Comment by zahlman
8 days ago
> 46K RAM
Not 64?
(Edit: I see part of the address space is reserved for ROM, but it still seems a bit wonky.)
8 days ago
> 46K RAM
Not 64?
(Edit: I see part of the address space is reserved for ROM, but it still seems a bit wonky.)
The 6502 doesn't have separate io addresses so you need to fit all devices in a 64k space, not just ROM.
Atari 130XE used bank switching to handle more memory along with the IO-reserved memory (i.e. you had an address $D301 where you would change bits for the memory bank, and it would redirect $4000 – $7FFF to another bank in the extended memory)
Yeah the Commodore 64 did something similar. I love that era of hardware.