                          OBJECT TO MACRO CONVERSION (ORC)
 
                              Version: V01.1/3-AUG-79
 
 
 
        1. INTRODUCTION
 
           ORC  is  a  utility  which  converts  PDP-11  object  code  to
           MACRO-11. Its uses include:
 
           * checking code produced by compilers
           * on-line debugging of code produced by a compiler which  does
             not give an assembly listing (eg. CORAL).
 
           For  ORC  to  produce  sensible output, the object code should
           have data and instructions in separate program sections with D
           and I attributes respectively. The object code produced by the
           CORAL and F4P compilers satisfy this requirement.
           The F4P compiler produces its branch instructions after it has
           produced the  other  object  code  which  may  look  a  little
           strange, but is in fact correct MACRO-11 code.
           The  threaded  code  produced by the FORTRAN compiler (FOR) is
           not suitable for conversion to MACRO-11.
 
           The MACRO-11 code produced by ORC  can  be  assembled  in  the
           usual way to produce an assembly listing.
 
 
        2. USING ORC
 
           When  the  task is initiated it issues a prompt and receives a
           command line of the form:
 
                     ORC>*outputfilespec=inputfilespec
 
           The usual RT-11 conventions for file specifications apply. No
           switches are allowed in the command line. If the extension  is
           not supplied in a file specification, it is assumed to be:
 
                     .OBJ for the input file
                     .MAC for the output file
 
           ORC converts the object code in the input file  into  MACRO-11
           and  writes  it to the output file. The MACRO-11 file can then
           be assembled in the usual way to produce an assembly listing.
 
           During processing, ORC allocates a  temporary  file  (ORC.TMP).
           If ORC is aborted, this file should be deleted.
 
           ORC uses in-core tables to store local symbols, labels, global
 
 
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                         OBJECT TO MACRO CONVERSION (ORC)
 
 
           symbols, and program section names. These can hold up to:
                     * LLLMAX local symbols
                     * LABMAX local labels
                     * GLOMAX global symbol definitions
                     * PSEMAX program section names
 
           This should be enough for most object  files,  but  the  first
           three  of  these tables can be extended by modifying the file
           ORCMAC.MAC and rebuilding the program.
 
           Local labels are used when referring to locations  within  the
           same  (instruction)  program  section. They are of the form n$
           where n is the location of the label.
           Example:
                   MOV     R0,R1
                   BEQ     6$
                   CLR     (R0)
           6$:     INC     R1
 
           Local symbols are used  when  referring  to  locations  within
           other  program sections, or within the same program section if
           it contains data. They are of the form xn, where x is a letter
           (A, B, C,...) defining  the  program  section  and  n  is  the
           location of the symbol within the program section.
           Example:
                   .PSECT  DATA,D
           C00000: .WORD   0
           C00002: .WORD   C00000
           ;
                   .PSECT  INSTR,I
                   MOV     #C00002,R0
 
           In  certain circumstances, ORC may reference symbols which are
           not defined. The positions of these symbols can be  determined
           from their names.
 
 
        3. ERROR MESSAGES
 
           ORC -- COMMAND I/O ERROR
                   An I/O error ocurred during input of the command line,
                   or  a bad indirect command file name was specified, or
                   indirect command files were nested.
 
           ORC -- SYNTAX ERROR
                   A syntax error was detected in the input line.
 
           ORC -- BAD INPUT FILE SPEC
           ORC -- BAD OUTPUT FILE SPEC
                   A switch was specified or 'wildcards' were used in the
                   file specification.
 
 
 
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                         OBJECT TO MACRO CONVERSION (ORC)
 
 
           ORC -- OPEN FAILURE ON xxxxxx FILE
           ORC -- I/O ERROR ON xxxxxx FILE
           ORC -- FAILED TO CLOSE xxxxxx FILE
                   These errors may be caused for a variety  of  reasons,
                   eg.  device offline, device full, privilege violation,
                   file does not exist. The message specifies whether the
                   error ocurred on the INPUT, OUTPUT or SCRATCH file.
 
           ORC -- PSECT TABLE OVERFLOW
                   Only PSEMAX program sections are allowed  in  one  object
                   file,  including  the  absolute  (.  ABS.)  and  blank
                   PSECTs. This number can be increased by editing ORCMAC.MAC
                   and rebuilding ORC.
 
           ORC -- LABEL TABLE OVERFLOW
                   Only LABMAX local labels are allowed in one object file.
                   This number can be increased by  editing  ORCMAC.MAC
                   and rebuilding ORC.
 
           ORC -- LOCAL SYMBOL TABLE OVERFLOW
                   Only  LABMAX local  symbols  are  allowed in one object
                   file. This number can  be  increased  by  editing ORCMAC.MAC
                   and rebuilding ORC.
 
           ORC -- GLOBAL SYMBOL TABLE OVERFLOW
                   Only GLOMAX global symbol definitions are allowed in one
                   object  file.  This number can be increased by editing
                   ORCMAC.MAC and rebuilding ORC.
 
 
        4. GENERATING ORC
 
           The following files are contained in the distribution kit:
 
           * ORC.COM - command file for compiling and linking
           * ORC.DOC - user document
           * MACRO-11 source files
 
           The object code uses instructions (such as SOB and ASH)  which
           are only supported on PDP-11/35 computers and upwards.


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