Adding Symmetric Multiprocessing to Amiga UNI

[Randell Jesup]

In article <1991Jan30.181208.1256 at convex.com> swarren at convex.com (Steve Warren) writes:
>I am assuming that an '040 board would include on-board memory designed
>to function optimally with an '040.  In this case you would want the '040
>to favor the coprocessor ram over the motherboard ram.  You would also
>want the '040 to release the bus on the motherboard when it is operating
>out of coprocessor ram.

	Even a simple '040 implementation would have similar effects due to
the large cache of the '040.  An '040 with external cache would be even
less affected, though probably still would be affected more than the local-
memory version.  An external cache might be faster having local '040 memory
if the '030 isn't being used.

>I/O processing should also be performed on the '030.  The SCSI controller is
>on the motherboard, and it just makes sense to put all the housekeeping out
>on the secondary processor.

	Yes, though this requires a fair bit of coding... (understatement
of the day).

>It would be nice if some utilization of the custom chips were possible, since
>they do have line drawing and other capabilities.

	For "simple" blits (scroll, etc) an '030/'040 is probably faster
than the existing blitter ('040 wouldn't be much faster than '030).  For
complex blits, longish lines, patterned fills, etc, the blitter is faster.
(Short lines and restricted-shape solid-filled polygons are faster on the
processor, even in some cases for 68000's, assuming there's nothing else
the CPU could be doing.)

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup at cbmvax.commodore.com  BIX: rjesup  
The compiler runs
Like a swift-flowing river
I wait in silence.  (From "The Zen of Programming")  ;-)