1 files changed, 281 insertions, 0 deletions
diff --git a/SrcShared/EmScreen.cpp b/SrcShared/EmScreen.cpp
new file mode 100644
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--- /dev/null
+++ b/SrcShared/EmScreen.cpp
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+/* -*- mode: C++; tab-width: 4 -*- */
+/* ===================================================================== *\
+	Copyright (c) 2000-2001 Palm, Inc. or its subsidiaries.
+	All rights reserved.
+
+	This file is part of the Palm OS Emulator.
+
+	This program is free software; you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation; either version 2 of the License, or
+	(at your option) any later version.
+\* ===================================================================== */
+
+#include "EmCommon.h"
+#include "EmScreen.h"
+
+#include "EmHAL.h"				// EmHAL:: GetLCDBeginEnd
+#include "EmMemory.h"			// CEnableFullAccess
+#include "MetaMemory.h"			// MetaMemory::MarkScreen
+
+
+static emuptr	gScreenDirtyLow;
+static emuptr	gScreenDirtyHigh;
+
+static emuptr	gScreenBegin;
+static emuptr	gScreenEnd;
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::Initialize
+ *
+ * DESCRIPTION: Standard initialization function.  Responsible for
+ *				initializing this sub-system when a new session is
+ *				created.  Will be followed by at least one call to
+ *				Reset or Load.
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+void EmScreen::Initialize (void)
+{
+	gScreenDirtyLow		= EmMemEOM;
+	gScreenDirtyHigh 	= EmMemNULL;
+
+	gScreenBegin		= EmMemNULL;
+	gScreenEnd			= EmMemNULL;
+}
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::Reset
+ *
+ * DESCRIPTION: Standard reset function.  Sets the sub-system to a
+ *				default state.	This occurs not only on a Reset (as
+ *				from the menu item), but also when the sub-system
+ *				is first initialized (Reset is called after Initialize)
+ *				as well as when the system is re-loaded from an
+ *				insufficient session file.
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+void EmScreen::Reset (void)
+{
+	gScreenDirtyLow		= EmMemNULL;
+	gScreenDirtyHigh	= EmMemEOM;
+
+	gScreenBegin		= EmMemNULL;
+	gScreenEnd			= EmMemNULL;
+}
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::Save
+ *
+ * DESCRIPTION: Standard save function.  Saves any sub-system state to
+ *				the given session file.
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+void EmScreen::Save (SessionFile&)
+{
+}
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::Load
+ *
+ * DESCRIPTION: Standard load function.  Loads any sub-system state
+ *				from the given session file.
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+void EmScreen::Load (SessionFile&)
+{
+	gScreenDirtyLow		= EmMemNULL;
+	gScreenDirtyHigh	= EmMemEOM;
+
+	EmHAL::GetLCDBeginEnd (gScreenBegin, gScreenEnd);
+}
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::Dispose
+ *
+ * DESCRIPTION: Standard dispose function.	Completely release any
+ *				resources acquired or allocated in Initialize and/or
+ *				Load.
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+void EmScreen::Dispose (void)
+{
+}
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::MarkDirty
+ *
+ * DESCRIPTION: .
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+void EmScreen::MarkDirty (emuptr address, uint32 size)
+{
+	/*	
+		SUBTLE BUG NOTE:  Both of these tests need to be performed.
+		Originally, I had this as an if (...) ... else if (...) ... After
+		all, how could a given address be above the high- water mark if it
+		was below the low-water mark?  "Obviously", it couldn't, so I didn't
+		see the need to test against the high-water mark if we were below
+		the low-water mark.
+
+		Well, duh, that assumption was false.  After the LCD buffer is
+		copied to the screen, we set the low-water mark to the end of the
+		buffer and the high-water mark to the beginning of the buffer.  If
+		the screen is modified in such a way that each pixel affected
+		appears lower in memory than any previous pixel (as happens when we
+		scroll a document down), then we always entered the low-water mark
+		of the code below; we never entered the high-water mark of the code.
+		Thus, the high-water mark stayed set to the beginning of the
+		buffer, giving us a NULL update range.
+	*/
+
+	if (address < gScreenDirtyLow)
+	{
+		gScreenDirtyLow = address;
+	}
+
+	if (address + size > gScreenDirtyHigh)
+	{
+		gScreenDirtyHigh = address + size;
+	}
+}
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::InvalidateAll
+ *
+ * DESCRIPTION: .
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+void EmScreen::InvalidateAll (void)
+{
+	gScreenDirtyLow		= EmMemNULL;
+	gScreenDirtyHigh	= EmMemEOM;
+
+	emuptr newScreenBegin;
+	emuptr newScreenEnd;
+	EmHAL::GetLCDBeginEnd (newScreenBegin, newScreenEnd);
+
+	if (newScreenBegin != gScreenBegin || newScreenEnd != gScreenEnd)
+	{
+		MetaMemory::UnmarkScreen (gScreenBegin, gScreenEnd);
+
+		gScreenBegin	= newScreenBegin;
+		gScreenEnd		= newScreenEnd;
+
+		MetaMemory::MarkScreen (gScreenBegin, gScreenEnd);
+	}
+}
+
+
+/***********************************************************************
+ *
+ * FUNCTION:	EmScreen::GetBits
+ *
+ * DESCRIPTION: .
+ *
+ * PARAMETERS:	None.
+ *
+ * RETURNED:	Nothing.
+ *
+ ***********************************************************************/
+
+Bool EmScreen::GetBits (EmScreenUpdateInfo& info)
+{
+	// Always return whether or not the LCD is on.
+
+	info.fLCDOn			= EmHAL::GetLCDScreenOn ();
+
+	// Get the first and last scanlines to update.	This is a *big* win
+	// when running Gremlins.  Without this check, a typical test ran
+	// 240 seconds.  With the check, the test ran 170 seconds.
+
+	// Get the screen begin and end.  We'll be clipping against this
+	// range (just in case screenLow and/or screenHigh got out of whack,
+	// which might happen in a multi-threaded system and we aren't using
+	// synchronization objects).
+
+	emuptr screenBegin;
+	emuptr screenEnd;
+	EmHAL::GetLCDBeginEnd (screenBegin, screenEnd);
+
+	// Get the range of bytes affected, clipping to the range of the
+	// screen.  From this information, we can determine the first and
+	// last affected scanlines.
+
+	info.fScreenLow		= max (gScreenDirtyLow, screenBegin);
+	info.fScreenHigh	= min (gScreenDirtyHigh, screenEnd);
+
+	// Reset gScreenDirtyLow/High with sentinel values so that they can
+	// be munged again by EmScreen::MarkDirty.
+
+	gScreenDirtyLow		= EmMemEOM;
+	gScreenDirtyHigh	= EmMemNULL;
+
+	// If no lines need to be updated, we can return now.
+
+	if (info.fScreenLow >= info.fScreenHigh)
+	{
+		return false;
+	}
+
+	// Get the current state of things.  Do this only if the LCD is on.
+	// If the LCD is off, we may not be able to get the contents of its
+	// frame buffer (the bus to the buffer may be disabled).
+
+	if (info.fLCDOn)
+	{
+		CEnableFullAccess	munge;	// Remove blocks on memory access.
+
+		EmHAL::GetLCDScanlines (info);
+	}
+
+	return true;
+}