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cpspk2.asm
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Assembly Source File
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; CPSPK2.ASM
; KERMIT - (Celtic for "FREE")
;
; This is the CP/M-80 implementation of the Columbia University
; KERMIT file transfer protocol.
;
; Version 4.0
;
; Copyright June 1981,1982,1983,1984
; Columbia University
;
; Originally written by Bill Catchings of the Columbia University Center for
; Computing Activities, 612 W. 115th St., New York, NY 10025.
;
; Contributions by Frank da Cruz, Daphne Tzoar, Bernie Eiben,
; Bruce Tanner, Nick Bush, Greg Small, Kimmo Laaksonen, Jeff Damens, and many
; others.
;
; This file contains the (system-independent) routines that implement
; the KERMIT protocol, and the commands that use them:
; RECEIVE, SEND, FINISH, and LOGOUT.
;
; revision history:
;
;edit 11, 21-Mar-1991 by MF. After "inchr7", close TAKE-file (if any) so
; ^C will halt all processing (including commands from TAKE-files)
; and put the user back at Kermit command-level.
;edit 10, 3-Jan-1991 by MF. Modify routine "inchr" after label "inchr5" to
; not take retry (nonskip) return if ^X/^Z seen on the Console. This
; will prevent multiple copies of packets being sent if user aborts
; some files in a stream being sent via ^X and is a better fix to this
; problem than flushing comm input before sending the "Z" packet
; requesting the remote Kermit to discard the current file being
; received (as implemented in CPSPK1.ASM edit of 2-jan-1991).
;edit 9, 14-Dec-1990 by MF. Modified "gofil" routine to allow for
; specification of a drive in the local filespec for GET and
; RECEIVE commands. Thus commands such as
; GET HELLO.TXT B:GOODBYE.TXT
; and
; RECEIVE B:GOODBYE.TXT
; now work as expected.
;edit 8, 22-Oct-1990 by MF. Fixed bug in completion-message routine
; "finmes" wherein the completion message was not printed if the
; terminal was set to QUIET because the message pointer was clobbered
; by prcrlf.
;edit 7, 14-Sep-1990 by MF. Add hooks for SET COLLISION command.
; Eliminate commented-out old file warning rename routine.
; Clear communication input buffers (call flsmdm) before
; BYE, FINISH and LOGOUT commands.
;edit 6, 9-Sep-1990 by MF. Implemented fixes in CPKERM.BWR for
; garbage printout during quiet transfers and for file existence/
; rename algorithm.
; Also implemented hooks for Remote commands.
; edit 5, 18 June 1990 by Russell Lang [rjl@monu1.cc.monash.edu.au]
; When trying to generate a unique file name on receive, zero
; the attribute bits between file opening attempts. This is
; to fix a bug which caused the unique file name to have the
; attributes of the already existing file. If the attribute
; was R/O, a bdos error occured later when an attempt was made
; to write to the file.
;
; edit 4, 27 October, 1987 By OBSchou. Changed the rename routine to
; be more like the MSDOS issue.
;
; edit 3, 28 July, by OBSchou. Added traps to NOT print to screen during
; file transfers if quietd is non zero (ie we SET TERMINAL QUIET)
; This hopefully speeds up transfers in systems spending an age
; updating the screen.
;
; edit 2, 8 April, 1987 by OBSchou. Minor edit to put drive and user number
; in the "filename" field on the transfer screen. This means that the
; offset on the line foe the file name proper has moved along 4 space.
; Also, it writes 15 spaces AFER the xxd: string to clear the field
; of any prevous file. Needed for thos terminals that cannot
; clear to end of line...
;
; edit 1, 28 January, 1987 by OBSchou.
; Hived off about 1/2 of CPSPKT.ASM to form two (smaller => easier
; to handle) files.
;
;
pk2ver: db 'CPSPK2.ASM (11) 21-Mar-1991$' ; name, edit number, date
;
; Get the file name (including host to micro translation)
; called by: rfile
gofil: xra a
sta fcb ;Set the drive to default to current.
lxi h,data ;Get the address of the file name.
; allow use of local name if one was given [gnn]
lda remlen ;[gnn]
ora a ;[gnn] anything there?
jz gofil0 ;[gnn] no, use the one in the data packet
lxi h,remnam ;[gnn] yes, use this instead
lda remnam+1 ;[MF]Get 2nd char of local filename
cpi ':' ;[MF]Was a drive specified?
jnz gofil0 ;[MF]No, proceed as of old
mov a,m ;[MF]Yes, get drive
ani 5fh ;[MF]Force uppercase
sui 'A'-1 ;[MF]Make valid drive for fcb
sta fcb ;[MF]and store in fcb
inx h ;[MF]Skip drive and delimiter
inx h ;[MF]...
gofil0: ;[gnn] continue to set up the file [gnn]
;
shld datptr ;Store the address.
lxi h,fcb+1 ;Address of the FCB.
shld fcbptr ;Save it.
xra a
sta temp1 ;Initialize the char count.
sta temp2
mvi b,' '
gofil1: mov m,b ;Blank the FCB.
inx h
inr a
; cpi 0CH ;Twelve?[5a]
cpi 0BH ; Eleven? [5a]
jm gofil1
mvi m,0 ; [5a] Specify extent 0
gofil2: lhld datptr ;Get the NAME field.
