Convert varchar to binary reprezentatio

Question

Hi,
I have simple problem i have varchar2 string for example something like this 01000001000011000000000000000000
this string represent 32 bit float number 8.75 in IEEE.
What i need ?
Simple thing and I am not able solve this for long time
I have to create its string binary representation
the result can be in (4 byte) blob ... and how can set the particular bit value.
here is se fragment of code
str='01000001000011000000000000000000';
while i<31 loop
     bit:=substr(str,i+1,1);
     if (bit='1')then
     /* here i need code to set bit to 1 on position i*/
     else
          /* here i need code to set bit to 1 on position i*/
     end if;
i:=i+1;
end loop;
return BL;

Answer 1

I googled and found specs formula on http://www.math.byu.edu/~schow/work/IEEEFloatingPoint.htm
HTH
Laurent Schneider
OCM DBA
SQL> create or replace function ieee_to_num ( ieee varChar2 ) return number
is
    rc     number;
    i_sign number;
    i_frac number;
    i_exp  number;
begin
    rc := 0; i_sign := 1; i_exp := 0; i_frac := 1;
    for i in -23 .. -1 loop
        i_frac := i_frac + power(2,i)*to_number(substr(ieee,9-i,1));
    end loop;
    for i in 0 .. 9 loop
        i_exp := i_exp + power(2,i)*to_number(substr(ieee,9-i,1));
    end loop;
    if (substr(ieee,1,1)='1') then
        i_sign := -1;
    end if;
    return i_sign*power(2,i_exp-127)*i_frac;
end;
SQL> select ieee_to_num('&ieee') from dual
Enter value for ieee: 01000001000011000000000000000000
IEEE_TO_NUM('01000001000011000
                          8.75