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MERGE command

The MERGE command places an executable program into the current  fork,
combining it with whatever program (if any) is already there.


Format

     @MERGE (PROGRAM) filespec /switch

     where:

     filespec     is the file specification of any executable program.
                       Default file type - .EXE

     /switch      is one or more of the following:

                       /OVERLAY       allows pages of the DDT  program
                                      to be loaded over pages occupied
                                      by  the  existing   program   in
                                      memory.

                       /USE-SECTION:n
                                      specifies  the  memory   section
                                      (from  0 to 37 octal) into which
                                      your program is  to  be  merged.
                                      You  can use this switch only if
                                      your program can be contained in
                                      one section.


Characteristics

     Executable Files Only

          If a program you try to merge is not in  executable  format,
          you   may   get   an   immediate  error  message  (that  is,
          "?UNEXPECTED END-OF-FILE TRAP...") or a  delayed  one  (that
          is,  "?ENTRY VECTOR LENGTH IS NOT LESS THAN 1000") after the
          merge.  In either case, be sure that you have  specified  an
          executable  program before investigating further.  The MERGE
          command does not alter the entry vector if  the  file  being
          merged is in the proper .EXE format.

     Existing Pages Not Overlaid

          If there is a program already in memory when  you  give  the
          MERGE  command, and pages of the new program overlay it, the
          new program is not placed into memory, and the system prints
          the  error message, "?Illegal to overlay existing pages." To
          force the existing pages to be overlaid, reissue  the  MERGE
          command using the /OVERLAY switch.


Effect on Memory

     The MERGE command combines the specified program with the program
     in  the  current  fork.   It  does not affect the contents of the
     current fork unless you specify the /OVERLAY switch.


Related Commands

     INFORMATION MEMORY-USAGE      for  examining  the   contents   of
                                   memory

     GET                           for putting  a  saved  (executable)
                                   file into memory

     SAVE                          for storing a copy of  the  program
                                   in  the  current  fork in a file in
                                   executable format

     START                         for starting the program in memory


Examples

     1.  Merge an executable program into memory.

         @MERGE TESTF1.EXE

     2.  Place an executable system program in memory,  then  merge  a
         system   debugging   program   with   it.   Give  INFORMATION
         MEMORY-USAGE  commands  to  verify  that  both  programs  are
         intact.

         @GET SYS:DUMPER
         @INFORMATION MEMORY-USAGE

         34. pages, Entry vector loc 4715 len 3

           Section 0     R, W, E,  Private
         0        RANDOM:<NEXT-RELEASE>DUMPER.EXE 4  1   R, CW, E
         4-44     RANDOM:<NEXT-RELEASE>DUMPER.EXE.4  2-42   R, CW, E
         @MERGE SYS:UDDT
         @INFORMATION MEMORY-USAGE

         45. pages, Entry vector loc 4715 len 3

           Section 0     R, W, E,  Private
         0        RANDOM:<NEXT-RELEASE>DUMPER.EXE.4  1   R, CW, E
         4-44     RANDOM:<NEXT-RELEASE>DUMPER.EXE.4  2-42   R, CW, E
         764-767  RANDOM:<NEXT-RELEASE>UDDT.EXE.1  1-4   R, CW, E
         770-776  RANDOM:<NEXT-RELEASE>UDDT.EXE.1  5-13   R, E