mov a,m
cpi 'a' ;Force upper case
jm gofl2a ;
ani 5FH ;
gofl2a: inx h
cpi '.' ;Seperator?
jnz gofil3
shld datptr ;[jd] update ptr (moved from above)
lxi h,fcb+9H
shld fcbptr
lda temp1
sta temp2
mvi a,9H
sta temp1
jmp gofil6
gofil3: ora a ;Trailing null?
jz gofil7 ;Then we're done.
shld datptr ;[jd] no, can update ptr now.
lhld fcbptr
mov m,a
inx h
shld fcbptr
lda temp1 ;Get the char count.
inr a
sta temp1
cpi 8H ;Are we finished with this field?
jm gofil2
gofil4: sta temp2
lhld datptr
mov a,m
inx h
shld datptr
ora a
jz gofil7
cpi '.' ;Is this the terminator?
jnz gofil4 ;Go until we find it.
gofil6: lhld datptr ;Get the TYPE field.
mov a,m
cpi 'a' ;Force upper case
jm gofl6a ;
ani 5FH ;
gofl6a: ora a ;Trailing null?
jz gofil7 ;Then we're done.
;[jd] move above two lines so we don't increment pointer if char is null
inx h
shld datptr
lhld fcbptr
mov m,a
inx h
shld fcbptr
lda temp1 ;Get the char count.
inr a
sta temp1
cpi 0CH ;Are we finished with this field?
jm gofil6
gofil7: lhld datptr
mvi m,'$' ;Put in a dollar sign for printing.
lda quietd ; quiet display?
ana a
jnz gofi70 ; yes, so skip it.
call scrfln ;Position cursor
gofi70: lxi d,data ;Print the file name
lda getrxflg ;[obs 8] are we doing a get or receive?
ana a ;[obs 8]
jz gofi7a ;[obs 8] if zero, receive
lxi d,remnam ;[obs 8]
gofi7a: ;[obs 8]
call prtstr
gofi7b: xra a ;[MF]Zero "discard" flag
sta dscflg ;[MF]...
lda flwflg ;Is file warning on?
ora a
jz gofil9 ;If not, just proceed.
mvi c,openf ;See if the file exists.
lxi d,fcb
call bdos
cpi 0FFH ;Does it exist?
jz gofil9 ;If not create it.
;
lda flwflg ;[MF]Get flag again
cpi 3 ;[MF]SET COLLISION DISCARD?
jnz gofi7h ;[MF]No
mvi a,0ffh ;[MF]Yes, order rejection of the file
sta dscflg ;[MF]...
jmp rskp ;[MF]and pretend successful open
gofi7h: push psw ;[MF]Save Collision status
lxi d,infms5
call error3
pop psw ;[MF]Restore Collision status
cpi 1 ;[MF]SET COLLISION RENAME?
jz gofi7i ;[MF]Yes, same as SET WARNING ON
;[MF]If we come here, SET COLLISION BACKUP
lxi h,fcb ;[MF]Copy original fcb to a safe place
lxi d,colfcb ;[MF]...
lxi b,33 ;[MF]...
call mover ;[MF]...
;[MF]and fall into rename code
gofi7i: ;[MF]
;
; Replacement file name renamer routine. Incomming
; files are renamed in this manner:
; original file name: filex.ext
; first rename: filex001.ext
; ... ...
; ninth rename filex009.ext
; 10th rename fail - would we really want 10
; files of the same name??
;
;
; 1)
; Assume that we need to "rename" the file, so lets make sure
; that there is a full. 8 character filename. (We make it if
; it does not already exist)
; 1a) If full file name, last character is to be replaced
; by a zero. This gives us up to no#ine renames.
; 2)open file
; 2a)If exists, increment last character by one
; 2b)if = '9' then abort
; 2c)If does not exist, got 2)
; 3)we have a valid 'renamed' file
;
;Part 1) - fill out filename part
mvi c,8 ; max 8 characters to test for
mvi a,'0' ; spaces to be replaced by a zero.
lxi h,fcb+8 ; start at the end
gofi7c: mov m,a ; put a zero in here
dcr c ; come to the end?
jz gofi7d ; should not have, but just in case...
dcx h ; previous chararcter
mov a,m ; get it
cpi ' ' ; if this character a space as well, zero it
mvi a,'0' ; set it to ascii zero just in case...
jz gofi7c ;
;
; Part 2) open the file (if success, then it exists)
gofi7d:
;zero the attribute bits. [rjl@monu1.cc.monash.edu.au]
lxi h,fcb+1 ;[rjl]
mvi c,11 ;[rjl]
gofi7z: mov a,m ;[rjl]
ani 07fh ;[rjl]
mov m,a ;[rjl]
inx h ;[rjl]
dcr c ;[rjl]
jnz gofi7z ;[rjl]
lxi d,fcb
mvi c,openf
call BDOS
inr a ; if 0ffh returned, error (ie does not exist)
jz gofi7e
lda fcb+8 ; get last character
inr a
sta fcb+8
cpi '9'+1 ; more than '9' => too far, lets give up.
