path: root/SrcShared/Hardware/EmRegs.cpp

/* -*- 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 "EmRegs.h"

#include "Byteswapping.h"		// Canonical
#include "EmBankRegs.h"			// EmBankRegs::InvalidAccess
#include "EmMemory.h"			// Memory::InitializeBanks, EmMemBankIndex

/*
	EmRegs is a base class for subclasses that manage the accessing of
	emulated memory at a byte, word, or long level.  See comments in
	EmRegsBank.cpp for a description on how EmRegs objects are managed,
	and EmMemory for how memory in general is emulated.

	EmRegs subclasses are suited for managing hardware registers, such
	as the Dragonball [EZ | VZ] hardware registers, the USB registers
	in the Handspring Visor, or the special PLD registers in some of the
	Palm VII devices.

	To create a new EmRegs subclass that can handle accesses to a special
	range of memory, do the following:

	* Create a subclass of EmRegs

	* Provide implementations for the pure virtual functions:

		* SetSubBankHandlers: this method needs to call EmRegs::SetHandler
		  to install a read and write function for each memory location
		  that can be accessed.  It should also first call the base
		  class SetSubBankHandlers in order to install default handlers
		  for all memory locations in the memory range the subclass manages.

		* GetRealAddress: given an address in emulated space, this function
		  returns the real address from the point of view of the emulator.
		  For instance, if your EmRegs subclass manages the memory range
		  0x17000000 to 0x17001000, and you have created a 4K buffer to
		  represent this memory range, then GetRealAddress would be like:

		  	return &fMyBuffer[address - 0x17000000];

		* GetAddressStart: returns the base address of the memory range
		  managed by this class.  In the example above, this method would
		  return 0x17000000.

		* GetAddressRange: returns the range of memory managed by this
		  class.  In the example above, this method would return 0x1000.

	* Define read and write function handlers for each memory location
	  in the managed range.  These functions handlers are installed in
	  your SetSubBankHandlers override.  EmBankRegs will call these
	  handlers as appropriate.

	* Optionally implement Initialize, Reset, Save, Load, and Dispose
	  overrides.  You will usually override Initialize to create any
	  buffers required to hold your data, and correspondingly dispose
	  of those resources in a Dispose override.  Most subclasses will
	  need to override Reset in order to initialize their emulated
	  registers.  And override Save and Load if you want to save and
	  restore your registers to the session (.psf) file.

	* In the appropriate case statement in EmDevice::CreateRegs, create
	  an instance of your EmRegs class and install it by calling
	  EmBankRegs::AddSubBank.
*/


// ---------------------------------------------------------------------------
//		¥ EmRegs::EmRegs
// ---------------------------------------------------------------------------

EmRegs::EmRegs (void) :
	fReadFunctions (),
	fWriteFunctions ()
{
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::~EmRegs
// ---------------------------------------------------------------------------

EmRegs::~EmRegs (void)
{
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::Initialize
// ---------------------------------------------------------------------------

void EmRegs::Initialize (void)
{
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::Reset
// ---------------------------------------------------------------------------

void EmRegs::Reset (Bool /*hardwareReset*/)
{
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::Save
// ---------------------------------------------------------------------------

void EmRegs::Save (SessionFile&)
{
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::Load
// ---------------------------------------------------------------------------

void EmRegs::Load (SessionFile&)
{
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::Dispose
// ---------------------------------------------------------------------------

void EmRegs::Dispose (void)
{
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::SetBankHandlers
// ---------------------------------------------------------------------------

void EmRegs::SetBankHandlers (EmAddressBank& bank)
{
	emuptr	address		= this->GetAddressStart ();
	uint32	range		= this->GetAddressRange ();
	uint32	numBanks	= EmMemBankIndex (address + range - 1) - EmMemBankIndex (address) + 1;

	Memory::InitializeBanks (bank, EmMemBankIndex (address), numBanks);

	this->SetSubBankHandlers ();
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::SetSubBankHandlers
// ---------------------------------------------------------------------------

void EmRegs::SetSubBankHandlers (void)
{
	this->SetHandler (&EmRegs::UnsupportedRead, &EmRegs::UnsupportedWrite,
						this->GetAddressStart (), this->GetAddressRange ());
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::GetLong
// ---------------------------------------------------------------------------

uint32 EmRegs::GetLong (emuptr address)
{
//	EmAssert (this->ValidAddress (address, 4));

	long			offset	= address - this->GetAddressStart ();
	ReadFunction	fn		= fReadFunctions [offset];
	EmAssert (fn);

	return (this->*fn) (address, 4);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::GetWord
// ---------------------------------------------------------------------------

uint32 EmRegs::GetWord (emuptr address)
{
//	EmAssert (this->ValidAddress (address, 2));

	long			offset	= address - this->GetAddressStart ();
	ReadFunction	fn		= fReadFunctions [offset];
	EmAssert (fn);

	return (this->*fn) (address, 2);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::GetByte
// ---------------------------------------------------------------------------

uint32 EmRegs::GetByte (emuptr address)
{
//	EmAssert (this->ValidAddress (address, 1));

	long			offset	= address - this->GetAddressStart ();
	ReadFunction	fn		= fReadFunctions [offset];
	EmAssert (fn);

	return (this->*fn) (address, 1);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::SetLong
// ---------------------------------------------------------------------------

void EmRegs::SetLong (emuptr address, uint32 value)
{
//	EmAssert (this->ValidAddress (address, 4));

	long			offset	= address - this->GetAddressStart ();
	WriteFunction	fn		= fWriteFunctions [offset];
	EmAssert (fn);

