inttobinarystr

function IntToBinaryStr(TheVal: LongInt): string;
var
counter: LongInt;
begin
{This part is here because we remove leading zeros. That
means that a zero value would return an empty string.}
if TheVal = 0 then begin
result := '0';
exit;
end;

result := '';
counter := $80000000;

{Suppress leading zeros}
while ((counter and TheVal) = 0) do begin
counter := counter shr 1;
if (counter = 0) then break; {We found our first "1".}
end;

while counter > 0 do begin
    if (counter and TheVal) = 0 then result := result + '0'
    else result := result + '1';
    counter := counter shr 1;
end;
end;