Carnivore2.cc

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#include "Carnivore2.hh"
#include "DummyAY8910Periphery.hh"
#include "IDEDevice.hh"
#include "IDEDeviceFactory.hh"
#include "CliComm.hh"
#include "MSXCPU.hh"
#include "narrow.hh"
#include "one_of.hh"
#include "ranges.hh"
#include "xrange.hh"
#include <array>
 
// TODO (besides what's in the code below):
// - FM-PAC mono/stereo setting (bit 7)
// - the PPI volume setting
// - slave slot support
 
// Note that the somewhat complex (and illogical?) behaviour of the
// user-defined ID and control port I/O is mimicking what the actual VHDL code
// is doing (in the released 2.50 firmware code).
 
namespace openmsx {
 
static constexpr auto sectorInfo = [] {
        // 8 * 8kB, followed by 127 * 64kB
        using Info = AmdFlash::SectorInfo;
        std::array<Info, 8 + 127> result = {};
        std::fill(result.begin(), result.begin() + 8, Info{ 8 * 1024, false});
        std::fill(result.begin() + 8, result.end(),   Info{64 * 1024, false});
        return result;
}();
 
Carnivore2::Carnivore2(const DeviceConfig& config)
        : MSXDevice(config)
        , MSXMapperIOClient(getMotherBoard())
        , flash(getName() + " flash", sectorInfo, 0x207e,
                AmdFlash::Addressing::BITS_12, config)
        , ram(config, getName() + " ram", "ram", 2048 * 1024)
        , eeprom(getName() + " eeprom",
                 DeviceConfig(config, config.getChild("eeprom")))
        , scc(getName() + " scc", config, getCurrentTime(), SCC::SCC_Compatible)
        , psg(getName() + " PSG", DummyAY8910Periphery::instance(), config,
              getCurrentTime())
        , ym2413(getName() + " ym2413", config)
{
        ideDevices[0] = IDEDeviceFactory::create(
                DeviceConfig(config, config.findChild("master")));
        ideDevices[1] = IDEDeviceFactory::create(
                DeviceConfig(config, config.findChild("slave")));
 
        configRegs[0x24] = 0; // to avoid UMR in powerUp -> reset -> writePSGAlt
        configRegs[0x30] = 0; // to avoid UMR in powerUp -> writePSGCtrl
        configRegs[0x35] = 0xf0; // to avoid UMR in powerUp -> writePFXN
        getCPUInterface().register_IO_Out(idControlPort(), this);
        getCPUInterface().register_IO_In (idControlPort(), this);
}
 
Carnivore2::~Carnivore2()
{
        // unregister PSG I/O ports, by disabling PSG
        writePSGCtrl(0, getCurrentTime());
        // unregister user-defined ID and control port
        getCPUInterface().unregister_IO_Out(idControlPort(), this);
        getCPUInterface().unregister_IO_In (idControlPort(), this);
}
 
void Carnivore2::powerUp(EmuTime::param time)
{
        writeSndLVL(0x1b, time);
        writePSGCtrl(0x1b, time);
        writePFXN(0xf0);
        scc.powerUp(time);
        reset(time);
}
 
void Carnivore2::reset(EmuTime::param time)
{
        subSlotReg = 0;
        port3C = 0;
 
        // config regs
        configRegs[0x00] = 0x30; // CardMDR
        for (int i : {0x01, 0x02, 0x03}) configRegs[i] = 0; // AddrM<i>
        configRegs[0x05] = shadowConfigRegs[0x05] = 0; // AddrFR
 
        configRegs[0x06] = shadowConfigRegs[0x06] = 0xF8; // R1Mask
        configRegs[0x07] = shadowConfigRegs[0x07] = 0x50; // R1Addr
        configRegs[0x08] = shadowConfigRegs[0x08] = 0x00; // R1Reg
        configRegs[0x09] = shadowConfigRegs[0x09] = 0x85; // R1Mult
        configRegs[0x0a] = shadowConfigRegs[0x0a] = 0x03; // B1MaskR
        configRegs[0x0b] = shadowConfigRegs[0x0b] = 0x40; // B1AdrD
 
        for (int i : {0x0f, 0x15, 0x1b}) {
                configRegs[i] = shadowConfigRegs[i] = 0; // R<i>Mult
        }
 
        configRegs[0x1e] = shadowConfigRegs[0x1e] = 0xff;
        configRegs[0x20] = 0x02;
        configRegs[0x28] = 0b11'10'01'00; // SLM_cfg
 
        writePSGAlt(0);
 
        writeCfgEEPR(0, time);
 