	(this->*fn) (address, 4, value);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::SetWord
// ---------------------------------------------------------------------------

void EmRegs::SetWord (emuptr address, uint32 value)
{
//	EmAssert (this->ValidAddress (address, 2));

	long			offset	= address - this->GetAddressStart ();
	WriteFunction	fn		= fWriteFunctions [offset];
	EmAssert (fn);

	(this->*fn) (address, 2, value);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::SetByte
// ---------------------------------------------------------------------------

void EmRegs::SetByte (emuptr address, uint32 value)
{
//	EmAssert (this->ValidAddress (address, 1));

	long			offset	= address - this->GetAddressStart ();
	WriteFunction	fn		= fWriteFunctions [offset];
	EmAssert (fn);

	(this->*fn) (address, 1, value);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::ValidAddress
// ---------------------------------------------------------------------------

int EmRegs::ValidAddress (emuptr address, uint32 size)
{
	UNUSED_PARAM (size);

	int				result	= false;
	unsigned long	offset	= address - this->GetAddressStart ();

	if (offset < fReadFunctions.size ())
	{
		ReadFunction	fn		= fReadFunctions [offset];
		result	= (fn != &EmRegs::UnsupportedRead);
	}

	return result;
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::GetRealAddress
// ---------------------------------------------------------------------------

uint8* EmRegs::GetRealAddress (emuptr address)
{
	UNUSED_PARAM (address);

	// Sub-class's responsibility.

	return NULL;
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::SetHandler
// ---------------------------------------------------------------------------

void EmRegs::SetHandler (ReadFunction read, WriteFunction write,
							uint32 start, int count)
{
	if (fReadFunctions.size () == 0)
	{
		uint32	range	= this->GetAddressRange ();

		fReadFunctions.resize (range, &EmRegs::UnsupportedRead);
		fWriteFunctions.resize (range, &EmRegs::UnsupportedWrite);
	}

	int index = start - this->GetAddressStart ();

	EmAssert (index >= 0);
	EmAssert (index < (long) fReadFunctions.size ());

	for (int ii = 0; ii < count; ++ii, ++index)
	{
		fReadFunctions[index] = read;
		fWriteFunctions[index] = write;
	}
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::UnsupportedRead
// ---------------------------------------------------------------------------

uint32 EmRegs::UnsupportedRead (emuptr address, int size)
{
	if (!CEnableFullAccess::AccessOK ())
	{
		EmBankRegs::PreventedAccess (address, size, true);
	}

	return ~0;
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::UnsupportedWrite
// ---------------------------------------------------------------------------

void EmRegs::UnsupportedWrite (emuptr address, int size, uint32 value)
{
	UNUSED_PARAM(value)

	if (!CEnableFullAccess::AccessOK ())
	{
		EmBankRegs::PreventedAccess (address, size, false);
	}
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::StdReadBE
// ---------------------------------------------------------------------------
// Read registers in a strict Big Endian fashion.

uint32 EmRegs::StdReadBE (emuptr address, int size)
{
	uint8*	realAddr = this->GetRealAddress (address);

	if (size == 1)
		return *(uint8*) realAddr;

	if (size == 2)
	{
		uint16	result16 = *(uint16*) realAddr;
		Canonical (result16);
		return result16;
	}

#if UNALIGNED_LONG_ACCESS

	uint32	result32 = *(uint32*) realAddr;
	Canonical (result32);
	return result32;

#else

	return	(realAddr[0] << 24) |
			(realAddr[1] << 16) |
			(realAddr[2] <<  8) |
			(realAddr[3] <<  0);

#endif
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::StdWriteBE
// ---------------------------------------------------------------------------
// Write registers in a strict Big Endian fashion.

void EmRegs::StdWriteBE (emuptr address, int size, uint32 value)
{
	uint8*	realAddr = this->GetRealAddress (address);

	if (size == 1)
	{
		*(uint8*) realAddr = value;
	}

	else if (size == 2)
	{
		uint16	value16 = value;
		Canonical (value16);
		*(uint16*) realAddr = value16;
	}

	else if (size == 4)
	{
#if UNALIGNED_LONG_ACCESS

		Canonical (value);
		*(uint32*) realAddr = value;

#else

		realAddr[0] = (uint8) (value >> 24);
		realAddr[1] = (uint8) (value >> 16);
		realAddr[2] = (uint8) (value >>  8);
		realAddr[3] = (uint8) (value >>  0);

#endif
	}
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::StdRead
// ---------------------------------------------------------------------------
// Read registers using the routines in maccess.h

uint32 EmRegs::StdRead (emuptr address, int size)
{
	uint8*	realAddr = this->GetRealAddress (address);

	if (size == 1)
		return EmMemDoGet8 (realAddr);

	if (size == 2)
		return EmMemDoGet16 (realAddr);

	return EmMemDoGet32 (realAddr);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::StdWrite
// ---------------------------------------------------------------------------
// Write registers using the routines in maccess.h

void EmRegs::StdWrite (emuptr address, int size, uint32 value)
{
	uint8*	realAddr = this->GetRealAddress (address);

	if (size == 1)
		EmMemDoPut8 (realAddr, value);

	else if (size == 2)
		EmMemDoPut16 (realAddr, value);

	else
		EmMemDoPut32 (realAddr, value);
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::ZeroRead
// ---------------------------------------------------------------------------

uint32 EmRegs::ZeroRead (emuptr address, int size)
{
	UNUSED_PARAM(address)
	UNUSED_PARAM(size)

	return 0;
}


// ---------------------------------------------------------------------------
//		¥ EmRegs::NullWrite
// ---------------------------------------------------------------------------

void EmRegs::NullWrite (emuptr address, int size, uint32 value)
{
	UNUSED_PARAM(address)
	UNUSED_PARAM(size)
	UNUSED_PARAM(value)

	// Do nothing (for read-only registers).
}