Re: 6502 illegal opcodes questions

[Bruce Tomlin <bruce#fanboy.net@127.0.0.1>]

In article <e598co$12ur$1@merope.saaf.se>,
 pausch@saaf.se (Paul Schlyter) wrote:

> In article <bruce#fanboy.net-7FEFE6.22195226052006@news.newsreader.com>,
> Bruce Tomlin  <bruce#fanboy.net@127.0.0.1> wrote:
> 
> > In article <e56rj1$7lo$1@merope.saaf.se>,
> >  pausch@saaf.se (Paul Schlyter) wrote:
> > 
> >> numbers for your number crunching stuff?  Forget about Java then....  or
> >> does your hardware have 1-complement signed integers?  Java requires
> >> integers to be 2-complement, i.e. you must then have some emulation layer
> >> on top of your native integer format - that's inefficient.
> > 
> > Seriously, has anyone used 1's complement arithmetic in the past 10-20 
> > years or so?  And why?
> 
> I used a CDC Cyber-720 twenty years ago: it has 60-bit word size,
> non-IEEE floating-point format, and one-complement arithmetic - not
> only for integer data but for floating-point data as well!  A few
> years later that machine was put out of service though.

Exactly.  Put out of service.  That's why I gave a range, because I know 
how some places can be about their expensive old mainframes and micros.

And you didn't answer my other question of WHY?  What advantage does 1's 
complement math have that would make someone _want_ to use it now?

> Btw one could also ask:
> 
> "Seriously, has anyone used the Apple II, or some other obsolete 8-bit
> micro, in the past 10-20 years?  If so, why?"
> 
> ...and the surprising (to some) answer is: yes!

Apples and oranges.  I'm talking about a way of doing math, and you're 
trying to bring up a specific hardware platform.  Old platforms are 
going to be obsolete, period.  Old math isn't necessarily so.  "That 
calculus stuff is over 200 years old, nobody uses it any more."