Re: Z80 Softcard speed?

[pausch@saaf.se (Paul Schlyter)]

In article <1170561217.421374.226310@p10g2000cwp.googlegroups.com>,
mdj <mdj.mdj@gmail.com> wrote:

> On Feb 4, 10:13 am, "Alex Freed" <a...@mirrow.com> wrote:
> 
> > Good idea. Plenty of free info on the 'net. I dare say Z80 was *THE* best
> > 8 bit CPU ever. Still used to the tune of 5,000,000 a year!
> > Not sure if this number included derivatives like z180.
> 
> You *do* realise this is csa2 don't you ;-)
> 
> More seriously, if best is units shipped you're probably right.
> Personally I would bestow 'best' on the 6809. Nice orthogonal
> instruction set, efficient execution speed. The only problem is
> whether a CPU with 16 bit index and stack registers and paired 8 bit
> accumulators qualifies as 8 bit, but I think it does ;-)

Are you referring to the 6809 or to the Z80 here?  :-)

The Z80 had a 16-bit stack register (of course!  Already the 8080 had
that), and no less than TWO 16-bit index registers (IX and IY).  In
addition, several 8-bit registers could be used as pairs and be used
to point to things (BC, DE and HL).  It had 16-bit add and subtract
instructions, provided the operands were placed in CPU registers.
But, alas, the Z80 had no multiply operation - that had to be done in
software.

The 6809 had an 8-bit multiply operation.  If the 6809 had had a 16-bit
multiply operation, I would have been tempted to label it as a 16-bit
CPU although with an 8-bit external data bus -- like the 8088 and 80188.
 
> Matt
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