jnz gofi7d ; else try again
;Giving up, so lets exit
lxi d,erms16 ;
call prtstr
ret ; return to error routine
gofi7e: lxi d,fnbuf ; make the file name into a character string
lxi h,fcb+1 ; point to source file name, less drive name
mvi c,8 ; 11 characters (8+3) + dot to copy across
;
gofi7f: mov a,m ; get character
stax d
inx h
inx d
dcr c
jnz gofi7f ; loop until all done
mvi a,'.' ; then the dot
stax d
inx d
mvi c,3 ; then the file extention
gofi7g: mov a,m
stax d
inx h
inx d
dcr c
jnz gofi7g ; loop until extention copied across
mvi a,'$' ; dollar terminate string
stax d
lxi d,fnbuf ;[MF]Point to string
call prtstr ; write string to console
lda flwflg ;[MF]Get warning (SET COLLISION) flag
cpi 2 ;[MF]SET COLLISION BACKUP?
jnz gofil9 ;[MF]No
lxi h,fcb ;[MF]Yes, get new filename fcb
lxi d,colfcb+16 ;[MF]Where to copy to for rename
lxi b,16 ;[MF]Copy 16 bytes
call mover ;[MF]...
lxi d,colfcb ;[MF]Point to rename fcb
mvi c,renam ;[MF]Rename function
call bdos ;[MF]Try to rename original file
cpi 0ffh ;[MF]Did we win?
jnz gofl82 ;[MF]Yes
lxi d,erms16 ;[MF]No, complain and bomb
jmp error3 ;[MF]...
gofl82: lxi h,colfcb ;[MF]Now recopy original filename into fcb
lxi d,fcb ;[MF]to create new file with original name
lxi b,16 ;[MF]...
call mover ;[MF]...
;
;
;Now lets make the file (create it)
gofil9: call makfil ; Create the file.
jmp gofl91 ; Disk was full.
jmp rskp ; Success.
gofl91: lxi d,erms11
call error3
ret
;
; This is the FINISH command. It tells the remote KERSRV to exit.
; here from kermit
finish: call cfmcmd
call selmdm ;[MF]Select modem
call flsmdm ;[MF]Flush buffers
call selcon ;[MF]Select keyboard again
xra a
sta numtry ;Inititialize count.
mvi a,'1' ;Reset block check type to single character
sta curchk ; . . .
finsh1: lda numtry ;How many times have we tried?
cpi maxtry ;Too many times?
jm finsh3 ;No, try it.
finsh2: lxi d,erms18 ;Say we couldn't do it.
call prtstr
jmp kermit ;Go home.
finsh3: inr a ;Increment the number of tries.
sta numtry
xra a
sta argblk ;Make it packet number zero.
mvi a,1
sta argblk+1 ;One piece of data.
lxi h,data
mvi m,'F' ;Finish running Kermit.
mvi a,'G' ;Generic command packet.
call spack
jmp finsh2 ; Tell the user and die.
call rpack ;Get an acknowledgement.
jmp finsh1 ; Go try again.
cpi 'Y' ;ACK?
jz kermit ;Yes, we are done.
cpi 'E' ;Is it an error packet?
jnz finsh1 ;Try sending the packet again.
call error1 ;Print the error message.
jmp kermit
;
; This is the LOGOUT command. It tells the remote KERSRV to logout.
; here from: kermit
logout: call cfmcmd
call logo ;Send the logout packet.
jmp kermit ;Go get another command
jmp kermit ; whether we succeed or not.
; do logout processing.
; called by: bye, logout
logo: call selmdm ;[MF]Select modem
call flsmdm ;[MF]Flush buffers
call selcon ;[MF]Select keyboard again
xra a
sta numtry ;Inititialize count.
mvi a,'1' ;Reset block check type to single character
sta curchk ; . . .
logo1: lda numtry ;How many times have we tried?
cpi maxtry ;Too many times?
jm logo3 ;No, try it.
logo2: lxi d,erms19 ;Say we couldn't do it.
call prtstr
ret ;Finished.
logo3: inr a ;Increment the number of tries.
sta numtry
xra a
sta argblk ;Make it packet number zero.
mvi a,1
sta argblk+1 ;One piece of data.
lxi h,data
mvi m,'L' ;Logout the remote host.
mvi a,'G' ;Generic command packet.
call spack
jmp logo2 ; Tell the user and die.
call rpack ;Get an acknowledgement
jmp logo1 ; Go try again.
cpi 'Y' ;ACK?
jz rskp ;Yes, we are done.
cpi 'E' ;Is it an error packet?
jnz logo1 ;Try sending the packet again.
call error1 ;Print the error message.
ret ;All done.
;
; Packet routines
; Send_Packet
; This routine assembles a packet from the arguments given and sends it
; to the host.
