Mercurial > sdl-ios-xcode
view README.Porting @ 1542:a8bf1aa21020
Fixed bug #15
SDL_blit_A.mmx-speed.patch.txt --
Speed improvements and a bugfix for the current GCC inline mmx
asm code:
- Changed some ops and removed some resulting useless ones.
- Added some instruction parallelism (some gain)
The resulting speed on my Xeon improved upto 35% depending on
the function (measured in fps).
- Fixed a bug where BlitRGBtoRGBSurfaceAlphaMMX() was
setting the alpha component on the destination surfaces (to
opaque-alpha) even when the surface had none.
SDL_blit_A.mmx-msvc.patch.txt --
MSVC mmx intrinsics version of the same GCC asm code.
MSVC compiler tries to parallelize the code and to avoid
register stalls, but does not always do a very good job.
Per-surface blending MSVC functions run quite a bit faster
than their pure-asm counterparts (upto 55% faster for 16bit
ones), but the per-pixel blending runs somewhat slower than asm.
- BlitRGBtoRGBSurfaceAlphaMMX and BlitRGBtoRGBPixelAlphaMMX (and all
variants) can now also handle formats other than (A)RGB8888. Formats
like RGBA8888 and some quite exotic ones are allowed -- like
RAGB8888, or actually anything having channels aligned on 8bit
boundary and full 8bit alpha (for per-pixel alpha blending).
The performance cost of this change is virtually 0 for per-surface
alpha blending (no extra ops inside the loop) and a single non-MMX
op inside the loop for per-pixel blending. In testing, the per-pixel
alpha blending takes a ~2% performance hit, but it still runs much
faster than the current code in CVS. If necessary, a separate function
with this functionality can be made.
This code requires Processor Pack for VC6.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 15 Mar 2006 15:39:29 +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)