From 4a3dbb926ae3f5410198d7cc4f4ebe4f62eebf05 Mon Sep 17 00:00:00 2001 From: marha Date: Sat, 25 Jul 2009 19:39:46 +0000 Subject: Added xorg-server-1.6.2.tar.gz --- xorg-server/hw/xfree86/xf4bpp/NOTES | 194 ------------------------------------ 1 file changed, 194 deletions(-) delete mode 100644 xorg-server/hw/xfree86/xf4bpp/NOTES (limited to 'xorg-server/hw/xfree86/xf4bpp/NOTES') diff --git a/xorg-server/hw/xfree86/xf4bpp/NOTES b/xorg-server/hw/xfree86/xf4bpp/NOTES deleted file mode 100644 index e3b77dcfd..000000000 --- a/xorg-server/hw/xfree86/xf4bpp/NOTES +++ /dev/null @@ -1,194 +0,0 @@ -This code originally hails from IBM. It was ported to an early XFree86 by -Gertjan Akkerman, whose BUGS file I append here. - -In turn, this is a port of Gertjan's work to the new server design. Among the -changes are: - -- The removal of almost all unreferenced code. -- The removal of this code's own copy of mfb (xf1bpp is used instead). -- The removal of banking support (mibank is used instead). -- External symbols were made static where this was sufficient. -- The remaining external names were renamed to xf4bpp*. -- Several minor cleanups too many to mention here. - -To understate the matter, this code is >UGLY<. This seems inherent in IBM's -corporate culture. Be that as it may, it *does* survive X11R4's xtest -(whatever that means these days...). For now, this is sufficient for 4bpp -support in the new design, but at some point, I'll have to sit down and -rewrite this from scratch. A more technical justification for a rewrite is -that the pixmap format is 8bpp, instead of 4bpp, which is causing me to -pepper the rest of the server with unclean accomodations. - -Marc. - -=============================================================================== -Section 1: From IBM's X11R4 contribution towards XFree86. - -This section describes what I did to obtain a 16 colour vga server. - -I started with the SYSV, ppc, vga and common directories from IBM's X11R4 -contribution. Those directories have the following function: -1. SYSV implements the mouse and keyboard. -2. ppc is a generic layer implementing ddx in terms of drawing operations - through rectangles. (With spans as a boundary case: height = 1.) -3. vga implements a layer of operations drawing through rectangles. -4. common implements ddx initialization and quitting, and screen saving. - -I eliminated SYSV and common since the functionality provided therein is -already provided in XFree86. Since XFree86 is actively being ported to -new operating systems, while X11R4 is out of date, I preferred the XFree86 -code here above the SYSV and common code. -Whatever functionality was still needed from common (default colormap -initialization -- not much code) was moved into ppc. - -Since XFree86 uses the mi-provided software cursor code, IBM's software -cursor code was deleted from ppc and vga. This is a pity, since it is -expected that it is more efficient than mi's code, but the XFree86 mouse and -keyboard code directly call mi, and I do not want to maintain the XFree86 -mouse and keyboard code. - -Since we cannot support a monolithic multi-screen server using all of the -x11r4 contributed code yet, all multi screen code was deleted. This includes -one header file containing a nasty copyright statement. - -Since glyph handling has changed between X11R4 and X11R5, the code handling -glyphs was replaced by appropriate calls to mi. -I hope it can be modified and put back one day. - -Provisionally, some code was added (viz. file vga/offscreen.c) to intercept -calls to the rectangle drawing code when we are switched out of the VT. -I hope this can be replaced by some window tree invalidation and GC validation -scheme. - - -Section 2: BUGS - -This section describes fixed and still unfixed bugs in this code. -All bugs not labeled otherwise also occur in IBM's X11R4 code, and may be of -interest to anybody using that code. - -1. (Fixed.) -I found (and provisionally fixed) a bug in the IBM bitblit code: -In file ddx/ibm/vga/vgaImages.c a function vgaReadColorImage is defined. -When this function is used to read less than 8 pixels starting on a byte -boundary it will always read precisely 8 pixels. -Thus, when space is allocated for 4 or less pixels, it will write beyond -the allocated space. -Since the code is rather convoluted, this may not be apparent at first sight, -but going through the code with an example shows the error. - -2. (Fixed.) -In ppcPixmapFS.c, function ppcStipplePixmapFS there was a bug -regarding the stipple origin: The horizontal origin is added while -the vertical one is subtracted. The horizontal origin should be subtracted -instead of added here. -This bug gets visible when backing-store is enabled and one uses twm: -the submenu icons get truncated on their left hand side. -(In case you wonder why this bug appears: under those circumstances -twm prepares its menus by drawing into an unmapped window. -The miCopyPlane function uses the ppcStipplePixmap (and many others) -to get the plane copied.) -I also fixed this bug in the other routines (ppcOpStipplePixmapFS, -ppcTilePixmapFS) in this file, although I had no visible clues for this. -I