        // multi-mapper
        scc.reset(time);
        sccMode = 0;
        ranges::iota(sccBank, byte(0));
 
        // PSG
        psgLatch = 0;
        psg.reset(time);
 
        // ide
        ideControlReg = 0;
        ideSelectedDevice = 0;
        ideSoftReset = false;
        ideDevices[0]->reset(time);
        ideDevices[1]->reset(time);
 
        // memory mapper
        ranges::iota(memMapRegs, byte(0)); // Note: different from how BIOS initializes these registers
 
        // fm-pac
        ym2413.reset(time);
        fmPacEnable = 0x10;
        fmPacBank = 0;
        fmPac5ffe = 0;
        fmPac5fff = 0;
 
        // User-defined ID and control port I/O
        PF0_RV = 0;
}
 
void Carnivore2::globalRead(word address, EmuTime::param /*time*/)
{
        if (!delayedConfig()) return;
 
        if ((!delayedConfig4000() && (address == 0x0000) && (getCPU().isM1Cycle(address))) ||
            ( delayedConfig4000() && (address <= 0x4000) && (address < 0x4010))) {
                // activate delayed configuration
                for (auto i : xrange(0x05, 0x1f)) {
                        configRegs[i] = shadowConfigRegs[i];
                }
        }
}
 
Carnivore2::SubDevice Carnivore2::getSubDevice(word address) const
{
        byte subSlot = 0xff;
 
        if (slotExpanded()) {
                auto page = narrow<byte>(address >> 14);
                byte selectedSubSlot = (subSlotReg >> (2 * page)) & 0x03;
                if (subSlotEnabled(selectedSubSlot)) {
                        subSlot = selectedSubSlot;
                }
        } else {
                for (auto i : xrange(byte(4))) {
                        if (subSlotEnabled(i)) {
                                subSlot = i;
                                break;
                        }
                }
        }
 
        if        (subSlot == (configRegs[0x28] & 0b00'00'00'11) >> 0) {
                return SubDevice::MultiMapper;
        } else if (subSlot == (configRegs[0x28] & 0b00'00'11'00) >> 2) {
                return SubDevice::IDE;
        } else if (subSlot == (configRegs[0x28] & 0b00'11'00'00) >> 4) {
                return SubDevice::MemoryMapper;
        } else if (subSlot == (configRegs[0x28] & 0b11'00'00'00) >> 6) {
                return SubDevice::FmPac;
        } else {
                return SubDevice::Nothing;
        }
}
 
byte Carnivore2::readMem(word address, EmuTime::param time)
{
        if (slotExpanded() && (address == 0xffff)) {
                return subSlotReg ^ 0xff;
        }
        switch (getSubDevice(address)) {
                case SubDevice::MultiMapper:  return readMultiMapperSlot(address, time);
                case SubDevice::IDE:          return readIDESlot(address, time);
                case SubDevice::MemoryMapper: return readMemoryMapperSlot(address);
                case SubDevice::FmPac:        return readFmPacSlot(address);
                default:                      return 0xff;
        }
}
 
byte Carnivore2::peekMem(word address, EmuTime::param time) const
{
        if (slotExpanded() && (address == 0xffff)) {
                return subSlotReg ^ 0xff;
        }
        switch (getSubDevice(address)) {
                case SubDevice::MultiMapper:  return peekMultiMapperSlot(address, time);
                case SubDevice::IDE:          return peekIDESlot(address, time);
                case SubDevice::MemoryMapper: return peekMemoryMapperSlot(address);
                case SubDevice::FmPac:        return peekFmPacSlot(address);
                default:                      return 0xff;
        }
}
 
void Carnivore2::writeMem(word address, byte value, EmuTime::param time)
{
        if (slotExpanded() && (address == 0xffff)) {
                subSlotReg = value;
                // this does not block the writes below
        }
 
