magic/README

Having abandoned the attempt to redefine a split tile as
two separate tile entries, I am returning to the problem
of removing TT_SIDE from the database.

TT_SIDE has been used to pass information to callback
routines to indicate which side of a tile should be
processed.  This should never have been done, because
it causes the database to be altered during searches,
which prevents searches from being parallelized.

To remove this dependency:

All the basic search functions will require an
additional argument which is a boolean and indicates
which side of a split tile is to be processed by the
callback.  It is probably fine to treat the argument
like "dinfo", which is to make it a TileType and
set TT_DIAGONAL, TT_SIDE, and TT_DIRECTION as
needed.  For the basic use of callbacks, it will
generally suffice to set only TT_SIDE.

-----------

Both TT_SIDE and SplitSide() are used frequently.
Which is why I have not done this before.

First, enumerate all callback functions which use each
of the above, and the search routine that will require
the extra argument.

Search functions or functions needing changes:
(Followed by the number of occurrences)
	DBSrPaintArea()		401
	DBTreeSrTiles()		 99	<done>
	DBSrPaintNMArea()	 16	<done>
	DBSrPaintClient()	 15	<done>
	SimTreeSrTiles()

	SelEnumPaint()
	GrClipTriangle()	 
	GrDrawTriangleEdge()
	GrDiagonal()
	DBTransformDiagonal()
	GrBox()

SplitSide():

	calmaMergePaintFunc() --- Comment, unused, remove.
	calmaWritePaintFunc()
	calmaMergePaintFuncZ() --- Comment, unused, remove.
	calmaWritePaintFuncZ()
	cifHierCopyFunc()
	cifHierErrorFunc()
	cmdDropPaintCell()

To be fixed:  STACKPUSH/STACKPOP stuff in resis/ResUtils.c
	      resAddField will need to do something similar to
		extract to handle two clientData records for split tiles
		in ResAddPlumbing and ResRemovePlumbing.

	      dbcUnconnectFunc() --- Need to handle side, or is this already handled?

	extConnFindFunc() --- Select proper region depending on side
	extInterSubtreeTile() --- Should handle non-Manhattan tiles.
	lefConnectFunc() --- write polygons to LEF?
	resExpandDevFunc() --- Probably needs to handle split types and replace STACKPUSH.
		(Lots to do in ResUtils.c)
	touchingTypesFunc() --- Should distinguish types between sides, and handle
				triangle geometry.

	cifInteractingRegions() --- Uses the cifSquares code, but cifSquares does not
			handle non-Manhattan geometry, and interacting/overlapping
			methods must.

	antennaAccumFunc() --- Needs to handle non-Manhattan geometry.

	extTransPerimFunc() --- Needs to set TT_SIDE based on boundary direction
			before calling DBSrConnectOnePlane (ExtBasic.c:3882)
	ResMultiPlaneFunc() --- Needs to call ResNewSDDevice() with dinfo information

Any routine that does not use "dinfo" should do "if (dinfo & TT_SIDE) return 0".

Ought to create a single function for simply returning "1" and replace all the
assorted functions that do that individually.

---------------------
First pass is done, minus issues reported above that need to be worked on.  The
basic issue of adding an extra argument to all the callback functions is basically
completed.

Moving on to compiling. . .
CIFgen.c has lots of warnings around PUSHTILE().  Probably an incorrect cast, but
I need to check all of the uses of PUSH and POP everywhere, anyway.

1/2/2026:
Compiles now!
Debug. . .
Errors in dbwind (missed a DBSrPaintArea() call)
Need to pass dinfo to GrBox() and GrBoxOutline()

Issue:  Paint square on top of diagonal edge, ends up with one part of the tile
not properly split at the edge;  the tile goes to infinity and has a non-space
type.

Reminder:  Need to check for all instances of SplitSide(), as there should not
be any.  There are still 38 references that need to be removed.

Fix:  extWalkTop (Bottom, Right, Left). . . type should not have been set by
the split side of tile "tp".  Should be according to the side being searched
and the diagonal directions of "tile" and "tp".

ResUtils:  Cannot use STACKPUSH and STACKPOP

A number of remaining uses of SplitSide() are in routines that were not fixed
for dinfo or are not directly called from modified search functions, so will
need to fix each one in turn.

Add dinfo to extSubtreeTileToNode() and extSubtreeHardNode()
extNodeToTile needs to return dinfo. . .

extGetRegion() will need to be handled but only when I'm done with this and
working on being able to attach two regions to a split tile.