CheckedRam.cc

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#include "CheckedRam.hh"
#include "MSXCPU.hh"
#include "MSXMotherBoard.hh"
#include "DeviceConfig.hh"
#include "GlobalSettings.hh"
#include "StringSetting.hh"
#include "narrow.hh"
#include "xrange.hh"
#include <cassert>
 
namespace openmsx {
 
CheckedRam::CheckedRam(const DeviceConfig& config, const std::string& name,
                       static_string_view description, size_t size)
        : ram(config, name, description, size)
        , msxcpu(config.getMotherBoard().getCPU())
        , umrCallback(config.getGlobalSettings().getUMRCallBackSetting())
{
        umrCallback.getSetting().attach(*this);
        init();
}
 
CheckedRam::~CheckedRam()
{
        umrCallback.getSetting().detach(*this);
}
 
byte CheckedRam::read(size_t addr)
{
        size_t line = addr >> CacheLine::BITS;
        if (!completely_initialized_cacheline[line]) [[unlikely]] {
                if (uninitialized[line][addr &  CacheLine::LOW]) [[unlikely]] {
                        umrCallback.execute(narrow<int>(addr), ram.getName());
                }
        }
        return ram[addr];
}
 
const byte* CheckedRam::getReadCacheLine(size_t addr) const
{
        return (completely_initialized_cacheline[addr >> CacheLine::BITS])
             ? &ram[addr] : nullptr;
}
 
byte* CheckedRam::getWriteCacheLine(size_t addr) const
{
        return (completely_initialized_cacheline[addr >> CacheLine::BITS])
             ? const_cast<byte*>(&ram[addr]) : nullptr;
}
 
byte* CheckedRam::getRWCacheLines(size_t addr, size_t size) const
{
        // TODO optimize
        size_t num = size >> CacheLine::BITS;
        size_t first = addr >> CacheLine::BITS;
        for (auto i : xrange(num)) {
                if (!completely_initialized_cacheline[first + i]) {
                        return nullptr;
                }
        }
        return const_cast<byte*>(&ram[addr]);
}
 
void CheckedRam::write(size_t addr, const byte value)
{
        size_t line = addr >> CacheLine::BITS;
        if (!completely_initialized_cacheline[line]) [[unlikely]] {
                uninitialized[line][addr & CacheLine::LOW] = false;
                if (uninitialized[line].none()) [[unlikely]] {
                        completely_initialized_cacheline[line] = true;
                        // This invalidates way too much stuff. But because
                        // (locally) we don't know exactly how this class ie
                        // being used in the MSXDevice, there's no easy way to
                        // figure out what exactly should be invalidated.
                        //
                        // This is anyway only a debug feature (usually it's
                        // not in use), therefor it's OK to implement this in a
                        // easy/slow way rather than complex/fast.
                        msxcpu.invalidateAllSlotsRWCache(0, 0x10000);
                }
        }
        ram[addr] = value;
}
 
void CheckedRam::clear()
{
        ram.clear();
        init();
}
 
void CheckedRam::init()
{
        auto lines = ram.size() / CacheLine::SIZE;
        if (umrCallback.getValue().empty()) {
                // there is no callback function,
                // do as if everything is initialized
                completely_initialized_cacheline.assign(lines, true);
                // 'uninitialized' won't be accessed, so don't even allocate
        } else {
                // new callback function, forget about initialized areas
                completely_initialized_cacheline.assign(lines, false);
 
                std::bitset<CacheLine::SIZE> allTrue;
                allTrue.set();
                uninitialized.assign(lines, allTrue);
        }
        msxcpu.invalidateAllSlotsRWCache(0, 0x10000);
}
 
void CheckedRam::update(const Setting& setting) noexcept
{
        assert(&setting == &umrCallback.getSetting());
        (void)setting;
        init();
}
 
} // namespace openmsx