nestopia/source/core/board/NstBoardBandai24c0x.cpp

378 lines
7.8 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 "NstBoardBandai24c0x.hpp"
namespace Nes
{
namespace Core
{
namespace Boards
{
namespace Bandai
{
#ifdef NST_MSVC_OPTIMIZE
#pragma optimize("s", on)
#endif
void X24C0X<0>::Reset()
{
line.scl = 0;
line.sda = 0;
mode = MODE_IDLE;
next = MODE_IDLE;
latch.bit = 0;
latch.address = 0;
latch.data = 0;
rw = false;
output = 0x10;
}
void X24C0X<0>::SaveState
(
State::Saver& state,
const dword baseChunk,
const byte* const mem,
const uint size
) const
{
state.Begin( baseChunk );
const byte data[6] =
{
line.scl | line.sda,
uint(mode << 0) | uint(next << 4),
latch.address,
latch.data,
latch.bit,
output | (rw ? 0x80 : 0x00)
};
state.Begin( AsciiId<'R','E','G'>::V ).Write( data ).End();
state.Begin( AsciiId<'R','A','M'>::V ).Compress( mem, size ).End();
state.End();
}
void X24C0X<0>::LoadState(State::Loader& state,byte* const mem,const uint size)
{
while (const dword chunk = state.Begin())
{
switch (chunk)
{
case AsciiId<'R','E','G'>::V:
{
State::Loader::Data<6> data( state );
line.scl = data[0] & 0x20;
line.sda = data[0] & 0x40;
if ((data[1] & 0xF) < MODE_MAX)
mode = static_cast<Mode>(data[1] & 0xF);
if ((data[1] >> 4) < MODE_MAX)
next = static_cast<Mode>(data[1] >> 4);
latch.address = data[2] & (size-1);
latch.data = data[3];
latch.bit = NST_MAX(data[4],8);
rw = data[5] & 0x80;
output = data[5] & 0x10;
break;
}
case AsciiId<'R','A','M'>::V:
state.Uncompress( mem, size );
break;
}
state.End();
}
}
#ifdef NST_MSVC_OPTIMIZE
#pragma optimize("s", on)
#endif
void X24C0X<0>::Stop()
{
mode = MODE_IDLE;
output = 0x10;
}
template<>
void X24C0X<128>::Start()
{
mode = MODE_ADDRESS;
latch.bit = 0;
latch.address = 0;
output = 0x10;
}
template<>
void X24C0X<256>::Start()
{
mode = MODE_DATA;
latch.bit = 0;
output = 0x10;
}
template<>
void X24C0X<128>::Rise(const uint bit)
{
NST_ASSERT( bit <= 1 );
if (mode == MODE_ADDRESS)
{
if (latch.bit < 7)
{
latch.address &= ~(1U << latch.bit);
latch.address |= bit << latch.bit++;
}
else if (latch.bit < 8)
{
latch.bit = 8;
if (bit)
{
next = MODE_READ;
latch.data = mem[latch.address];
}
else
{
next = MODE_WRITE;
}
}
}
else if (mode == MODE_ACK)
{
output = 0x00;
}
else if (mode == MODE_READ && (latch.bit < 8))
{
output = (latch.data & 1U << latch.bit++) ? 0x10 : 0x00;
}
else if (mode == MODE_WRITE && (latch.bit < 8))
{
latch.data &= ~(1U << latch.bit);
latch.data |= bit << latch.bit++;
}
else if (mode == MODE_ACK_WAIT && (bit == 0))
{
next = MODE_IDLE;
}
}
template<>
void X24C0X<128>::Fall()
{
if (mode == MODE_ADDRESS && (latch.bit == 8))
{
mode = MODE_ACK;
output = 0x10;
}
else if (mode == MODE_ACK)
{
mode = next;
latch.bit = 0;
output = 0x10;
}
else if (mode == MODE_READ && (latch.bit == 8))
{
mode = MODE_ACK_WAIT;
latch.address = (latch.address+1) & 0x7F;
}
else if (mode == MODE_WRITE && (latch.bit == 8))
{
mode = MODE_ACK;
next = MODE_IDLE;
mem[latch.address] = latch.data;
latch.address = (latch.address+1) & 0x7F;
}
}
template<>
void X24C0X<256>::Rise(const uint bit)
{
NST_ASSERT( bit <= 1 );
switch (mode)
{
case MODE_DATA:
if (latch.bit < 8)
{
latch.data &= ~(1U << (7-latch.bit));
latch.data |= bit << (7-latch.bit++);
}
break;
case MODE_ADDRESS:
if (latch.bit < 8)
{
latch.address &= ~(1U << (7-latch.bit));
latch.address |= bit << (7-latch.bit++);
}
break;
case MODE_READ:
if (latch.bit < 8)
output = (latch.data & 1U << (7-latch.bit++)) ? 0x10 : 0x00;
break;
case MODE_WRITE:
if (latch.bit < 8)
{
latch.data &= ~(1U << (7-latch.bit));
latch.data |= bit << (7-latch.bit++);
}
break;
case MODE_NOT_ACK:
output = 0x10;
break;
case MODE_ACK:
output = 0x00;
break;
case MODE_ACK_WAIT:
if (bit == 0)
{
next = MODE_READ;
latch.data = mem[latch.address];
}
break;
case MODE_IDLE:
case MODE_MAX:
default:
break;
}
}
template<>
void X24C0X<256>::Fall()
{
switch (mode)
{
case MODE_DATA:
if (latch.bit == 8)
{
if ((latch.data & 0xA0) == 0xA0)
{
latch.bit = 0;
mode = MODE_ACK;
rw = latch.data & 0x01;
output = 0x10;
if (rw)
{
next = MODE_READ;
latch.data = mem[latch.address];
}
else
{
next = MODE_ADDRESS;
}
}
else
{
mode = MODE_NOT_ACK;
next = MODE_IDLE;
output = 0x10;
}
}
break;
case MODE_ADDRESS:
if (latch.bit == 8)
{
latch.bit = 0;
mode = MODE_ACK;
next = (rw ? MODE_IDLE : MODE_WRITE);
output = 0x10;
}
break;
case MODE_READ:
if (latch.bit == 8)
{
mode = MODE_ACK_WAIT;
latch.address = (latch.address+1) & 0xFF;
}
break;
case MODE_WRITE:
if (latch.bit == 8)
{
latch.bit = 0;
mode = MODE_ACK;
next = MODE_WRITE;
mem[latch.address] = latch.data;
latch.address = (latch.address+1) & 0xFF;
}
break;
case MODE_NOT_ACK:
mode = MODE_IDLE;
latch.bit = 0;
output = 0x10;
break;
case MODE_ACK:
case MODE_ACK_WAIT:
mode = next;
latch.bit = 0;
output = 0x10;
break;
case MODE_IDLE:
case MODE_MAX:
default:
break;
}
}
}
}
}
}