Overview Features Coding Performance Forum Downloads Products OrderV4 Contact

Welcome to the Apollo Forum

This forum is for people interested in the APOLLO CPU.
Please read the forum usage manual.



All TopicsNewsPerformanceGamesDemosApolloVampireAROSWorkbenchATARIReleases
Information about the Apollo CPU and FPU.

Q AMMX.doc About Bank Switching.

Tommo Noorduin

Posts 23
25 Sep 2021 16:05


ammx instruction:
$FE00 0000 > extract bits ABD AAAAAA BBBB DDDD ooooo

extension before normal instruction:
$7180 > extract bits AA BB CCCCC DD

About the last one.
AA are the extended bits for operand a.
and BB are the extended bits for operand b.
and we get a new operand: C.

Now,
in AA or BB
Data become 4 banks (default D0..7 and 3 new E0..23)
and Address : lsb switch A0..7 and B0..7(if lsb=1)

So does the other bit of Address
when <ea> is present
switches <ea> to <vea>  (for $7100, line7 unused moveq)
like the lineF does?

I am thinking how a debugger would interpret it.

Thanks.

posts 1