Hi Ruud,
> It's logical to assume that the IRQ routine does reset this bit
somewhere.
> The original IRQ routine calls $F2B0. At $F2E9 it checks $0020. I
don't know
> where this variable is intialised. Following both possibilities $F2F9
or
> $F99C I have no idea where the JMP instruction at $0600 is executed.
> As you see JOBSZP+x ($00+x) is filled with a code. Where is this code
> examined and acted upon?
[...]
From memory, what Rialto wrote is correct. Anyway, it's a long time
since I looked at it last time.
You can read german, don't you? If you want, I can search for my 1541
Book (Karsten Schramm: "Die Floppy 1541"; M&T) and send the relevant
parts, which describe the mechanisms, to you. Would that help you?
Spiro.
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