRING
;	CALL	CRCCLC
;
;16-BIT CRC VALUE IS RETURNED IN DE.
;
;REGISTERS BC AND HL ARE PRESERVED.
;
CRCCLC	PUSH	HL		;SAVE HL
	PUSH	BC		;AND BC
	LD	DE,0		;INITIAL CRC VALUE IS 0
CRCCL0	LD	A,(HL)		;GET A CHARACTER
	OR	A		;CHECK IF ZERO
	JP	Z,CRCCL1	;IF SO, ALL DONE
	PUSH	HL		;SAVE THE POINTER
	XOR	E		;ADD IN WITH PREVIOUS VALUE
	AND	0FH		;Keep only 4 bits
	LD	B,0
	GETCRCTAB
	CALL	SRLDE4		;Shift CRC right by 4
	XORATHL	E
	INC	HL
	XORATHL	D
	POP	HL
	PUSH	HL
	LD	A,(HL)
	SRL	A
	SRL	A
	SRL	A
	SRL	A
	XOR	E
	AND	0FH
	GETCRCTAB
	CALL	SRLDE4
	XORATHL	E
	INC	HL
	XORATHL	D
	POP	HL		;AND H
	INC	HL		;POINT TO NEXT CHARACTER
	JP	CRCCL0		;GO GET NEXT CHARACTER
CRCCL1	POP	BC		;RESTORE B
	POP	HL		;AND HL
	RET			;AND RETURN, DE=CRC-CCITT
;
;	Shift DE right by 4 bits
;
SRLDE4	SRL	D
	RR	E
	SRL	D
	RR	E
	SRL	D
	RR	E
	SRL	D
	RR	E
	RET
;
CRCTAB	DW	00000H
	DW	01081H
	DW	02102H
	DW	03183H
	DW	04204H
	DW	05285H
	DW	06306H
	DW	07387H
	DW	08408H
	DW	09489H
	DW	0A50AH
	DW	0B58BH
	DW	0C60CH
	DW	0D68DH
	DW	0E70EH
	DW	0F78FH
;
GETNPNT	LD	A,(HL)
	INC	HL
	LD	(OUTPNT),HL
	RET
;
;	Check if RFIDCB points at FCB.
;
CHKFCB	LD	DE,(RFIDCB)	;Get the current FCB/DCB pointer
	LD	HL,FCB		;Get the Address of FCB
	OR	A		;Reset the carry
	SBC	HL,DE		;Compute the difference
	RET			;Return the flags
;
INCKTRANS	PUSH	HL	;Save the regs
	PUSH	AF
	LD	HL,(KTRANS)	;Get the current count
	INC	HL		;Add one to it
	LD	A,H		;Check for overflow
	OR	L		;Set the flags
	LD	A,1		;Set the ok to change curtrans flag
	CALL	Z,ADD64K	;Add 64K if overflow
	LD	(KTRANS),HL	;Save the new counter
	LD	(CURTRANS),HL	;Store as current count too
	POP	AF		;Restore the regs
	POP	HL
	RET			;Return to caller
;
;	Add 64k to the current counter (RTRANS, or STRANS, as well as
;	CURTRANS which is used for TRANSACTION logs).
;
ADD64K	EQU	$
	PUSH	HL		;Save the regs
	LD	L,(IX)		;Get the current Kbyte counter
	LD	H,(IX+1)
	LD	BC,64		;Add 64 to it
	ADD	HL,BC
	LD	(IX),L		;Store it back
	LD	(IX+1),H
	IFZ	ADD64K_1
	LD	HL,(CURTRANS+2)	;Get the current value
	ADD	HL,BC		;Add 64
	LD	(CURTRANS+2),HL	;Store new value
ADD64K_1	POP	HL		;Restore HL
	RET			;Return
;
;	Wait for the turn around character in A
;
TTURN	DB	0
;
WAITT	OR	A		;Check for no turn around
	RET	Z		;return on ZERO
	LD	(TTURN),A	;Save the character
WAITT1	CALL	INCHR		;Get a character
	JP	INPKT7		;Process keyboard character
	LD	C,A		;Save the character
	LD	A,(TTURN)	;Check for turn around
	CP	C		;Is the character received it?
