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04-06-88/MANUAL
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » CEEFAX disks » telesoftware7.adl |
| Filename: | 04-06-88/MANUAL |
| Read OK: | ✔ |
| File size: | 4FEC bytes |
| Load address: | 0000 |
| Exec address: | FFFFFFFF |
File contents
TELETEXT SERVER SYSTEM
The system consists of three programs
1. A basic program 'TFS' which runs in the machine with the teletext
adaptor (henceforth called the SERVER)
2. A machine code routine 'code' which is *RUN by the program TFS.
3. A machine code program 'TELETEXT' which runs in the local machine
(henceforth called the CLIENT)
The server and client communicate on ports &B2, &B3, &B4 and &B5. The base
port number of &B2 is transmitted to the client in accordance with the
Find Server protocol. It is possible to write programs to communicate with
the TELETEXT-SERVER using these ports but it could be that updates of the
server software may use a different base port number, in which case such
programs will cease to work.
The TELETEXT program
This locates at &FFFF6E00 and so should not corrupt any BASIC program in
the CLIENT's memory. It will work with all versions of the BBC B, B+,
MASTER and ET. The program will also communicate with a SERVER across a
bridge although some of the headers may be lost as these are broadcast and
there is no collision detect across a bridge.
1. The first action is to open a receive block to receive a
TELETEXT-SERVER's reply to a find server request. This receive block
listens on port &B1 to all stations, as at this stage the CLIENT does not
know the station number of the SERVER.
2. The CLIENT broadcasts to all stations on port &B0 with a data field
containing 'TELETEXT' this being the name to which a TELETEXT-SERVER will
respond. The first SERVER to respond will be the one with which the CLIENT
subsequently interacts. Should more than one server be available then it
is possible to connect to a specific server by using its station number eg
*TELETEXT 2.45. You may wish to do this if you know that one server
receives a better signal than another, on the channel you wish to use.
3. The CLIENT polls the receive block until a SERVER responds or <ESCAPE>
is pressed.
4. The CLIENT reads the SERVER's reply and stores the SERVER's station and
network number. The base port number (&B2) is used to calculate the ports
for further communication. The CLIENT selects MODE 7, prints the SERVER's
station number (suppressing the network number if it is zero) and also the
version number.
5. The CLIENT opens three receive blocks. One on port &B5 (base+3) ready
to receive any page headers which arrive, one on port &B2 (base) ready to
receive any SERVER replies and one on port &B4 (base+2) to receive any
pages.
6. The CLIENT sends a request for page 1100 (the first digit indicates the
channel number). This is on port &B3 (base+1) with a control byte of &81.
The reply receive block is then polled until the SERVER responds. The
position in the queue returned by the SERVER is printed at the bottom of
the page. A new receive block for replies on port &B2 is set up. If an
error occurs then the error message is displayed at the bottom of the
screen and the page input routine is entered or if the error was a 'Bad
channel' error then the channel input routine is entered.
7. The CLIENT polls both receive blocks for a page (port &B4) and for a
header (port &B5), until one or the other receives a transmission.
8. If a page header is received then the cursor is moved to the header
position and it is printed out. An identical receive block is then set up
to replace the one which has been used.
9. If a requested page is received the first action is to test the control
byte. If this is &80 then it indicates the page has been found and is in
the receive block buffer ready to be transferred to the screen. If the
control byte is &81 then this indicates some error has occurred and that
an error message is in the receive block buffer waiting to be printed.
10. If an error has occurred then the error message is printed at the
bottom of the screen and the CLIENT program jumps to the page number input
routine to get another page number. A new receive block for a page is set
up.
11. If a page is successfully received then it is displayed. A new receive
block for a page is set up. The header receive block continues to be
polled and displayed until a key is pressed.
12. All the time the receive blocks are being polled the CLIENT program
also tests to see if a key has been pressed. If a key is pressed this is
taken to mean that you are about to request a new page. If 'C' is pressed
then the input channel routine is entered followed by the input page
routine. If <RETURN> is pressed then the last page you requested is
requested again. If 'R' is pressed the 'REVEAL' routine is called and this
toggles between revealing and concealing. If '*' is pressed then the star
command routine is entered. This allows the CLIENT to *SAVE pages etc. If
any other key is pressed the page input routine is entered.
13. The first action taken by both the channel input and page input
routines is to send a 'cancel page request' to the SERVER and then delete
the current page receive block. This means the SERVER will no longer have
to bother trying to find your last requested page. The prompt for a
channel input is 'C' and for a page input is 'P'. Both routines make use
of OSWORD 0 to read a line of input and so both need to be exited by
pressing <RETURN>. A new receive page block is set up and then the new
page number is transmitted to the SERVER.
14. The escape flag is continually polled so that the CLIENT can exit at
any time by pressing <ESCAPE>. This will send a logoff instruction to the
SERVER which stops it looking for any more pages for you. All receive
blocks are deleted.
Sub-pages
One of the features of the normal use of teletext is that pages will roll
so that they are constantly updated eg. for cricket scores or pages with
more than one screen of information. An approximation to this facility is
available from the SERVER. Pressing 'S' will enable the automatic rolling
of sub-pages. This is done by a call to the SERVER which signals that the
requested page must not be sent until at least 0.5 of the cycle time has
elapsed. Automatic rolling of sub-pages can be disabled by pressing 'S'
again. Enabling is signalled by a high beep and disabling by a low beep.
The rolling is disabled whenever a new page is requested.
This implementation of sub-pages is a compromise in that as more clients
use this feature the more full will be the queues and it is for this
reason automatic rolling must be deliberately selected for every new page.
It is also not possible to guarantee that you will get the immediately
following sub-page in the sequence.
The TFS program
This program makes as full use as possible of the ATFS rom's ability to
search for several pages at once. The theoretical maximum is 20 at once
but the size of the TFS program limits this to about 10. The main problem
is that it is only possible to search for pages on one channel at a time
and some way has to be found to deal with this.
The approach adopted is to place a page request into one of 4 queues, one
for each channel. If the number of pages in a queue exceeds the maximum
number of pages for which the ATFS rom has space then a 'Channel busy'
error will be returned. This maximum number of pages is the number
returned by the max users per channel call. A record is kept of the total
number of pages requested and this is the queue position returned to the
CLIENT ie this is the overall queue position and not the position in the
queue for a particular channel. Whenever a page request is received the
whole queue is checked to see if that CLIENT (identified by the station
number) has any other page requested. If this is the case then that page
is dropped from the queue. Thus it is not possible for a CLIENT to request
more than one page at once. A cancel page request or a logoff will result
in all page requests for that CLIENT being dropped from the queue.
The way the ATFS rom works means that if you are 3rd in the queue you may
still receive your page before the CLIENT who is in 1st position. This is
probably best illustrated by example.
Suppose the following requests are issued :
Station 12 page 170 on channel 1
Station 14 page 400 on channel 4
Station 17 page 123 on channel 1
The TFS program will select channel 1 as this is the highest priority item
in the queue. When station 14's request arrives it will be stored in the
queue for channel 4. However when station 17's request arrives not only is
it added to the queue for channel 1 but a record is set up to receive the
page if it is transmitted. Suppose all these three requests arrive almost
simultaneously and at the moment the TFS program selects channel 1 the
page being transmitted is page 112. This means that station 17's page
(123) will arrive before station 12's page(170). Thus station 17 will
receive it's page first even though it was 3rd in the queue. The next page
to be sent will be 170 to station 12 and station 14 will receive its page
last even though it was 2nd in the queue. This is not disaster as in fact
station 12 has had no longer to wait than it would have had anyway. What
we have managed to do is also deal with station 17 as a spin-off from
station 1's request.
If more than one station requests the same page then this is spotted and
only one of the ATFS records is used. This means that it is possible to
have more than the maximum number of users per channel queued if that
channel is the currently selected one.
When an ATFS record has been used the page it was looking for is
remembered and once that page has been found the record is not cleared.
This means that provided the channel is not changed this page will
continue to be updated and will be permanently available. Suppose a CLIENT
requests page 171; the page is received and then transmitted. If another
CLIENT (or indeed the same one) requests the same page then it is
instantly available. This is particularly useful if you happen to be the
only CLIENT using the system as it means that the last 10 or so pages you
have requested on a given channel are not only buffered by the TFS
program, but also updated and instantly available.
The TFS program broadcasts whatever page number is currently at the top of
the screen by using the timer crossing zero event. This occurs every half
second.
Overall the response time of the system is very fast although it will
obviously be slowed down if CLIENTs request non-existent pages. The cycle
times for the different channels are important to the efficiency of the
TFS program and as these times may be subject to change they have been
included in a DATA statement at the very end of the program. The first
DATA statement is the fraction of the cycle time for which the TFS program
will wait before sending a sub-page. This is currently 0.5. The second
DATA statement consists of the cycle times for the four channels in
hundredths of a second. They are currently set to 40 seconds each.
Installing the programs
1. Place 'TELETEXT' program in $.LIBRARY
2. Put 'TFS' and 'code' in a directory of their own. This might be the
root directory of a user TFS. If this user has a !BOOT file which CHAINs
the 'TFS' program then the whole system can be initialised by simply
typing *I AM TFS. The machine running the TFS program must not use shadow
screens as the header is POKED in to memory at &7C00 by the ATFS Rom. The
program may run in a second processor, in which case the whole of the I/O
processor memory becomes available for buffering pages and there will be
an associated increase in performance. There is no advantage in using
HIBASIC as the pages are buffered in the I/O processor.
