mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-07-26 02:29:03 +00:00
83 lines
1.7 KiB
C++
83 lines
1.7 KiB
C++
#pragma once
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#include <array>
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#include <cstdint>
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#include <string>
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#if defined(_M_X64) || defined(_M_IX86 )
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# define HOST_LITTLE_ENDIAN
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#else
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# define HOST_BIG_ENDIAN
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#endif
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namespace EightBit {
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typedef union {
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struct {
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#ifdef HOST_LITTLE_ENDIAN
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uint8_t low;
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uint8_t high;
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#endif
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#ifdef HOST_BIG_ENDIAN
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uint8_t high;
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uint8_t low;
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#endif
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};
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uint16_t word;
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} register16_t;
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class Memory {
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public:
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static uint8_t highByte(uint16_t value) {
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return value >> 8;
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}
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static uint8_t lowByte(uint16_t value) {
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return value & 0xff;
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}
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Memory(uint16_t addressMask);
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register16_t& ADDRESS() { return m_address; }
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uint8_t& DATA() { return *m_data; }
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uint8_t& placeDATA(uint8_t value) {
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m_temporary = value;
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m_data = &m_temporary;
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return DATA();
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}
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uint8_t& referenceDATA(uint8_t& value) {
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m_data = &value;
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return DATA();
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}
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virtual uint8_t peek(uint16_t address) const;
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virtual uint16_t peekWord(uint16_t address) const;
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virtual uint8_t& reference() {
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auto effective = effectiveAddress(ADDRESS().word);
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return m_locked[effective] ? placeDATA(m_bus[effective]) : referenceDATA(m_bus[effective]);
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}
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virtual uint16_t effectiveAddress(uint16_t address) const {
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return address & m_addressMask;
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}
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void clear();
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void loadRom(const std::string& path, uint16_t offset);
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void loadRam(const std::string& path, uint16_t offset);
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protected:
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std::array<uint8_t, 0x10000> m_bus;
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std::array<bool, 0x10000> m_locked;
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uint16_t m_addressMask; // Mirror
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uint8_t m_temporary; // Used to simulate ROM
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register16_t m_address;
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uint8_t* m_data;
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int loadMemory(const std::string& path, uint16_t offset);
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};
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} |