;
; Expects the following:
; A - Type of packet (D,Y,N,S,R,E,F,Z,T)
; ARGBLK - Packet sequence number
; ARGBLK+1 - Number of data characters
; Returns: nonskip if failure
; skip if success
; called by: read, rinit, rfile, rdata, sinit, sfile, sdata, seof, seot,
; finish, logout, nak, ackp
spack: sta argblk+2
lxi h,packet ;Get address of the send packet.
lda sndsop ;[gnn] send start-of-pkt char.
mov m,a ;Put in the packet.
inx h ;Point to next char.
lda curchk ;Get current checksum type
sui '1' ;Determine extra length of checksum
mov b,a ;Copy length
lda argblk+1 ;Get the number of data chars.
adi ' '+3 ;Real packet character count made printable.
add b ;Determine overall length
mov m,a ;Put in the packet.
inx h ;Point to next char.
lxi b,0 ;Zero the checksum AC.
mov c,a ;Start the checksum.
lda argblk ;Get the packet number.
adi ' ' ;Add a space so the number is printable.
mov m,a ;Put in the packet.
inx h ;Point to next char.
add c
mov c,a ;Add the packet number to the checksum.
mvi a,0 ;Clear A (Cannot be XRA A, since we can't
; touch carry flag)
adc b ;Get high order portion of checksum
mov b,a ;Copy back to B
lda argblk+2 ;Get the packet type.
mov m,a ;Put in the packet.
inx h ;Point to next char.
add c
mov c,a ;Add the packet number to the checksum.
mvi a,0 ;Clear A
adc b ;Get high order portion of checksum
mov b,a ;Copy back to B
spack2: lda argblk+1 ;Get the packet size.
ora a ;Are there any chars of data?
jz spack3 ; No, finish up.
dcr a ;Decrement the char count.
sta argblk+1 ;Put it back.
mov a,m ;Get the next char.
inx h ;Point to next char.
add c
mov c,a ;Add the packet number to the checksum.
mvi a,0 ;Clear A
adc b ;Get high order portion of checksum
mov b,a ;Copy back to B
jmp spack2 ;Go try again.
spack3: lda curchk ;Get the current checksum type
cpi '2' ;Two character?
jz spack4 ;Yes, go handle it
jnc spack5 ;No, go handle CRC if '3'
mov a,c ;Get the character total.
ani 0C0H ;Turn off all but the two high order bits.
;Shift them into the low order position.
rlc ;Two left rotates same as 6 rights
rlc ; . . .
add c ;Add it to the old bits.
ani 3FH ;Turn off the two high order bits. (MOD 64)
adi ' ' ;Add a space so the number is printable.
mov m,a ;Put in the packet.
inx h ;Point to next char.
jmp spack7 ;Go store eol character
;Here for 3 character CRC-CCITT
spack5: mvi m,0 ;Store a null for current end
push h ;Save H
lxi h,packet+1 ;Point to first checksumed character
call crcclc ;Calculate the CRC
pop h ;Restore the pointer
mov c,e ;Get low order half for later
mov b,d ;Copy the high order
mov a,d ;Get the high order portion
rlc ;Shift off low 4 bits
rlc ; . . .
rlc ; . . .
rlc ; . . .
ani 0FH ;Keep only low 4 bits
adi ' ' ;Put into printing range
mov m,a ;Store the character
inx h ;Point to next position
;Here for two character checksum
spack4: mov a,b ;Get high order portion
ani 0FH ;Only keep last four bits
rlc ;Shift up two bits
rlc ; . . .
mov b,a ;Copy back into safe place
mov a,c ;Get low order half
rlc ;Shift high two bits
rlc ;to low two bits
ani 03H ;Keep only two low bits
ora b ;Get high order portion in
adi ' ' ;Convert to printing character range
mov m,a ;Store the character
inx h ;Point to next character
mov a,c ;get low order portion
ani 3FH ;Keep only six bits
adi ' ' ;Convert to printing range
mov m,a ;Store it
inx h ;Bump the pointer
spack7: lda dbgflg
ora a ; is debugging enabled?
jz spack8
push h ; yes. save address of end of packet
mvi m,0 ; null-terminate the packet for display
lda quietd ; a quiet display?
ana a
jnz spac7a ; so dont say a thing
call sppos ; position cursor
lxi h,packet+1 ; print the packet
call dmptxt
lda prnflg ; is the printer on too?
ana a
jz spac7a
lxi h,sstatm ; print state
call printm ; dumptext but to printer
lda state
mov e,a
call outprn
lxi h,princr ; cr lf to printer
call printm
lxi h,spackm
call printm
lxi h,packet+1
call printm
lxi h,princr
call printm
lxi h,princr
call printm
spac7a: pop h ; restore address of end of packet
spack8: lda seol ;Get the EOL the other host wants.
mov m,a ;Put in the packet.
inx h ;Point to next char.
xra a ;Get a null.
mov m,a ;Put in the packet.
; Write out the packet.
outpkt: call selmdm ; Set up for output to comm port if iobyt
lda spad ;Get the number of padding chars.
sta temp1
outpk2: lda temp1 ;Get the count.
dcr a
ora a
jm outpk6 ;If none left proceed.
sta temp1
lda spadch ;Get the padding char.
call setpar ;Set parity appropriately
mov e,a ;Put the char in right AC.
call outmdm ;Output it.
jmp outpk2
outpk6: lxi h,packet ; Point to the packet.
outlup: mov a,m ; Get the next character.
ora a ; Is it a null?
jz outlud ; If so return success.
call setpar ; Set parity for the character
mov e,a ; Put it in right AC
call outmdm ; and output it.
