I8255.hh

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// This class implements the Intel 8255 chip
//
// * Only the 8255 is emulated, no surrounding hardware.
//   Use the class I8255Interface to do that.
// * Only mode 0 (basic input/output) is implemented
 
#ifndef I8255_HH
#define I8255_HH
 
#include "EmuTime.hh"
#include "TclCallback.hh"
#include "openmsx.hh"
 
namespace openmsx {
 
class I8255Interface;
class StringSetting;
 
class I8255
{
public:
        I8255(I8255Interface& interface, EmuTime::param time,
              StringSetting& invalidPpiModeSetting);
 
        // CPU side
        void reset(EmuTime::param time);
        [[nodiscard]] byte read(byte port, EmuTime::param time);
        [[nodiscard]] byte peek(byte port, EmuTime::param time) const;
        void write(byte port, byte value, EmuTime::param time);
 
        // Peripheral side, pull-interface
        // (the I8255Interface class implements the push-interface)
        byte getPortA() const;
        byte getPortB() const;
        byte getPortC() const;
 
        template<typename Archive>
        void serialize(Archive& ar, unsigned version);
 
private:
        [[nodiscard]] byte readPortA(EmuTime::param time);
        [[nodiscard]] byte readPortB(EmuTime::param time);
        [[nodiscard]] byte readPortC(EmuTime::param time);
        [[nodiscard]] byte readControlPort(EmuTime::param time) const;
        [[nodiscard]] byte peekPortA(EmuTime::param time) const;
        [[nodiscard]] byte peekPortB(EmuTime::param time) const;
        [[nodiscard]] byte peekPortC(EmuTime::param time) const;
        void writePortA(byte value, EmuTime::param time);
        void writePortB(byte value, EmuTime::param time);
        void writePortC(byte value, EmuTime::param time);
        void writeControlPort(byte value, EmuTime::param time);
 
        [[nodiscard]] byte readC0(EmuTime::param time);
        [[nodiscard]] byte readC1(EmuTime::param time);
        [[nodiscard]] byte peekC0(EmuTime::param time) const;
        [[nodiscard]] byte peekC1(EmuTime::param time) const;
        void outputPortA(byte value, EmuTime::param time);
        void outputPortB(byte value, EmuTime::param time);
        void outputPortC(byte value, EmuTime::param time);
 
private:
        I8255Interface& interface;
 
        byte control;
        byte latchPortA;
        byte latchPortB;
        byte latchPortC;
 
        TclCallback ppiModeCallback;
};
 
} // namespace openmsx
 
#endif