 
      operate on:
      <ul>
        <li>
          <b>B4</b> - a 4 byte word;
        </li>
        <li>
          <b>CH</b> - a character;
        </li>
        <li>
          <b>CHVEC</b> - a vector of characters;
        </li>
        <li>
          <b>DEC</b> - a decimal fraction;
        </li>
        <li>
          <b>DIGIT</b> - a character representing a numeric digit;
        </li>
        <li>
          <b>I4</b> - an integer ( kind = 4 );
        </li>
        <li>
          <b>R4</b> - a real