; TAC trap: If this character is the TAC intercept character, and the TAC
; trap is enabled, we have to output it twice. If the TAC trap is enabled,
; tacflg contains the intercept character. (The current character cannot
; be NUL, so we don't have to worry about doubling nulls in the message)
lda tacflg ; get current intercept character, or zero.
cmp m ; compare against current data character.
jnz outpk8 ; if different, do nothing.
call setpar ; match. set appropriate parity,
mov e,a ; put it in the right register,
call outmdm ; and output it a second time.
outpk8:
inx h ; Increment the char pointer.
jmp outlup
outlud: call selcon ; select console
jmp rskp ; and return success
;
; Receive_Packet
; This routine waits for a packet to arrive from the host. It reads
; characters until it finds a SOH. It then reads the packet into packet.
;
; Returns: nonskip if failure (checksum wrong or packet trashed)
; skip if success, with
; A - message type
; ARGBLK - message number
; ARGBLK+1 - length of data
; called by: rinit, rfile, rdata,
; sinit, sfile, sdata, seof, seot, finish, logout
rpack: call inpkt ;Read up to the end-of-line character
jmp r ; Return bad.
rpack0: call getchr ;Get a character.
jmp rpack ; Hit eol;null line;just start over.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jnz rpack0 ; No, go until it is.
rpack1: call getchr ;Get a character.
jmp r ; Hit end of line, return bad.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jz rpack1 ; Yes, then go start over.
sta packet+1 ;Store in packet also
mov c,a ;Start the checksum.
lda curchk ;Get block check type
sui '1' ;Determine extra length of block check
mov b,a ;Get a copy
mov a,c ;Get back length character
sui ' '+3 ;Get the real data count.
sub b ;Get total length
sta argblk+1
mvi b,0 ;Clear high order half of checksum
call getchr ;Get a character.
jmp r ; Hit end of line, return bad.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jz rpack1 ; Yes, then go start over.
sta argblk
sta packet+2 ;Save also in packet
add c
mov c,a ;Add the character to the checksum.
mvi a,0 ;Clear A
adc b ;Get high order portion of checksum
mov b,a ;Copy back to B
lda argblk
sui ' ' ;Get the real packet number.
sta argblk
call getchr ;Get a character.
jmp r ; Hit end of line, return bad.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jz rpack1 ; Yes, then go start over.
sta temp1 ;Save the message type.
sta packet+3 ;Save in packet
add c
mov c,a ;Add the character to the checksum.
mvi a,0 ;Clear A
adc b ;Get high order portion of checksum
mov b,a ;Copy back to B
lda argblk+1 ;Get the number of data characters.
sta temp2
lxi h,data ;Point to the data buffer.
shld datptr
rpack2: lda temp2
sui 1 ;Any data characters?
jm rpack3 ; If not go get the checksum.
sta temp2
call getchr ;Get a character.
jmp r ; Hit end of line, return bad.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jz rpack1 ; Yes, then go start over.
lhld datptr
mov m,a ;Put the char into the packet.
inx h ;Point to the next character.
shld datptr
add c
mov c,a ;Add the character to the checksum.
mvi a,0 ;Clear A
adc b ;Get high order portion of checksum
mov b,a ;Copy back to B
jmp rpack2 ;Go get another.
rpack3: call getchr ;Get a character.
jmp r ; Hit end of line, return bad.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jz rpack1 ; Yes, then go start over.
sui ' ' ;Turn the char back into a number.
sta temp3
;Determine type of checksum
lda curchk ;Get the current checksum type
cpi '2' ;1, 2 or 3 character?
jz rpack4 ;If zero, 2 character
jnc rpack5 ;Go handle 3 character
mov a,c ;Get the character total.
ani 0C0H ;Turn off all but the two high order bits.
;Shift them into the low order position.
rlc ;Two left rotates same as six rights
rlc ; . . .
add c ;Add it to the old bits.
ani 3FH ;Turn off the two high order bits. (MOD 64)
mov b,a
lda temp3 ;Get the real received checksum.
cmp b ;Are they equal?
jz rpack7 ;If so, proceed.
rpack9: call updrtr ;If not, update the number of retries.
ret ;Return error.
;Here for three character CRC-CCITT
rpack5: lhld datptr ;Get the address of the data
mvi m,0 ;Store a zero in the buffer to terminate packet
lxi h,packet+1 ;Point at start of checksummed region
call crcclc ;Calculate the CRC
mov c,e ;Save low order half for later
mov b,d ;Also copy high order
mov a,d ;Get high byte
rlc ;Want high four bits
rlc ; . . .
rlc ;And shift two more
rlc ; . . .
ani 0FH ;Keep only 4 bits
mov d,a ;Back into D
lda temp3 ;Get first value back
cmp d ;Correct?
jnz rpack9 ;No, punt
call getchr ;Get a character.
jmp r ; Hit end of line, return bad.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jz rpack1 ; Yes, then go start over.
sui ' ' ;Remove space offset
sta temp3 ;Store for later check
;...
