1. not_bits() not_working()
Hello,
I've found that Euphorias not_bits() function doesnt really work
correctly.
For example:
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?
Take care for now,
Al
2. Re: not_bits() not_working()
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 ]
3. Re: not_bits() not_working()
- Posted by rolf at rschr.de
Jun 26, 2003
Al Getz wrote:
> atom a,x
> a=2
>
> x=not_bits(a)
>
> --now x equals -3, which isnt correct.
It is correct! look at this (or try it yourself):
---------------------------------------------------
printf(1,"%08x\n", 2 ) -- 00000002
printf(1,"%08x\n", not_bits(2) ) -- FFFFFFFD
---------------------------------------------------
Please notice also:
0000 0000 0000 0000 0000 0000 0000 0010 = 2 = #00000002
1111 1111 1111 1111 1111 1111 1111 1101 = -3 = #FFFFFFFD
Have a nice day, Rolf
4. Re: not_bits() not_working()
----- Original Message -----
From: "Al Getz" <Xaxo at aol.com>
To: "EUforum" <EUforum at topica.com>
Subject: not_bits() not_working()
>
>
> Hello,
>
> I've found that Euphorias not_bits() function doesnt really work
> correctly.
>
> For example:
>
> 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?
>
Sorry Al, but it does exactly what I'd expect it to do. Each bit in the
32-bit value is reversed. If it didn't work this way a number of functions
in win32lib would fail.
--
Derek
