[Coco] 6309 microprocessor project 01-16-2004

[John Collyer]

6309 microprocessor project.

Hello,

I decided for the memory functions I would use a dedicated 64K
memory extent.  I tried the other way, which used pointers to 8k
memory regions.  This allowed for singlebank and fixbanks to only
change the memory pointers when needed, but increased getbyte
and putbyte's complexity.

Since getbyte and putbyte are constantly being used as opposed to
singlebank or fixbanks it was a easy decision.  This was the most
convincing argument for the choice.

Also with using the pointer method the special opcodes $11FD
and $11FF were confined to 8k memory boundaries.  With the
dedicated 64k memory extent using these special opcodes can
exist anywhere in the 16MB physical memory space because
singlebank and fixbanks not only calculate everything but also
blast the 8k banks to the 64k address space so the 64k memory
extent always contains the right banks, and getbyte and putbyte
are then greatly simplified.

This goes against the grain, so to speak.  Usually you'd want to
change pointers instead of moving memory chunks around, but
not in this case.

I was still wondering what the emulator lacks in making the
Sockmaster demos work?  Any insights will be appreciated.

John Collyer