80-Bus News

  

January–March 1982, Volume 1, Issue 1











Page 27 of 55











AddressOld CodeNew Code
080031 00 1000 00 00
019B21 0A 0821 0A F8
023611 0A 0811 0A F8
023E11 BA 0B11 BA FB
025411 CA 0B11 CA FB
026511 0A 0811 0A F8
026821 4A 0821 8A FB

The jump table addresses are:

D0788
F078C
P07A0
407B2

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


This is an OCR’d version of the scanned page and likely contains recognition errors.











Page 27 of 55