        switch (getSubDevice(address)) {
                case SubDevice::MultiMapper:
                        writeMultiMapperSlot(address, value, time);
                        break;
                case SubDevice::IDE:
                        writeIDESlot(address, value, time);
                        break;
                case SubDevice::MemoryMapper:
                        writeMemoryMapperSlot(address, value);
                        break;
                case SubDevice::FmPac:
                        writeFmPacSlot(address, value, time);
                        break;
                default:
                        // unmapped, do nothing
                        break;
        }
}
 
unsigned Carnivore2::getDirectFlashAddr() const
{
        return (configRegs[0x01] <<  0) |
               (configRegs[0x02] <<  8) |
               (configRegs[0x03] << 16);  // already masked to 7 bits
}
 
byte Carnivore2::peekConfigRegister(word address, EmuTime::param time) const
{
        address &= 0x3f;
        if ((0x05 <= address) && (address <= 0x1e)) {
                // only these registers have a shadow counterpart,
                // reads happen from the shadowed version
                return shadowConfigRegs[address];
        } else {
                switch (address) {
                        case 0x04: return flash.peek(getDirectFlashAddr());
                        case 0x1f: return configRegs[0x00]; // mirror 'CardMDR' register
                        case 0x23: return byte(configRegs[address] |
                                               byte(eeprom.read_DO(time)));
                        case 0x2C: return '2';
                        case 0x2D: return '5';
                        case 0x2E: return '0';
                        default:   return configRegs[address];
                }
        }
}
 
byte Carnivore2::readConfigRegister(word address, EmuTime::param time)
{
        address &= 0x3f;
        if (address == 0x04) {
                return flash.read(getDirectFlashAddr());
        } else {
                return peekConfigRegister(address, time);
        }
}
 
static constexpr float volumeLevel(byte volume)
{
        constexpr std::array<byte, 8> tab = {5, 6, 7, 8, 10, 12, 14, 16};
        return narrow<float>(tab[volume & 7]) / 16.0f;
}
 
void Carnivore2::writeSndLVL(byte value, EmuTime::param time)
{
        configRegs[0x22] = value;
        ym2413.setSoftwareVolume(volumeLevel(value >> 3), time);
        scc   .setSoftwareVolume(volumeLevel(value >> 0), time);
}
 
void Carnivore2::writeCfgEEPR(byte value, EmuTime::param time)
{
        configRegs[0x23] = value & 0x0e;
        eeprom.write_DI (value & 2, time);
        eeprom.write_CLK(value & 4, time);
        eeprom.write_CS (value & 8, time);
}
 
void Carnivore2::writePSGCtrl(byte value, EmuTime::param time)
{
        // TODO: PPI clicker
        if ((value ^ configRegs[0x24]) & 0x80) {   // enable changed
                byte ioBase = (configRegs[0x30] & 0x01) ?  0x10 : 0xa0;
                if (value & 0x80) {
                        getCPUInterface().  register_IO_Out(ioBase + 0, this);
                        getCPUInterface().  register_IO_Out(ioBase + 1, this);
                } else {
                        getCPUInterface().unregister_IO_Out(ioBase + 0, this);
                        getCPUInterface().unregister_IO_Out(ioBase + 1, this);
                }
        }
        configRegs[0x24] = value;
        psg.setSoftwareVolume(volumeLevel((value >> 3) & 7), time);
}
 
void Carnivore2::writePSGAlt(byte value)
{
        if ((value ^ configRegs[0x30]) & 0x01) { // ports changed
                if (configRegs[0x24] & 0x80) {
                        byte ioBaseOld = (configRegs[0x30] & 0x01) ? 0x10 : 0xa0;
                        byte ioBaseNew = (value            & 0x01) ? 0x10 : 0xa0;
                        getCPUInterface().unregister_IO_Out(ioBaseOld + 0, this);
                        getCPUInterface().unregister_IO_Out(ioBaseOld + 1, this);
                        getCPUInterface().  register_IO_Out(ioBaseNew + 0, this);
                        getCPUInterface().  register_IO_Out(ioBaseNew + 1, this);
                }
        }
        configRegs[0x30] = value;
}
 
void Carnivore2::writePFXN(byte value)
{
        byte oldPort = idControlPort();
        configRegs[0x35] = 0xf0 | (value & 0b11);
        if (auto newPort = idControlPort(); newPort != oldPort) {
                getCPUInterface().unregister_IO_Out(oldPort, this);
                getCPUInterface().unregister_IO_In (oldPort, this);
                getCPUInterface().  register_IO_Out(newPort, this);
                getCPUInterface().  register_IO_In (newPort, this);
        }
}
 
