TrackedRam.hh

Go to the documentation of this file.

#ifndef TRACKED_RAM_HH
#define TRACKED_RAM_HH
 
#include "Ram.hh"
 
namespace openmsx {
 
// Ram with dirty tracking
class TrackedRam
{
public:
        // Most methods simply delegate to the internal 'ram' object.
        TrackedRam(const DeviceConfig& config, const std::string& name,
                   static_string_view description, size_t size)
                : ram(config, name, description, size) {}
 
        TrackedRam(const XMLElement& xml, size_t size)
                : ram(xml, size) {}
 
        [[nodiscard]] size_t size() const {
                return ram.size();
        }
 
        [[nodiscard]] const std::string& getName() const {
                return ram.getName();
        }
 
        // Allow read via an explicit read() method or via backdoor access.
        [[nodiscard]] byte read(size_t addr) const {
                return ram[addr];
        }
 
        [[nodiscard]] const byte& operator[](size_t addr) const {
                return ram[addr];
        }
 
        [[nodiscard]] auto begin() const { return ram.begin(); }
        [[nodiscard]] auto end()   const { return ram.end(); }
 
        // Only allow write/clear via an explicit method.
        void write(size_t addr, byte value) {
                writeSinceLastReverseSnapshot = true;
                ram[addr] = value;
        }
 
        void clear(byte c = 0xff) {
                writeSinceLastReverseSnapshot = true;
                ram.clear(c);
        }
 
        // Some write operations are more efficient in bulk. For those this
        // method can be used. It will mark the ram as dirty on each
        // invocation, so the resulting pointer (although the same each time)
        // should not be reused for multiple (distinct) bulk write operations.
        [[nodiscard]] std::span<byte> getWriteBackdoor() {
                writeSinceLastReverseSnapshot = true;
                return {ram.data(), size()};
        }
 
        template<typename Archive>
        void serialize(Archive& ar, unsigned version);
 
private:
        Ram ram;
        bool writeSinceLastReverseSnapshot = true;
};
 
} // namespace openmsx
 
#endif