Re: Whether something is RISC or not (Re: PDP-8 theology, not Concertina II Progress)

Lawrence D'Oliveiro <ldo@nz.invalid> wrote:

On Tue, 1 Oct 2024 23:38:10 -0000 (UTC), Brett wrote:
 

My wish list for the 68k was a barrel roller for fast shifts, would have
made a HUGE difference for the first Macintosh.

 
The 68020 certainly had that. It also added bit-field instructions, on top
of the single-bit instructions of the original 68000.
 
And in typical big-endian fashion, they added yet another inconsistency to
the way the bits were numbered ...

I noticed that, there is a tiny chance that Apple wanted that to make
QuickDraw one cycle faster. But other changes hint that the clue train was
not sharp at Motorola.

Everyone was muddling back in that era, and being quick to market was the
rule, hard to blame them. I can see myself making the very same choices, or
much more likely seeing my coworkers make bad choices and not being able to
do anything about it. You do what you can with what you have.