[Coco] [Color Computer] Holy Mods Batman!

James Diffendaffer jdiffendaffer at yahoo.com
Thu Apr 14 12:56:21 EDT 2005

The 6502 is mistakenly compared to RISC all the time.  There's more to
RISC than executing one instruction per clock cycle.  RISC cpus use
general purpose registers rather than special purpose ones like the
6502 has.  A RISC cpu would have been easier to program and faster
than the 6502 because it would have taken fewer instructions to do the
same work.  If given the same math and indexing capabilities a RISC
chip would also have supported high level languages better... more by
chance than by design.

I think the addition of a DP like register would have made a huge
difference with the 6502.  Being tied to the Zero Page for it's
fastest instructions was one of it's biggest weaknesses even though it
was innovative at the time.  But I guess when 4K is a huge amount of
RAM you don't think about stuff like that.

--- In ColorComputer at yahoogroups.com, Charles Richmond <richmond at p...>
> >--- In ColorComputer at yahoogroups.com, "John R. Hogerhuis"
> >      [snip...]          [snip...]          [snip...]
> >The 6502 was too simple.  Building a compiler for it is a nightmare.
> >Just check out how much code the cc65 compiler cranks out to do
> >
> It is true that the 6502 is messy to code for. And the stack is 
> restricted to 256 bytes and all. But the 6502 instruction set is very 
> RISC-like...simple instructions that execute quickly. Instructions 
> took from one to three clock cycles to execute. I believe that was 
> *part* of the attraction of the 6502.

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