// check whether each of the 4 bit pairs are unique in the given byte x
[[nodiscard]] static bool bitPairsUnique(uint8_t x)
{
        uint8_t seen = 0;
        for (int i = 0; i < 4; ++i) {
                seen |= 1 << (x & 3);
                x >>= 2;
        }
        return seen == 0b1111;
}
 
void Carnivore2::writeConfigRegister(word address, byte value, EmuTime::param time)
{
        address &= 0x3f;
        if ((0x05 <= address) && (address <= 0x1e)) {
                // shadow registers
                if (address == 0x05) value &= 0x7f;
                if ((address == 0x1e) && ((value & 0x8f) == 0x0f)) return; // ignore write
 
                shadowConfigRegs[address] = value;
                if (!delayedConfig()) configRegs[address] = value;
        } else {
                switch (address) {
                        case 0x03: configRegs[address] = value & 0x7f; break;
                        case 0x04: flash.write(getDirectFlashAddr(), value); break;
                        case 0x1f: configRegs[0x00] = value; break; // mirror 'CardMDR' register
                        case 0x20: configRegs[address] = value & 0x07; break;
                        case 0x22: writeSndLVL(value, time); break;
                        case 0x23: writeCfgEEPR(value, time); break;
                        case 0x24: writePSGCtrl(value, time); break;
                        case 0x30: writePSGAlt(value); break;
                        case 0x35: writePFXN(value); break;
                        case 0x28:
                                if (!bitPairsUnique(value)) {
                                           getCliComm().printWarning(
                                                "Illegal value of ", value,
                                                "written to SLM_cfg register");
                                }
                                [[fallthrough]];
                        default:   configRegs[address] = value; break;
                }
        }
}
 
bool Carnivore2::isConfigReg(word address) const
{
        if (configRegs[0x00] & 0x80) return false; // config regs disabled
        unsigned base = ((configRegs[0x00] & 0x60) << 9) | 0xF80;
        return (base <= address) && (address < (base + 0x40));
}
 
std::pair<unsigned, byte> Carnivore2::decodeMultiMapper(word address) const
{
        // check up to 4 possible banks
        for (auto i : xrange(4)) {
                auto base = subspan<6>(configRegs, (i * 6) + 6); // points to R<i>Mask
                byte mult = base[3];
                if (mult & 8) continue; // bank disabled
 
                byte sizeCode = mult & 7;
                if (sizeCode < 3) continue; // invalid size
 
                // check address
                bool mirroringDisabled = mult & 0x40;
                static constexpr std::array checkMasks = {
                        std::array<byte, 8>{0x00, 0x00, 0x00, 0x30, 0x60, 0xc0, 0x80, 0x00}, // mirroring enabled
                        std::array<byte, 8>{0x00, 0x00, 0x00, 0xf0, 0xe0, 0xc0, 0x80, 0x00}, // mirroring disabled
                };
                byte checkMask = checkMasks[mirroringDisabled][sizeCode];
                if (((address >> 8) & checkMask) != (base[5] & checkMask)) continue;
 
                // found bank
                byte bank = base[2] & base[4];
                unsigned size = 512 << sizeCode; // 7->64k, 6->32k, ..., 3->4k
                unsigned addr = (bank * size) | (address & (size - 1));
                addr += configRegs[0x05] * 0x10000; // 64kB block offset
                addr &= 0x7fffff; // 8MB
                return {addr, mult};
        }
        return {unsigned(-1), byte(-1)};
}
 
bool Carnivore2::sccAccess(word address) const
{
        if (!sccEnabled()) return false;
        if (sccMode & 0x20) {
                // check scc plus
                return (0xb800 <= address) && (address < 0xc000) &&
                       ((sccBank[3] & 0x80) == 0x80);
        } else {
                // check scc compatible
                return (0x9800 <= address) && (address < 0xa000) &&
                       ((sccBank[2] & 0x3f) == 0x3f);
        }
}
 
