annotate README-SDL.txt @ 3899:081aecdb0911
SDL-1.2
From: Gabriel Gambetta
To: SDL Mailing List <sdl@libsdl.org>
Date: Fri, 17 Nov 2006 00:39:29 -0200
Subject: [SDL] Alpha blending bug - fixed?
It turns out mm5 never got the correct value. This failed :
[...]
"movd %1, %%mm5\n\t"
: : "m" (amask), "m" (sf->Ashift) );
mm5 got 0xFF000018 instead of 0x00000018. However I did this :
Uint32 ashift = sf->Ashift;
[...]
"movd %1, %%mm5\n\t"
: : "m" (amask), "m" (ashift) );
and everything worked fine.
The only thing I could find out was that ashift is 32-bit aligned but
sf->Ashift isn't:
printf("ashift %8X [%d]\n", &ashift, (int)(&ashift) % 4);
printf("sf->Ashift %8X [%d]\n", &sf->Ashift, (int)(&sf->Ashift) % 4);
ashift at BFF0E0C4 [0]
sf->Ashift at 08AFB9CD [1]
Could this be the problem? If it is, the fix is extremely trivial.
Should I submit a patch?
--Gabriel
| author |
Ryan C. Gordon <icculus@icculus.org> |
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Tue, 21 Nov 2006 23:17:00 +0000 |
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2 Please distribute this file with the SDL runtime environment:
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4 The Simple DirectMedia Layer (SDL for short) is a cross-platfrom library
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5 designed to make it easy to write multi-media software, such as games and
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6 emulators.
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8 The Simple DirectMedia Layer library source code is available from:
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9 http://www.libsdl.org/
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11 This library is distributed under the terms of the GNU LGPL license:
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12 http://www.gnu.org/copyleft/lesser.html
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