;Here for a two character checksum and last two characters of CRC
rpack4: mov a,b ;Get high order portion
ani 0FH ;Only four bits
rlc ;Shift up two bits
rlc ; . . .
mov b,a ;Save back in B
mov a,c ;Get low order
rlc ;move two high bits to low bits
rlc ; . . .
ani 03H ;Save only low two bits
ora b ;Get other 4 bits
mov b,a ;Save back in B
lda temp3 ;Get this portion of checksum
cmp b ;Check first half
jnz rpack9 ;If bad, go give up
call getchr ;Get a character.
jmp r ; Hit end of line, return bad.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jz rpack1 ; Yes, then go start over.
sui ' ' ;Remove space offset
mov b,a ;Save in safe place
mov a,c ;Get low 8 bits of checksum
ani 3FH ;Keep only 6 bits
cmp b ;Correct value
jnz rpack9 ;Bad, give up
rpack7: lhld datptr
mvi m,0 ;Put a null at the end of the data.
lda temp1 ;Get the type.
jmp rskp
;
; inpkt - receive and buffer packet
; returns: nonskip if error (timeout)
; skip if success; packet starts at recpkt (which holds the SOH)
; and is terminated by a null.
; console is selected in either case.
; called by: rpack
inpkt: lxi h,recpkt ;Point to the beginning of the packet.
shld pktptr
inpkt1: call inchr ;Get first character
jmp r ;Return failure
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jnz inpkt1 ;if not, ignore leading junk
jmp inpkt3 ;else go put it in packet
inpkt2: call inchr ;Get a character.
jmp r ; Return failure.
lxi h,rcvsop ;[gnn] Is it receive start-of-pkt char.
cmp m ;[gnn]
jnz inpkt3 ;if not continue
lxi h,recpkt ;else throw away what we've got so far
shld pktptr ;
inpkt3: lhld pktptr ;
mov m,a ;Put the char in the packet.
inx h
shld pktptr
mov b,a
lxi d,-recpkx ;Start over if packet buffer overflow
dad d ;
jc inpkt ;buffer overflow
lda reol ;Get the EOL char.
cmp b
jnz inpkt2 ;If not loop for another.
;[gnn] *** added by Godfrey Nix Nottingham University ***
;[gnn] to allow Kermit server to echo our packets back
lxi h,recpkt+3 ;[gnn] point to packet type
lda packet+3 ;[gnn] get the one we sent
cmp m ;[gnn] are they the same?
jz inpkt ;[gnn] yes, get another packet
;[gnn] *** end of patch *****
;...
;...
;Begin IBM change/fdc
;This moved from OUTPK7 -- it appears that waiting until we're
;ready to send a packet before looking for turnaround character
;is long enough for it to get lost. Better to look now.
lda ibmflg ;Is this the IBM?
ora a
jz inpkt6 ;If not then proceed.
lda state ;Check if this is the Send-Init packet.
cpi 'S'
jz inpkt6 ;If so don't wait for the XON.
inpkt5: call inchr ;Wait for the turn around char.
jmp inpkt6
cpi xon ;Is it the IBM turn around character?
jnz inpkt5 ;If not, go until it is.
inpkt6: lhld pktptr ;Reload packet pointer
;End IBM change/fdc.
dcx h ;Back up to end of line character
mvi m,0 ;Replace it with a null to stop rpack:
call selcon ;We've got the packet. Return to console.
lda dbgflg ; Is debugging enabled?
ora a
jz inpkt7
inx h ; Point to next char.
lda quietd ; a quiet display?
ana a
jnz inpkt7 ; so dont say a thing
call rppos ; position cursor
lxi h,recpkt+1 ; print the packet
call dmptxt
lda prnflg ; is the printer on too?
ana a
jz inpkt7
lxi h,rstatm ; print state
call printm ; dumptext but to printer
lda state
mov e,a
call outprn
lxi h,princr ; cr lf to printer
call printm
lxi h,rpackm
call printm
lxi h,recpkt+1
call printm
lxi h,princr
call printm
lxi h,princr
call printm
inpkt7: lxi h,recpkt
shld pktptr ;Save the packet pointer.
jmp rskp ;If so we are done.
; getchr - get next character from buffered packet.
; returns nonskip at end of packet.
; called by: rpack
getchr: lhld pktptr ;Get the packet pointer.
mov a,m ;Get the char.
inx h
shld pktptr
ora a ;Is it the null we put at the end of the packet?
jnz rskp ;If not return retskp.
ret ;If so return failure.
;
;
; inchr - character input loop for file transfer
; returns: nonskip if timeout or character typed on console
; (console selected)
; skip with character from modem in A (parity stripped
; if necessary; modem selected)
; preserves bc, de, hl in either case.
; called by: inpkt
inchr: push h ; save hl and bc
push b
lhld timout ;Get initial value for timeout
shld timval ;[jd]
inchr0: call selmdm ;select modem
call inpmdm ;Try to get a character from the modem
ora a
jz inchr2 ;if zero, nothing there.
mov b,a
lda parity ;Is the parity none?
cpi parnon
mov a,b
jz inchr1 ;If so just return.
ani 7FH ;Turn off the parity bit.
inchr1: pop b ;restore registers
pop h
jmp rskp ;take skip return, character in A
inchr2: call selcon ;select console
call inpcon ; Try to get a character from the console
ora a
jz inchr6 ;If not go do timer thing
cpi cr ;Is it a carriage return?
jz inchr4 ;If so return
cpi ('Z'-100O) ;Control-Z?
jz inchr5 ;Yes, go flag it
cpi ('C'-100O) ;Control-C?
jz inchr7 ;re-enter, he wants to get out
cpi ('X'-100O) ;Control-X?
jnz inchr6 ;No, ignore it. do timer thing.