byte Carnivore2::readMultiMapperSlot(word address, EmuTime::param time)
{
        if (isConfigReg(address)) {
                return readConfigRegister(address, time);
        }
        if (sccAccess(address)) {
                return scc.readMem(narrow_cast<uint8_t>(address & 0xff), time);
        }
 
        auto [addr, mult] = decodeMultiMapper(address);
        if (addr == unsigned(-1)) return 0xff; // unmapped
 
        if (mult & 0x20) {
                return ram[addr & 0x1fffff]; // 2MB
        } else {
                return flash.read(addr);
        }
}
 
byte Carnivore2::peekMultiMapperSlot(word address, EmuTime::param time) const
{
        if (isConfigReg(address)) {
                return peekConfigRegister(address, time);
        }
 
        auto [addr, mult] = decodeMultiMapper(address);
        if (addr == unsigned(-1)) return 0xff; // unmapped
 
        if (mult & 0x20) {
                return ram[addr & 0x1fffff]; // 2MB
        } else {
                return flash.peek(addr);
        }
}
 
void Carnivore2::writeMultiMapperSlot(word address, byte value, EmuTime::param time)
{
        if (isConfigReg(address)) {
                // this blocks writes to switch-region and bank-region
                return writeConfigRegister(address, value, time);
        }
 
        // check (all) 4 bank switch regions
        for (auto i : xrange(4)) {
                auto base = subspan<6>(configRegs, (i * 6) + 6); // points to R<i>Mask
                byte mask = base[0];
                byte addr = base[1];
                byte mult = base[3];
                if (mult & 0x80) { // enable bit in R<i>Mult
                        if (((address >> 8) & mask) == (addr & mask)) {
                                // update actual+shadow reg
                                      configRegs[(i * 6) + 6 + 2] = value;
                                shadowConfigRegs[(i * 6) + 6 + 2] = value;
                        }
                }
        }
 
        auto [addr, mult] = decodeMultiMapper(address);
        if ((addr != unsigned(-1)) && (mult & 0x10)) { // write enable
                if (mult & 0x20) {
                        ram[addr & 0x1fffff] = value; // 2MB
                } else {
                        flash.write(addr, value);
                }
        }
 
        if (sccEnabled() && ((address | 1) == 0xbfff)) {
                // write scc mode register (write-only)
                sccMode = value;
                scc.setChipMode((sccMode & 0x20) ? SCC::SCC_plusmode : SCC::SCC_Compatible);
        }
        if (((sccMode & 0x10) == 0x00) && // note: no check for sccEnabled()
            ((address & 0x1800) == 0x1000)) {
                auto region = narrow<byte>((address >> 13) - 2);
                sccBank[region] = value;
        } else if (sccAccess(address)) {
                scc.writeMem(narrow_cast<uint8_t>(address & 0xff), value, time);
        }
}
 
byte Carnivore2::readIDESlot(word address, EmuTime::param time)
{
        // TODO mirroring is different from SunriseIDE
        if (ideRegsEnabled() && ((address & 0xfe00) == 0x7c00)) {
                // 0x7c00-0x7dff   IDE data register
                switch (address & 1) {
                        case 0: { // data low
                                auto tmp = ideReadData(time);
                                ideRead = narrow_cast<byte>(tmp >> 8);
                                return narrow_cast<byte>(tmp & 0xff);
                        }
                        case 1: // data high
                                return ideRead;
                }
        }
        if (ideRegsEnabled() && ((address & 0xff00) == 0x7e00)) {
                // 0x7e00-0x7eff   IDE registers
                return ideReadReg(address & 0xf, time);
        }
        if ((0x4000 <= address) && (address < 0x8000)) {
                // read IDE flash rom
                unsigned addr = (address & 0x3fff) + (ideBank() * 0x4000) + 0x10000;
                if (readBIOSfromRAM()) {
                        return ram[addr];
                } else {
                        return flash.read(addr);
                }
        }
        return 0xff;
}
 
