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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;
}
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