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view docs/html/sdlsempost.html @ 3899:081aecdb0911 SDL-1.2
From: Gabriel Gambetta
To: SDL Mailing List <sdl@libsdl.org>
Date: Fri, 17 Nov 2006 00:39:29 -0200
Subject: [SDL] Alpha blending bug - fixed?
It turns out mm5 never got the correct value. This failed :
[...]
"movd %1, %%mm5\n\t"
: : "m" (amask), "m" (sf->Ashift) );
mm5 got 0xFF000018 instead of 0x00000018. However I did this :
Uint32 ashift = sf->Ashift;
[...]
"movd %1, %%mm5\n\t"
: : "m" (amask), "m" (ashift) );
and everything worked fine.
The only thing I could find out was that ashift is 32-bit aligned but
sf->Ashift isn't:
printf("ashift %8X [%d]\n", &ashift, (int)(&ashift) % 4);
printf("sf->Ashift %8X [%d]\n", &sf->Ashift, (int)(&sf->Ashift) % 4);
ashift at BFF0E0C4 [0]
sf->Ashift at 08AFB9CD [1]
Could this be the problem? If it is, the fix is extremely trivial.
Should I submit a patch?
--Gabriel
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Tue, 21 Nov 2006 23:17:00 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_SemPost</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="Multi-threaded Programming" HREF="thread.html"><LINK REL="PREVIOUS" TITLE="SDL_SemWaitTimeout" HREF="sdlsemwaittimeout.html"><LINK REL="NEXT" TITLE="SDL_SemValue" HREF="sdlsemvalue.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="sdlsemwaittimeout.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlsemvalue.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLSEMPOST" ></A >SDL_SemPost</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN8170" ></A ><H2 >Name</H2 >SDL_SemPost -- Unlock a semaphore.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN8173" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN8174" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h" #include "SDL_thread.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_SemPost</B ></CODE >(SDL_sem *sem);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8180" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_SemPost</TT > unlocks the semaphore pointed to by <TT CLASS="PARAMETER" ><I >sem</I ></TT > and atomically increments the semaphores value. Threads that were blocking on the semaphore may be scheduled after this call succeeds.</P ><P ><TT CLASS="FUNCTION" >SDL_SemPost</TT > should be called after a semaphore is locked by a successful call to <A HREF="sdlsemwait.html" >SDL_SemWait</A >, <A HREF="sdlsemtrywait.html" >SDL_SemTryWait</A > or <A HREF="sdlsemwaittimeout.html" >SDL_SemWaitTimeout</A >.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8190" ></A ><H2 >Return Value</H2 ><P >Returns <SPAN CLASS="RETURNVALUE" >0</SPAN > if successful or <SPAN CLASS="RETURNVALUE" >-1</SPAN > if there was an error (leaving the semaphore unchanged).</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8195" ></A ><H2 >Examples</H2 ><P ><PRE CLASS="PROGRAMLISTING" >SDL_SemPost(my_sem);</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN8199" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcreatesemaphore.html" ><TT CLASS="FUNCTION" >SDL_CreateSemaphore</TT ></A >, <A HREF="sdldestroysemaphore.html" ><TT CLASS="FUNCTION" >SDL_DestroySemaphore</TT ></A >, <A HREF="sdlsemwait.html" ><TT CLASS="FUNCTION" >SDL_SemWait</TT ></A >, <A HREF="sdlsemtrywait.html" ><TT CLASS="FUNCTION" >SDL_SemTryWait</TT ></A >, <A HREF="sdlsemwaittimeout.html" ><TT CLASS="FUNCTION" >SDL_SemWaitTimeout</TT ></A >, <A HREF="sdlsemvalue.html" ><TT CLASS="FUNCTION" >SDL_SemValue</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="sdlsemwaittimeout.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="sdlsemvalue.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_SemWaitTimeout</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="thread.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_SemValue</TD ></TR ></TABLE ></DIV ></BODY ></HTML >