Z80 instruction fetch mechanism

[Jim Battle]

Jim Battle wrote:
> Steven Hirsch wrote:
> ...
>>
>> Wasn't the Z80 a microcoded design?
> 
> no!  the same guy who did the 8080 layout, masatoshi shima, did the z80 
> layout.  He also did the z8000 layout, which was much more complex, but 
> was also not microcode, just random logic.
> 
> I just found this while googling to support my answer, but i've only 
> skimmed it - a 47 page interview with Shima, done by the CHM:
> 
> http://www.ieee.org/portal/cms_docs_iportals/iportals/aboutus/history_center/oral_history/pdfs/Shima197.pdf 
> 
> 

Having read more, Shima did the logic design on the 4004, 8080 and z80, and did the layout 
on the 8080.  I've also heard he led the layout for the z8000.

It is quite interesting to compare Shima's version of 4004 history and Federico Fagin's. 
In Fagin's version, he virtually did everything himself, with a bit of help from Shima. 
In Shima's version of events, he and Ted Hoff did all the spec work and design down to the 
transistor level, and Fagin was the guy who knew the process and layout end of things. 
Fagin believes Intel has tried to erase his contribution to the 4004 and later intel 
processors in retaliation against his starting Zilog, yet Shima also went to zilog and 
isn't erased, and obviously Fagin and Shima had a good enough relationship to work 
together at zilog for years, and Shima gives Fagin credit only for the back end of the 
4004 design flow.