Compatibility with the new GIS adapter
The software is compatible with the new GIS teletext adapter although as
this connects to the user port rather than the 1MHz Bus the speed of
response is slightly slower. There appears to be a problem with the
routine to calculate the checksum of a page in that the GIS Rom gets it
wrong if a page header was broadcast while performing the check. There
does seem to be a problem with the MASTER 128 and the TUBE in that the
software will not work with either adapter in this configuration. This
looks like it may be a problem with the ANFS.
Writing your own software
Below is an example of a BASIC program which illustrates how to write your
own software using the SERVER protocols. Using this principle it is
possible to write programs for automatically receiving and saving pages.
Read the time from a TELETEXT server
10 osword=&FFF1:osbyte=&FFF4
20 DIM blk% &100,buff &100
30 REPEAT
40 :REM Set up receive blk for SERVER reply
50 rx_no=FNset_up_rx(&B1,0,buff,&20)
:REM Listen for all stations as we don't know the server station number
70 REPEAT
80 PROCbcast(&B0,&80,"TELETEXT") :REM Broadcast for a TELETEXT server
90 TIME=0
100 REPEAT UNTIL TIME>50 :REM Wait for a while before retrying
110 UNTIL FNpoll_rx(rx_no)>127 :REM Keep trying until a reply received
120
130 PROCread_rx(rx_no) :REM Read the receive block
140 buff?11=13 :REM Check that it really was a TELETEXT
150 UNTIL $(buff+3)="TELETEXT" :REM server which responded
160 server%=blk%!3 AND &FFFF :REM Read the server's number
170 base_port=buff?1 :REM Read the base port number
180 rx_no=FNset_up_rx(base_port,server%,buff,&20)
:REM Set up a receive blk
190 REPEAT :REM for the time
200 REPEAT
210 PROCtx(&84,base_port+1,server%,buff,1)
:REM Transmit request for the time
220 TIME=0 :REM Wait for a while before retrying
230 REPEAT UNTIL TIME>50
240 result%=FNpoll_tx
250 UNTIL result%=0 :REM Keep trying until transmit succeeds
260 UNTIL FNpoll_rx(rx_no)>127 :REM Keep trying until we get a reply
270 PROCread_rx(rx_no) :REM Read the receive block
280
290 buff?19=13
300 date$=$(buff+9) :REM Read the date
310 buff?9=13
320 time$=$(buff+1) :REM Read the time
330 PRINT"The time is ";time$;" on ";date$
340 END
350
360 DEFPROCbcast(p%,cb%,server$)
370 ?blk%=cb%
380 blk%?1=p%
390 blk%!2=&FFFF
400 $(blk%+4)=server$
410 X%=blk%:Y%=X% DIV 256:A%=&10
420 CALL osword
430 ENDPROC
440
450 DEFFNset_up_rx(p%,st%,b%,l%)
460 ?blk%=0
470 blk%?1=&7F
480 blk%?2=p%
490 blk%!3=st%
500 blk%!5=b%
510 blk%!9=b%+l%
520 X%=blk%:Y%=X% DIV 256:A%=&11
530 CALL osword
540 =?blk%
550
560 DEFFNpoll_rx(r%)
570 A%=&33:X%=r%
580 =USR(osbyte) AND &8000
590
600 DEFPROCread_rx(r%)
610 ?blk%=r%
620 X%=blk%:Y%=X% DIV 256:A%=&11
630 CALL osword
640 ENDPROC
650
660 DEFPROCtx(cb%,p%,st%,b%,l%)
670 ?blk%=cb%
680 blk%?1=p%
690 blk%!2=st%
700 blk%!4=b%
710 blk%!8=b%+l%
720 X%=blk%:Y%=X% DIV 256:A%=&10
730 CALL osword
740 ENDPROC
750
760 DEFFNpoll_tx
770 REPEAT
780 A%=&32
790 test%=(USR(osbyte) AND &FF00) DIV &100
800 UNTIL test%<128
810 =test%
SERVER Extensions
As you will find in the protocols section of this article a further
non-teletext related call has been included in the SERVER. This call
returns the value of the analogue ports. This means various devices can be
attached to the analogue port of the SERVER and can be sampled from
anywhere on the network. We are using this to monitor the outside
temperature.
TELETEXT SERVER PROTOCOLS
All communications between teleserver and client are conducted on ports
base-base+3 (currently &B2-&B5). Transmissions from client to server are
on port &B3 and replies from the server are on port &B2. Port &B5 is
reserved for broadcasting the current page number being picked up by the
server and port &B4 is used for transmitting the page itself.
It is necessary to use four ports because the client may wish to have
three receive blocks open at the same time. One to continually update the
page header, one to request other information and one to receive the page
itself.
The page currently being received is broadcast on port &B5 and consists of
4 bytes:
Byte 1 Channel number in ASCII
Bytes 2-4 Page number in ASCII
All transmissions to the teleserver will result in a reply being sent. The
teleserver gives up if a 'Not listening' error occurs 5 times. There are
two standard forms of reply.
a) If an error has occurred (eg you have requested a silly page number or
channel number) then the first byte of the reply data will be an error
number and the following bytes will be an error message terminated by a
carriage return.
b) If no error has occurred the first byte of the reply data will be zero
and the subsequent bytes will be dependent on the call issued.
read teleserver version number
1/client to teleserver
port &B3
control byte &80
data nil
2/teleserver to client
port &B2
control byte &80
data 0 or error number
data+1 version number as character string terminated by c/r
issue page request
1/client to teleserver
port &B3
control byte &81
data channel number in ASCII
data+1-data+3 page number in ASCII
2/teleserver to client
port &B2
control byte &81
data 0 or error number
data+1 position in queue
cancel page request
1/client to teleserver
port &B3
control byte &82
data nil
2/teleserver to client
port &B2
control byte &82
data 0 or error number
data+1 nil
read max users per channel
1/client to teleserver
port &B3
control byte &83
data nil
2/teleserver to client
port &B2
control byte &83
data 0 or error number
data+1 max users
read date and time
1/client to teleserver
port &B3
control byte &84
data nil
2/teleserver to client
port &B2
control byte &84
data 0 or error number
data+1 time and date in ASCII (HH:MM:SSDD/MM/YYYY)
logoff
1/client to teleserver
port &B3
control byte &85
data nil
2/teleserver to client
port &B2
control byte &85
data 0 or error number
data+1 nil
page request with time delay
1/client to teleserver
port &B3
control byte &86
data channel number in ASCII
data+1-data+3 page number in ASCII
2/teleserver to client
port &B2
control byte &86
data 0 or error number
data+1 position in queue
request port value
1/client to teleserver
port &B3
control byte &87
data port number in range 0 to 3
2/teleserver to client
port &B2
control byte &87
data 0 or error number
data+1-data+2 port value
Reception of the teletext page
The teleserver sends the page on port &B4. The control byte will be &80 if
no error has occurred otherwise the control byte will be &81. The only
error that will occur will be a 'Timed out' error ie you have probably
asked for a non-existent page. The data in the receive block buffer will
be the page requested if there is no error, otherwise the data will be an
error message terminated by a carriage return.If you successfully receive
a page then locations &3FE and &3FF into the receive block buffer will
contain the sub page number in BCD format. &3FE contains the hi-byte and
&3FF contains the lo-byte
========================================================
ERROR NUMBERS
Possible error numbers are:
1 Bad page number
2 Bad channel
3 Channel busy
4 Time unavailable
5 Bad port
If an error is received then an error message terminated by a carriage
return will be returned in data+1.
The SERVER's receive buffer is &50 bytes.
The SERVER transmits a block of &400 bytes on port &B3 when transmitting a
page. It transmits a block of &20 bytes in all other cases.
-------------------------------
Logging on to the server
Client to Server
port &B0
control byte &80
Data The string TELETEXT as standard ASCII (the server type)
Server to Client
port &B1
control byte &80
Data 0 or error number
Data+1 base port number for further exchanges
Data+2 binary verison number of the server software
Data+3 Server type (8 chars, format as for Client to Server)
Data+11 Length of server name (=0 if not present)
Data+12 Server name (optional)
Data+12+NameLen Server type dependant OR error string
The length of the receive block buffer needed to receive this response
from the server will not exceed &20 bytes.
