      SKP **                           ** ***  STACK STRING CONSTANT  *** **                           ** * *  SEE NOTE AT FOR13 OF ROUTINE FORMX * #STST ISZ OPDST     STACK       ISZ OPDST       NEGATIVE      LDA TEMP1         OF      CMA                 STRING      STA OPDST,I           ADDRESS       LDA TEMP1,I   COMPUTE       AND B377        STRING      CCB               LENGTH      ADB 0               -1      ADA .+3       UPDATE      ARS             INTRA-STATEMENT       ADA TEMP1          POINTER      STA TEMP1           PAST STRING       JSB RSCHK     CREATE TEMPORARY      CLA           RECORD      DST TMPST,I     (0,(B) )      JMP STSTR,I **                           ** ***  PREPARE STRING OPERAND  ** **                           ** * *  THE STRING ADDRESS ON TOP OF THE OPERAND STACK IS COMBINED *  WITH THE SUBSCRIPTS IN A PSUEDO-ENTRY ON THE TEMPORARY STACK *  TO FORM A STRING OPERAND.  (A) = 0 UPON ENTRY FOR A SOURCE *  STRING; (A) = -1 FOR A DESTINATION STRING.  THE ADDRESS OF *  THE FIRST CHARACTER OF THE STRING OPERAND IS LEFT IN TEMP5;*  FOR SOURCE STRINGS (A) = TEMP5 UPON EXIT.  THE REQUESTED *  STRING LENGTH (IN CHARACTERS)S) IS LEFT IN TNULL; FOR SOURCE *  STRINGS THE ACTUAL STRING LENGTH (WHICH MAY BE LESS THAN THE *  REQUESSTED LENGTH) IS IN (B) UPON EXIT.  THE FOLLOWING *  CONDITIONS EXIT TO ERROR:  NEGATIVE STRING LENGTH, REQUESTED *  DESTINATION STRING WOULD EXCEED PHYSICAL STRING BOUNDARY, OR *  REQUESTED DESTINATION STRING WOULD PRODUCE A STRING QUANTITY *  WITH TWO UNCONNECTED PARTS.  THE LOGICAL LENGTH OF A *  DESTINATION STRING IS ADJUSTED AS NEEDED.* #PSTR STA PS0       SAVE MODE FLAG      JSB OPCHK     UNSTACK OPERAND       STB PS1       SET FLAG POSITIVE       BLS           SAVE AADDRESS OF FIRST        STB TEMP5       CHARACTER OF STRING       BRS           SAVE      ADB .-1         POINTER TO      STB TEMP6         STRING LENGTH       LDB TMPST     LOAD      ADB .+2          START-OF-STRING        LDA 1,I           DESIGNATOR      STA MPT       SAVE IT       ADA TEMP5     RECORD CHARACTER ADDRESS      STA  TEMP5       OF START-OF-STRING        STA SBPTR     SAVE ADDRESS 