Meaning of "architecture width" - Re: 68K Macs with MacOS 7.5 still in production use...

Chuck Guzis cclist at
Sat Sep 17 12:10:56 CDT 2016

On 09/17/2016 09:23 AM, Eric Smith wrote:

> I don't know what the width of the TMS9900 ALU is, but I'm pretty
> sure it's not bit-serial, as an add instruction only takes 14 clock
> cycles, including four memory cycles. I'd be very surprised if the
> ALU isn't either 8 or 16 bits, though 4 might be possible.
> Possibly someone is confused by the bit-serial "CRU' I/O space, but 
> that is unrelated to the ALU width.

Could very well be--I'm just going by other's appraisals of the

But there were some "8 bit" MPUs with bit-serial ALUs, so the question
is still valid.


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