RomPanasonic.cc

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#include "RomPanasonic.hh"
#include "PanasonicMemory.hh"
#include "MSXMotherBoard.hh"
#include "DeviceConfig.hh"
#include "SRAM.hh"
#include "CacheLine.hh"
#include "one_of.hh"
#include "ranges.hh"
#include "serialize.hh"
#include "xrange.hh"
#include <memory>
 
namespace openmsx {
 
const unsigned SRAM_BASE = 0x80;
const unsigned RAM_BASE  = 0x180;
 
RomPanasonic::RomPanasonic(const DeviceConfig& config, Rom&& rom_)
        : Rom8kBBlocks(config, std::move(rom_))
        , panasonicMem(getMotherBoard().getPanasonicMemory())
{
        unsigned sramSize = config.getChildDataAsInt("sramsize", 0);
        if (sramSize) {
                sram = std::make_unique<SRAM>(
                        getName() + " SRAM", sramSize * 1024, config);
        }
 
        if (config.getChildDataAsBool("sram-mirrored", false)) {
                maxSRAMBank = SRAM_BASE + 8;
        } else {
                maxSRAMBank = SRAM_BASE + (sramSize / 8);
        }
 
        // Inform base class about PanasonicMemory (needed for serialization).
        // This relies on the order of MSXDevice instantiation, the PanasonicRam
        // device must be create before this one. (In the hardwareconfig.xml
        // we added a device-reference from this device to the PanasonicRam
        // device, this should protected against wrong future edits in the
        // config file).
        setExtraMemory({panasonicMem.getRamBlock(0), panasonicMem.getRamSize()});
 
        reset(EmuTime::dummy());
}
 
void RomPanasonic::reset(EmuTime::param /*time*/)
{
        control = 0;
        ranges::fill(bankSelect, 0);
        for (auto region : xrange(8)) {
                setRom(region, 0);
        }
        invalidateDeviceRCache(0x7FF0 & CacheLine::HIGH, CacheLine::SIZE);
}
 
byte RomPanasonic::peekMem(word address, EmuTime::param time) const
{
        if ((control & 0x04) && (0x7FF0 <= address) && (address < 0x7FF8)) {
                // read mapper state (lower 8 bit)
                return bankSelect[address & 7] & 0xFF;
        } else if ((control & 0x10) && (address == 0x7FF8)) {
                // read mapper state (9th bit)
                byte result = 0;
                for (int i = 7; i >= 0; i--) {
                        result <<= 1;
                        if (bankSelect[i] & 0x100) {
                                result++;
                        }
                }
                return result;
        } else if ((control & 0x08) && (address == 0x7FF9)) {
                // read control byte
                return control;
        } else {
                return Rom8kBBlocks::peekMem(address, time);
        }
}
 
byte RomPanasonic::readMem(word address, EmuTime::param time)
{
        return RomPanasonic::peekMem(address, time);
}
 
const byte* RomPanasonic::getReadCacheLine(word address) const
{
        if ((0x7FF0 & CacheLine::HIGH) == address) {
                // TODO check mirrored
                return nullptr;
        } else {
                return Rom8kBBlocks::getReadCacheLine(address);
        }
}
 
void RomPanasonic::writeMem(word address, byte value, EmuTime::param /*time*/)
{
        if ((0x6000 <= address) && (address < 0x7FF0)) {
                // set mapper state (lower 8 bits)
                auto region = (address & 0x1C00) >> 10;
                if (region == one_of(5, 6)) region ^= 3;
                auto selectedBank = bankSelect[region];
                auto newBank = (selectedBank & ~0xFF) | value;
                changeBank(region, newBank);
        } else if (address == 0x7FF8) {
                // set mapper state (9th bit)
                for (auto region : xrange(8)) {
                        if (value & 1) {
                                changeBank(region, bankSelect[region] |  0x100);
                        } else {
                                changeBank(region, bankSelect[region] & ~0x100);
                        }
                        value >>= 1;
                }
        } else if (address == 0x7FF9) {
                // write control byte
                control = value;
        } else {
                // Tested on real FS-A1GT:
                //  SRAM/RAM can be written to from all regions, including e.g.
                //  address 0x7ff0. (I didn't actually test 0xc000-0xffff).
                auto region = address >> 13;
                auto selectedBank = bankSelect[region];
                if (sram && (SRAM_BASE <= selectedBank) &&
                    (selectedBank < maxSRAMBank)) {
                        // SRAM
                        auto block = selectedBank - SRAM_BASE;
                        sram->write((block * 0x2000) | (address & 0x1FFF), value);
                } else if (RAM_BASE <= selectedBank) {
                        // RAM
                        const_cast<byte*>(bankPtr[region])[address & 0x1FFF] = value;
                }
        }
}
 
byte* RomPanasonic::getWriteCacheLine(word address)
{
        if ((0x6000 <= address) && (address < 0x8000)) {
                // mapper select (low/high), control
                return nullptr;
        } else {
                auto region = address >> 13;
                auto selectedBank = bankSelect[region];
                if (sram && (SRAM_BASE <= selectedBank) &&
                    (selectedBank < maxSRAMBank)) {
                        // SRAM
                        return nullptr;
                } else if (RAM_BASE <= selectedBank) {
                        // RAM
                        return const_cast<byte*>(&bankPtr[region][address & 0x1FFF]);
                } else {
                        return unmappedWrite.data();
                }
        }
}
 
void RomPanasonic::changeBank(unsigned region, unsigned bank)
{
        if (bank == bankSelect[region]) {
                return;
        }
        bankSelect[region] = bank;
 
        if (sram && (SRAM_BASE <= bank) && (bank < maxSRAMBank)) {
                // SRAM
                auto offset = (bank - SRAM_BASE) * size_t(0x2000);
                if (auto sramSize = sram->size(); offset >= sramSize) {
                        offset &= (sramSize - 1);
                }
                // TODO RomBlock debuggable is only 8 bits, here bank is 9 bits
                setBank(region, &sram->operator[](offset), narrow_cast<byte>(bank));
        } else if (panasonicMem.getRamSize() && (RAM_BASE <= bank)) {
                // RAM
                // TODO RomBlock debuggable is only 8 bits, here bank is 9 bits
                setBank(region, panasonicMem.getRamBlock(bank - RAM_BASE), narrow_cast<byte>(bank));
        } else {
                // ROM
                setRom(region, bank);
        }
        invalidateDeviceWCache(0x2000 * region, 0x2000); // 'R' is already handled
        if (region == 3) {
                // don't pre-fill [0x7ff0, 0x7fff]
                invalidateDeviceRCache(0x7FF0 & CacheLine::HIGH, CacheLine::SIZE);
        }
}
 
template<typename Archive>
void RomPanasonic::serialize(Archive& ar, unsigned /*version*/)
{
        ar.template serializeBase<Rom8kBBlocks>(*this);
        ar.serialize("bankSelect", bankSelect,
                     "control",    control);
}
INSTANTIATE_SERIALIZE_METHODS(RomPanasonic);
REGISTER_MSXDEVICE(RomPanasonic, "RomPanasonic");
 
} // namespace openmsx