	JR	NZ,WAITT1	;No, get another
	RET
;
SHOTRANS	EQU	$
	STROUT	NPKTSTR		;Print number of packets
	LD	HL,(NUMPKT)
	CALL	NOUT
	STROUT	NRTRSTR		;Print retries
	LD	HL,(NUMRTR)
	CALL	NOUT
	STROUT	NCHRSTR		;Print number of characters
	LD	HL,(KTRANS)
	CALL	NOUT
	STROUT	NRECCH		;Number K of characters recvd
	LD	HL,(RTRANS)
	CALL	NOUT
	LD	A,'K'
	CALL	CONOUT
	STROUT	NSNDCH		;Print number of characters sent
	LD	HL,(STRANS)
	CALL	NOUT
	LD	A,'K'
	CALL	CONOUT
	JP	NEWLIN
;
CHKECHO	PUSH	BC
	LD	A,(SNDTYP)
	LD	C,A
	LD	A,(RECTYP)
	CP	C
	POP	BC
	RET	Z
	JP	RSKP
;
;	Convert KERMIT filename to TRSDOS filename
;
GOFIL	LD	HL,RMTDATA	;Where to put the name
	LD	A,(ARGBLK+1)	;Number of characters
	CALL	GETDATA		;Get the name in RMTDATA (HL saved)
	LD	DE,MFREQ	;Destination
	LD	BC,8		;Max characters for first field
GOFIL1	EQU	$
	LD	A,(HL)		;At end of field?
	IFA	'.',GOFIL8	;Jump if at separator
	IFALT	' ',GOFIL15	;Stop if at end of string
	LD	A,C		;Check range
	IFANOT	8,GOFIL2	;If not first character, then skip
	LD	A,(HL)		;Get the character
	CALL	ISALPHA		;Is it alphabetic?
	JR	Z,GOFIL5	;Jump if it is
	LD	(HL),'Z'	;Change name
	JR	GOFIL5		;Join code
GOFIL2	EQU	$		;Second or later character...
	LD	A,(HL)
	CALL	ISALNUM		;Is it alphanumeric?
	JR	Z,GOFIL5	;Jump if so
	INC	HL		;Skip this one
	JR	GOFIL1		;Go to the next character
GOFIL5	EQU	$
	LDI			;Move the character
	LD	A,B		;Check the remaining count
	OR	C
	JR	NZ,GOFIL1	;Jump if still OK
GOFIL7	EQU	$
	LD	A,(HL)		;Are we at the end yet
	IFA	'.',GOFIL8	;Jump if at the separator
	IFALT	' ',GOFIL15	;Stop it at the end
	INC	HL		;Point to next source character
	JR	GOFIL7		;Loop
GOFIL8	EQU	$
	LD	A,C		;Check the count of characters moved
	IFANOT	8,GOFIL9	;Jump if at least one moved
	LD	A,'X'		;Use this as the first character
	LD	(DE),A		;Put it in
	INC	DE		;Point to next slot
GOFIL9	LD	(HL),'/'	;Put in separator
	LDI			;Move it too
	LD	BC,3		;Length of next field
GOFIL10	EQU	$
	LD	A,(HL)		;Get the character
	IFALT	' ',GOFIL15	;Jump if at the end
	LD	A,C		;Check ranges
	IFANOT	3,GOFIL12	;Jump if not first character
	LD	A,(HL)		;Get the character (Must be alphabetic)
	CALL	ISALPHA		;Is it alphbetic?
	JR	Z,GOFIL13	;Jump if it is
	LD	(HL),'Z'	;Make it alphabetic
	JR	GOFIL13		;Join other code
GOFIL12	EQU	$		;Second or third character in extension
	LD	A,(HL)		;Get the character back
	CALL	ISALNUM		;Is it alphanumeric?
	JR	Z,GOFIL13	;Jump if so
	INC	HL		;Skip it
	JR	GOFIL10		;Check the next one
GOFIL13	EQU	$
	LDI			;Move a char
	LD	A,B		;Check the count
	OR	C
	JR	NZ,GOFIL10	;Loop if OK
GOFIL15	EQU	$
	PUSH	DE		;Put dest into HL
	POP	HL
	PUTHL	':'		;Add the default drive
	LD	A,(DEFDSK)
	PUTHL	A		;Add the drive number
	LD	(HL),EOS	;Add the end of string byte
	PUSH	HL		;Save that address
	LD	HL,MFREQ	;Move the string to the save area
	LD	DE,TFILNAM	;Get the destination
	LD	BC,32
	LDIR			;Move the bytes
	POP	HL
	LD	(HL),3		;Put in FSPEC terminator
	LD	(FCBPTR),HL	;Save the end
	LD	HL,MFREQ	;Validate the filespec
	LD	DE,FCB
	CALL	XFSPEC		;Call TRSDOS
	JR	Z,GOFIL18	;Jump if OK
	LD	HL,(FCBPTR)	;Get end of string
	LD	(HL),EOS	;Put in print terminator
	STROUT	FCB		;Print the name
	JP	XERROR0		;Print system error message and return
GOFIL18	LD	HL,FCB		;Get start
	LD	BC,40		;Maximum to look
	LD	A,':'		;Find drive spec to index off of
	CPIR			;Look for it.  MUST be there
	INC	HL		;Point after for terminator
	LD	(FCBPTR),HL	;Save it
	DEC	HL		;Back up to just after extension
	DEC	HL
	LD	(DATPTR),HL	;Save it for renaming
	LD	A,(FLWFLG)	;Is file warning on?
