Path: utzoo!utgpu!watserv1!watmath!att!att!bu.edu!rpi!batcomputer!munnari.oz.au!brolga!bunyip.cc.uq.oz.au!iceman!cpca
From: cpca@iceman.jcu.oz (C Adams)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: RISC Amiga
Summary: FASTER!!!
Keywords: well there's going to be a RISC Mac!!
Message-ID: <1176@iceman.jcu.oz>
Date: 1 Nov 90 02:00:02 GMT
References: <1156@iceman.jcu.oz> <22914@grebyn.com>
Organization: JCUNQ, Townsville, Qld, Australia
Lines: 40

In article <22914@grebyn.com>, ckp@grebyn.com (Checkpoint Technologies) writes:
> In article <1156@iceman.jcu.oz> cpca@iceman.jcu.oz (C Adams) writes:
> >So what would we want a RISC Amiga to be based on, 88k? Sparc? i860? MIPS?
> 
> Given the Amiga product philosphy of "inexpensive", I'd have to guess
> the AMD29K.  They're real cheap, and quite fast. After that I think 88K,
> because of the Motorola heritage of the Amiga.  Plus I just read that
> Motorola dropped the price of the 88K chip set, don't remember how low.
> Still much higher than a 68030.

I quite like the AMD29k, but to get good performance out the them
I think you need separate external buses to memory (1 for instruction,
and 1 for data), as this is how the chip goes quick.  I don't think
you get on-chip caches yet.  I could be wrong on this stuff so don't
flame, correct me.

> >What about compatibility with existing software? 
> 
> Forget about it.  RISC is a new architecture, a new instruction set, a
> new philosophy.

Not what I was thinking.  How about putting an emulator in the OS, and
having two different formats for executables.  If the OS detects a 
old 68000 executable, it automatically runs it under the emuator, otherwise
it runs in normally.

> On the other hand, the 68040 is as fast as current-generation RISC
> chips.  So why go RISC at all?

No way.  The 68040 uses 1.2 million transistors to make it as 
quick as RISC chips with 300,000 transistors.  The i860 RISC chip
uses 1 million transistors and is MUCH quicker than the i486/68040 which
uses a similar amount.  It may be possible to build a CISC as fast as
a RISC, but with current technology it takes more hardware.

Macintosh can see the death of the 680X0 series, but can C=.  I
have heard the next 88k chip, the 88110, will be VERY rapid....

Colin Adams        You need to have a woman, before you can have a Sun :-)
Email Address -    cpca@marlin.jcu.edu.au