Commodore 128 Alive!

Commodore 128 => 128 programmers => Topic started by: MIRKOSOFT on March 04, 2010, 05:40 AM

Title: READY prompt - indirect vector?
Post by: MIRKOSOFT on March 04, 2010, 05:40 AM
Hi!


I want to ask about READY prompt of C128.
Has any vector to change? I want only after every BASIC command have my info and then print READY, e.g. active drive is 8, so my prompt will be:


8>
READY.


It's simple if I'm using my own commands (BASIC extension), but how to do it with all BASIC commands? Problem is when I'm checking of my commands and is not found, I let control to BASIC, then I can't write any own prompt, only before standard command output, e.g.:
8>
READY.
LIST

8>
10 PRINT "COMMODORE 128"
20 END
READY.
Title: Re: READY prompt - indirect vector?
Post by: Hydrophilic on March 04, 2010, 04:11 PM
I think you want to change ($0302) vector.

The bad thing about changing this vector, is BASIC ROM is stupid... it does not a set a specific MMU configuration before JMP ($0302).  What this means is MMU will be either in RAM Bank 0 or RAM Bank 1... and I/O or char ROM will be active... you can never know for sure in advance!

The same warning / danger also applies to ($0300) vector for error messages; if program has error, it will JMP ($0300), otherwise it will end okay with JMP ($0302).  After direct-mode command or entry of a program line, BASIC will again JMP ($0302).

I hope this helps!
Title: Re: READY prompt - indirect vector?
Post by: MIRKOSOFT on March 04, 2010, 06:38 PM
Yes, I used $0302 to checking my own commands... so this way is unusable.
And also error messages are not usable 'cause no everytime error happens.


But thank you very much.


Miro
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