	IFZ	GOFIL30		;Jump if not
	LD	DE,FCB		;Get the file name
	LD	HL,BUFF		;Buffer address
	LD	B,0		;LRL=256
	CALL	XOPEN		;Is it there?
	JR	NZ,GOFIL30	;Jump if not
	LD	DE,INFMS5	;Print renaming message
	CALL	ERROR3
	LD	DE,FCB		;Close the file
	CALL	XCLOSE		;Close restores the filename with @FNAME
GOFIL20	LD	HL,(DATPTR)	;Get the pointer to extension
	LD	DE,FCB		;Get the start
	OR	A		;Reset the carry
	PUSH	HL		;Save it
	SBC	HL,DE		;At the beginning yet
	POP	HL		;Restore it
	JR	NZ,GOFIL21	;Jump if not
	LD	DE,ERMS16	;Oops, Can't rename it, stop
	JP	PRTSTR		;Print, and return
;
GOFIL21	DEC	HL		;Point to previous character
	LD	(DATPTR),HL	;Save the new pointer
GOFIL24	LD	HL,(DATPTR)	;Get the pointer
	LD	A,(HL)		;Get the character
	IFALT	'B',GOFIL20	;Jump if we can't change it
	DEC	(HL)		;Change the file name
	LD	HL,FCB		;Get the source address
	PUSH	HL		;Save it for later
	LD	DE,TFILNAM	;Get the destination
	LD	BC,32		;Number to move
	LDIR			;Move them
	POP	DE		;Restore stack and get FCB address
	LD	HL,BUFF
	LD	B,0
	CALL	XOPEN		;Is it there?
	JR	NZ,GOFIL27	;Jump if not
	LD	DE,FCB		;Close it up
	CALL	XCLOSE
	JR	GOFIL24		;Try another name
;
GOFIL27	LD	HL,(FCBPTR)	;Get the end of the file name
	LD	(HL),EOS	;Add the print terminator
	STROUT	FCB		;Print the new name
	LD	(HL),3		;Put the @OPEN terminator back
GOFIL30	LD	DE,FCB		;Get the FCB
	LD	HL,BUFF		;Get the buffer
	LD	B,0		;LRL=256
	CALL	XINIT		;Create it or zap old file
	JP	Z,RSKP		;Return on success +4
	PUSH	AF		;Save error code
	LD	DE,ERMS11	;Print the error message
	CALL	ERROR3
	POP	AF		;Get the error code back
	JP	ERRORD		;Print a system error
;
;	Restart timer for receive packet timeout
;
STARTTIMER	PUSH	HL	;Save the clobbered regs
	PUSH	DE
	PUSH	BC
	LD	C,0		;Get no timer flag for next test
	LD	HL,(SVTIMER)	;Get the timer value
	LD	A,H		;Check if not timeout wanted
	OR	L
	JR	Z,STARTT3	;Don't start timer if none needed
	LD	(TIMER),HL	;Set the real counter
	LD	C,8		;Get the task slot number
STARTT1	CALL	XCKTSK		;Check is slot in use
	JR	NZ,STARTT2
	LD	DE,RECTIME	;Get the TCB
	PUSH	BC
	CALL	XADTSK		;Try to add the task
	POP	BC		;Restore the task slot
	JR	STARTT3		;Go save slot used
STARTT2	INC	C		;Get next possible slot
	IFANOT	11,STARTT1	;Loop if not at max task slot
	STROUT	NOTIMER		;Print error message
	LD	HL,1
	LD	(SVTIMER),HL	;Zap timer
	LD	C,0		;Make sure no timer flag is on
STARTT3	LD	A,C		;Save task to stop
	LD	(TASKSLOT),A
	POP	BC		;Restore registers
	POP	DE
	POP	HL
	RET
;
;	Stop the timeout task
;
STOPTIMER	PUSH	HL	;Save the registers
	PUSH	DE
	PUSH	BC
	LD	C,8		;Get the task slot number
TASKSLOT	EQU	$-1
	CALL	XRMTSK
	LD	HL,0		;Zero out the timer
	LD	(TIMER),HL
	POP	BC		;Restore the registers
	POP	DE
	POP	HL
	RET
;
;	Check if character in A is alphabetic.  Z status means YES,
;	NZ status means NO
;
ISALPHA	CP	'A'		;Check upper case
	RET	C		;Return if less than
	CP	'Z'+1		;If less than or equal to Z, then A-Z
	JR	C,ISAL_1	;Jump to TRUE return
	CP	'a'		;Check lower case
	RET	C		;Return less than
	CP	'z'+1		;Check for a-z
	RET	NC		;NC means greater than 'z'
ISAL_1	CP	A		;Set Z status
	RET			;Return
;
;	Check if character in A is alphanumeric
;
ISALNUM	CP	'0'		;Check digits
	RET	C		;Return too small
	CP	'9'+1		;Check max+1
	JR	NC,ISALPHA	;If too big, go try alphabetic
	CP	A		;Set Z status
	RET			;return it
; end of file