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view README.Porting @ 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> |
---|---|
date | Tue, 21 Nov 2006 23:17:00 +0000 |
parents | b2b476a4a73c |
children | 103760c3a5dc |
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* Porting To A New Platform The first thing you have to do when porting to a new platform, is look at include/SDL_platform.h and create an entry there for your operating system. The standard format is __PLATFORM__, where PLATFORM is the name of the OS. Ideally SDL_platform.h will be able to auto-detect the system it's building on based on C preprocessor symbols. There are two basic ways of building SDL at the moment: 1. The "UNIX" way: ./configure; make; make install If you have a GNUish system, then you might try this. Edit configure.in, take a look at the large section labelled: "Set up the configuration based on the target platform!" Add a section for your platform, and then re-run autogen.sh and build! 2. Using an IDE: If you're using an IDE or other non-configure build system, you'll probably want to create a custom SDL_config.h for your platform. Edit SDL_config.h, add a section for your platform, and create a custom SDL_config_{platform}.h, based on SDL_config.h.minimal and SDL_config.h.in Add the top level include directory to the header search path, and then add the following sources to the project: src/*.c src/audio/*.c src/cdrom/*.c src/cpuinfo/*.c src/events/*.c src/file/*.c src/joystick/*.c src/stdlib/*.c src/thread/*.c src/timer/*.c src/video/*.c src/audio/disk/*.c src/video/dummy/*.c src/joystick/dummy/*.c src/cdrom/dummy/*.c src/thread/generic/*.c src/timer/dummy/*.c src/loadso/dummy/*.c Once you have a working library without any drivers, you can go back to each of the major subsystems and start implementing drivers for your platform. If you have any questions, don't hesitate to ask on the SDL mailing list: http://www.libsdl.org/mailing-list.php Enjoy! Sam Lantinga (slouken@libsdl.org)