Re: Binary value

["Smark" <nobody@home.com>]

"chris.danx" <chris.danx@ntlworld.com> wrote in message
news:K84x6.4066$MZ2.743519@news2-win.server.ntlworld.com...
> > I see... that answers half of my question. This presumes I wanna convert
> > from binary to Integer. But is it possible to "convert" a Integer value to
> > binary.
>
> Suppose you have the value 123 in binary.  To convert to binary you need to
> follow this algorithm.
>
> while num /= 0 loop
>     rem := num mod 2;    -- get remainder
>     num := num - rem;
>     add rem'image to front* of string;
> end loop;
>
> {I think this is the correct algorithm!}

Well, Chris, you would probably change your mind if you tried it!
As in your example, say you start with 123.

First pass through loop:
rem := 123 mod 2 ( = 1)
num := 123 - 1 ( = 122)
add "1" to front of string   -- so the string now looks like "1"

Second pass:
rem := 122 mod 2 ( = 0)
num := 122 - 0 ( = 122)
add "0" to front of string   -- so the string now looks like "01"

Third pass:
rem := 122 mod 2 ( = 0)
num := 122 - 0 ( = 122)
add "0" to front of string   -- so the string now looks like "001"

Beginning to see a problem here?

I think the algorithm you were trying to think of goes something like:

Rem := Num;
Exp := 31;
Index := 1;
while Exp >= 0 loop
    Check := 2 ** Exp;
    if Rem >= Check then
        Bit_String(Index) := '1';
    else
        Bit_String(Index) := '0';
    end if;
    Rem := Rem - Check;
    Exp := Exp - 1;
    Index := Index + 1;
end loop;

However, there are much easier ways.  You should take a look at the
facilities provided in Text_Io, as Marin mentioned.  Also, if you
want to do something with the bits other than display them, you could
do an unchecked_conversion to a packed bit array of the same size as
the number.

Regards,
Mark
Arlington, Texas