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From: torbenm@diku.dk (Torben [gidius Mogensen)
Newsgroups: comp.sys.acorn
Subject: Re: ARM4
Message-ID: <1990Dec28.135619.21679@odin.diku.dk>
Date: 28 Dec 90 13:56:19 GMT
References: <1990Dec21.031201.3334@odin.diku.dk> <1990Dec21.172006.14061@watdragon.waterloo.edu> <2577@krafla.rhi.hi.is>
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Organization: Institute of Computer Science, U of Copenhagen
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kvj@rhi.hi.is (Kristjan Valur Jonsson) writes:

>In <1990Dec21.172006.14061@watdragon.waterloo.edu> gcwilliams@watdragon.waterloo.edu (Graeme Williams) writes:

>>This is not the first time I've seen an ARM4 reference - presumably
>>there is an ARM4 under development. Anyone know anything about it ??
>>(like it's clock speed for instance)

>It is only logical to believe that after the ARM3 comes an ARM4.
>After all, ARM Ltd. are not expected to sit idle handed.
>But then again, What can be done to improve on the ARM3's spec.?
>Are there some incredible performance techniques out there just
>waiting to be inplemented in a new ARM? What makes other RISC processors
>that fast (those that are faster than the ARM that is, which means most of
>them, I understand.), for example?

>K.V.J

>>Graeme Williams
>>gcwilliams@watdragon.waterloo.edu

I *know* nothing about the developments of an ARM4, but I have some
guesses. Acorn announced that a FPU would be available for the new
workstation series, so I expect this to be one of the first new
products that ARM Ltd. will produce.

Also, given the fact that the 4-chip set used in A3000 and A400
contains a smaller number of transistors combined than for example
Intel 386 or Motorola 68030, I would expect a single-chip version of
that set (ARM2, MEMC, VIDC & IOC) to be produced. This could be used
to make low cost machines (a cheaper A3000?). This would be similar to
the chip used in the Active Book.

A variant of this with an ARM3 and FPU would be a logical next step.

Also, I expect improved versions of MEMC and VIDC to be produced. The
fact that MEMC only have 128 pages has always been one of the great
limiting factors in the ARM design. A MEMC with 512 or 1024 pages
would be essential for high end machines. A new VIDC could be equipped
with a larger colour table (256 entries) and the possibility of doing
direct mapped 15 or 30 bit RGB. The numbers 15 and 30 seem logical, as
they fit into 16 or 32 bit words, continuing the present bit-doubling
strategy. Even if not all bits are sent to the DACs, 15 and 30 bit
formats seems like good aiming points.

As for other manufacturing techniques, I think that it is too early to
aim for ECL, bipolar or GaAs. Low power CMOS versions (like used in
the Active Book) seems more propable.


	Torben Mogensen (torbenm@diku.dk)