Hi,
this is my function which I'm using to determine the bit width of
a given value.
int getBWidth( long long constValue )
{
int bWidth = 0;
for ( int n = 64; n >= 1; n-- )
if ( ( constValue >= -pow( (float) 2, n - 1 ) ) &&
( constValue <= pow( (float) 2, n - 1 ) - 1 ) )
bWidth = n;
else
return bWidth;
return bWidth;
}
This function works fine for small arguments. But for larger
long long values the results deviate, e.g.
passing 4294967295 ( 2^32 - 1 ) as signed long long argument should result
in a return value of bWidth=33 while argument 4294967296 should return
the value 34.
However, the function returns for both values the value 34. After playing
around with some function arguments I figured out that the threshold
among 33 and 34 bits is the value 4294967168.
So, my question is where the deviation between 4294967296 and
4294967168 comes from?
Thank you.
Chris
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