SIGN_EXTEND: PROCEDURE OPTIONS (MAIN);

DECLARE LIB$EXTV ENTRY
        (FIXED BINARY (31),     /* Address of longword containing
                                /*   beginning bit position             */
         FIXED BINARY (7),      /* Address of byte containing size
                                /*   of field                           */
         FIXED BINARY (31))     /* Address of field                     */
         RETURNS (FIXED BINARY (31));   /* Return value                 */

DECLARE (VALUE, SMALL_INT) FIXED BINARY (31);

ON ENDFILE (SYSIN) STOP;

DO WHILE ('1'B);                /* Loop continuously, until end of file */
        PUT SKIP(2);
        GET LIST (VALUE) OPTIONS (PROMPT ('Value: '));
        SMALL_INT = LIB$EXTV ( 0, 4, VALUE);    /* Extract and sign-extend
                                                /*   first 4 bits       */
        PUT SKIP LIST (VALUE, SMALL_INT);
        END;

END SIGN_EXTEND;