How CPU's work (was Re: Hi, I'm new...)

Don THX1138 at
Tue Aug 8 18:50:45 CDT 2006

woodelf wrote:
> Don wrote:
>> Alternate registers are useful for interrupt handlers -- *if*
>> you ensure that they can't be nested.  You can cheat and
>> use AF in one IRQ and the other pairs (EXX) in another IRQ
>> (of course, assuming you only need AF in the one and don't
>> need A or F in the other!  :> )
> Well one use could be a dedicated controler -- IO ports,
> ROM,CPU and OSC. The alternate set would provide the ram.

Pretty skimpy to try to work with just 8 bytes of RAM  :>
(and F would be difficult to access).

The '7180 was a great part during it day as it had 512 bytes
of RAM, internal (and 16K of OTP).  I would use them to
throw together dog-and-ponies for prospective clients.
You could even *leave* the prototype with them and not
fear that they were going to "dump the ROM"...  ;>

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