byte Carnivore2::peekIDESlot(word address, EmuTime::param /*time*/) const
{
        if (ideRegsEnabled() && ((address & 0xfe00) == 0x7c00)) {
                // 0x7c00-0x7dff   IDE data register
                return 0xff; // TODO not yet implemented
        }
        if (ideRegsEnabled() && ((address & 0xff00) == 0x7e00)) {
                // 0x7e00-0x7eff   IDE registers
                return 0xff; // TODO not yet implemented
        }
        if ((0x4000 <= address) && (address < 0x8000)) {
                // read IDE flash rom
                unsigned addr = (address & 0x3fff) + (ideBank() * 0x4000) + 0x10000;
                if (readBIOSfromRAM()) {
                        return ram[addr];
                } else {
                        return flash.peek(addr);
                }
        }
        return 0xff;
}
 
void Carnivore2::writeIDESlot(word address, byte value, EmuTime::param time)
{
        // TODO mirroring is different from SunriseIDE
        if (address == 0x4104) {
                ideControlReg = value;
 
        } else if (ideRegsEnabled() && ((address & 0xfe00) == 0x7c00)) {
                // 0x7c00-0x7dff   IDE data register
                switch (address & 1) {
                        case 0: // data low
                                ideWrite = value;
                                break;
                        case 1: { // data high
                                auto tmp = word((value << 8) | ideWrite);
                                ideWriteData(tmp, time);
                                break;
                        }
                }
 
        } else if (ideRegsEnabled() && ((address & 0xff00) == 0x7e00)) {
                // 0x7e00-0x7eff   IDE registers
                ideWriteReg(address & 0xf, value, time);
        }
}
 
word Carnivore2::ideReadData(EmuTime::param time)
{
        return ideDevices[ideSelectedDevice]->readData(time);
}
 
void Carnivore2::ideWriteData(word value, EmuTime::param time)
{
        ideDevices[ideSelectedDevice]->writeData(value, time);
}
 
byte Carnivore2::ideReadReg(byte reg, EmuTime::param time)
{
        if (reg == 14) reg = 7; // alternate status register
 
        if (ideSoftReset) {
                if (reg == 7) { // read status
                        return 0xff; // busy
                } else { // all others
                        return 0x7f; // don't care
                }
        } else {
                if (reg == 0) {
                        return narrow_cast<byte>(ideReadData(time) & 0xff);
                } else {
                        auto result = ideDevices[ideSelectedDevice]->readReg(reg, time);
                        if (reg == 6) {
                                result = (result & 0xef) | (ideSelectedDevice ? 0x10 : 0x00);
                        }
                        return result;
                }
        }
}
 
void Carnivore2::ideWriteReg(byte reg, byte value, EmuTime::param time)
{
        if (ideSoftReset) {
                if ((reg == 14) && !(value & 0x04)) {
                        // clear SRST
                        ideSoftReset = false;
                }
                // ignore all other writes
        } else {
                if (reg == 0) {
                        ideWriteData(narrow_cast<word>((value << 8) | value), time);
                } else {
                        if ((reg == 14) && (value & 0x04)) {
                                // set SRST
                                ideSoftReset = true;
                                ideDevices[0]->reset(time);
                                ideDevices[1]->reset(time);
                        } else {
                                if (reg == 6) {
                                        ideSelectedDevice = (value & 0x10) ? 1 : 0;
                                }
                                ideDevices[ideSelectedDevice]->writeReg(reg, value, time);
                        }
                }
        }
}
 
bool Carnivore2::isMemMapControl(word address) const
{
        return (port3C & 0x80) &&
               (( (port3C & 0x08) && ((address & 0xc000) == 0x4000)) ||
                (!(port3C & 0x08) && ((address & 0xc000) == 0x8000)));
}
 
unsigned Carnivore2::getMemoryMapperAddress(word address) const
{
        return (address & 0x3fff) +
               0x4000 * memMapRegs[address >> 14] +
               0x100000; // 2nd half of 2MB
}
 
bool Carnivore2::isMemoryMapperWriteProtected(word address) const
{
        auto page = address >> 14;
        return (port3C & (1 << page)) != 0;
}
 
byte Carnivore2::peekMemoryMapperSlot(word address) const
{
        if (isMemMapControl(address)) {
                switch (address & 0xff) {
                case 0x3c:
                        return port3C;
                case 0xfc: case 0xfd: case 0xfe: case 0xff:
                        return memMapRegs[address & 0x03];
                }
        }
        return ram[getMemoryMapperAddress(address)];
}
 
