Acorn 610 as processor/coprocessor?

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3 total messages Started by Sherwood Botsford Fri, 06 Nov 1992 22:20

#958

Author: Sherwood Botsford
Date: Fri, 06 Nov 1992 22:20

14 lines
1075 bytes

Apples Newton uses a UK chip called the Acorn 610.  32 bit, lots of  
registers, orthogonal instruction set, a speed that is faster than the  
68040, and all in something like 32000 transistors.

 Assuming the truth of this, that I haven't mangled this too badly:

1.  How do they get all this in only 32000 transistors?  Ok, even  
without cache, FPU and MMU?

2.  Something this simple should be cheap to make.  Why haven't we  
started to see machines with a hoard of these on board?  Think about a  
machine with 1 of these dedicated to the screen, 1 to handling IO, a  
dozen to slave for you...

Re: Acorn 610 as processor/coprocessor?

#984

Author: Bill Williams
Date: Sun, 08 Nov 1992 10:08

37 lines
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misconceptions regarding number of IC gates (transistors) on large scale
CPU chips....

A MC68000 was labled such a name because it had a whopping 68,000 or so
transistors. Since that era, CPUs have been supplied with larger and
larger DAta and Code caches, memory management, floating point processors
(with trancendental table aids),barrel shifters, etc. etc. But the LARGEST
PERCENTAGE of the transitors on a one million transistor CPU chip are used
to support 4K data cache and 4K code cache. These caches are sometimes
larger and such but from what I was told long ago 7 gates are needed
minimum for retaining a single bit of memory storage and 4K + 4K = 8K; 8K
is 8192 bytes (65536 bits of cache storage). This cache storage if using
the minimalistic 7 gates per bit is over HALF A MILLION GATES!!!!!!

You see then there is absolutely nothing special about a 32000 gate CPU or
a 68,000 gate CPU that is not precisely on par with complexity of the
million gate chips of todays era. The reason is because the majority of
the gates ar just simple minded arrays of memory storage (usually machine
designed and layed out) No football field sized blueprints, No million man
hours of research and development. Nothing.


This foolish and reoccuring fallacy regarding the complexity of a CPU
based on its gate count annoys the shit out of me. I read it in MacWeek,
Byte, Dr. Dobbs, etc at least 4 times of year, and have NEVER seen anyone
stop and point out that a huge portion of the gates are merely used for
cache storage.

I have no real background in hardware (I am a software developer) but I
can use a calculator easily enough as the next guy to burst the bubbles of
these COMPLEXITY=NUMBER-OF-GATES fallacies.

Once you see what can be done with just 68000 transistors, you will
realize that the Acorn 610 is not totally deviant from the engineering
realm of possibilities with its claim of merely 32000 transistors.

Bill Williams

Re: Acorn 610 as processor/coprocessor?

#985

Author: Yamanari
Date: Sun, 08 Nov 1992 13:06

17 lines
1240 bytes

In article <BxE6uH.IEt@iat.holonet.net> bwilliam@iat.holonet.net (Bill Williams) writes:
>Once you see what can be done with just 68000 transistors, you will
>realize that the Acorn 610 is not totally deviant from the engineering
>realm of possibilities with its claim of merely 32000 transistors.
>

	1)  I believe that the Acorn 610 has a 4k on chip cache. 
	2)  It also has no FPU.
	3)  It sells for <$100 in quantity.



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