nestopia/source/core/board/NstBoardMmc6.cpp
2021-08-25 22:20:30 -04:00

149 lines
3.5 KiB
C++

////////////////////////////////////////////////////////////////////////////////////////
//
// Nestopia - NES/Famicom emulator written in C++
//
// Copyright (C) 2003-2008 Martin Freij
//
// This file is part of Nestopia.
//
// Nestopia 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.
//
// Nestopia is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Nestopia; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
////////////////////////////////////////////////////////////////////////////////////////
#include "NstBoard.hpp"
#include "NstBoardMmc6.hpp"
#include "../NstFile.hpp"
namespace Nes
{
namespace Core
{
namespace Boards
{
#ifdef NST_MSVC_OPTIMIZE
#pragma optimize("s", on)
#endif
Mmc6::Mmc6(const Context& c)
: Mmc3(c,REV_A) {}
void Mmc6::SubReset(const bool hard)
{
Mmc3::SubReset( hard );
reg = 0;
Map( 0x6000U, 0x6FFFU, NOP_POKE );
Map( 0x7000U, 0x7FFFU, &Mmc6::Peek_7000, &Mmc6::Poke_7000 );
for (uint i=0xA001; i < 0xC000; i += 0x2)
Map( i, &Mmc6::Poke_A001 );
}
void Mmc6::Load(File& file)
{
if (board.HasBattery())
file.Load( File::BATTERY, ram, sizeof(ram) );
}
void Mmc6::Save(File& file) const
{
if (board.HasBattery())
file.Save( File::BATTERY, ram, sizeof(ram) );
}
void Mmc6::SubLoad(State::Loader& state,const dword baseChunk)
{
if (baseChunk == AsciiId<'M','M','6'>::V)
{
while (const dword chunk = state.Begin())
{
switch (chunk)
{
case AsciiId<'R','E','G'>::V:
reg = state.Read8();
break;
case AsciiId<'R','A','M'>::V:
state.Uncompress( ram );
break;
}
state.End();
}
}
else
{
Mmc3::SubLoad( state, baseChunk );
}
}
void Mmc6::SubSave(State::Saver& state) const
{
Mmc3::SubSave( state );
state.Begin( AsciiId<'M','M','6'>::V );
state.Begin( AsciiId<'R','E','G'>::V ).Write8( reg ).End();
state.Begin( AsciiId<'R','A','M'>::V ).Compress( ram ).End();
state.End();
}
#ifdef NST_MSVC_OPTIMIZE
#pragma optimize("", on)
#endif
inline bool Mmc6::IsRamEnabled() const
{
return reg & (RAM_LO_BANK_ENABLED|RAM_HI_BANK_ENABLED);
}
inline bool Mmc6::IsRamReadable(uint address) const
{
return (reg >> (address >> 8 & 0x2)) & 0x20;
}
inline bool Mmc6::IsRamWritable(uint address) const
{
return ((reg >> (address >> 8 & 0x2)) & 0x30) == 0x30;
}
NES_POKE_AD(Mmc6,7000)
{
NST_VERIFY( IsRamWritable(address) );
if (IsRamWritable( address ))
ram[address & 0x3FF] = data;
}
NES_PEEK_A(Mmc6,7000)
{
NST_VERIFY( IsRamEnabled() && IsRamReadable(address) );
if (IsRamEnabled())
return IsRamReadable(address) ? ram[address & 0x3FF] : 0x00;
else
return address >> 8;
}
NES_POKE_D(Mmc6,A001)
{
if ((reg & 0x1) | (regs.ctrl0 & RAM_ENABLE))
reg = data | 0x1;
}
}
}
}