Posted By
JamesD
on 2016-09-21
04:51:14
|  Re: What would I do differently in the Plus/4
@Litwr
The 6516/6509 spec I'm talking about had a lot of the features of the 65816 but I don't think it supported the 24 bit address buss. It is not the same as the MOS 6509. The MOS 6509 way of addressing memory isn't as useful as an MMU.
JMP ($1FF) crosses a page, it shouldn't wrap around but it does. I don't care if someone on the C64 used it to be tricky, it shouldn't wrap around. But that's just me. Most code won't do that.
BCD is commonly used for a quick way to do score keeping in games and it's used in some business software. I don't see that changing even if it is slower. I really don't use it so... I don't care.
Changing the cpu obviously wasn't in Commodore's plans, but I think several of us agree it probably should have been.
"So the way to improve C+4 is to change the Commodore architecture at all."
Do you mean not to change?
I know that 1571 isn't fast with the Plus/4, I was suggesting they adopt that change earlier.
The reason I didn't suggest the 1581 was 3.5" drives were brand new in 1983 and not everybody chose the same standard. They also weren't even double sided until some time in 1984.
If that were available in time it would certainly be a nice option, but you can't stick in an existing VIC20 or C64 disk in a 3.5" drive either. It's another tradeoff.
While you can use the disk drives to do additional number crunching, the slow interface limits that use.
You definitely need more RAM to do anything complicated, which is pretty much why you would try to use the drive in the first place though.
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