RomBlocks.cc

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#include "MSXCliComm.hh"
#include "RomBlocks.hh"
#include "SRAM.hh"
#include "narrow.hh"
#include "serialize.hh"
#include "unreachable.hh"
#include "xrange.hh"
#include <bit>
 
namespace openmsx {
 
// minimal attempt to avoid seeing this warning too often
static Sha1Sum alreadyWarnedForSha1Sum;
 
template<unsigned BANK_SIZE>
RomBlocks<BANK_SIZE>::RomBlocks(
                const DeviceConfig& config, Rom&& rom_,
                unsigned debugBankSizeShift)
        : MSXRom(config, std::move(rom_))
        , romBlockDebug(
                *this,  blockNr, 0x0000, 0x10000,
                std::bit_width(BANK_SIZE) - 1, debugBankSizeShift)
{
        static_assert(std::has_single_bit(BANK_SIZE), "BANK_SIZE must be a power of two");
        auto extendedSize = (rom.size() + BANK_SIZE - 1) & ~(BANK_SIZE - 1);
        if (extendedSize != rom.size() && alreadyWarnedForSha1Sum != rom.getOriginalSHA1()) {
                config.getCliComm().printWarning(
                        "(uncompressed) ROM image filesize was not a multiple "
                        "of ", BANK_SIZE / 1024, "kB (which is required for mapper type ",
                        config.findChild("mappertype")->getData(), "), so we "
                        "padded it to be correct. But if the ROM you are "
                        "running was just dumped, the dump is probably not "
                        "complete/correct!");
                alreadyWarnedForSha1Sum = rom.getOriginalSHA1();
        }
        rom.addPadding(extendedSize);
        nrBlocks = narrow<decltype(nrBlocks)>(rom.size() / BANK_SIZE);
        assert((nrBlocks * BANK_SIZE) == rom.size());
 
        // by default no extra mappable memory block
        extraMem = {};
 
        // Default mask: wraps at end of ROM image.
        blockMask = nrBlocks - 1;
        for (auto i : xrange(NUM_BANKS)) {
                setRom(i, 0);
        }
}
 
template<unsigned BANK_SIZE>
RomBlocks<BANK_SIZE>::~RomBlocks() = default;
 
template<unsigned BANK_SIZE>
unsigned RomBlocks<BANK_SIZE>::getBaseSizeAlignment() const
{
        return BANK_SIZE;
}
 
template<unsigned BANK_SIZE>
byte RomBlocks<BANK_SIZE>::peekMem(word address, EmuTime::param /*time*/) const
{
        return bankPtr[address / BANK_SIZE][address & BANK_MASK];
}
 
template<unsigned BANK_SIZE>
byte RomBlocks<BANK_SIZE>::readMem(word address, EmuTime::param time)
{
        return RomBlocks<BANK_SIZE>::peekMem(address, time);
}
 
template<unsigned BANK_SIZE>
const byte* RomBlocks<BANK_SIZE>::getReadCacheLine(word address) const
{
        return &bankPtr[address / BANK_SIZE][address & BANK_MASK];
}
 
template<unsigned BANK_SIZE>
void RomBlocks<BANK_SIZE>::setBank(unsigned region, const byte* adr, byte block)
{
        assert("address passed to setBank() is not serializable" &&
               ((adr == unmappedRead.data()) ||
                ((&rom[0] <= adr) && (adr <= &rom[rom.size() - 1])) ||
                (sram && (&(*sram)[0] <= adr) &&
                               (adr <= &(*sram)[sram->size() - 1])) ||
                (!extraMem.empty() && (&extraMem.front() <= adr) && (adr <= &extraMem.back()))));
        bankPtr[region] = adr;
        blockNr[region] = block; // only for debuggable
        fillDeviceRCache(region * BANK_SIZE, BANK_SIZE, adr);
}
 
template<unsigned BANK_SIZE>
void RomBlocks<BANK_SIZE>::setUnmapped(unsigned region)
{
        setBank(region, unmappedRead.data(), 255);
}
 
