On 3/13/18 3:55 PM, Dr Jefyll wrote: > In Native Mode the '816 would see all sixteen 64K banks as a single, > /contiguous/ space. Arrays and other data structures could even straddle > bank boundaries. And long (alternate bank) subroutine calls would be > trivial rather than torturous. This should not be overlooked. This small, plug-in upgrade would allow all of a CBM-II machine's 128K+ internal RAM to be used at the same time as the I/O devices. That is very useful. In the CBM-II design, all of the I/O devices are in the system bank but that bank only has a tiny amount of RAM for user programs. Commodore intended for user programs to run from other banks and then use their far call scheme to call the KERNAL in the system bank. This has large overhead that impacts programs that do a lot of I/O. For example, consider a terminal program that needs to constantly service 6551 interrupts and update the screen. Even though my CBM-II machine has 256K RAM internally that's mostly unused, I have a 24K RAM cartridge hanging out the back just so I can have more RAM in the bank with the I/O. Several other people here are doing this as well. Regards, Mike -- Mike Naberezny (mike@naberezny.com) http://6502.orgReceived on 2018-03-15 21:00:59
Archive generated by hypermail 2.2.0.