/* ********************************************************************** *\
 *         Copyright IBM Corporation 1988,1991 - All Rights Reserved      *
 *        For full copyright information see:'andrew/config/COPYRITE'     *
\* ********************************************************************** */

/*
	$Disclaimer: 
 * Permission to use, copy, modify, and distribute this software and its 
 * documentation for any purpose is hereby granted without fee, 
 * provided that the above copyright notice appear in all copies and that 
 * both that copyright notice, this permission notice, and the following 
 * disclaimer appear in supporting documentation, and that the names of 
 * IBM, Carnegie Mellon University, and other copyright holders, not be 
 * used in advertising or publicity pertaining to distribution of the software 
 * without specific, written prior permission.
 * 
 * IBM, CARNEGIE MELLON UNIVERSITY, AND THE OTHER COPYRIGHT HOLDERS 
 * DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING 
 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT 
 * SHALL IBM, CARNEGIE MELLON UNIVERSITY, OR ANY OTHER COPYRIGHT HOLDER 
 * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY 
 * DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, 
 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 *  $
*/


#ifndef _ness_envt_
#define _ness_envt_




/*
 * $Log: envt.h,v $
 * Revision 1.15  1994/03/01  23:05:54  rr2b
 * Commented out text after #endif's
 * BUG
 *
 * Revision 1.14  1993/05/04  01:23:55  susan
 * RCS Tree Split
 *
 * Revision 1.12.1.1  1993/02/02  03:00:31  rr2b
 * new R6tape branch
 *
 * Revision 1.12  1992/12/14  20:49:20  rr2b
 * disclaimerization
 *
 * Revision 1.11  1992/06/05  16:39:31  rr2b
 * added sysmarknextptrs
 *
 * Revision 1.10  1991/09/12  19:43:43  bobg
 * Update copyright notice
 *
 * Revision 1.9  1991/05/21  17:47:25  gk5g
 * Removed reference to hpux in cpp declarations surrounding CLASS macro.
 * HPUX isn't completely ANSI yet.
 * .
 *
 * Revision 1.8  1991/02/21  10:19:16  wjh
 * adapted for ANSI-C.  Thanks to Bill Cattey.
 *
 * Revision 1.7  90/09/16  20:14:20  wjh
 * see ness/objects/changes.sept.90
 * 
 * Revision 1.6  89/09/03  22:49:46  wjh
 * newness
 * 
 * Revision 1.5  89/06/01  16:02:36  wjh
 * campus release version
 * 
 * Revision 1.2  88/12/20  19:46:47  wjh
 * fixed various bugs
 * 
 * Revision 1.1  88/10/21  10:56:59  wjh
 * Initial revision
 * 
 * Creation 0.0  88/04/01 15:00  wjh
 * Initial creation by WJHansen
 * 
*/

/* The Ness run-time environment has these components:

	object code: a string containing the compilation of all functions
	execution stack: arguments, locals, and temporaries for execution
	system mark list: constant strings and goto targets
	some global pointers accessing the above

*/

#include "nessmark.ih"
#include "smpltext.ih"
#include "interp.h"		/* for TType */


/* each of the following are initialized (in interp.c) to point to the value needed for class_IsType() */

extern struct classinfo *celClass;
extern struct classinfo *textClass;
extern struct classinfo *textviewClass;
extern struct classinfo *dataobjectClass;
extern struct classinfo *lpairClass;
extern struct classinfo *viewClass;
extern struct classinfo *celviewClass;
extern struct classinfo *valueviewClass;
extern struct classinfo *imClass;

#if defined(__STDC__) && !defined(__HIGHC__) || defined(_IBMR2)
#define CLASS(d) ((d##Class == NULL) ? (d##Class = class_Load(#d)) : d##Class)
#else /* defined(__STDC__) && !defined(__HIGHC__) */
#define CLASS(d) ((d/**/Class == NULL) ? (d/**/Class = class_Load("d")) : d/**/Class)
#endif /* defined(__STDC__) && !defined(__HIGHC__) */

extern struct simpletext *ObjectCode;	/* the compiled bytecode for the functions */

extern struct simpletext *EmptyText;	/* points to the special mark for error extent */


/* SysMark -  the system marks array

	retains marks for constants and goto's

Each constant is an entry in SysMark.

