[openMSX-commits] SF.net SVN: openmsx:[11974] openmsx/trunk/src/video/VDPVRAM.cc

[<m97...@us...>]

Revision: 11974
          http://openmsx.svn.sourceforge.net/openmsx/?rev=11974&view=rev
Author:   m9710797
Date:     2011-02-26 22:57:40 +0000 (Sat, 26 Feb 2011)

Log Message:
-----------
Swapped order of cmdEngine->sync() and renderer->updateXXX()

Before this patch I could trigger this scenario:

VDPVRAM::updateDisplayEnabled()
{
	...
	renderer->updateDisplayEnabled();
	   --> PixelRenderer::updateDisplayEnabled()
	    --> PixelRenderer::sync()
	     --> PixelRenderer::renderUntil()
	cmdEngine->sync();
	   --> VDPCmdEngine::sync()
	    --> HmmmCommand::execute()
	     --> VDPVRAM::cmdWrite()
	      --> VDPVRAM::writeCommon()
	       --> VRAMWindow::notify()
	        --> PixelRenderer::updateVRAM()
	         --> PixelRenderer::renderUntil()
	...
}

So in VDPVRAM::updateDisplayEnabled(), the first statement
renderer->updateDisplayEnabled() indirectly triggers
PixelRenderer::renderUntil(), this is done for timestamp 'now'. The second
statement cmdEngine->sync() also triggers PixelRenderer::renderUntil(), but
this is possibly done for timestamps between 'last-cmdEngine-sync' and 'now'.
So from the standpoint of PixelRenderer::renderUntil(), time appears to go
backwards.

Simply swapping the order of the two statements above fixes the problem. There
is a similar situation in updateSpritesEnabled() and updateDisplayMode().

Modified Paths:
--------------
    openmsx/trunk/src/video/VDPVRAM.cc

Modified: openmsx/trunk/src/video/VDPVRAM.cc
===================================================================
--- openmsx/trunk/src/video/VDPVRAM.cc	2011-02-26 22:57:23 UTC (rev 11973)
+++ openmsx/trunk/src/video/VDPVRAM.cc	2011-02-26 22:57:40 UTC (rev 11974)
@@ -175,24 +175,25 @@
 
 void VDPVRAM::updateDisplayMode(DisplayMode mode, EmuTime::param time)
 {
+	assert(vdp.isInsideFrame(time));
+	cmdEngine->updateDisplayMode(mode, time);
 	renderer->updateDisplayMode(mode, time);
-	cmdEngine->updateDisplayMode(mode, time);
 	spriteChecker->updateDisplayMode(mode, time);
 }
 
 void VDPVRAM::updateDisplayEnabled(bool enabled, EmuTime::param time)
 {
 	assert(vdp.isInsideFrame(time));
+	cmdEngine->sync(time);
 	renderer->updateDisplayEnabled(enabled, time);
-	cmdEngine->sync(time);
 	spriteChecker->updateDisplayEnabled(enabled, time);
 }
 
 void VDPVRAM::updateSpritesEnabled(bool enabled, EmuTime::param time)
 {
 	assert(vdp.isInsideFrame(time));
+	cmdEngine->sync(time);
 	renderer->updateSpritesEnabled(enabled, time);
-	cmdEngine->sync(time);
 	spriteChecker->updateSpritesEnabled(enabled, time);
 }
 


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