*procedure
**
WRITEHEX
      To write out a number in hexadecimal format.
      writehex ( n, w )
      The number 'n' is written to  the  currently  selected
output  stream  in  hexadecimal  format  in  a  field of 'w'
spaces. If the field is not wide enough then only the lowest
order 'w' digits are written. Otherwise the number is right-
justified in the field and padded with zeroes.