00000000 20 20 20 20 20 20 20 20 20 20 20 20 20 20 54 45 | TE| 00000010 4c 45 54 45 58 54 20 53 45 52 56 45 52 20 53 59 |LETEXT SERVER SY| 00000020 53 54 45 4d 0d 0d 54 68 65 20 73 79 73 74 65 6d |STEM..The system| 00000030 20 63 6f 6e 73 69 73 74 73 20 6f 66 20 74 68 72 | consists of thr| 00000040 65 65 20 70 72 6f 67 72 61 6d 73 0d 0d 31 2e 20 |ee programs..1. | 00000050 41 20 62 61 73 69 63 20 70 72 6f 67 72 61 6d 20 |A basic program | 00000060 27 54 46 53 27 20 77 68 69 63 68 20 72 75 6e 73 |'TFS' which runs| 00000070 20 69 6e 20 74 68 65 20 6d 61 63 68 69 6e 65 20 | in the machine | 00000080 77 69 74 68 20 74 68 65 20 74 65 6c 65 74 65 78 |with the teletex| 00000090 74 0d 61 64 61 70 74 6f 72 20 28 68 65 6e 63 65 |t.adaptor (hence| 000000a0 66 6f 72 74 68 20 63 61 6c 6c 65 64 20 74 68 65 |forth called the| 000000b0 20 53 45 52 56 45 52 29 0d 32 2e 20 41 20 6d 61 | SERVER).2. A ma| 000000c0 63 68 69 6e 65 20 63 6f 64 65 20 72 6f 75 74 69 |chine code routi| 000000d0 6e 65 20 27 63 6f 64 65 27 20 77 68 69 63 68 20 |ne 'code' which | 000000e0 69 73 20 2a 52 55 4e 20 62 79 20 74 68 65 20 70 |is *RUN by the p| 000000f0 72 6f 67 72 61 6d 20 54 46 53 2e 0d 33 2e 20 41 |rogram TFS..3. A| 00000100 20 6d 61 63 68 69 6e 65 20 63 6f 64 65 20 70 72 | machine code pr| 00000110 6f 67 72 61 6d 20 27 54 45 4c 45 54 45 58 54 27 |ogram 'TELETEXT'| 00000120 20 77 68 69 63 68 20 72 75 6e 73 20 69 6e 20 74 | which runs in t| 00000130 68 65 20 6c 6f 63 61 6c 20 6d 61 63 68 69 6e 65 |he local machine| 00000140 0d 28 68 65 6e 63 65 66 6f 72 74 68 20 63 61 6c |.(henceforth cal| 00000150 6c 65 64 20 74 68 65 20 43 4c 49 45 4e 54 29 0d |led the CLIENT).| 00000160 0d 54 68 65 20 73 65 72 76 65 72 20 61 6e 64 20 |.The server and | 00000170 63 6c 69 65 6e 74 20 63 6f 6d 6d 75 6e 69 63 61 |client communica| 00000180 74 65 20 6f 6e 20 70 6f 72 74 73 20 26 42 32 2c |te on ports &B2,| 00000190 20 26 42 33 2c 20 26 42 34 20 61 6e 64 20 26 42 | &B3, &B4 and &B| 000001a0 35 2e 20 54 68 65 20 62 61 73 65 0d 70 6f 72 74 |5. The base.port| 000001b0 20 6e 75 6d 62 65 72 20 6f 66 20 26 42 32 20 69 | number of &B2 i| 000001c0 73 20 74 72 61 6e 73 6d 69 74 74 65 64 20 74 6f |s transmitted to| 000001d0 20 74 68 65 20 63 6c 69 65 6e 74 20 69 6e 20 61 | the client in a| 000001e0 63 63 6f 72 64 61 6e 63 65 20 77 69 74 68 20 74 |ccordance with t| 000001f0 68 65 0d 46 69 6e 64 20 53 65 72 76 65 72 20 70 |he.Find Server p| 00000200 72 6f 74 6f 63 6f 6c 2e 20 49 74 20 69 73 20 70 |rotocol. It is p| 00000210 6f 73 73 69 62 6c 65 20 74 6f 20 77 72 69 74 65 |ossible to write| 00000220 20 70 72 6f 67 72 61 6d 73 20 74 6f 20 63 6f 6d | programs to com| 00000230 6d 75 6e 69 63 61 74 65 20 77 69 74 68 0d 74 68 |municate with.th| 00000240 65 20 54 45 4c 45 54 45 58 54 2d 53 45 52 56 45 |e TELETEXT-SERVE| 00000250 52 20 75 73 69 6e 67 20 74 68 65 73 65 20 70 6f |R using these po| 00000260 72 74 73 20 62 75 74 20 69 74 20 63 6f 75 6c 64 |rts but it could| 00000270 20 62 65 20 74 68 61 74 20 75 70 64 61 74 65 73 | be that updates| 00000280 20 6f 66 20 74 68 65 0d 73 65 72 76 65 72 20 73 | of the.server s| 00000290 6f 66 74 77 61 72 65 20 6d 61 79 20 75 73 65 20 |oftware may use | 000002a0 61 20 64 69 66 66 65 72 65 6e 74 20 62 61 73 65 |a different base| 000002b0 20 70 6f 72 74 20 6e 75 6d 62 65 72 2c 20 69 6e | port number, in| 000002c0 20 77 68 69 63 68 20 63 61 73 65 20 73 75 63 68 | which case such| 000002d0 0d 70 72 6f 67 72 61 6d 73 20 77 69 6c 6c 20 63 |.programs will c| 000002e0 65 61 73 65 20 74 6f 20 77 6f 72 6b 2e 0d 0d 20 |ease to work... | 000002f0 20 20 20 20 20 20 20 20 20 20 20 20 20 54 68 65 | The| 00000300 20 54 45 4c 45 54 45 58 54 20 70 72 6f 67 72 61 | TELETEXT progra| 00000310 6d 0d 0d 54 68 69 73 20 6c 6f 63 61 74 65 73 20 |m..This locates | 00000320 61 74 20 26 46 46 46 46 36 45 30 30 20 61 6e 64 |at &FFFF6E00 and| 00000330 20 73 6f 20 73 68 6f 75 6c 64 20 6e 6f 74 20 63 | so should not c| 00000340 6f 72 72 75 70 74 20 61 6e 79 20 42 41 53 49 43 |orrupt any BASIC| 00000350 20 70 72 6f 67 72 61 6d 20 69 6e 0d 74 68 65 20 | program in.the | 00000360 43 4c 49 45 4e 54 27 73 20 6d 65 6d 6f 72 79 2e |CLIENT's memory.| 00000370 20 49 74 20 77 69 6c 6c 20 77 6f 72 6b 20 77 69 | It will work wi| 00000380 74 68 20 61 6c 6c 20 76 65 72 73 69 6f 6e 73 20 |th all versions | 00000390 6f 66 20 74 68 65 20 42 42 43 20 42 2c 20 42 2b |of the BBC B, B+| 000003a0 2c 0d 4d 41 53 54 45 52 20 61 6e 64 20 45 54 2e |,.MASTER and ET.| 000003b0 20 54 68 65 20 70 72 6f 67 72 61 6d 20 77 69 6c | The program wil| 000003c0 6c 20 61 6c 73 6f 20 63 6f 6d 6d 75 6e 69 63 61 |l also communica| 000003d0 74 65 20 77 69 74 68 20 61 20 53 45 52 56 45 52 |te with a SERVER| 000003e0 20 61 63 72 6f 73 73 20 61 0d 62 72 69 64 67 65 | across a.bridge| 000003f0 20 61 6c 74 68 6f 75 67 68 20 73 6f 6d 65 20 6f | although some o| 00000400 66 20 74 68 65 20 68 65 61 64 65 72 73 20 6d 61 |f the headers ma| 00000410 79 20 62 65 20 6c 6f 73 74 20 61 73 20 74 68 65 |y be lost as the| 00000420 73 65 20 61 72 65 20 62 72 6f 61 64 63 61 73 74 |se are broadcast| 00000430 20 61 6e 64 0d 74 68 65 72 65 20 69 73 20 6e 6f | and.there is no| 00000440 20 63 6f 6c 6c 69 73 69 6f 6e 20 64 65 74 65 63 | collision detec| 00000450 74 20 61 63 72 6f 73 73 20 61 20 62 72 69 64 67 |t across a bridg| 00000460 65 2e 0d 0d 31 2e 20 54 68 65 20 66 69 72 73 74 |e...1. The first| 00000470 20 61 63 74 69 6f 6e 20 69 73 20 74 6f 20 6f 70 | action is to op| 00000480 65 6e 20 61 20 72 65 63 65 69 76 65 20 62 6c 6f |en a receive blo| 00000490 63 6b 20 74 6f 20 72 65 63 65 69 76 65 20 61 0d |ck to receive a.