context.h

Dos6.0

typedef struct mrs {
   ushort   cbFrameVars;   /* Cb of variables in the frame.                   */
   ushort   cbFrameTemp;   /* Temp space needed                               */
   ushort   ogNam;         /* [1] source file path name (global name table
                              [1] offset, or 0 in the case of an untitled
			      [1] module or OGNAM_GMRS for the global mrs     */
   bd       bdVar;         /* Table of all module's variables (including
                              variables which are local to procedures         */
   char     flags;         /* bit flags; FM_ constants defined above          */
   char     flags2;        /* bit flags; FM2_ constants defined above         */
   char     flags3;        /* bit flags; FM3_ constants defined above         */
   char     dummy1;        /* Extra byte to word align                        */

/* WARNING: Before this point data is initialized to zero.    
 *          After this point, data is initialized to UNDEFINED.               */

   ushort  oMrsNext;	   /* [4] offset to next mrs in the Rs table	      */
   ushort   otxHandler;    /* Text offset to error handler                    */
   bdl      bdlNam;        /* Module's Name table                             */
   txd      txd;           /* Text Descriptor for pcode for module            */

/* WARNING: Binary SAVE/LOAD depend on otxDefFnLink, oPastLastVar, and the
	    'data' struct being contiguous and in the following order	      */

   ushort   otxDefFnLink;  /* textmgr maintains this linked list of DEF FN's  */
   ushort   oPastLastVar;  /* offset to first byte past last variable in the
                              module variable table; used to ensure dead
                              direct mode FOR entries don't waste tVar space  */
   struct {                /* Head of data chain */
      ushort   otxFirst;   /* opTxt operand for 1st data statement            */
      ushort   otxCur;     /* opTxt operand for current data statement        */
      ushort   oLineCur;   /* byte offset for next READ                       */
      } data;
   } mrs;

/**==================== Global Register Set =================================
The global register set owns heap entries which define the current context.

Only one module table entry or procedure table entry may be active at any
one time.  These tables are managed by swapping a new mrs into mrsCur or
swapping a new procedure into prsCur.

While a module or procedure is loaded into mrsCur or prsCur, its entry
in the global Rs table should not be referenced or updated.

=======================================================================**/
/* WARNING: the context manager initialization code depends on the prs, mrs,
            and grs structures being setup such that all items to be zero-
            filled (on struct init.) are at the beginning of the structure    */

typedef struct grsType {
   char     fScan;         /* TRUE if all modules and procedures are scanned */
   char     fDirect;       /* TRUE if we're executing instructions out of
                              direct-mode text buffer bdlDirect.
                              This is set by UserInterface(), procedure exit,
			      RETURN.  Reset by opStDmGoto, GOSUB, CALL etc.  */
	bd  bdRs;	   /* [4] */
   bd       bdtComBlk;     /* COMMON block table owner */
   char     flags;         /* These are general flags which are independently
                                                              set and reset */
   char     filler;        /* unused */
/* WARNING: Before this point grs struct is initialized to zero.
            After this point, it's initialized to UNDEFINED.                  */

   ushort   oMrsMain;      /* Offset within mrs table for main module. Can be
                              modified by UI. Note that if mrs with this offset
                              is discarded, oMrsMain is set to UNDEFINED and
                              there is NO main module - - - RunInit checks for
                              this condition.                                 */

   ushort   oRsCur;        /* Redundant copy of oMrsCur and oPrsCur.
                              If high bit is set, a procedure is active and
                                 low 15 bits = oPrsCur
                              else
				 no procedure is active and oRsCur == oMrsCur */
   ushort   pMrsCur;
   ushort   pRsCur;
   ushort   offsetTxdSeg;  /* offset into bdtMrs or bdtPrs to the segment
                              address for the current txd                     */
   ushort   oMrsCur;       /* Offset within mrs table for module currently
                              loaded into mrsCur */
   ushort   oPrsCur;       /* Offset within prs table for procedure currently
                              loaded into prsCur */
   ushort   otxCur;        /* Offset within current text table to next
                              instruction to be executed.  This is only valid
                              while we're in UserInterface().  While executing,
                              this value is always maintained in SI reg */
   ushort   oRsCONT;       /* register set where we are to CONTinue */
   ushort   otxCONT;       /* text offset where we are to CONTinue.  Set by
                              UserInterface(), CantCONT().  Used by ExStCONT.
                              We can't continue if grs.otxCONT == UNDEFINED */
   ushort   oRsContTxtTbl; /* Identical to oRsCONT, except when oRsCONT is
                              for a DEF FN, this is the oRs of the module
                              containing the DEF FN.  It always identifies
                              the text table where containing next stmt to
                              be executed */
   bdl      bdlDirect;     /* Direct mode pcode buffer owner */
   char     flagsDir;      /* These flags get reset every time we begin
                              begin executing pcode, and when a runtime error
                              occurs.  They are defined below (FDIR_xxx) */
   } grsType; 

#define FDIR_cleared  0x01 /* TRUE when ClearWorld has been called.  Reset
                              at end of CLEAR statement.  It is strictly a
                              speed optimization */
#define FDIR_new      0x02  /* Set at start of NewStmt and reset at end of
                               NewStmt.  Speed optimization for Text Manager. */
/* bits for general grs flags */
#define FG_WatchActive  0x01  /* set if watch pcode is active */
#define FG_RetDir       0x02  /* 1 return address to direct-mode buffer
                               * exists on the stack.  Entry of direct-mode
                               * stmts when this is true causes FG_RetDirBad
                               * to be set.                                   */
#define FG_AllSsExecute 0x04H /* set if all text tables are in SS_EXECUTE */
#define FG_OtxInDir	0x08H /* set if dir mode stmt contains an oxt ref */

