OpenEuphoria

RE: not_bits() not_working()

• Posted by Al Getz <Xaxo at aol.com> Jun 26, 2003
• 452 views

Carl W. wrote:
> 
> 
> Al Getz wrote:
> 
> > atom a,x
> > a=2
> > 
> > x=not_bits(a)
> > 
> > --now x equals -3, which isnt correct.
> > --x should be equal to the 8 digit hex equivalent of -3,
> > --right?
> 
> The *_bits() functions all return negative if the high bit of the result 
> 
> is 1. They use signed 32-bit ints internally I presume.
> 
> try:
> 
> function not_bitsU(atom a) -- U = Unsigned
>      return #FFFFFFFF - a
> end function
> 
> or better (but slower):
> 
> constant B32m1 = power(2,32)-1
> function not_bitsU(atom a) -- U = Unsigned
>      return B32m1 - and_bits(a, B32m1)
> end function
> 
> Carl
> 
> -- 
> [ Carl R White == aka () = The Domain of Cyrek = ]
> [ Cyrek the Illogical /\ www.cyreksoft.yorks.com ]
> 
> 

Hello there Carl,

I have been using poke4 and peek4u right after the not_bits(),
but i'll also take a look now at your subtraction functions.
I think 'a' in my use will always be positive, but ill have to
double check first.


Thanks for the ideas,
Al