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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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<HTML
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>SDL_DestroySemaphore</TITLE
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>SDL_DestroySemaphore</H1
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><H2
>Name</H2
>SDL_DestroySemaphore&nbsp;--&nbsp;Destroys a semaphore that was created by <A
HREF="sdlcreatesemaphore.html"
>SDL_CreateSemaphore</A
>.</DIV
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><H2
>Synopsis</H2
><DIV
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><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"
#include "SDL_thread.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>void <B
CLASS="FSFUNC"
>SDL_DestroySemaphore</B
></CODE
>(SDL_sem *sem);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
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><A
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></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_DestroySemaphore</TT
> destroys the semaphore pointed to
by <TT
CLASS="PARAMETER"
><I
>sem</I
></TT
> that was created by
<A
HREF="sdlcreatesemaphore.html"
><TT
CLASS="FUNCTION"
>SDL_CreateSemaphore</TT
></A
>.
It is not safe to destroy a semaphore if there are threads currently blocked
waiting on it.</P
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><A
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><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>if (my_sem != NULL) {
        SDL_DestroySemaphore(my_sem);
        my_sem = NULL;
}</PRE
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>SDL_CreateSemaphore</TT
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>,
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><TT
CLASS="FUNCTION"
>SDL_SemWait</TT
></A
>,
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>SDL_SemTryWait</TT
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>SDL_SemWaitTimeout</TT
></A
>,
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><TT
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>SDL_SemPost</TT
></A
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>SDL_SemValue</TT
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