| 000004a0 54 45 4c 45 54 45 58 54 2d 53 45 52 56 45 52 27 |TELETEXT-SERVER'| 000004b0 73 20 72 65 70 6c 79 20 74 6f 20 61 20 66 69 6e |s reply to a fin| 000004c0 64 20 73 65 72 76 65 72 20 72 65 71 75 65 73 74 |d server request| 000004d0 2e 20 54 68 69 73 20 72 65 63 65 69 76 65 20 62 |. This receive b| 000004e0 6c 6f 63 6b 0d 6c 69 73 74 65 6e 73 20 6f 6e 20 |lock.listens on | 000004f0 70 6f 72 74 20 26 42 31 20 74 6f 20 61 6c 6c 20 |port &B1 to all | 00000500 73 74 61 74 69 6f 6e 73 2c 20 61 73 20 61 74 20 |stations, as at | 00000510 74 68 69 73 20 73 74 61 67 65 20 74 68 65 20 43 |this stage the C| 00000520 4c 49 45 4e 54 20 64 6f 65 73 20 6e 6f 74 0d 6b |LIENT does not.k| 00000530 6e 6f 77 20 74 68 65 20 73 74 61 74 69 6f 6e 20 |now the station | 00000540 6e 75 6d 62 65 72 20 6f 66 20 74 68 65 20 53 45 |number of the SE| 00000550 52 56 45 52 2e 0d 0d 32 2e 20 54 68 65 20 43 4c |RVER...2. The CL| 00000560 49 45 4e 54 20 62 72 6f 61 64 63 61 73 74 73 20 |IENT broadcasts | 00000570 74 6f 20 61 6c 6c 20 73 74 61 74 69 6f 6e 73 20 |to all stations | 00000580 6f 6e 20 70 6f 72 74 20 26 42 30 20 77 69 74 68 |on port &B0 with| 00000590 20 61 20 64 61 74 61 20 66 69 65 6c 64 0d 63 6f | a data field.co| 000005a0 6e 74 61 69 6e 69 6e 67 20 27 54 45 4c 45 54 45 |ntaining 'TELETE| 000005b0 58 54 27 20 74 68 69 73 20 62 65 69 6e 67 20 74 |XT' this being t| 000005c0 68 65 20 6e 61 6d 65 20 74 6f 20 77 68 69 63 68 |he name to which| 000005d0 20 61 20 54 45 4c 45 54 45 58 54 2d 53 45 52 56 | a TELETEXT-SERV| 000005e0 45 52 20 77 69 6c 6c 0d 72 65 73 70 6f 6e 64 2e |ER will.respond.| 000005f0 20 54 68 65 20 66 69 72 73 74 20 53 45 52 56 45 | The first SERVE| 00000600 52 20 74 6f 20 72 65 73 70 6f 6e 64 20 77 69 6c |R to respond wil| 00000610 6c 20 62 65 20 74 68 65 20 6f 6e 65 20 77 69 74 |l be the one wit| 00000620 68 20 77 68 69 63 68 20 74 68 65 20 43 4c 49 45 |h which the CLIE| 00000630 4e 54 0d 73 75 62 73 65 71 75 65 6e 74 6c 79 20 |NT.subsequently | 00000640 69 6e 74 65 72 61 63 74 73 2e 20 53 68 6f 75 6c |interacts. Shoul| 00000650 64 20 6d 6f 72 65 20 74 68 61 6e 20 6f 6e 65 20 |d more than one | 00000660 73 65 72 76 65 72 20 62 65 20 61 76 61 69 6c 61 |server be availa| 00000670 62 6c 65 20 74 68 65 6e 20 69 74 0d 69 73 20 70 |ble then it.is p| 00000680 6f 73 73 69 62 6c 65 20 74 6f 20 63 6f 6e 6e 65 |ossible to conne| 00000690 63 74 20 74 6f 20 61 20 73 70 65 63 69 66 69 63 |ct to a specific| 000006a0 20 73 65 72 76 65 72 20 62 79 20 75 73 69 6e 67 | server by using| 000006b0 20 69 74 73 20 73 74 61 74 69 6f 6e 20 6e 75 6d | its station num| 000006c0 62 65 72 20 65 67 0d 2a 54 45 4c 45 54 45 58 54 |ber eg.*TELETEXT| 000006d0 20 32 2e 34 35 2e 20 59 6f 75 20 6d 61 79 20 77 | 2.45. You may w| 000006e0 69 73 68 20 74 6f 20 64 6f 20 74 68 69 73 20 69 |ish to do this i| 000006f0 66 20 79 6f 75 20 6b 6e 6f 77 20 74 68 61 74 20 |f you know that | 00000700 6f 6e 65 20 73 65 72 76 65 72 0d 72 65 63 65 69 |one server.recei| 00000710 76 65 73 20 61 20 62 65 74 74 65 72 20 73 69 67 |ves a better sig| 00000720 6e 61 6c 20 74 68 61 6e 20 61 6e 6f 74 68 65 72 |nal than another| 00000730 2c 20 6f 6e 20 74 68 65 20 63 68 61 6e 6e 65 6c |, on the channel| 00000740 20 79 6f 75 20 77 69 73 68 20 74 6f 20 75 73 65 | you wish to use| 00000750 2e 0d 0d 33 2e 20 54 68 65 20 43 4c 49 45 4e 54 |...3. The CLIENT| 00000760 20 70 6f 6c 6c 73 20 74 68 65 20 72 65 63 65 69 | polls the recei| 00000770 76 65 20 62 6c 6f 63 6b 20 75 6e 74 69 6c 20 61 |ve block until a| 00000780 20 53 45 52 56 45 52 20 72 65 73 70 6f 6e 64 73 | SERVER responds| 00000790 20 6f 72 20 3c 45 53 43 41 50 45 3e 0d 69 73 20 | or <ESCAPE>.is | 000007a0 70 72 65 73 73 65 64 2e 0d 0d 34 2e 20 54 68 65 |pressed...4. The| 000007b0 20 43 4c 49 45 4e 54 20 72 65 61 64 73 20 74 68 | CLIENT reads th| 000007c0 65 20 53 45 52 56 45 52 27 73 20 72 65 70 6c 79 |e SERVER's reply| 000007d0 20 61 6e 64 20 73 74 6f 72 65 73 20 74 68 65 20 | and stores the | 000007e0 53 45 52 56 45 52 27 73 20 73 74 61 74 69 6f 6e |SERVER's station| 000007f0 20 61 6e 64 0d 6e 65 74 77 6f 72 6b 20 6e 75 6d | and.network num| 00000800 62 65 72 2e 20 54 68 65 20 62 61 73 65 20 70 6f |ber. The base po| 00000810 72 74 20 6e 75 6d 62 65 72 20 28 26 42 32 29 20 |rt number (&B2) | 00000820 69 73 20 75 73 65 64 20 74 6f 20 63 61 6c 63 75 |is used to calcu| 00000830 6c 61 74 65 20 74 68 65 20 70 6f 72 74 73 0d 66 |late the ports.f| 00000840 6f 72 20 66 75 72 74 68 65 72 20 63 6f 6d 6d 75 |or further commu| 00000850 6e 69 63 61 74 69 6f 6e 2e 20 54 68 65 20 43 4c |nication. The CL| 00000860 49 45 4e 54 20 73 65 6c 65 63 74 73 20 4d 4f 44 |IENT selects MOD| 00000870 45 20 37 2c 20 70 72 69 6e 74 73 20 74 68 65 20 |E 7, prints the | 00000880 53 45 52 56 45 52 27 73 0d 73 74 61 74 69 6f 6e |SERVER's.station| 00000890 20 6e 75 6d 62 65 72 20 28 73 75 70 70 72 65 73 | number (suppres| 000008a0 73 69 6e 67 20 74 68 65 20 6e 65 74 77 6f 72 6b |sing the network| 000008b0 20 6e 75 6d 62 65 72 20 69 66 20 69 74 20 69 73 | number if it is| 000008c0 20 7a 65 72 6f 29 20 61 6e 64 20 61 6c 73 6f 20 | zero) and also | 000008d0 74 68 65 0d 76 65 72 73 69 6f 6e 20 6e 75 6d 62 |the.version numb| 000008e0 65 72 2e 0d 0d 35 2e 20 54 68 65 20 43 4c 49 45 |er...5. The CLIE| 000008f0 4e 54 20 6f 70 65 6e 73 20 74 68 72 65 65 20 72 |NT opens three r| 00000900 65 63 65 69 76 65 20 62 6c 6f 63 6b 73 2e 20 4f |eceive blocks. O| 00000910 6e 65 20 6f 6e 20 70 6f 72 74 20 26 42 35 20 28 |ne on port &B5 (| 00000920 62 61 73 65 2b 33 29 20 72 65 61 64 79 0d 74 6f |base+3) ready.to| 00000930 20 72 65 63 65 69 76 65 20 61 6e 79 20 70 61 67 | receive any pag| 00000940 65 20 68 65 61 64 65 72 73 20 77 68 69 63 68 20 |e headers which | 00000950 61 72 72 69 76 65 2c 20 6f 6e 65 20 6f 6e 20 70 |arrive, one on p| 00000960 6f 72 74 20 26 42 32 20 28 62 61 73 65 29 20 72 |ort &B2 (base) r| 00000970 65 61 64 79 20 74 6f 0d 72 65 63 65 69 76 65 20 |eady to.receive | 00000980 61 6e 79 20 53 45 52 56 45 52 20 72 65 70 6c 69 |any SERVER repli| 00000990 65 73 20 61 6e 64 20 6f 6e 65 20 6f 6e 20 70 6f |es and one on po| 000009a0 72 74 20 26 42 34 20 28 62 61 73 65 2b 32 29 20 |rt &B4 (base+2) | 000009b0 74 6f 20 72 65 63 65 69 76 65 20 61 6e 79 0d 70 |to receive any.p| 000009c0 61 67 65 73 2e 0d 0d 36 2e 20 54 68 65 20 43 4c |ages...6. The CL| 000009d0 49 45 4e 54 20 73 65 6e 64 73 20 61 20 72 65 71 |IENT sends a req| 000009e0 75 65 73 74 20 66 6f 72 20 70 61 67 65 20 31 31 |uest for page 11| 000009f0 30 30 20 28 74 68 65 20 66 69 72 73 74 20 64 69 |00 (the first di| 00000a00 67 69 74 20 69 6e 64 69 63 61 74 65 73 20 74 68 |git indicates th| 00000a10 65 0d 63 68 61 6e 6e 65 6c 20 6e 75 6d 62 65 72 |e.channel number| 00000a20 29 2e 20 54 68 69 73 20 69 73 20 6f 6e 20 70 6f |). This is on po| 00000a30 72 74 20 26 42 33 20 28 62 61 73 65 2b 31 29 20 |rt &B3 (base+1) | 00000a40 77 69 74 68 20 61 20 63 6f 6e 74 72 6f 6c 20 62 |with