template<unsigned BANK_SIZE>
void RomBlocks<BANK_SIZE>::setExtraMemory(std::span<const byte> mem)
{
        extraMem = mem;
}
 
template<unsigned BANK_SIZE>
void RomBlocks<BANK_SIZE>::setRom(unsigned region, unsigned block)
{
        // Note: Some cartridges have a number of blocks that is not a power of 2,
        //       for those we have to make an exception for "block < nrBlocks".
        block = (block < nrBlocks) ? block : block & blockMask;
        if (block < nrBlocks) {
                setBank(region, &rom[block * BANK_SIZE],
                        narrow_cast<byte>(block)); // only used for debug, narrowing is fine
        } else {
                setBank(region, unmappedRead.data(), 255);
        }
}
 
// version 1: initial version
// version 2: added blockNr
template<unsigned BANK_SIZE>
template<typename Archive>
void RomBlocks<BANK_SIZE>::serialize(Archive& ar, unsigned /*version*/)
{
        // skip MSXRom base class
        ar.template serializeBase<MSXDevice>(*this);
 
        if (sram) ar.serialize("sram", *sram);
 
        std::array<size_t, NUM_BANKS> offsets;
        auto romSize = rom.size();
        auto sramSize = sram ? sram->size() : 0;
        if constexpr (Archive::IS_LOADER) {
                ar.serialize("banks", offsets);
                for (auto i : xrange(NUM_BANKS)) {
                        if (offsets[i] == size_t(-1) ||
                            offsets[i] == unsigned(-1)) { // for bw-compat with old savestates
                                bankPtr[i] = unmappedRead.data();
                        } else if (offsets[i] < romSize) {
                                bankPtr[i] = &rom[offsets[i]];
                        } else if (offsets[i] < (romSize + sramSize)) {
                                assert(sram);
                                bankPtr[i] = &(*sram)[offsets[i] - romSize];
                        } else if (offsets[i] < (romSize + sramSize + extraMem.size())) {
                                bankPtr[i] = &extraMem[offsets[i] - romSize - sramSize];
                        } else {
                                // TODO throw
                                UNREACHABLE;
                        }
                }
        } else {
                for (auto i : xrange(NUM_BANKS)) {
                        if (bankPtr[i] == unmappedRead.data()) {
                                offsets[i] = size_t(-1);
                        } else if ((&rom[0] <= bankPtr[i]) &&
                                   (bankPtr[i] <= &rom[romSize - 1])) {
                                offsets[i] = size_t(bankPtr[i] - &rom[0]);
                        } else if (sram && (&(*sram)[0] <= bankPtr[i]) &&
                                   (bankPtr[i] <= &(*sram)[sramSize - 1])) {
                                offsets[i] = size_t(bankPtr[i] - &(*sram)[0] + romSize);
                        } else if (!extraMem.empty() &&
                                   (&extraMem.front() <= bankPtr[i]) &&
                                   (bankPtr[i] <= &extraMem.back())) {
                                offsets[i] = size_t(bankPtr[i] - extraMem.data() + romSize + sramSize);
                        } else {
                                UNREACHABLE;
                        }
                }
                ar.serialize("banks", offsets);
        }
 
        // Commented out because versioning doesn't work correct on subclasses
        // that don't override the serialize() method (e.g. RomPlain)
        /*if (ar.versionAtLeast(version, 2)) {
                ar.serialize("blockNr", blockNr);
        } else {
                assert(Archive::IS_LOADER);
                // set dummy value, anyway only used for debuggable
                ranges::fill(blockNr, 255);
        }*/
}
 
template class RomBlocks<0x1000>;
template class RomBlocks<0x2000>;
template class RomBlocks<0x4000>;
INSTANTIATE_SERIALIZE_METHODS(Rom4kBBlocks);
INSTANTIATE_SERIALIZE_METHODS(Rom8kBBlocks);
INSTANTIATE_SERIALIZE_METHODS(Rom16kBBlocks);
 
} // namespace openmsx