byte Carnivore2::readMemoryMapperSlot(word address)
{
        return peekMemoryMapperSlot(address);
}
 
void Carnivore2::writeMemoryMapperSlot(word address, byte value)
{
        if (isMemMapControl(address)) {
                switch (address & 0xff) {
                case 0x3c:
                        value |= (value & 0x02) << 6; // TODO should be '(.. 0x20) << 2' ???
                        port3C = value;
                        return;
                case 0xfc: case 0xfd: case 0xfe: case 0xff:
                        memMapRegs[address & 0x03] = value & 0x3f;
                        return;
                }
        }
        if (!isMemoryMapperWriteProtected(address)) {
                ram[getMemoryMapperAddress(address)] = value;
        }
}
 
byte Carnivore2::readFmPacSlot(word address)
{
        if (address == 0x7ff6) {
                return fmPacEnable; // enable
        } else if (address == 0x7ff7) {
                return fmPacBank; // bank
        } else if ((0x4000 <= address) && (address < 0x8000)) {
                if (fmPacSramEnabled()) {
                        if (address < 0x5ffe) {
                                return ram[(address & 0x1fff) | 0xfe000];
                        } else if (address == 0x5ffe) {
                                return fmPac5ffe; // always 0x4d
                        } else if (address == 0x5fff) {
                                return fmPac5fff; // always 0x69
                        } else {
                                return 0xff;
                        }
                } else {
                        unsigned addr = (address & 0x3fff) + (0x4000 * fmPacBank) + 0x30000;
                        if (readBIOSfromRAM()) {
                                return ram[addr];
                        } else {
                                return flash.read(addr);
                        }
                }
        }
        return 0xff;
}
 
byte Carnivore2::peekFmPacSlot(word address) const
{
        if (address == 0x7ff6) {
                return fmPacEnable; // enable
        } else if (address == 0x7ff7) {
                return fmPacBank; // bank
        } else if ((0x4000 <= address) && (address < 0x8000)) {
                if (fmPacSramEnabled()) {
                        if (address < 0x5ffe) {
                                return ram[(address & 0x1fff) | 0xfe000];
                        } else if (address == 0x5ffe) {
                                return fmPac5ffe; // always 0x4d
                        } else if (address == 0x5fff) {
                                return fmPac5fff; // always 0x69
                        } else {
                                return 0xff;
                        }
                } else {
                        unsigned addr = (address & 0x3fff) + (0x4000 * fmPacBank) + 0x30000;
                        if (readBIOSfromRAM()) {
                                return ram[addr];
                        } else {
                                return flash.peek(addr);
                        }
                }
        }
        return 0xff;
}
 
void Carnivore2::writeFmPacSlot(word address, byte value, EmuTime::param time)
{
        if ((0x4000 <= address) && (address < 0x5ffe)) {
                if (fmPacSramEnabled()) {
                        ram[(address & 0x1fff) | 0xfe000] = value;
                }
        } else if (address == 0x5ffe) {
                fmPac5ffe = value;
        } else if (address == 0x5fff) {
                fmPac5fff = value;
        } else if (address == one_of(0x7ff4, 0x7ff5)) {
                ym2413.writePort(address & 1, value, time);
        } else if (address == 0x7ff6) {
                fmPacEnable = value & 0x11;
        } else if (address == 0x7ff7) {
                fmPacBank = value & 0x03;
        }
}
 
byte Carnivore2::readIO(word port, EmuTime::param time)
{
        return peekIO(port, time);
}
 
byte Carnivore2::peekIO(word port, EmuTime::param /*time*/) const
{
        // reading ports 0x3c, 0x7c, 0x7d has no effect
        if (memMapReadEnabled() && ((port & 0xfc) == 0xfc)) {
                // memory mapper registers
                return getSelectedSegment(port & 3);
        } else if ((port & 0xff) == idControlPort() && PF0_RV != 0) {
                if (PF0_RV == 1) {
                        return '2';
                } else if (PF0_RV == 2) {
                        return 0x30 | getPrimarySlot();
                }
        }
        return 0xff;
}
 
