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k15_gb_emulator.h
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k15_gb_emulator.h
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#define K15_ENABLE_EMULATOR_DEBUG_FEATURES 0
#define K15_BREAK_ON_UNKNOWN_INSTRUCTION 1
#define K15_BREAK_ON_ILLEGAL_INSTRUCTION 1
#define K15_GB_EMULATOR
#include "k15_types.h"
#include "k15_gb_opcodes.h"
#include "k15_gb_font.h"
#ifdef _MSC_VER
# pragma warning( push )
# pragma warning( disable : 4334)
#endif
#define MINIZ_USE_UNALIGNED_LOADS_AND_STORES 1
#define MINIZ_LITTLE_ENDIAN 1
#define MINIZ_HAS_64BIT_REGISTERS 1
#define MINIZ_NO_STDIO
#define MINIZ_NO_TIME
#define MINIZ_NO_DEFLATE_APIS
#define MINIZ_NO_ARCHIVE_WRITING_APIS
#define MINIZ_NO_MALLOC
#include "../thirdparty/miniz/miniz.c"
#ifdef _MSC_VER
# pragma warning( pop )
#endif
static constexpr uint8_t gbStateVersion = 6;
static constexpr uint32_t gbStateFourCC = FourCC( 'K', 'G', 'B', 'C' ); //FK: FourCC of state files
static constexpr uint8_t gbNintendoLogo[] = { 0xCE, 0xED, 0x66, 0x66, 0xCC, 0x0D, 0x00, 0x0B, 0x03, 0x73, 0x00, 0x83, 0x00, 0x0C, 0x00, 0x0D, 0x00, 0x08, 0x11, 0x1F, 0x88, 0x89, 0x00, 0x0E, 0xDC, 0xCC, 0x6E, 0xE6, 0xDD, 0xDD, 0xD9, 0x99, 0xBB, 0xBB, 0x67, 0x63, 0x6E, 0x0E, 0xEC, 0xCC, 0xDD, 0xDC, 0x99, 0x9F, 0xBB, 0xB9, 0x33, 0x3E };
static constexpr char gbRamFileExtension[] = ".k15_gb_ram";
static constexpr char gbStateFileExtension[] = ".k15_gb_state";
static constexpr uint32_t gbCyclesPerFrame = 70224u;
static constexpr uint32_t gbSerialClockCyclesPerBitTransfer = 512u;
static constexpr uint32_t gbEmulatorFrameRate = 60u;
static constexpr uint8_t gbOAMSizeInBytes = 0x9Fu;
static constexpr uint8_t gbDMACycleCount = 160u;
static constexpr uint8_t gbSpriteHeight = 16u;
static constexpr uint8_t gbTileResolutionInPixels = 8u; //FK: Tiles are 8x8 pixels
static constexpr uint8_t gbHalfTileResolutionInPixels = 4u;
static constexpr uint8_t gbHorizontalResolutionInPixels = 160u;
static constexpr uint8_t gbVerticalResolutionInPixels = 144u;
static constexpr uint8_t gbHorizontalResolutionInTiles = gbHorizontalResolutionInPixels / gbTileResolutionInPixels;
static constexpr uint8_t gbVerticalResolutionInTiles = gbVerticalResolutionInPixels / gbTileResolutionInPixels;
static constexpr uint8_t gbBackgroundTileCount = 32u; //FK: BG maps are 32x32 tiles
static constexpr uint8_t gbTileSizeInBytes = 16u; //FK: 8x8 pixels with 2bpp
static constexpr uint8_t gbOpcodeHistoryBufferCapacity = 255u;
static constexpr uint8_t gbObjectAttributeCapacity = 40u;
static constexpr uint8_t gbSpritesPerScanline = 10u; //FK: the hardware allowed no more than 10 sprites per scanline
static constexpr uint8_t gbFrameBufferScanlineSizeInBytes = gbHorizontalResolutionInPixels / 4;
static constexpr size_t gbFrameBufferSizeInBytes = gbFrameBufferScanlineSizeInBytes * gbVerticalResolutionInPixels;
static constexpr uint8_t gbFrameBufferCount = 2;
static constexpr size_t gbMappedMemorySizeInBytes = 0x10000;
