Character manipulation in 7090 FORTRAN

The IBM 7090 FORTRAN II language requires that a programmer desiring toa mnipulate characters or strings of characters either assign each character to a separate 7090 word or write special subroutines for handling packed words containing 6 characters. The one-character-per-word approach is superior in most cases due to the much smaller machine time it requires. One pays for this speed advantage in additional core requirements, however, plus more complex logic requirements in some cases. Applications exist where considerations of storage and logic make a packed-word approach competitive. One such application, and the one which led to the work described here, was the desire to manipulate information sent via telephone lines by a remote 7090 user to and from the central computer. The results of this work are not completed, but the methods used for manipulating character strings were felt to be of sufficient interest to warrant a report. The following paragraphs describe the approach taken.

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