a control b| 00000a50 79 74 65 20 6f 66 20 26 38 31 2e 0d 54 68 65 20 |yte of &81..The | 00000a60 72 65 70 6c 79 20 72 65 63 65 69 76 65 20 62 6c |reply receive bl| 00000a70 6f 63 6b 20 69 73 20 74 68 65 6e 20 70 6f 6c 6c |ock is then poll| 00000a80 65 64 20 75 6e 74 69 6c 20 74 68 65 20 53 45 52 |ed until the SER| 00000a90 56 45 52 20 72 65 73 70 6f 6e 64 73 2e 20 54 68 |VER responds. Th| 00000aa0 65 0d 70 6f 73 69 74 69 6f 6e 20 69 6e 20 74 68 |e.position in th| 00000ab0 65 20 71 75 65 75 65 20 72 65 74 75 72 6e 65 64 |e queue returned| 00000ac0 20 62 79 20 74 68 65 20 53 45 52 56 45 52 20 69 | by the SERVER i| 00000ad0 73 20 70 72 69 6e 74 65 64 20 61 74 20 74 68 65 |s printed at the| 00000ae0 20 62 6f 74 74 6f 6d 20 6f 66 0d 74 68 65 20 70 | bottom of.the p| 00000af0 61 67 65 2e 20 41 20 6e 65 77 20 72 65 63 65 69 |age. A new recei| 00000b00 76 65 20 62 6c 6f 63 6b 20 66 6f 72 20 72 65 70 |ve block for rep| 00000b10 6c 69 65 73 20 6f 6e 20 70 6f 72 74 20 26 42 32 |lies on port &B2| 00000b20 20 69 73 20 73 65 74 20 75 70 2e 20 49 66 20 61 | is set up. If a| 00000b30 6e 0d 65 72 72 6f 72 20 6f 63 63 75 72 73 20 74 |n.error occurs t| 00000b40 68 65 6e 20 74 68 65 20 65 72 72 6f 72 20 6d 65 |hen the error me| 00000b50 73 73 61 67 65 20 69 73 20 64 69 73 70 6c 61 79 |ssage is display| 00000b60 65 64 20 61 74 20 74 68 65 20 62 6f 74 74 6f 6d |ed at the bottom| 00000b70 20 6f 66 20 74 68 65 0d 73 63 72 65 65 6e 20 61 | of the.screen a| 00000b80 6e 64 20 74 68 65 20 70 61 67 65 20 69 6e 70 75 |nd the page inpu| 00000b90 74 20 72 6f 75 74 69 6e 65 20 69 73 20 65 6e 74 |t routine is ent| 00000ba0 65 72 65 64 20 6f 72 20 69 66 20 74 68 65 20 65 |ered or if the e| 00000bb0 72 72 6f 72 20 77 61 73 20 61 20 27 42 61 64 0d |rror was a 'Bad.| 00000bc0 63 68 61 6e 6e 65 6c 27 20 65 72 72 6f 72 20 74 |channel' error t| 00000bd0 68 65 6e 20 74 68 65 20 63 68 61 6e 6e 65 6c 20 |hen the channel | 00000be0 69 6e 70 75 74 20 72 6f 75 74 69 6e 65 20 69 73 |input routine is| 00000bf0 20 65 6e 74 65 72 65 64 2e 0d 0d 37 2e 20 54 68 | entered...7. Th| 00000c00 65 20 43 4c 49 45 4e 54 20 70 6f 6c 6c 73 20 62 |e CLIENT polls b| 00000c10 6f 74 68 20 72 65 63 65 69 76 65 20 62 6c 6f 63 |oth receive bloc| 00000c20 6b 73 20 66 6f 72 20 61 20 70 61 67 65 20 28 70 |ks for a page (p| 00000c30 6f 72 74 20 26 42 34 29 20 61 6e 64 20 66 6f 72 |ort &B4) and for| 00000c40 20 61 0d 68 65 61 64 65 72 20 28 70 6f 72 74 20 | a.header (port | 00000c50 26 42 35 29 2c 20 75 6e 74 69 6c 20 6f 6e 65 20 |&B5), until one | 00000c60 6f 72 20 74 68 65 20 6f 74 68 65 72 20 72 65 63 |or the other rec| 00000c70 65 69 76 65 73 20 61 20 74 72 61 6e 73 6d 69 73 |eives a transmis| 00000c80 73 69 6f 6e 2e 0d 0d 38 2e 20 49 66 20 61 20 70 |sion...8. If a p| 00000c90 61 67 65 20 68 65 61 64 65 72 20 69 73 20 72 65 |age header is re| 00000ca0 63 65 69 76 65 64 20 74 68 65 6e 20 74 68 65 20 |ceived then the | 00000cb0 63 75 72 73 6f 72 20 69 73 20 6d 6f 76 65 64 20 |cursor is moved | 00000cc0 74 6f 20 74 68 65 20 68 65 61 64 65 72 0d 70 6f |to the header.po| 00000cd0 73 69 74 69 6f 6e 20 61 6e 64 20 69 74 20 69 73 |sition and it is| 00000ce0 20 70 72 69 6e 74 65 64 20 6f 75 74 2e 20 41 6e | printed out. An| 00000cf0 20 69 64 65 6e 74 69 63 61 6c 20 72 65 63 65 69 | identical recei| 00000d00 76 65 20 62 6c 6f 63 6b 20 69 73 20 74 68 65 6e |ve block is then| 00000d10 20 73 65 74 20 75 70 0d 74 6f 20 72 65 70 6c 61 | set up.to repla| 00000d20 63 65 20 74 68 65 20 6f 6e 65 20 77 68 69 63 68 |ce the one which| 00000d30 20 68 61 73 20 62 65 65 6e 20 75 73 65 64 2e 0d | has been used..| 00000d40 0d 39 2e 20 49 66 20 61 20 72 65 71 75 65 73 74 |.9. If a request| 00000d50 65 64 20 70 61 67 65 20 69 73 20 72 65 63 65 69 |ed page is recei| 00000d60 76 65 64 20 74 68 65 20 66 69 72 73 74 20 61 63 |ved the first ac| 00000d70 74 69 6f 6e 20 69 73 20 74 6f 20 74 65 73 74 20 |tion is to test | 00000d80 74 68 65 20 63 6f 6e 74 72 6f 6c 0d 62 79 74 65 |the control.byte| 00000d90 2e 20 49 66 20 74 68 69 73 20 69 73 20 26 38 30 |. If this is &80| 00000da0 20 74 68 65 6e 20 69 74 20 69 6e 64 69 63 61 74 | then it indicat| 00000db0 65 73 20 74 68 65 20 70 61 67 65 20 68 61 73 20 |es the page has | 00000dc0 62 65 65 6e 20 66 6f 75 6e 64 20 61 6e 64 20 69 |been found and i| 00000dd0 73 20 69 6e 0d 74 68 65 20 72 65 63 65 69 76 65 |s in.the receive| 00000de0 20 62 6c 6f 63 6b 20 62 75 66 66 65 72 20 72 65 | block buffer re| 00000df0 61 64 79 20 74 6f 20 62 65 20 74 72 61 6e 73 66 |ady to be transf| 00000e00 65 72 72 65 64 20 74 6f 20 74 68 65 20 73 63 72 |erred to the scr| 00000e10 65 65 6e 2e 20 49 66 20 74 68 65 0d 63 6f 6e 74 |een. If the.cont| 00000e20 72 6f 6c 20 62 79 74 65 20 69 73 20 26 38 31 20 |rol byte is &81 | 00000e30 74 68 65 6e 20 74 68 69 73 20 69 6e 64 69 63 61 |then this indica| 00000e40 74 65 73 20 73 6f 6d 65 20 65 72 72 6f 72 20 68 |tes some error h| 00000e50 61 73 20 6f 63 63 75 72 72 65 64 20 61 6e 64 20 |as occurred and | 00000e60 74 68 61 74 0d 61 6e 20 65 72 72 6f 72 20 6d 65 |that.an error me| 00000e70 73 73 61 67 65 20 69 73 20 69 6e 20 74 68 65 20 |ssage is in the | 00000e80 72 65 63 65 69 76 65 20 62 6c 6f 63 6b 20 62 75 |receive block bu| 00000e90 66 66 65 72 20 77 61 69 74 69 6e 67 20 74 6f 20 |ffer waiting to | 00000ea0 62 65 20 70 72 69 6e 74 65 64 2e 0d 0d 31 30 2e |be printed...10.| 00000eb0 20 49 66 20 61 6e 20 65 72 72 6f 72 20 68 61 73 | If an error has| 00000ec0 20 6f 63 63 75 72 72 65 64 20 74 68 65 6e 20 74 | occurred then t| 00000ed0 68 65 20 65 72 72 6f 72 20 6d 65 73 73 61 67 65 |he error message| 00000ee0 20 69 73 20 70 72 69 6e 74 65 64 20 61 74 20 74 | is printed at t| 00000ef0 68 65 0d 62 6f 74 74 6f 6d 20 6f 66 20 74 68 65 |he.bottom of the| 00000f00 20 73 63 72 65 65 6e 20 61 6e 64 20 74 68 65 20 | screen and the | 00000f10 43 4c 49 45 4e 54 20 70 72 6f 67 72 61 6d 20 6a |CLIENT program j| 00000f20 75 6d 70 73 20 74 6f 20 74 68 65 20 70 61 67 65 |umps to the page| 00000f30 20 6e 75 6d 62 65 72 20 69 6e 70 75 74 0d 72 6f | number input.ro| 00000f40 75 74 69 6e 65 20 74 6f 20 67 65 74 20 61 6e 6f |utine to get ano| 00000f50 74 68 65 72 20 70 61 67 65 20 6e 75 6d 62 65 72 |ther page number| 00000f60 2e 20 41 20 6e 65 77 20 72 65 63 65 69 76 65 20 |. A new receive | 00000f70 62 6c 6f 63 6b 20 66 6f 72 20 61 20 70 61 67 65 |block for a page| 00000f80 20 69 73 20 73 65 74 0d 75 70 2e 0d 0d 31 31 2e | is set.up...11.