void Carnivore2::writeIO(word port, byte value, EmuTime::param time)
{
        // note: we only get writes to either PSG ports if they're enabled/configured
        if (((port & 0xff) == 0xa0) || ((port & 0xff) == 0x10)) {
                psgLatch = value & 0x0f;
        } else if ((port & 0xff) == 0xa1 || (port & 0xff) == 0x11) {
                psg.writeRegister(psgLatch, value, time);
        } else if (((port & 0xfe) == 0x7c) &&
            (fmPacPortEnabled1() || fmPacPortEnabled2())) {
                // fm-pac registers
                ym2413.writePort(port & 1, value, time);
        } else if (((port & 0xff) == 0x3c) && writePort3cEnabled()) {
                // only change bit 7
                port3C = (port3C & 0x7F) | (value & 0x80);
 
        } else if ((port & 0xfc) == 0xfc) {
                // memory mapper registers
                memMapRegs[port & 0x03] = value & 0x3f;
                invalidateDeviceRWCache(0x4000 * (port & 0x03), 0x4000);
        } else if ((port & 0xff) == idControlPort()) {
                if (value == 'C') {
                        PF0_RV = 1;
                } else if (value == 'S') {
                        PF0_RV = 2;
                } else if (value == 'H') {
                        configRegs[0x00] |=  1;
                } else if (value == 'R') {
                        configRegs[0x00] &= ~1;
                } else if ('0' <= value && value <= '3') {
                        configRegs[0x00] &= ~(0b11 << 5);
                        configRegs[0x00] |= byte((value - '0') << 5);
                } else if (value == 'A') {
                        shadowConfigRegs[0x1e] &= ~1; // Mconf
                } else if (value == 'M') {
                        shadowConfigRegs[0x1e] |=  1; // Mconf
                } else {
                        // yes, this is the only case where we will reset this
                        PF0_RV = 0;
                }
        }
}
 
byte Carnivore2::getSelectedSegment(byte page) const
{
        return memMapRegs[page];
}
 
// version 1: initial version
// version 2: removed fmPacRegSelect
// version 3: added PSG and user-defined ID and control port I/O
template<typename Archive>
void Carnivore2::serialize(Archive& ar, unsigned version)
{
        ar.template serializeBase<MSXDevice>(*this);
        ar.serialize("flash",            flash,
                     "ram",              ram,
                     "eeprom",           eeprom,
                     "configRegs",       configRegs,
                     "shadowConfigRegs", shadowConfigRegs,
                     "subSlotReg",       subSlotReg,
                     "port3C",           port3C,
 
                     "scc",              scc,
                     "sccMode",          sccMode,
                     "sccBank",          sccBank);
        if (ar.versionAtLeast(version, 3)) {
                ar.serialize("psg",      psg,
                             "psgLatch", psgLatch,
                             "PF0_RV",   PF0_RV);
        } else {
                psgLatch = 0;
                PF0_RV = 0;
        }
 
        ar.serializePolymorphic("master", *ideDevices[0]);
        ar.serializePolymorphic("slave",  *ideDevices[1]);
        ar.serialize("ideSoftReset",      ideSoftReset,
                     "ideSelectedDevice", ideSelectedDevice,
                     "ideControlReg",     ideControlReg,
                     "ideRead",           ideRead,
                     "ideWrite",          ideWrite,
 
                     "memMapRegs",        memMapRegs,
 
                     "ym2413",            ym2413,
                     "fmPacEnable",       fmPacEnable,
                     "fmPacBank",         fmPacBank,
                     "fmPac5ffe",         fmPac5ffe,
                     "fmPac5fff",         fmPac5fff);
 
        if constexpr (Archive::IS_LOADER) {
                auto time = getCurrentTime();
                writeSndLVL (configRegs[0x22], time);
                writeCfgEEPR(configRegs[0x23], time);
                // make sure changes are seen by setting the register to 0 first
                auto backup24 = configRegs[0x24];
                configRegs[0x24] = 0;
                writePSGCtrl(backup24, time);
                auto backup35 = configRegs[0x35];
                configRegs[0x35] = 0xf0;
                writePFXN(backup35);
        }
}
INSTANTIATE_SERIALIZE_METHODS(Carnivore2);
REGISTER_MSXDEVICE(Carnivore2, "Carnivore2");
 
} // namespace openmsx