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////////////////////////////////////////////////////////////////////////////////////////
//
// Nestopia - NES/Famicom emulator written in C++
//
// Copyright (C) 2022 Rupert Carmichael
//
// 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 "NstBoardUnl158b.hpp"
/* References:
https://github.com/SourMesen/Mesen/blob/master/Core/Unl158B.h
https://github.com/TASVideos/fceux/blob/master/src/boards/158B.cpp
*/
namespace Nes
{
namespace Core
{
namespace Boards
{
namespace Unlicensed
{
Gd98158b::Gd98158b(const Context& c)
: Mmc3(c) {}
void Gd98158b::SubReset(const bool hard)
{
lut[0] = lut[1] = lut[2] = lut[7] = 0x00;
lut[3] = 0x01;
lut[4] = 0x02;
lut[5] = 0x04;
lut[6] = 0x0F;
if (hard)
reg = 0;
banks.prg[0] = 0x00;
banks.prg[1] = 0x01;
banks.prg[2] = 0x3E;
banks.prg[3] = 0x3F;
Mmc3::SubReset( hard );
Map( 0x5000U, 0x5FFFU, &Gd98158b::Peek_5000 );
Map( 0x5000U, 0x5FFFU, &Gd98158b::Poke_5000 );
}
void Gd98158b::SubLoad(State::Loader& state,const dword baseChunk)
{
if (baseChunk == AsciiId<'1','5','8'>::V)
{
while (const dword chunk = state.Begin())
{
if (chunk == AsciiId<'R','E','G'>::V)
reg = state.Read8();
state.End();
}
}
else
{
Mmc3::SubLoad( state, baseChunk );
}
}
void Gd98158b::SubSave(State::Saver& state) const
{
Mmc3::SubSave( state );
state.Begin( AsciiId<'1','5','8'>::V ).Begin( AsciiId<'R','E','G'>::V ).Write8( reg ).End().End();
}
void NST_FASTCALL Gd98158b::UpdatePrg(uint address, uint data)
{
if (reg & 0x80)
{
const uint bank = reg & 0x7;
if (reg & 0x20)
{
prg.SwapBank<SIZE_32K>( 0x0000, bank >> 1 );
}
else
{
prg.SwapBank<SIZE_16K>( 0x0000, bank );
prg.SwapBank<SIZE_16K>( 0x4000, bank );
}
}
else
{
prg.SwapBank<SIZE_8K>( (address & 0x6000), data & 0xF );
}
}
NES_PEEK_A(Gd98158b,5000)
{
// Fake Open Bus read by always using 0x50
return 0x50 | lut[address & 0x7];
}
NES_POKE_AD(Gd98158b,5000)
{
if ((address & 0x7) == 0)
{
reg = data;
Mmc3::UpdatePrg();
}
}
}
}
}
}
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