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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
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>SDL_Delay</TITLE
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>SDL_Delay</H1
><DIV
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><H2
>Name</H2
>SDL_Delay&nbsp;--&nbsp;Wait a specified number of milliseconds before returning.</DIV
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
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>void <B
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>SDL_Delay</B
></CODE
>(Uint32 ms);</CODE
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><H2
>Description</H2
><P
>Wait a specified number of milliseconds before returning. <TT
CLASS="FUNCTION"
>SDL_Delay</TT
> will wait at <SPAN
CLASS="emphasis"
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>least</I
></SPAN
> the specified time, but possible longer due to OS scheduling.</P
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><BLOCKQUOTE
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><P
><B
>Note: </B
>Count on a delay granularity of <SPAN
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>at least</I
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> 10 ms.
Some platforms have shorter clock ticks but this is the most common.</P
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