vinace/src/core/busses/c-main-memory-bus.cpp

57 lines
1.6 KiB
C++

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*- */
/*
* Vinace
* Copyright (C) P.Y. Rollo 2009 <dev@pyrollo.com>
*
* Vinace 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 3 of the License, or
* (at your option) any later version.
*
* Vinace 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "c-main-memory-bus.hpp"
CMainMemoryBus::CMainMemoryBus(CMemory *ram, CMemory *iou, CMemory *ioBus, CMemory *lcBus) {
this->ram = ram;
this->iou = iou;
this->ioBus = ioBus;
this->lcBus = lcBus;
}
BYTE CMainMemoryBus::read(WORD addr) {
// Language Card ($D000-$FFFF)
if (addr >= 0xD000) return lcBus->read(addr-0xD000);
// Main ram ($0000-$BFFF)
if (addr < 0xC000) return ram->read(addr);
// Slot rom
if (addr >= 0xC100) return ioBus->read(addr-0xC000);
// Input Output Unit
return iou->read(addr-0xC000);
}
void CMainMemoryBus::write(WORD addr, BYTE byte) {
// Main ram ($0000-$BFFF)
if (addr < 0xC000) { ram->write(addr, byte); return; }
// Language Card ($D000-$FFFF)
if (addr >= 0xD000) { lcBus->write(addr-0xD000, byte); return; }
// Input Output Unit
if (addr < 0xC100) { iou->write(addr-0xC000, byte); return; }
// Slot rom -> No write
};