Microcoded RISC, was (something else)

[payner@netcom.com (Rich Payne)]

In article <cf9LGvS00YUoMZhVIv@andrew.cmu.edu> gregt+@CMU.EDU (Gregory Ross Thompson) writes:
>payner@netcom.com (Rich Payne) writes:
>> I was reading in Byte (I think) of a new micro-programmable RISC
>> chip which could emulate a fast 486 (and run slightly faster) when
>> programmed as a 486. It said that the design team had already
>> written the microcode to emulate a 68040 and the i486. At production
>> volume the prices mentioned were around $10-$15/CPU.
>
>  Hmm.  I haven't read this article, so I'm simply speculating here.
>I find it VERY hard to believe that someone has made a general purpose
>microprogrammed RISC that is faster at being a 486 than a 486 itself.
>For one thing, one of the main "definitions" of RISC is that it's not
>a microcoded machine.  I know, everyone has their own opinion in the
>RISC/CISC debate, but I'd personally rather hear something like
>"pipelined CISC" than "microcoded RISC".  Please don't send me flame
>mail for that. 

Is not the i486 pipelined? That is, the new CISC stuff has RISClike
features, I believe.
 
>  Next, unless a major chip manufacturer is fabing the chip, I'd doubt
>that they could get the cost down to $10.  It's probably costing Intel
>more than that to make the 486.  Also, their useful yeild would be
>really low for a while, making the cost initially high.

Well, I did recall wrong. It is $50-60 per in production quantities.

Here is the article

====================================================================

NEW RISC CHIP TO EMULATE 486 and 68040

International Meta Systems (Torrance, CA) claims it has a new RISC 
microprocessor that can emulate an Intel 486 or Motorola 68040 at
their full native speeds at a fraction of their cost. IMS is pitching
the CPU for pen computers that need high performance for tasks such 
as handwriting recognition. It also says the chip could be used in a 
"chameleon computer" that runs PC or MAC software.

The IMS 3250, slated for mid-1993 production, is a two-chip set with 
a RISC CPU and an I/O controller. IMS says the 3250 will use 0.7 or 0.8 
micron CMOS technology with the equivalant of 400,000 transistors.
Clocked at 100 MHZ, the CPU reportedly runs at 90 MIPS in native RISC
mode.

What sets the 3250 apart from other RISC chips is it's programmable
microcode. Although many CISC processors impliment their instruction
sets in microcode, most RISC processors do not. Systems design can
reprogram the 3250's microcode using assembler-like tools. IMS says it
has written modules that emulate a 68040 at 30 MHZ, including FPU
support.

To build a computer that runs both PC and MAC applications, the designer
would still have to add the appropriate software. PC clones are easy to
make, but a MAC clonewould require either licensed MAC ROM chips or their
legal equivalant. One possiblity is a MAC "compatibility engine" such as
a toolbox emulator from Quorom. IMS says the 3250 will cost just $50 to
$60 in production quantities.

- Tom R. Halfhill

-----------------------------------------------------------------------

Fromk BYTE Nov 1992 Nanobytes, copied without permission.
 
=======================================================================

>  Next, if you can make a general purpose chip that can emulate an
>'816, then you can ALWAYS make a dedicated '816 that'll be faster.
>Why not just do that?
>
>  Oh well.  I just wanna get an Alpha to go with my Alfa...
>
>  Lastly: everything I've said in this post is MY OPINION.  I haven't
>read the article, so PLEASE don't send me mail saying that I'm wrong,
>and the chip does exist.

Is not, you stole someone -else's- opinion. Fess up...
 
>		-Greg
>		 InterNet: gregt+@cmu.edu
>		       or: gt0t+@andrew.cmu.edu
>		 BITNet  : R746GT0T@CMCCVB
>		 AOL     : GRThompson
>
>'cause I got more spice than the frugle gormet

Rich

payner@netcom.com