view README @ 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 3f395c825b14
children f12379c41042
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                         Simple DirectMedia Layer

                                  (SDL)

                                Version 1.2

---
http://www.libsdl.org/

This is the Simple DirectMedia Layer, a general API that provides low
level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL,
and 2D framebuffer across multiple platforms.

SDL is written in C, but works with C++ natively, and has bindings to
several other languages, including Ada, C#, Eiffel, Java, Lua, ML,
Objective C, Pascal, Perl, PHP, Pike, Python, and Ruby.

The current version supports Linux, Windows, BeOS, MacOS, MacOS X,
FreeBSD, OpenBSD, BSD/OS, Solaris, IRIX, and QNX.  The code contains
support for Windows CE, AmigaOS, Dreamcast, Atari, NetBSD, AIX, OSF/Tru64,
RISC OS, SymbianOS, and OS/2, but these are not officially supported.

This library is distributed under GNU LGPL version 2, which can be
found in the file  "COPYING".  This license allows you to use SDL
freely in commercial programs as long as you link with the dynamic
library.

The best way to learn how to use SDL is to check out the header files in
the "include" subdirectory and the programs in the "test" subdirectory.
The header files and test programs are well commented and always up to date.
More documentation is available in HTML format in "./docs/index.html"

The test programs in the "test" subdirectory are in the public domain.

Frequently asked questions are answered online:
	http://www.libsdl.org/faq.php

If you need help with the library, or just want to discuss SDL related
issues, you can join the developers mailing list:
	http://www.libsdl.org/mailing-list.php

Enjoy!
	Sam Lantinga				(slouken@libsdl.org)