| 00000f90 20 49 66 20 61 20 70 61 67 65 20 69 73 20 73 75 | If a page is su| 00000fa0 63 63 65 73 73 66 75 6c 6c 79 20 72 65 63 65 69 |ccessfully recei| 00000fb0 76 65 64 20 74 68 65 6e 20 69 74 20 69 73 20 64 |ved then it is d| 00000fc0 69 73 70 6c 61 79 65 64 2e 20 41 20 6e 65 77 20 |isplayed. A new | 00000fd0 72 65 63 65 69 76 65 0d 62 6c 6f 63 6b 20 66 6f |receive.block fo| 00000fe0 72 20 61 20 70 61 67 65 20 69 73 20 73 65 74 20 |r a page is set | 00000ff0 75 70 2e 20 54 68 65 20 68 65 61 64 65 72 20 72 |up. The header r| 00001000 65 63 65 69 76 65 20 62 6c 6f 63 6b 20 63 6f 6e |eceive block con| 00001010 74 69 6e 75 65 73 20 74 6f 20 62 65 0d 70 6f 6c |tinues to be.pol| 00001020 6c 65 64 20 61 6e 64 20 64 69 73 70 6c 61 79 65 |led and displaye| 00001030 64 20 75 6e 74 69 6c 20 61 20 6b 65 79 20 69 73 |d until a key is| 00001040 20 70 72 65 73 73 65 64 2e 0d 0d 31 32 2e 20 41 | pressed...12. A| 00001050 6c 6c 20 74 68 65 20 74 69 6d 65 20 74 68 65 20 |ll the time the | 00001060 72 65 63 65 69 76 65 20 62 6c 6f 63 6b 73 20 61 |receive blocks a| 00001070 72 65 20 62 65 69 6e 67 20 70 6f 6c 6c 65 64 20 |re being polled | 00001080 74 68 65 20 43 4c 49 45 4e 54 20 70 72 6f 67 72 |the CLIENT progr| 00001090 61 6d 0d 61 6c 73 6f 20 74 65 73 74 73 20 74 6f |am.also tests to| 000010a0 20 73 65 65 20 69 66 20 61 20 6b 65 79 20 68 61 | see if a key ha| 000010b0 73 20 62 65 65 6e 20 70 72 65 73 73 65 64 2e 20 |s been pressed. | 000010c0 49 66 20 61 20 6b 65 79 20 69 73 20 70 72 65 73 |If a key is pres| 000010d0 73 65 64 20 74 68 69 73 20 69 73 0d 74 61 6b 65 |sed this is.take| 000010e0 6e 20 74 6f 20 6d 65 61 6e 20 74 68 61 74 20 79 |n to mean that y| 000010f0 6f 75 20 61 72 65 20 61 62 6f 75 74 20 74 6f 20 |ou are about to | 00001100 72 65 71 75 65 73 74 20 61 20 6e 65 77 20 70 61 |request a new pa| 00001110 67 65 2e 20 49 66 20 27 43 27 20 69 73 20 70 72 |ge. 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If <RETURN> | 00001180 69 73 20 70 72 65 73 73 65 64 20 74 68 65 6e 20 |is pressed then | 00001190 74 68 65 20 6c 61 73 74 20 70 61 67 65 20 79 6f |the last page yo| 000011a0 75 20 72 65 71 75 65 73 74 65 64 20 69 73 0d 72 |u requested is.r| 000011b0 65 71 75 65 73 74 65 64 20 61 67 61 69 6e 2e 20 |equested again. | 000011c0 49 66 20 27 52 27 20 69 73 20 70 72 65 73 73 65 |If 'R' is presse| 000011d0 64 20 74 68 65 20 27 52 45 56 45 41 4c 27 20 72 |d the 'REVEAL' r| 000011e0 6f 75 74 69 6e 65 20 69 73 20 63 61 6c 6c 65 64 |outine is called| 000011f0 20 61 6e 64 20 74 68 69 73 0d 74 6f 67 67 6c 65 | and this.toggle| 00001200 73 20 62 65 74 77 65 65 6e 20 72 65 76 65 61 6c |s between reveal| 00001210 69 6e 67 20 61 6e 64 20 63 6f 6e 63 65 61 6c 69 |ing and conceali| 00001220 6e 67 2e 20 49 66 20 27 2a 27 20 69 73 20 70 72 |ng. 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W| 00002390 68 61 74 0d 77 65 20 68 61 76 65 20 6d 61 6e 61 |hat.we have mana| 000023a0 67 65 64 20 74 6f 20 64 6f 20 69 73 20 61 6c 73 |ged to do is als| 000023b0 6f 20 64 65 61 6c 20 77 69 74 68 20 73 74 61 74 |o deal with stat| 000023c0 69 6f 6e 20 31 37 20 61 73 20 61 20 73 70 69 6e |ion 17 as a spin| 000023d0 2d 6f 66 66 20 66 72 6f 6d 0d 73 74 61 74 69 6f |-off from.statio| 000023e0 6e 20 31 27 73 20 72 65 71 75 65 73 74 2e 0d 0d |n 1's request...| 000023f0 49 66 20 6d 6f 72 65 20 74 68 61 6e 20 6f 6e 65 |If more than one| 00002400 20 73 74 61 74 69 6f 6e 20 72 65 71 75 65 73 74 | station request| 00002410 73 20 74 68 65 20 73 61 6d 65 20 70 61 67 65 20 |s the same page | 00002420 74 68 65 6e 20 74 68 69 73 20 69 73 20 73 70 6f |then this is spo| 00002430 74 74 65 64 20 61 6e 64 0d 6f 6e 6c 79 20 6f 6e |tted and.only on| 00002440 65 20 6f 66 20 74 68 65 20 41 54 46 53 20 72 65 |e of the ATFS re| 00002450 63 6f 72 64 73 20 69 73 20 75 73 65 64 2e 20 54 |cords is used. 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This is pa| 000026b0 72 74 69 63 75 6c 61 72 6c 79 20 75 73 65 66 75 |rticularly usefu| 000026c0 6c 20 69 66 20 79 6f 75 20 68 61 70 70 65 6e 20 |l if you happen | 000026d0 74 6f 20 62 65 20 74 68 65 0d 6f 6e 6c 79 20 43 |to be the.only C| 000026e0 4c 49 45 4e 54 20 75 73 69 6e 67 20 74 68 65 20 |LIENT using the | 000026f0 73 79 73 74 65 6d 20 61 73 20 69 74 20 6d 65 61 |system as it mea| 00002700 6e 73 20 74 68 61 74 20 74 68 65 20 6c 61 73 74 |ns that the last| 00002710 20 31 30 20 6f 72 20 73 6f 20 70 61 67 65 73 20 | 10 or so pages | 00002720 79 6f 75 0d 68 61 76 65 20 72 65 71 75 65 73 74 |you.have request| 00002730 65 64 20 6f 6e 20 61 20 67 69 76 65 6e 20 63 68 |ed on a given ch| 00002740 61 6e 6e 65 6c 20 61 72 65 20 6e 6f 74 20 6f 6e |annel are not on| 00002750 6c 79 20 62 75 66 66 65 72 65 64 20 62 79 20 74 |ly buffered by t| 00002760 68 65 20 54 46 53 0d 70 72 6f 67 72 61 6d 2c 20 |he TFS.program, | 00002770 62 75 74 20 61 6c 73 6f 20 75 70 64 61 74 65 64 |but also updated| 00002780 20 61 6e 64 20 69 6e 73 74 61 6e 74 6c 79 20 61 | and instantly a| 00002790 76 61 69 6c 61 62 6c 65 2e 0d 0d 54 68 65 20 54 |vailable...The T| 000027a0 46 53 20 70 72 6f 67 72 61 6d 20 62 72 6f 61 64 |FS program broad| 000027b0 63 61 73 74 73 20 77 68 61 74 65 76 65 72 20 70 |casts whatever p| 000027c0 61 67 65 20 6e 75 6d 62 65 72 20 69 73 20 63 75 |age number is cu| 000027d0 72 72 65 6e 74 6c 79 20 61 74 20 74 68 65 20 74 |rrently at the t| 000027e0 6f 70 20 6f 66 0d 74 68 65 20 73 63 72 65 65 6e |op of.the screen| 000027f0 20 62 79 20 75 73 69 6e 67 20 74 68 65 20 74 69 | by using the ti| 00002800 6d 65 72 20 63 72 6f 73 73 69 6e 67 20 7a 65 72 |mer crossing zer| 00002810 6f 20 65 76 65 6e 74 2e 20 54 68 69 73 20 6f 63 |o event. 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Place 'TELETEX| 00002af0 54 27 20 70 72 6f 67 72 61 6d 20 69 6e 20 24 2e |T' program in $.| 00002b00 4c 49 42 52 41 52 59 0d 0d 32 2e 20 50 75 74 20 |LIBRARY..2. Put | 00002b10 27 54 46 53 27 20 61 6e 64 20 27 63 6f 64 65 27 |'TFS' and 'code'| 00002b20 20 69 6e 20 61 20 64 69 72 65 63 74 6f 72 79 20 | in a directory | 00002b30 6f 66 20 74 68 65 69 72 20 6f 77 6e 2e 20 54 68 |of their own. Th| 00002b40 69 73 20 6d 69 67 68 74 20 62 65 20 74 68 65 0d |is might be the.