<I believe (guessing because I've learned memory doesn't serve as it once
<did) The load is two clock ticks and the indirect, indexed jump is five, s
<that's 3.5 microseconds, give or take a tick. it's less at 4 MHz, which i
<what the 65C02C is rated, though it readily will run at 4.9152 (24.576
<MHz/5) over a wide temperature and voltage range provided the clock is
<phased correctly. the divice-by five yields a 40/60 h/l which must be
<inverted to give a little longer phase-2 than phase-1.
The point was apparently missed. Of course I can take a cmos z80 and blow
that out of the water using a 6 or 8 mhz clock. Heck using a 1989 version
of the z80, the Z280 at 12.5mhz I can get the execution time way down. In
the time frame before 1982 (as a marker) there werent any 4mhz 650c02s and
there were 4mhz z80s and pdp-8s were still produced. In that context the
the example represent programming style rather that absolute speed as they
didn't vary that much over all to represent a great diffferece unless you
needed a characteristic that was specific to a given CPU.
I'm not slamming the 6502 or it heirs as it's also a very popular embedded
CPU still. For that fact so are the Z8 and Z80 heirs. Just from that it's
possible to conclude they all had desirable enough characteristics to keep
them in the running.
As a CPU the 8051 is ok, I use it. As a controller it's without question
a popular part still. But as a general purpose cpu, it's a really bad
C or Pascal compiler host/target.
Allison
Received on Sun Apr 11 1999 - 08:16:18 BST