Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!decvax!savax!thompson
From: thompson@savax.UUCP (thompson mark)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 80860 as a math processor
Keywords: Super bit belching
Message-ID: <877@savax.UUCP>
Date: 21 Apr 89 00:47:02 GMT
References: <14716@gryphon.COM>
Reply-To: thompson@savax.UUCP (thompson mark)
Organization: Disturbing Products, Inc.
Lines: 35

In article <14716@gryphon.COM> richard@gryphon.COM (Richard Sexton) writes:
>Yes, the 80860 looks like the only decent piece of silicon to come
>out of intel since the 8051.
>
>However, I believe it would be impossible to sustain that FLOP rate
>as a math coprocessor in an Amiga.
>
>Consider the 68881/2 or the Weitek chip: when a floating point
>instruction is hit, BINGO, the hardware executes it.
>
>But since the 80860 is not a 680x0 coprocessor..[stuff about a slow interface]

I didn't realize the Weitek part was so compatible with 680x0's.
Actually, I never envisioned the i860 (Intel N10) as replacing the 68881/2
but using it as a somewhat dedicated auxillary processor in some sort of
multi-processor scheme with shared memory. The application I specifically had
in mind was a graphics card using the i860 for display list traversal,
3D transformations, smooth shaded solid rendering, and hidden surface removal.
The Amiga would simply DMA the display list into the i860's memory and off
it would go cranking out Phong shaded unicycles in real time. (This implies
that you put the display buffer on the i860 graphics card.) The thing to
remember is that the i860 is processor all by itself (unlike the 68881/2),
but I guess you knew that already.

>Where it would really
>shine though, would be where you could unbundle a monolithic
>process, such as a matrix inversion or the like. Clearly this
>is something a pure math coprocessor could not do.

Yeah.
--------------------------------------------------------------------------
|      Mark Thompson                                                     |
|      decvax!savax!thompson       Designing high performance graphics   |
|      (603)885-9583               silicon today for a better tomorrow.  |
--------------------------------------------------------------------------