| 00002b50 72 6f 6f 74 20 64 69 72 65 63 74 6f 72 79 20 6f |root directory o| 00002b60 66 20 61 20 75 73 65 72 20 54 46 53 2e 20 49 66 |f a user TFS. If| 00002b70 20 74 68 69 73 20 75 73 65 72 20 68 61 73 20 61 | this user has a| 00002b80 20 21 42 4f 4f 54 20 66 69 6c 65 20 77 68 69 63 | !BOOT file whic| 00002b90 68 20 43 48 41 49 4e 73 0d 74 68 65 20 27 54 46 |h CHAINs.the 'TF| 00002ba0 53 27 20 70 72 6f 67 72 61 6d 20 74 68 65 6e 20 |S' program then | 00002bb0 74 68 65 20 77 68 6f 6c 65 20 73 79 73 74 65 6d |the whole system| 00002bc0 20 63 61 6e 20 62 65 20 69 6e 69 74 69 61 6c 69 | can be initiali| 00002bd0 73 65 64 20 62 79 20 73 69 6d 70 6c 79 0d 74 79 |sed by simply.ty| 00002be0 70 69 6e 67 20 2a 49 20 41 4d 20 54 46 53 2e 20 |ping *I AM TFS. | 00002bf0 54 68 65 20 6d 61 63 68 69 6e 65 20 72 75 6e 6e |The machine runn| 00002c00 69 6e 67 20 74 68 65 20 54 46 53 20 70 72 6f 67 |ing the TFS prog| 00002c10 72 61 6d 20 6d 75 73 74 20 6e 6f 74 20 75 73 65 |ram must not use| 00002c20 20 73 68 61 64 6f 77 0d 73 63 72 65 65 6e 73 20 | shadow.screens | 00002c30 61 73 20 74 68 65 20 68 65 61 64 65 72 20 69 73 |as the header is| 00002c40 20 50 4f 4b 45 44 20 69 6e 20 74 6f 20 6d 65 6d | POKED in to mem| 00002c50 6f 72 79 20 61 74 20 26 37 43 30 30 20 62 79 20 |ory at &7C00 by | 00002c60 74 68 65 20 41 54 46 53 20 52 6f 6d 2e 20 54 68 |the ATFS Rom. Th| 00002c70 65 0d 70 72 6f 67 72 61 6d 20 6d 61 79 20 72 75 |e.program may ru| 00002c80 6e 20 69 6e 20 61 20 73 65 63 6f 6e 64 20 70 72 |n in a second pr| 00002c90 6f 63 65 73 73 6f 72 2c 20 69 6e 20 77 68 69 63 |ocessor, in whic| 00002ca0 68 20 63 61 73 65 20 74 68 65 20 77 68 6f 6c 65 |h case the whole| 00002cb0 20 6f 66 20 74 68 65 20 49 2f 4f 0d 70 72 6f 63 | of the I/O.proc| 00002cc0 65 73 73 6f 72 20 6d 65 6d 6f 72 79 20 62 65 63 |essor memory bec| 00002cd0 6f 6d 65 73 20 61 76 61 69 6c 61 62 6c 65 20 66 |omes available f| 00002ce0 6f 72 20 62 75 66 66 65 72 69 6e 67 20 70 61 67 |or buffering pag| 00002cf0 65 73 20 61 6e 64 20 74 68 65 72 65 20 77 69 6c |es and there wil| 00002d00 6c 20 62 65 0d 61 6e 20 61 73 73 6f 63 69 61 74 |l be.an associat| 00002d10 65 64 20 69 6e 63 72 65 61 73 65 20 69 6e 20 70 |ed increase in p| 00002d20 65 72 66 6f 72 6d 61 6e 63 65 2e 20 54 68 65 72 |erformance. 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C| 00002d90 6f 6d 70 61 74 69 62 69 6c 69 74 79 20 77 69 74 |ompatibility wit| 00002da0 68 20 74 68 65 20 6e 65 77 20 47 49 53 20 61 64 |h the new GIS ad| 00002db0 61 70 74 65 72 0d 0d 54 68 65 20 73 6f 66 74 77 |apter..The softw| 00002dc0 61 72 65 20 69 73 20 63 6f 6d 70 61 74 69 62 6c |are is compatibl| 00002dd0 65 20 77 69 74 68 20 74 68 65 20 6e 65 77 20 47 |e with the new G| 00002de0 49 53 20 74 65 6c 65 74 65 78 74 20 61 64 61 70 |IS teletext adap| 00002df0 74 65 72 20 61 6c 74 68 6f 75 67 68 20 61 73 0d |ter although as.| 00002e00 74 68 69 73 20 63 6f 6e 6e 65 63 74 73 20 74 6f |this connects to| 00002e10 20 74 68 65 20 75 73 65 72 20 70 6f 72 74 20 72 | the user port r| 00002e20 61 74 68 65 72 20 74 68 61 6e 20 74 68 65 20 31 |ather than the 1| 00002e30 4d 48 7a 20 42 75 73 20 74 68 65 20 73 70 65 65 |MHz Bus the spee| 00002e40 64 20 6f 66 0d 72 65 73 70 6f 6e 73 65 20 69 73 |d of.response is| 00002e50 20 73 6c 69 67 68 74 6c 79 20 73 6c 6f 77 65 72 | slightly slower| 00002e60 2e 20 54 68 65 72 65 20 61 70 70 65 61 72 73 20 |. There appears | 00002e70 74 6f 20 62 65 20 61 20 70 72 6f 62 6c 65 6d 20 |to be a problem | 00002e80 77 69 74 68 20 74 68 65 0d 72 6f 75 74 69 6e 65 |with the.routine| 00002e90 20 74 6f 20 63 61 6c 63 75 6c 61 74 65 20 74 68 | to calculate th| 00002ea0 65 20 63 68 65 63 6b 73 75 6d 20 6f 66 20 61 20 |e checksum of a | 00002eb0 70 61 67 65 20 69 6e 20 74 68 61 74 20 74 68 65 |page in that the| 00002ec0 20 47 49 53 20 52 6f 6d 20 67 65 74 73 20 69 74 | GIS Rom gets it| 00002ed0 0d 77 72 6f 6e 67 20 69 66 20 61 20 70 61 67 65 |.wrong if a page| 00002ee0 20 68 65 61 64 65 72 20 77 61 73 20 62 72 6f 61 | header was broa| 00002ef0 64 63 61 73 74 20 77 68 69 6c 65 20 70 65 72 66 |dcast while perf| 00002f00 6f 72 6d 69 6e 67 20 74 68 65 20 63 68 65 63 6b |orming the check| 00002f10 2e 20 54 68 65 72 65 0d 64 6f 65 73 20 73 65 65 |. There.does see| 00002f20 6d 20 74 6f 20 62 65 20 61 20 70 72 6f 62 6c 65 |m to be a proble| 00002f30 6d 20 77 69 74 68 20 74 68 65 20 4d 41 53 54 45 |m with the MASTE| 00002f40 52 20 31 32 38 20 61 6e 64 20 74 68 65 20 54 55 |R 128 and the TU| 00002f50 42 45 20 69 6e 20 74 68 61 74 20 74 68 65 0d 73 |BE in that the.s| 00002f60 6f 66 74 77 61 72 65 20 77 69 6c 6c 20 6e 6f 74 |oftware will not| 00002f70 20 77 6f 72 6b 20 77 69 74 68 20 65 69 74 68 65 | work with eithe| 00002f80 72 20 61 64 61 70 74 65 72 20 69 6e 20 74 68 69 |r adapter in thi| 00002f90 73 20 63 6f 6e 66 69 67 75 72 61 74 69 6f 6e 2e |s configuration.| 00002fa0 20 54 68 69 73 0d 6c 6f 6f 6b 73 20 6c 69 6b 65 | This.looks like| 00002fb0 20 69 74 20 6d 61 79 20 62 65 20 61 20 70 72 6f | it may be a pro| 00002fc0 62 6c 65 6d 20 77 69 74 68 20 74 68 65 20 41 4e |blem with the AN| 00002fd0 46 53 2e 0d 0d 20 20 20 20 20 20 20 20 20 20 20 |FS... | 00002fe0 20 20 57 72 69 74 69 6e 67 20 79 6f 75 72 20 6f | Writing your o| 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20 20 20 20 20 20 20 20 20 20 3a | :| 00003350 52 45 4d 20 43 68 65 63 6b 20 74 68 61 74 20 69 |REM Check that i| 00003360 74 20 72 65 61 6c 6c 79 20 77 61 73 20 61 20 54 |t really was a T| 00003370 45 4c 45 54 45 58 54 0d 31 35 30 20 55 4e 54 49 |ELETEXT.150 UNTI| 00003380 4c 20 24 28 62 75 66 66 2b 33 29 3d 22 54 45 4c |L $(buff+3)="TEL| 00003390 45 54 45 58 54 22 20 20 20 20 3a 52 45 4d 20 20 |ETEXT" :REM | 000033a0 73 65 72 76 65 72 20 77 68 69 63 68 20 72 65 73 |server which res| 000033b0 70 6f 6e 64 65 64 0d 31 36 30 20 73 65 72 76 65 |ponded.160 serve| 000033c0 72 25 3d 62 6c 6b 25 21 33 20 41 4e 44 20 26 46 |r%=blk%!3 AND &F| 000033d0 46 46 46 20 20 20 20 20 20 3a 52 45 4d 20 52 65 |FFF :REM Re| 000033e0 61 64 20 74 68 65 20 73 65 72 76 65 72 27 73 20 |ad the server's | 000033f0 6e 75 6d 62 65 72 0d 31 37 30 20 62 61 73 65 5f |number.170 base_| 00003400 70 6f 72 74 3d 62 75 66 66 3f 31 20 20 20 20 20 |port=buff?1 | 00003410 