Mercurial > sdl-ios-xcode
view docs/html/sdlcdstop.html @ 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 | 355632dca928 |
children |
line wrap: on
line source
<HTML ><HEAD ><TITLE >SDL_CDStop</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="CD-ROM" HREF="cdrom.html"><LINK REL="PREVIOUS" TITLE="SDL_CDResume" HREF="sdlcdresume.html"><LINK REL="NEXT" TITLE="SDL_CDEject" HREF="sdlcdeject.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlcdresume.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlcdeject.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCDSTOP" ></A >SDL_CDStop</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN7485" ></A ><H2 >Name</H2 >SDL_CDStop -- Stops a CDROM</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN7488" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN7489" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_CDStop</B ></CODE >(SDL_CD *cdrom);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7495" ></A ><H2 >Description</H2 ><P >Stops play on the given <TT CLASS="PARAMETER" ><I >cdrom</I ></TT >.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7499" ></A ><H2 >Return Value</H2 ><P >Returns <SPAN CLASS="RETURNVALUE" >0</SPAN > on success, or <SPAN CLASS="RETURNVALUE" >-1</SPAN > on an error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7504" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcdplay.html" ><TT CLASS="FUNCTION" >SDL_CDPlay</TT ></A >,</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlcdresume.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlcdeject.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_CDResume</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="cdrom.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_CDEject</TD ></TR ></TABLE ></DIV ></BODY ></HTML >