DEFINITION MODULE VLCGlobal;
(*
Title   : VLCGlobal.MOD
Author  : Kim Moser
System  : JPI TopSpeed Modula-2 with PMI Repertoire 1.5c
Descrip : Global variables, types, procedures, etc. for VLC
*)

CONST
  MaxMC=3;  (*Most operands that any operator can have [+1 for operator]*)
  MaxSymbolLength=8;

TYPE
  LineType=ARRAY[0..79] OF CHAR;

VAR
  TheLine: LineType;  (*Used to hold lines of text from source file*)

  Operator: ARRAY[0..79] OF CHAR;  (*First parsed word from TheLine [could be
            a label]*)
  Operands: ARRAY[0..MaxMC],[0..79] OF CHAR;  (*Parsed words after first*)
  MC: ARRAY[1..MaxMC] OF CARDINAL;  (*Machine code for Operands[n]*)
  MCCount: CARDINAL;  (*Counter of how much MC has been generated for this
                        line*)

  SourceErrors: CARDINAL;  (*Counts number of source errors (updated by
    procedure VLCGlobal.SourceError)*)
  LC: CARDINAL;  (*Location counter*)

  Debug: BOOLEAN;  (*For debugging during developing*)
  ShowMC: BOOLEAN;  (*Indicates to WriteMC [in main] whether or not to
                      write MC; set to FALSE by SourceError]*)

(******************************************************************************
                                 PROCEDURES
******************************************************************************)

(* These are necessary because JPI uses non-standard procedures to do the
   following: *)
PROCEDURE WriteString( s: ARRAY OF CHAR );
PROCEDURE WriteLn();
PROCEDURE WriteStringLn( s: ARRAY OF CHAR );
PROCEDURE WriteCard( c, w: CARDINAL );
PROCEDURE WriteInt( i, w: CARDINAL );

PROCEDURE InternalError(TheMessage: ARRAY OF CHAR);
(* Writes a message describing an internal error in the VLC code *)

PROCEDURE SourceError(TheColumn: CARDINAL; TheMessage: ARRAY OF CHAR);
(* If TheColumn > 0 then writes a caret (^) in column (TheColumn), followed by
   a newline.  Writes TheMessage regardless. *)

PROCEDURE ParseWord(TheLine: ARRAY OF CHAR; VAR TheIndex: CARDINAL; VAR
          TheWord: ARRAY OF CHAR): BOOLEAN;
(* Read a word starting at first valid char (i.e. not " " or ",") at or after
   TheLine[TheIndex]; set TheIndex to position AFTER last char in word, if any,
   or to HIGH(TheLine) if string is not properly terminated; returns TRUE
   if any valid chars were found, else sets TheWord to NULL and returns FALSE
   [Assumes that commas and/or spaces are used as word delimiters] *)


PROCEDURE WriteDebug(TheString: ARRAY OF CHAR);
(* Writes TheString preceeded by "***" to indicate that is a debug message.
   Used only for debugging during developing. *)

END VLCGlobal.