For each label and function in the interpretive code, there is an entry in the SysMark array.  The length field within the function mark gives the length of the code compiled for the function.  A branch to a label has a two byte quantity L which is an index into SysMark.  The position in the code is given by
	mark_GetPos(SysMarkLowEnd+L)

SysMarkFree indicates the first of the list of unallocated marks.
SysMarkLowEnd indicates which element is the bottom of the array
	{SysMark[0] is not used so no function has index 0. }
SysMarkHiEnd points one past the topmost marker and is thus 
	(SysMarkLowEnd+SysMarkSize)
*/
    
extern struct nessmark *SysMarkFree, *SysMarkLowEnd, *SysMarkHiEnd;
extern long *SysMarkNextPtrs;
extern long SysMarkSize;
#define InitialSysMarkSize 1000



/* 
STACK

Each stack element begins with a pointer called a "objhdr".  Eventually it may point to an array of methods for dealing with this type of value on the stack.  For now it is a simple integer, except that the objhdr value for a mark is the actual pointer value.

*/

extern TType nessmarkHdr;
	/* the value found in the first word of all nessmarks */

/* elements that may appear on stack */
struct longstkelt {		/* LONG or INT or INTEGER or FIXED */
   TType hdr;
   long v;
};

struct boolstkelt {		/* BOOLEAN or LOGICAL */
    TType hdr;
    unsigned long v;
};

struct dblstkelt {		/* FLOAT or REAL */
    TType hdr;
    double v;
};

struct ptrstkelt {			/* object ptr */
    TType hdr;
    struct basicobject *v;
};

union stackelement {
    struct longstkelt  l;
    struct boolstkelt  b;
    struct dblstkelt  d;
    struct ptrstkelt  p;
    struct nessmark m;		/* STRING */
    /* ->m  *is*  a nessmark.  It is not a pointer to a nessmark. It has a objhdr.  */
    struct frameelt  f;
};

extern struct frameelt *FramePtr;	/* points to current stack frame */

/* extern long nArgsGiven;	/* number of arguments on stack when interpreter is called 
				(was used with stackArg) */

extern union stackelement *NSPstore, *NSPbase, *NSLowEnd, *NSHiEnd;
extern long NSSize;		/* the number of words in the stack. */
#define InitialNSSize 5000  /* initial size allocated to stack */

/* the execution stack 
	  NSPstore points to topmost stackelement in use; initially it equals NSHiEnd
	  NSPbase has the value of NSP after the initial frame is on it.
	  NSLowEnd points to the bottom most word in the stack.
	  NSHiEnd points one past the topmost word in the stack
*/

/* The stack grows downward.  The objhdr of each element is thus at the lower end of the stack.  Thus the word at the top of the stack  {*(long *)NSP}  is a objhdr.  (Got that straight?) */

/* A stack frame has this structure:

 	temporary variables	top end (lower address)
	struct frameelt
	local variables
	arguments		bottom end (higher address)

FramePtr->prevframe points to the hdr of the next earlier frame.
Arguments and locals are addressed with positive offsets from FramePtr.

When a function returns, the return value replaces the first argument.

The initial stack has only a dummy frame record.

*/

/* in interp.c */
union stackelement *popValue(/* union stackelement *NSP */);

#define NSPushSpace(type) (NSPstore=NSP=(union stackelement *)(((unsigned long)NSP) - sizeof(struct type)))
#define NSPopSpace(type) (NSPstore=NSP=(union stackelement *)(((unsigned long)NSP) + sizeof(struct type)))

#endif /* _ness_envt_ */