hope this is appropriate. - -3. (Fixed.) -I find it suspect that ppcSetSpans gives different output when one -claims that an actually sorted list of spans is unsorted. -The unsorted code is wrong, and should be made to look more like the sorted -code. I.e., use ( xStart - ppt->x ) instead of ( xStart - pbox->x1 ) - -4. (Fixed.) -There used to be another bug that became visible when using twm and backing -store: popping up a submenu, and moving the cursor upwards til it leaves the -submenu, the submenu would disappears, as it should. -But the submenu icon would not get restored, while it should be. -10b. By replacing the clip-computing code in ppcValidateGC by that in -cfbValidateGC, I *finally* fixed the disappearing twm menu icon problem. - -5. Added mfbRegisterCopyplaneProc call. [Its omission was an error on my - part.] - Fixing a server core dump in XTest. - -6. Fixed not-very-high tile bug in function ppcTileRect, file emulTile.c - (I.e., if the tile was higher than the area to be tiled, far too much - was drawn, causing server core dumps in XTest.) - Actually, "savey" ought to be used to determine the height of the tiles in - the top line to be tiled, instead of "pTile->drawable.height". -7. A use of height where width was intended was fixed in ppcTileRect: - "savehcount = w / pTile->drawable.height;" should use "... .width" and - "savehcount = ( x + w - htarget ) / pTile->drawable.height;" too. - -8. Deleted overly clever code in ppcCReduce.c - (All code that tried to pre-compute how alu's could be replaced by - other alu's with inverted colors, etc. was deleted. I think it is - at least wrong for FillSolid.) - -9. Looked at suspicious code in ppcSetSp.c - "tmpx = *pdst;" was never updated during the loop. We took it out of the - initialization position of the for and moved it into the loop. - -10. Add xSrc := GC->patOrg.x + pDrawable.x and ySrc := ... in ppcPixmapFS.c, - functions ppcStipplePixmapFS, ppcOpStipplePixmapFS, and ppcTilePixmapFS. - This because stipple and tile origins are taken relative to the drawable. - Also use a "modulo" function that gets the cases of a negative stipple - or tile offset right. (When the stipple origin is to the right of or - below the origin of the drawable.) - -11. File vgaSolid.c, function vgaFillSolid: - Inverting is XORing with all ones. Not with the color we want to AND/OR - later. So we'll have to set the color to VGA_ALLPLANES - whenever we want to invert existing data, and reset it before the - AND/OR is done. - Also we replaced an outb( 0x3CF, tmp2 ) by the SetVideoGraphicsData( tmp2 ) - it is representing. (Just a cosmetic replacement.) - -12. File vgaImages, function vgaDrawColorImage. - Moved a line "invert_existing_data = TRUE;" two lines down, past a case - label. Now it is also part of the code executed for GXorReverse, as it - should be. - -13. The pixmap FillSpans routines (file ppcPixmapFS.c) got somewhat better - after importing some code from ddx/ibm/vga. (A getbits function that does - wrapping.) - They were wrong for the FillStippled and FillOpaqueStippled modes. - I don't understand the old code. How could it handle stipples of a size not - an exact multiple of 32? (or 8, for that matter.) - -14. In function vgaBitBlt file vgaBitBlt.c, in the shortcuts for - GXSet, GXClear and GXInvert, the source (x0,y0) is accidentally operated - upon by vgaFillSolid, instead of the destination (x1,y1). - -15. Notice that in DoMonoSingle and DoMonoMany in file vgaStipple.c, the left - edge of the square to be stippled is treated wrong. - Correct would be to get the bits with getbits using offset xshift, and - to shift them right (x & 07) places. - [One might wish to use the variable tmp1 at this place, since it had been - set to (x & 07) at this place; but that is already re-used at this point.] - Also note that NeedValX is set wrong: The implicit assumption was that - stipples are more than 8 wide. - This only fixes the problem when miPushPixel is used instead of ppcPushPixel. - I think I should look some more into this. - -16. I took out some code of the CopyArea function, in which a no-op function - was called while a real one was needed. My fix does not completely work, - although it improved the behaviour of GetImage somewhat. - -17. After finding three kinds of errors in this single function, - -- the new kinds being the right side not being always written due to - an incorrect if scope, and the lower end not always being written due - to variables being updated at the wrong place -- - (requiring modifications to be made at at least 10 places, - I decided to REWRITE the body of the ppcTileRect function from scratch. - This version simply computes all relevant margins in advance, and does - not try to reuse temporary variables. I leave that to the compiler. - (This was a maintenance and robustness nightmare anyway.) - -MORE NOTES: - It is funny that there are two files in mi that require compilation - with the proper #defines ( -DXF86VGA16 in my case ): - Besides the obvious mibitblt.c, there is also mipushpxl.c. - - - -$XFree86: xc/programs/Xserver/hw/xfree86/xf4bpp/NOTES,v 1.1.2.2 1998/06/27 15:15:45 dawes Exp $ -- cgit v1.2.3