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)