inchr5: adi 100O ;Convert to printing range
sta czseen ;Flag we saw a control-Z
jmp inchr6 ;[MF] and do timer thing
inchr4: pop b ; restore registers
pop h
ret ;And return
inchr6: lda timflg ;[jd] pick up timer flag
ora a ;[jd] are we allowed to use timer?
jz inchr0 ;[jd] no, don't time out
lhld timval ; decrement fuzzy time-out
dcx h ;
shld timval ;((timout-1) * loop time)
mov a,h ;(Retry if not time-out)
ora l ;
jnz inchr0 ;
call updrtr ;Count as retry (?)
pop b ;restore registers
pop h
ret ;and return to do retry
inchr7: call clrtop ;[hh] clear screen and home cursor
lda takflg ;[MF]Take-file in progress?
ani 1 ;[MF]...
cnz closet ;[MF]Yes, close it and reset TAKE-flag
;[MF]so all processing is halted
jmp kermit ;[hh] then re-enter kermit
;
; CRCCLC - Routine to calculate a CRC-CCITT for a string.
;
; This routine will calculate a CRC using the CCITT polynomial for
; a string.
;
; call with: HL/ Address of null-terminated string
; 16-bit CRC value is returned in DE.
; Registers BC and HL are preserved.
;
; called by: spack, rpack
crcclc: push h ;Save HL
push b ;And BC
lxi d,0 ;Initial CRC value is 0
crccl0: mov a,m ;Get a character
ora a ;Check if zero
jz crccl1 ;If so, all done
push h ;Save the pointer
xra e ;Add in with previous value
mov e,a ;Get a copy
ani 0FH ;Get last 4 bits of combined value
mov c,a ;Get into C
mvi b,0 ;And make high order zero
lxi h,crctb2 ;Point at low order table
dad b ;Point to correct entry
dad b ; . . .
push h ;Save the address
mov a,e ;Get combined value back again
rrc ;Shift over to make index
rrc ; . . .
rrc ; . . .
ani 1EH ;Keep only 4 bits
mov c,a ;Set up to offset table
lxi h,crctab ;Point at high order table
dad b ;Correct entry
mov a,m ;Get low order portion of entry
xra d ;XOR with previous high order half
inx h ;Point to high order byte
mov d,m ;Get into D
pop h ;Get back pointer to other table entry
xra m ;Include with new high order half
mov e,a ;Copy new low order portion
inx h ;Point to other portion
mov a,m ;Get the other portion of the table entry
xra d ;Include with other high order portion
mov d,a ;Move back into D
pop h ;And H
inx h ;Point to next character
jmp crccl0 ;Go get next character
crccl1: pop b ;Restore B
pop h ;And HL
ret ;And return, DE=CRC-CCITT
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
CRCTB2: DW 00000H
DW 01189H
DW 02312H
DW 0329BH
DW 04624H
DW 057ADH
DW 06536H
DW 074BFH
DW 08C48H
DW 09DC1H
DW 0AF5AH
DW 0BED3H
DW 0CA6CH
DW 0DBE5H
DW 0E97EH
DW 0F8F7H
;
; This is where we go if we get an error during a protocol communication.
; error prints the error packet on line 6 or so, and aborts the
; transfer.
; called by: rinit, rfile, rdata, sinit, sfile, sdata, seof, seot
; error1 print CRLF followed by the error packet.
; called by: finish, logout
; error2 just prints the error packet.
; error3 positions cursor and prints error message specified in DE.
; called by: rinit, rfile, rdata, sinit, sfile, sdata, seof,
; seot, parwrn, gofil, outbuf
error: lda quietd ; a quiet display?
ana a
jnz error0 ; so dont say a thing
lda remtxt ;[MF]Doing a remote command?
ora a ;[MF]...
jnz error0 ;[MF]Yes, don't position cursor
call screrr ;Position the cursor.
error0: mvi a,'A' ;Set the state to abort.
sta state
jmp error2
error1: lxi d,crlf ;Print a CRLF.
lda quietd ; a quiet display?
ana a
jnz error2 ; so dont say a thing
call prtstr
error2: lda argblk+1 ;Get the length of the data.
mov c,a
mvi b,0 ;Put it into BC
lxi h,data ;Get the address of the data.
dad b ;Get to the end of the string.
mvi m,'$' ;Put a dollar sign at the end.
lxi d,data ;Print error message
lda remtxt ;[MF]Doing a remote command?
ora a ;[MF]...
jnz errr2a ;[MF]Yes, print message, quiet or not!
lda quietd ; a quiet display?
ana a
rnz ; so dont say a thing
errr2a: call prtstr
ret
error3: lda quietd ; a quiet display?
ana a
rnz ; so dont say a thing
lda remtxt ;[MF]Doing a remote command?
ora a ;[MF]...
jnz err3a ;[MF]Yes, don't position cursor
push d ;Save the pointer to the message.
call screrr ;Position the cursor.
pop d ;Get the pointer back.
err3a: call prtstr ;Print error message
ret
;
; Set up for file transfer.
