XRF - FORTRAN Cross-Referencer
		==============================

			Users' Guide
			============

 XRF is a FORTRAN cross-referencing task. It can be run in most of the
 common ways, viz:-

    XRF			XRF Command-Line	RUN $XRF 
    XRF> Command-Line				XRF> Command-Line

 the   only  major  restriction  being  that  it  will  not  accept  a
 commandfile as input.
 The Command-Line is of the form:-

	outfile=infile[/LI]

 Where  'outfile'  is  the  file  to  put  the  cross-reference map in
 (default  extension  .XRF)  and  'infile'  is the input file (default
 extension .FTN). If /LI is specified the output file is prefixed by a
 listing  of  the file with line and statement numbers appended.  Note
 that  the  statement  numbers  will be the same as those on a FORTRAN
 compilation  listing  only  if  FORTRAN  IV-PLUS  is used (FORTRAN IV
 treats some IF statements as double statements).

 Current known restrictions on XRF are:-

	1) Maximum on 2048 input statements (excluding comments)
	2) Maximum of 2000 symbol definitions/references
	3) Statement labels above 32767 cannot be handled.

 The  Cross-Reference map contains various symbols against each symbol
 defining in which way it is used in the given statement.  The symbols
 (and their meanings) are:-

	AS	ASSIGN
	CA	ARGUMENT IN CALL STATEMENT
	CM	COMMON VARIABLE
	DA	DATA
	DF	DEFINE FILE
	DI	DIMENSION
	DO	DO
	DT	BYTE, COMPLEX, DOUBLE PRECISION, INTEGER, LOGICAL, REAL
	ED	ENCODE, DECODE
	EN	ENTRY
	EQ	EQUIVALENCE, PAUSE, RETURN, STOP
	GO	GO TO
	ID	CLOSE, OPEN
	IF	IF
	IN	INCLUDE
	IO	ACCEPT, PRINT, READ, TYPE, WRITE
	IU	BAKSPACE, ENDFILE, FIND, REWIND
	PD	BLOCKDATA, FUNCTION, PROGRAM, SUBROUTINE
	PM	PARMETER
	PS	COMMON BLOCK NAME
	XP	SUBPROGRAM NAME
	=	STORED INTO BY REPLACEMENT STATEMENT
	@	STATEMENT LABEL DEFINITION

 XRF may produce a number of error messages.  The first appears on the
 requesting  terminal, the others in the output file.  The output file
 also contains a count of the errors detected (if any were).

 1.  !!!CMD ERROR!!! OUT=IN PLEASE!

     The  command-line  specified  to  XRF  was  not of the form shown
     above.

 2.  ******   Unrecognised Statement Type in Statement nnn ******

     The  statement referred to did not contain a recognisable keyword
     or symbol.

 3.  ******   Statement Syntax Error in Statement nnn ******

     The  statement referred to did not conform to the syntax expected
     for the given keyword.

 4.  ******   Unbalanced Quotation Marks in Statement nnn ******

     The  statement  referred  to  appeared to open a Hollerith quoted
     string but did not close it.

		XRF - FORTRAN Cross-Referencer
		==============================

			System Guide
			============

 XRF consists of 22 modules (12 FORTRAN and 10 MACRO-11) which are overlaid as follows:-

			       XRF
				!
			     XRFDAT
				!
			     NXTCHR
				!
			      ERROR
				!
			     FRMCTL
				!
			     LINEIN
				!
			     ITSTCH
				!
	-----------------------------------------------------
	!			!			!
     XRFINI		      XREF		     OUTPUT
	!			!			!
     GETMCX		      ENTER		     GETSYM
				!
			     NXNCHR
				!
			     NXTSYM
				!
			     IISHFT
				!
			     SRCTBL
				!
			     MAKENT
				!
			     ADDREF
				!
			      IPACK
				!
			     LOFSET
				!
			      ISTMT


 I  have  not  investigated  the  structure  of  the task in any great
 detail,  but  roughly  speaking  the  modules  perform  the following
 functions:-

 ADDREF (MACRO)   - Adds a reference to the Symbol Table
 ENTER  (FORTRAN) - Enter symbol or statement label into Symbol Table
 ERROR  (FORTRAN) - Output any syntax error messages
 FRMCTL (FORTRAN) - Count lines in output & throw new pages
 GETMCX (MACRO)   - Get command line from MCR
 GETSYM (MACRO)   - Get values for symbol from Symbol Table
 IISHFT (MACRO)   - Shift Integer n bits left
 IPACK  (MACRO)   - Convert characters to RAD50
 ISTMT  (MACRO)   - Identify statement type by keyword
 ITSTCH (MACRO)   - Test type of character passed
 LINEIN (FORTRAN) - Read line from input file
 LOFSET (MACRO)   - See if character appears in given string
 MAKENT (MACRO)   - Make entry in Symbol Table
 NXNCHR (FORTRAN) - Get next non-space/tab char from input
 NXTCHR (FORTRAN) - Get next line, print it if required, and calculate
                    the new line and statement numbers for it
 NXTSYM (FORTRAN) - Find next symbol in input line
 OUTPUT (FORTRAN) - output the symbol table
 SRCTBL (MACRO)   - Search Symbol Table for given symbol
 XREF   (FORTRAN) - Process each statement according to its type
 XRF    (FORTRAN) - Main calling module
 XRFDAT (FORTRAN) - Initialize common data areas
 XRFINI (FORTRAN) - Get command line from user & open files

 XRF  is  built by the commandfile XRF.CMD.  If just @XRF is typed, it
 will assemble/compile all the relevant modules and then taskbuild the
 task.     Alternatively,  if  @XRF  xxxxxx  is  typed  it  will  just
 assemble/compile  xxxxxx and taskbuild the task.  XRF.CMD dynamically
 creates XRF.BLD and XRF.ODL if they do not exist.

 XRF is a non-privileged task, with 4 units (1 & 4 assigned to TI:), a
 taskname  of  ...XRF and an ACTFIL count of 2.  It is currently built
 with the following overlay:-
   ;
   ;	 X R E F . O D L
   ;
   ;	OVERLAY DESCRIPTOR FOR X-REF (FORTRAN) TASK
   ;
   	.ROOT	XRFROT-LIB-*(O1,O2,O3)
   XRFROT:	.FCTR	XRF-XRFDAT-NXTCHR-ERROR-FRMCTL-LINEIN-ITSTCH
   O1:	.FCTR	XRFINI-GETMCX-LIB
   O2:	.FCTR	XREF-ENTER-NXNCHR-NXTSYM-IISHFT-SRCTBL-MAKENT-O21
   O21:	.FCTR	ADDREF-IPACK-LOFSET-ISTMT-LIB
   O3:	.FCTR	OUTPUT-GETSYM-LIB
   LIB:	.FCTR	LB:[1,1]FOROTS/LB
	.END