z80 timing... 6502 timing - test-drb@ccmp.vtda.org

17 Apr 1999

Were you aware of the neat little opcodes that were built into the 6502?  I
don't have my list of them any more, but back in the KIM days, there were
several lists in circulation.  As I recall, one of them was a double load,
i.e it loaded a value into both a register and the accumulator.  I believe
another loaded a register and pushed the value on the stack at the same
time.  Esoteric, for sure, but you never know . . .

Dick

-----Original Message-----
From: Hans Franke &lt;Hans.Franke(a)mch20.sbs.de&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Saturday, April 17, 1999 9:27 AM
Subject: Re: z80 timing... 6502 timing

...
 > <65C02, because it was buillt in several
conflicting versions.  What about
...
 > <the Z-80 core?  Whose?  Which one?  Speed, of
course, should be "limited" t
...
 > <whatever was available in 1982.  That
certainly includes the Synertek (MOS
...

> In 1982 all of the z80s in the market had the same hidden features
> including the IX/IY 8bit ops. I know of no z80 that didn't have them.
> Not all of them were available to the 6mhz spec though many could be
> pushed. Also allowed is the 8085 (available as a 5-6mhz part then). Again
...
   all of the
8085s had the extra unsupported instructions as they were deem
 important! 
a) The speed (of a particular CPU) used is not important for this, since
(I assume) we all can handle the transformation - the goal is still the
factor to use to judge the relative power.
b) unsupported OPCs in the 8085 ? Did I miss them ? I did 2 years of
8085 development projects, and never heared of (also of course never
used) - can you tell what they where alike ?

Gruss
H.

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