Starting from Scratch (was Re: OT: Modern college educa - test-drb@ccmp.vtda.org

24 Oct 1998

On Oct 24,  9:53, Sam Ismail wrote:
...
  Subject: Re: Starting from Scratch (was Re: OT: Modern
college educa
 On Fri, 23 Oct 1998, Ethan Dicks wrote:

 > can provide one.  It depends on logical statements working as follows:
 > The statement C=(A>B) would set C to 0 if A weren't greater than B, and
 > would set C=-1 if A were greater than B.  Not all micro BASICs support this.
...
   I'm pretty
sure Applesoft is onethat does _not_. 
 AppleSoft would logically return a +1 for the above statement rather than
 a -1.  Why the PET returns a -1 is beyond me.  Couldn't they have added
 one more machine instruction to strip off the sign bit? 
The PET is actually following the more common convention.  The bitwise
complement of 0 (all zero bits) is -1 (all one bits), at least in a
2's-complement environment.

-- 

Pete						Peter Turnbull
						Dept. of Computer Science
						University of York