OpenEuphoria

Re: fast bit rotation

• Posted by "Juergen Luethje" <j.lue at gmx.de> Jan 01, 2004
• 444 views

Derek wrote:

> ----- Original Message ----- 
> From: "jiri babor"
>
>> Thanks, guys, for your tremendous response. Tommy's machine code looks most
>> promising. Currently I am looking at 24 bit integers, later I might even be
>> forced beyond the Euphoria's 31-bit limit. So, sorry, look up tables and
>> similar 8-bit solutions are interesting, but not of much practical use.
>
> Doesn't the INTEGER type only support 30-bit integers? I make the range
> for INTEGER types to be from (-power(2,30)) to (power(2,30) - 1). It
> seems that Euphoria uses 30-bits to hold the value, one bit to hold the
> sign

I think the sign bit must be counted, too. So 30 bits + 1 bit = 31 bits.
If we add power(2,30) to both the minimum value and the maximum value
that you mentioned above, that does not alter the range. Then we get an
unsigned integer type from 0 to (power(2,31)-1.
Now it's pretty clear, that the range consists of 31 bit. Whether or not
one bit is used to hold the sign, is a different question, IMHO.

> and the 32nd bit to hold the flag to tell if its an integer or
> something else? Just guessing.

<snip>

Regards,
   Juergen

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