|Address||Old Code||New Code|
|0800||31 00 10||00 00 00|
|019B||21 0A 08||21 0A F8|
|0236||11 0A 08||11 0A F8|
|023E||11 BA 0B||11 BA FB|
|0254||11 CA 0B||11 CA FB|
|0265||11 0A 08||11 0A F8|
|0268||21 4A 08||21 8A FB|
The jump table addresses are:
and if you want any others, calculate it from these, remembering that they’re
in alphabetical order, with 2 bytes per letter.
All in all, it’s nice to be able to run NAS-SYS programs without
having to multimap the computer, and it’s wonderful being able to load
programs to and from disk, to anywhere in memory, with CP/M looking after all
the disk functions. It’s far easier than writing your own DOS as some poor
fool has done in Computing Today, ignoring the fact that he already has all of
the necessary code, bar the 180 bytes that Chris has written.
Incidentally, the Find routine that I use is based on that in the same
issue of Micropower, but has been modified
a) to make it work
b) it saves ARG1 to ARG10
then asks you what you want to find, and restores the ARGS when all done,
rather than corrupting the values that are used to format the T command.
HERE WE GO AGAIN
Wonderful news for those of you who have just upgraded from CP/M 1.4
to CP/M 2.2. The father of CP/M, Gary Kildall, has let it be known that CP/M
version 3 will be with us just as soon as it’s debugged, probably during ’82.
Let’s hope that they get it right this time, so it doesn’t have to go through
several versions before it’s OK, as happened with version 2.
Beyond the features of version 2, version 3 will add passwords, file
lockout, and record lockout, thereby increasing the security of your programs
when others have access to them, plus features to make life easier for us
hackers, such as the ability to type ahead of the system, which will catch up
with you when it has time (the Gemini IVC and keyboard allow this already –
Ed.), the ability to test and write a record, support of a real time
clock/calendar, an updated ED.COM which is screen oriented hooray!), much
better documentation (hooray hoorah!), and of course a smaller TPA (booo!).
In readiness for this I’m building a couple of real time clocks, the
first using National Semiconductor’s 58174 chip with battery backup, and the
second based on a receiver for the NPL’s radio clock at Rugby. I’ll try to
write up a report on which is best, and why, for the mag. when I’ve finished
(probably with circuit diagrams and layouts for those of you who want to have
a go yourselves).
MAKE D.R. UTILITIES FIT YOUR SCREEN
The utility programs supplied with CP/M are all written for an 80 x 24
character video screen, not the Little 48 x 15 Nascom screen that we all know
and love. (It’s interesting, the Gemini double density implementation of CP/M
2.2, in the version for the Nascom 48 column screen, is 48 x 16, seems
no-one’s noticed! – Ed.) The result is that the information we want either
wraps round onto the next line, or scrolls off the top of the screen. Short of
spending a hundred and fifty quid on either the new Nascom Advanced Video