; called by read, send.
init: lxi d,version ; point at Kermit's version string
lda quietd ; a quiet display?
ana a
jnz init1 ; so dont say a thing
call sysscr ; fix up screen
init1: call selmdm ; select modem
call flsmdm ; purge any pending data
call selcon ; select console again.
ret
; Set state to ABORT
; called by: rinit, rfile, rdata, sinit, sfile, sdata, seof, seot,
; nak, ackp
abort: mvi a,'A' ;Otherwise abort.
sta state
ret
; nak - send NAK packet
; here from: rinit, rfile, rdata
; nak0 - update retry count and send NAK packet
; here from: rinit, rfile, rdata, tryagn
nak0: call updrtr ;Update number of retries.
nak: lda pktnum ;Get the packet number we're waiting for.
sta argblk
xra a ;No data.
sta argblk+1
mvi a,'N' ;NAK that packet.
call spack
jmp abort ; Give up.
ret ;Go around again.
; increment and display retry count
; called by: rfile, sinit, sfile, sdata, seof, seot,
; nak, rpack, inchr, tryagn
updrtr: lhld numrtr
inx h ;Increment the number of retries
shld numrtr
lda remtxt ;[MF]Doing a remote server command?
ora a ;[MF]...
rnz ;[MF]Yes, keep mum
lda quietd ; a quiet display?
ana a
rnz ; so dont say a thing
call scrnrt ;Position cursor
lhld numrtr ;[MF]
call nout ;Write the number of retries.
ret
; [jd] this routine prints parity warnings. All registers are
; saved except for a.
; called by: sdata
parwrn: push b
push d
push h
lxi d,inms25
call error3
pop h
pop d
pop b
ret
;[jd] end of addition
; print message in status field. address of message is in DE.
; called by: read, send
finmes: lda quietd ; a quiet display?
ana a
jz finme0 ; so do usual stuff
push d ;[MF]Save pointer to completion message
call prcrlf ; best do a new line
pop d ;[MF]Restore completion message pointer
call prtstr ; and send message
mvi e,space ; send a space or two
mvi c,dconio
push b
push d
call bdos
pop d
pop b
call bdos
ret ; and exit back
;
;else for screaming screens...
finme0: push d ;Save message.
call scrst ;Position cursor
pop d ;Print the termination message
call prtstr
ret ; may not want this **************
mvi c,4 ;[2] copy across user no and drive
lxi h,kerm1 ;[2] as we have the text already
finme1: mov e,m
push h ;[2] conout probably destroys these
push b
call conout
pop b
pop h
inx h ;[2] next character
dcr c ;[2] ah, but have we done?
jnz finme1 ;[2] nope
lxi d,spac15 ;[2] send 15 spaces (clears previous filename)
call prtstr ;[2]
call scrend ;Position cursor for prompt
ret
; Compare expected packet number against received packet number.
; return with flags set (Z = packet number valid)
; called by: rfile, rdata, sinit, sfile, sdata, seof, seot
compp: lda pktnum ;Get the packet Nr.
mov b,a
lda argblk
cmp b
ret
; Increment the packet number, modulo 64.
; called by: rinit, rfile, rdata, sinit, sfile, sdata, seof, seot
countp: inr a ;Increment packet Nr.
ani 3FH ;Turn off the two high order bits
sta pktnum ;Save modulo 64 of number
lhld numpkt
inx h ;Increment Nr. of packets
shld numpkt
ret
; Send an ACK-packet
; called by: rfile, rdata, tryagn
ackp: xra a
sta numtry ;Reset number of retries
sta argblk+1 ;No data. (The packet number is in argblk)
mvi a,'Y' ;Acknowledge packet
call spack ;Send packet
jmp abort
ret
; ?
; called with A/ current retry count
; called by: rfile, rdata
tryagn: inr a ;Increment it.
sta oldtry ;Save the updated number of tries.
lda pktnum ;Get the present packet number.
dcr a ;Decrement
ani 3FH ; modulo 64
mov b,a
lda argblk ;Get the packet's number
cmp b ;Is the packet's number one less than now?
jnz nak0 ;No, NAK it and try again.
call updrtr ;Update the number of retries.
call ackp
ret
; Output a null-terminated string to the console. We assume that the
; console has been selected. Called with HL = address of string.
; called by: spack, inpkt
dmptxt: mov a,m ; get character from string
ora a
rz ; done if null
push h ; save string address
mov e,a ; move character to E for outcon
call outcon ; output character to console
pop h ; restore string address
inx h ; point past printed character
jmp dmptxt ; go output rest of string
; Output a null-terminated string to the PRINTER We assume that the
; console has been selected. Called with HL = address of string.
; called by: spack, inpkt
printm: mov a,m ; get character from string
ora a
rz ; done if null
push h ; save string address
mov e,a ; move character to E for outcon
call outprn ; output character to printer
pop h ; restore string address
inx h ; point past printed character
jmp printm ; go output rest of string
;
; test if character in A is the start of header character. We get
; the start of packet character from sohchr, which can be SET
tstsoh: push b ; save these registers for a bit
mov c,a ; we have to test if this is the character
lda sohchr
cmp c ; if zero, then it is
mov a,c ; restore accumulator but not flags
pop b
ret ; return with flags set
;
; Little code to allow some expansion of code without changing
; every futher address, only up to the end of this file.
; TO BE REMOVED FRO RELEASE!
; org ($+100h) AND 0FF00H
IF lasm
LINK CPSREM
ENDIF;lasm