64-bit CPU

[Henry Spencer]

On Thu, 16 Sep 2004, James Knott wrote:
> Was it the old Texas Instruments CPU, used in the TI/99, that didn't 
> have any on chip registers?  As I recall, the "registers" were in fact, 
> reserved memory locations.

The processor was the TI 9900.  The memory wasn't exactly "reserved" --
the block of 16 "registers" could be anywhere in memory, with a control
register specifying where it was.  (Possibly it had to be on a 16-word
boundary; I no longer remember.)

An interesting architecture, and although the initial implementation was
understandably slow, you could throw more transistors at it to do things
like caching, and TI was promising to do so.

But the marketing of the computer they designed around it, the 99/4A,
could be described politely as grossly incompetent.  So they lost a bundle
on the computer, and I think the chip got dragged down with it. 

                                                          Henry Spencer
                                                       henry-lqW1N6Cllo0sV2N9l4h3zg at public.gmane.org

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