RomBlockDebuggable.hh

Go to the documentation of this file.

#ifndef ROMBLOCKDEBUGGABLE_HH
#define ROMBLOCKDEBUGGABLE_HH
 
#include "SimpleDebuggable.hh"
#include "MSXDevice.hh"
#include <span>
#include <string>
 
namespace openmsx {
 
class RomBlockDebuggableBase : public SimpleDebuggable
{
public:
        explicit RomBlockDebuggableBase(const MSXDevice& device)
                : SimpleDebuggable(
                        device.getMotherBoard(),
                        device.getName() + " romblocks",
                        "Shows for each byte of the mapper which memory block is selected.",
                        0x10000)
        {
        }
 
        // For the 'Debuggable' interface we need to have an 8-bit read(). For most mappers that's sufficient.
        [[nodiscard]] byte read(unsigned address) override {
                return narrow_cast<byte>(readExt(address));
        }
 
        // To support larger than 8 bit segment numbers.
        [[nodiscard]] virtual unsigned readExt(unsigned address) = 0;
 
protected:
        ~RomBlockDebuggableBase() = default;
};
 
// Generic implementation. This (only) works when the segment numbers are stored
// in some byte-array (so limited to 8-bit segment numbers).
class RomBlockDebuggable final : public RomBlockDebuggableBase
{
public:
        RomBlockDebuggable(const MSXDevice& device, std::span<const byte> blockNr_,
                           unsigned startAddress_, unsigned mappedSize_,
                           unsigned bankSizeShift_, unsigned debugShift_ = 0)
                : RomBlockDebuggableBase(device)
                , blockNr(blockNr_.data()), startAddress(startAddress_)
                , mappedSize(mappedSize_), bankSizeShift(bankSizeShift_)
                , debugShift(debugShift_), debugMask(~((1 << debugShift) - 1))
        {
                assert((mappedSize >> bankSizeShift) == blockNr_.size()); // no need to include 'debugMask' here
        }
        RomBlockDebuggable(const MSXDevice& device, std::span<const byte> blockNr_,
                           unsigned startAddress_, unsigned mappedSize_,
                           unsigned bankSizeShift_, unsigned debugShift_,
                           unsigned debugMask_)
                : RomBlockDebuggableBase(device)
                , blockNr(blockNr_.data()), startAddress(startAddress_)
                , mappedSize(mappedSize_), bankSizeShift(bankSizeShift_)
                , debugShift(debugShift_), debugMask(debugMask_)
        {
                assert(((mappedSize >> bankSizeShift) & debugMask) < blockNr_.size()); // here we do need 'debugMask'
        }
 
        [[nodiscard]] unsigned readExt(unsigned address) override
        {
                unsigned addr = address - startAddress;
                if (addr < mappedSize) {
                        byte tmp = blockNr[(addr >> bankSizeShift) & debugMask];
                        return (tmp != 255) ? (tmp >> debugShift) : tmp;
                } else {
                        return unsigned(-1); // outside mapped address space
                }
        }
 
private:
        const byte* blockNr;
        const unsigned startAddress;
        const unsigned mappedSize;
        const unsigned bankSizeShift;
        const unsigned debugShift;
        const unsigned debugMask;
};
 
} // namespace openmsx
 
#endif