/* bits for mask passed to ForEach[CP]: */
#define FE_PcodeMrs     0x01  /* TRUE if mrs's containing pcode are to
                                 be visited */
#define FE_TextMrs      0x02  /* TRUE if FM_TEXT and FM_TEXTFILE mrs's
                                 are to be visited (i.e. command window's
                                 mrs, docuemnt files) */
#define FE_CallMrs      0x04  /* TRUE if pFunc is to be called for mrs's
                                 text table BEFORE it is called for prs's
                                 text tables */
#define FE_PcodePrs     0x08  /* TRUE if prs's with text tables (SUBs/
                                 FUNCTIONs) are to be visited */
#define FE_NoPcodePrs   0x10  /* TRUE if DEF FN and DECLARE prs's are
                                 to be visited */
#define FE_FarCall      0x20  /* TRUE if function to be called is FAR */
#define FE_SaveRs       0x40  /* TRUE if ForEach is to restore caller's
                                 oRsCur on exit */
#define FE_CallMrsAfter 0x80  /* TRUE if pFunc is to be called for mrs's
                                 text table AFTER it is called for prs's
                                 text tables. */



/**========================= Binary SAVE/LOAD Constants ========================
/* these three bit fields are OR'd together as inputs to Binary SAVE; the
   first two are also used in the header of a binary SAVEd file:              */
#define BINSAV_SingleModule       0x01
#define BINSAV_MultipleModule     0x02
#define BINSAV_fProtected         0x0100

/**========================= EXTERNAL VARIABLES ===============================

context.c includes this file after defining EXTERNAL as empty, causing these
variables to actually be defined.

============================================================================**/
EXTERNAL grsType  PLM grs;    /* global register set */
EXTERNAL mrs      PLM mrsCur; /* module register set for active module       */
EXTERNAL prs      PLM prsCur; /* procedure register set for active procedure */
EXTERNAL txd      PLM txdCur; /* current text table (from prs or mrs)        */
EXTERNAL ushort   PLM pGosubLast; /* Pointer to last stack GOSUB frame	     */
EXTERNAL ushort   PLM fNonQBI_Active; /* set non-zero whenever non-QBI code
					 is activated (non-0 ==> old BP)   */
EXTERNAL ushort   PLM bcurlevel_QBI;  /* value of b$curlevel for most recent
					 QBI frame when fNonQBI_Active != 0 */

#ifndef CONTEXT_NOFUNCS
VOID     FAR   InitContext(VOID);
ushort	FAR	MrsFind(ushort);
ushort	FAR	PrsFind(ushort);
VOID	 FAR   RsActivate(ushort);		/* EB_API */
VOID     NEAR  RsActivateCP(ushort);
ushort   FAR   MrsMake(ushort, ushort);
VOID     NEAR  MrsDeActivate(VOID);
VOID     FAR   MrsActivate(ushort);
boolean  FAR   MrsDiscard(VOID);
boolean  FAR   ForEachMrs(boolean (far *)());
ushort   NEAR  PrsRef(ushort, uchar, ushort);
ushort   FAR   PrsMake(ushort, char);
VOID     NEAR  PrsDeActivate(VOID);
VOID     FAR   PrsDeActivateFar(VOID);
VOID     NEAR  PrsActivateCP(ushort);
VOID     FAR   PrsActivate(ushort);
boolean  FAR   ForEachPrsInMrs(boolean (far *)());
ushort   FAR   NextPrsInMrs(VOID);
ushort   FAR   NextTextPrsInMrs(VOID);
ushort	 FAR   NextMrsFile_All(VOID);
ushort   FAR   NextMrsFile(VOID);
boolean  FAR   PrsDiscard(VOID);
VOID     FAR   PrsFree(VOID);
ushort   NEAR  FieldsOfPrs(ushort);
ushort   FAR   FieldsOfPrsFar(ushort);
ushort   NEAR  SetPrsField(ushort, ushort, ushort);
VOID     FAR   NewStmt(VOID);
VOID     FAR   RunInit(VOID);
VOID     FAR   ContReinit(VOID);
VOID     FAR   ContReinitStat(VOID);
boolean  FAR   ClearStmt(ushort, ushort);
VOID     FAR   CantCont(VOID);
VOID     NEAR  VarDealloc(VOID);
boolean  FAR   FreeAllUnrefdPrs(VOID);
VOID     FAR   AdjustITable(char *, ushort, uchar);
boolean  FAR   ForEach(uchar, boolean (far *)());
ushort	 FAR   AlphaBuildORs(void);	//[23]
ushort   FAR   oRsOfAlpha(ushort);
ushort   FAR   NextAlphaPrs(void);
VOID     FAR   AlphaORsFree(void);
boolean  FAR   FindORsFrame(void);
ushort FAR OTypeOfTypeCharFar(char);	//[22]



/**========================= Non-RELEASE Macros ===============================

Non-RELEASE and DEBUG macros, used with context.c

============================================================================**/

#define DbChkGrs()            {;}
#define DbChkMrsCur()         {;}
#define DbChkPrsCur()         {;}
#define DbChkoMrs(oMrs)       {;}
#define DbChkoPrs(oPrs)       {;}
#define DbOMrsCur()           {;}
#define DbOPrsCur()           {;}

#endif /* ifndef CONTEXT_NOFUNCS */