20 20 20 20 20 20 20 20 20 3a 52 45 4d 20 52 65 | :REM Re| 00003420 61 64 20 74 68 65 20 62 61 73 65 20 70 6f 72 74 |ad the base port| 00003430 20 6e 75 6d 62 65 72 0d 31 38 30 20 72 78 5f 6e | number.180 rx_n| 00003440 6f 3d 46 4e 73 65 74 5f 75 70 5f 72 78 28 62 61 |o=FNset_up_rx(ba| 00003450 73 65 5f 70 6f 72 74 2c 73 65 72 76 65 72 25 2c |se_port,server%,| 00003460 62 75 66 66 2c 26 32 30 29 0d 20 3a 52 45 4d 20 |buff,&20). :REM | 00003470 53 65 74 20 75 70 20 61 20 72 65 63 65 69 76 65 |Set up a receive| 00003480 20 62 6c 6b 0d 31 39 30 20 52 45 50 45 41 54 20 | blk.190 REPEAT | 00003490 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000034a0 20 20 20 20 20 20 20 3a 52 45 4d 20 20 66 6f 72 | :REM for| 000034b0 20 74 68 65 20 74 69 6d 65 0d 32 30 30 20 52 45 | the time.200 RE| 000034c0 50 45 41 54 0d 32 31 30 20 50 52 4f 43 74 78 28 |PEAT.210 PROCtx(| 000034d0 26 38 34 2c 62 61 73 65 5f 70 6f 72 74 2b 31 2c |&84,base_port+1,| 000034e0 73 65 72 76 65 72 25 2c 62 75 66 66 2c 31 29 0d |server%,buff,1).| 000034f0 20 3a 52 45 4d 20 54 72 61 6e 73 6d 69 74 20 72 | :REM Transmit r| 00003500 65 71 75 65 73 74 20 66 6f 72 20 74 68 65 20 74 |equest for the t| 00003510 69 6d 65 0d 32 32 30 20 54 49 4d 45 3d 30 20 20 |ime.220 TIME=0 | 00003520 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00003530 20 20 20 20 20 20 3a 52 45 4d 20 57 61 69 74 20 | :REM Wait | 00003540 66 6f 72 20 61 20 77 68 69 6c 65 20 62 65 66 6f |for a while befo| 00003550 72 65 20 72 65 74 72 79 69 6e 67 0d 32 33 30 20 |re retrying.230 | 00003560 52 45 50 45 41 54 20 55 4e 54 49 4c 20 54 49 4d |REPEAT UNTIL TIM| 00003570 45 3e 35 30 0d 32 34 30 20 72 65 73 75 6c 74 25 |E>50.240 result%| 00003580 3d 46 4e 70 6f 6c 6c 5f 74 78 0d 32 35 30 20 55 |=FNpoll_tx.250 U| 00003590 4e 54 49 4c 20 72 65 73 75 6c 74 25 3d 30 20 20 |NTIL result%=0 | 000035a0 20 20 20 20 20 20 20 20 20 20 20 20 20 3a 52 45 | :RE| 000035b0 4d 20 4b 65 65 70 20 74 72 79 69 6e 67 20 75 6e |M Keep trying un| 000035c0 74 69 6c 20 74 72 61 6e 73 6d 69 74 20 73 75 63 |til transmit suc| 000035d0 63 65 65 64 73 0d 32 36 30 20 55 4e 54 49 4c 20 |ceeds.260 UNTIL | 000035e0 46 4e 70 6f 6c 6c 5f 72 78 28 72 78 5f 6e 6f 29 |FNpoll_rx(rx_no)| 000035f0 3e 31 32 37 20 20 20 20 3a 52 45 4d 20 4b 65 65 |>127 :REM Kee| 00003600 70 20 74 72 79 69 6e 67 20 75 6e 74 69 6c 20 77 |p trying until w| 00003610 65 20 67 65 74 20 61 20 72 65 70 6c 79 0d 32 37 |e get a reply.27| 00003620 30 20 50 52 4f 43 72 65 61 64 5f 72 78 28 72 78 |0 PROCread_rx(rx| 00003630 5f 6e 6f 29 20 20 20 20 20 20 20 20 20 20 20 20 |_no) | 00003640 3a 52 45 4d 20 52 65 61 64 20 74 68 65 20 72 65 |:REM Read the re| 00003650 63 65 69 76 65 20 62 6c 6f 63 6b 0d 32 38 30 0d |ceive block.280.| 00003660 32 39 30 20 62 75 66 66 3f 31 39 3d 31 33 0d 33 |290 buff?19=13.3| 00003670 30 30 20 64 61 74 65 24 3d 24 28 62 75 66 66 2b |00 date$=$(buff+| 00003680 39 29 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |9) | 00003690 20 3a 52 45 4d 20 52 65 61 64 20 74 68 65 20 64 | :REM Read the d| 000036a0 61 74 65 0d 33 31 30 20 62 75 66 66 3f 39 3d 31 |ate.310 buff?9=1| 000036b0 33 0d 33 32 30 20 74 69 6d 65 24 3d 24 28 62 75 |3.320 time$=$(bu| 000036c0 66 66 2b 31 29 20 20 20 20 20 20 20 20 20 20 20 |ff+1) | 000036d0 20 20 20 20 3a 52 45 4d 20 52 65 61 64 20 74 68 | :REM Read th| 000036e0 65 20 74 69 6d 65 0d 33 33 30 20 50 52 49 4e 54 |e time.330 PRINT| 000036f0 22 54 68 65 20 74 69 6d 65 20 69 73 20 22 3b 74 |"The time is ";t| 00003700 69 6d 65 24 3b 22 20 6f 6e 20 22 3b 64 61 74 65 |ime$;" on ";date| 00003710 24 0d 33 34 30 20 45 4e 44 0d 33 35 30 0d 33 36 |$.340 END.350.36| 00003720 30 20 44 45 46 50 52 4f 43 62 63 61 73 74 28 70 |0 DEFPROCbcast(p| 00003730 25 2c 63 62 25 2c 73 65 72 76 65 72 24 29 0d 33 |%,cb%,server$).3| 00003740 37 30 20 3f 62 6c 6b 25 3d 63 62 25 0d 33 38 30 |70 ?blk%=cb%.380| 00003750 20 62 6c 6b 25 3f 31 3d 70 25 0d 33 39 30 20 62 | blk%?1=p%.390 b| 00003760 6c 6b 25 21 32 3d 26 46 46 46 46 0d 34 30 30 20 |lk%!2=&FFFF.400 | 00003770 24 28 62 6c 6b 25 2b 34 29 3d 73 65 72 76 65 72 |$(blk%+4)=server| 00003780 24 0d 34 31 30 20 58 25 3d 62 6c 6b 25 3a 59 25 |$.410 X%=blk%:Y%| 00003790 3d 58 25 20 44 49 56 20 32 35 36 3a 41 25 3d 26 |=X% DIV 256:A%=&| 000037a0 31 30 0d 34 32 30 20 43 41 4c 4c 20 6f 73 77 6f |10.420 CALL oswo| 000037b0 72 64 0d 34 33 30 20 45 4e 44 50 52 4f 43 0d 34 |rd.430 ENDPROC.4| 000037c0 34 30 0d 34 35 30 20 44 45 46 46 4e 73 65 74 5f |40.450 DEFFNset_| 000037d0 75 70 5f 72 78 28 70 25 2c 73 74 25 2c 62 25 2c |up_rx(p%,st%,b%,| 000037e0 6c 25 29 0d 34 36 30 20 3f 62 6c 6b 25 3d 30 0d |l%).460 ?blk%=0.| 000037f0 34 37 30 20 62 6c 6b 25 3f 31 3d 26 37 46 0d 34 |470 blk%?1=&7F.4| 00003800 38 30 20 62 6c 6b 25 3f 32 3d 70 25 0d 34 39 30 |80 blk%?2=p%.490| 00003810 20 62 6c 6b 25 21 33 3d 73 74 25 0d 35 30 30 20 | blk%!3=st%.500 | 00003820 62 6c 6b 25 21 35 3d 62 25 0d 35 31 30 20 62 6c |blk%!5=b%.510 bl| 00003830 6b 25 21 39 3d 62 25 2b 6c 25 0d 35 32 30 20 58 |k%!9=b%+l%.520 X| 00003840 25 3d 62 6c 6b 25 3a 59 25 3d 58 25 20 44 49 56 |%=blk%:Y%=X% DIV| 00003850 20 32 35 36 3a 41 25 3d 26 31 31 0d 35 33 30 20 | 256:A%=&11.530 | 00003860 43 41 4c 4c 20 6f 73 77 6f 72 64 0d 35 34 30 20 |CALL osword.540 | 00003870 3d 3f 62 6c 6b 25 0d 35 35 30 0d 35 36 30 20 44 |=?blk%.550.560 D| 00003880 45 46 46 4e 70 6f 6c 6c 5f 72 78 28 72 25 29 0d |EFFNpoll_rx(r%).| 00003890 35 37 30 20 41 25 3d 26 33 33 3a 58 25 3d 72 25 |570 A%=&33:X%=r%| 000038a0 0d 35 38 30 20 3d 55 53 52 28 6f 73 62 79 74 65 |.580 =USR(osbyte| 000038b0 29 20 41 4e 44 20 26 38 30 30 30 0d 35 39 30 0d |) AND &8000.590.| 000038c0 36 30 30 20 44 45 46 50 52 4f 43 72 65 61 64 5f |600 DEFPROCread_| 000038d0 72 78 28 72 25 29 0d 36 31 30 20 3f 62 6c 6b 25 |rx(r%).610 ?blk%| 000038e0 3d 72 25 0d 36 32 30 20 58 25 3d 62 6c 6b 25 3a |=r%.620 X%=blk%:| 000038f0 59 25 3d 58 25 20 44 49 56 20 32 35 36 3a 41 25 |Y%=X% DIV 256:A%| 00003900 3d 26 31 31 0d 36 33 30 20 43 41 4c 4c 20 6f 73 |=&11.630 CALL os| 00003910 77 6f 72 64 0d 36 34 30 20 45 4e 44 50 52 4f 43 |word.640 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04-06-88/MANUAL.m0
04-06-88/MANUAL.m1
04-06-88/MANUAL.m2
04-06-88/MANUAL.m4
04-06-88/MANUAL.m5
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