static constexpr size_t gbCompressionTokenSizeInBytes = 1;
static constexpr size_t gbRamBankSizeInBytes = Kbyte( 8 );
static constexpr size_t gbRomBankSizeInBytes = Kbyte( 16 );
static constexpr size_t gbMaxRomSizeInBytes = Mbyte( 8 );
static constexpr size_t gbMinRomSizeInBytes = Kbyte( 32 );
typedef uint32_t GBEmulatorInstanceEventMask;
enum
{
K15_GB_NO_EVENT_FLAG = 0x00,
K15_GB_VBLANK_EVENT_FLAG = 0x01,
K15_GB_STATE_SAVED_EVENT_FLAG = 0x02,
K15_GB_STATE_LOADED_EVENT_FLAG = 0x04,
};
enum
{
K15_GB_COUNTER_FREQUENCY_BIT_00 = 9,
K15_GB_COUNTER_FREQUENCY_BIT_01 = 3,
K15_GB_COUNTER_FREQUENCY_BIT_10 = 5,
K15_GB_COUNTER_FREQUENCY_BIT_11 = 7,
};
enum GBStateLoadResult
{
K15_GB_STATE_LOAD_SUCCESS = 0,
K15_GB_STATE_LOAD_FAILED_OLD_VERSION,
K15_GB_STATE_LOAD_FAILED_INCOMPATIBLE_DATA,
K15_GB_STATE_LOAD_FAILED_WRONG_ROM
};
enum GBMapCartridgeResult
{
K15_GB_CARTRIDGE_MAPPED_SUCCESSFULLY = 0,
K15_GB_CARTRIDGE_TYPE_UNSUPPORTED
};
enum GBMappedIOAdresses
{
K15_GB_MAPPED_IO_ADDRESS_JOYP = 0xFF00,
K15_GB_MAPPED_IO_ADDRESS_SC = 0xFF02,
K15_GB_MAPPED_IO_ADDRESS_DIV = 0xFF04,
K15_GB_MAPPED_IO_ADDRESS_TIMA = 0xFF05,
K15_GB_MAPPED_IO_ADDRESS_TMA = 0xFF06,
K15_GB_MAPPED_IO_ADDRESS_TAC = 0xFF07,
K15_GB_MAPPED_IO_ADDRESS_NR10 = 0xFF10,
K15_GB_MAPPED_IO_ADDRESS_NR11 = 0xFF11,
K15_GB_MAPPED_IO_ADDRESS_NR12 = 0xFF12,
K15_GB_MAPPED_IO_ADDRESS_NR13 = 0xFF13,
K15_GB_MAPPED_IO_ADDRESS_NR14 = 0xFF14,
K15_GB_MAPPED_IO_ADDRESS_NR21 = 0xFF16,
K15_GB_MAPPED_IO_ADDRESS_NR22 = 0xFF17,
K15_GB_MAPPED_IO_ADDRESS_NR23 = 0xFF18,
K15_GB_MAPPED_IO_ADDRESS_NR24 = 0xFF19,
K15_GB_MAPPED_IO_ADDRESS_NR30 = 0xFF1A,
K15_GB_MAPPED_IO_ADDRESS_NR31 = 0xFF1B,
K15_GB_MAPPED_IO_ADDRESS_NR32 = 0xFF1C,
K15_GB_MAPPED_IO_ADDRESS_NR33 = 0xFF1D,
K15_GB_MAPPED_IO_ADDRESS_NR34 = 0xFF1E,
K15_GB_MAPPED_IO_ADDRESS_NR41 = 0xFF20,
K15_GB_MAPPED_IO_ADDRESS_NR42 = 0xFF21,
K15_GB_MAPPED_IO_ADDRESS_NR43 = 0xFF22,
K15_GB_MAPPED_IO_ADDRESS_NR44 = 0xFF23,
K15_GB_MAPPED_IO_ADDRESS_NR50 = 0xFF24,
K15_GB_MAPPED_IO_ADDRESS_NR51 = 0xFF25,
K15_GB_MAPPED_IO_ADDRESS_NR52 = 0xFF26,
K15_GB_MAPPED_IO_ADDRESS_LCDC = 0xFF40,
K15_GB_MAPPED_IO_ADDRESS_STAT = 0xFF41,
K15_GB_MAPPED_IO_ADDRESS_DMA = 0xFF46,
K15_GB_MAPPED_IO_ADDRESS_BGP = 0xFF47,
K15_GB_MAPPED_IO_ADDRESS_OBP0 = 0xFF48,
K15_GB_MAPPED_IO_ADDRESS_OBP1 = 0xFF49,
K15_GB_MAPPED_IO_ADDRESS_IF = 0xFF0F,
K15_GB_MAPPED_IO_ADDRESS_IE = 0xFFFF
};
struct GBEmulatorJoypadState
{
union
{
struct
{
union
{
struct
{
uint8_t a : 1;
uint8_t b : 1;
uint8_t select : 1;
uint8_t start : 1;
};
uint8_t actionButtonMask;
};
union
{
struct
{
uint8_t right : 1;
uint8_t left : 1;
uint8_t up : 1;
uint8_t down : 1;
};
uint8_t dpadButtonMask;
};
};
uint16_t value = 0;
};
};
struct GBCpuFlags
{
union
{
struct
{
uint8_t NOP : 4;
uint8_t C : 1;
uint8_t H : 1;
uint8_t N : 1;
uint8_t Z : 1;
};
uint8_t value;
};
};
struct GBCpuRegisters
{
union
{
struct
{
GBCpuFlags F;
uint8_t A;
};
uint16_t AF;
};
union
{
struct
{
uint8_t C;
uint8_t B;
};
uint16_t BC;
};
union
{
struct
{
uint8_t E;
uint8_t D;
};
uint16_t DE;
};
union
{
struct
{
uint8_t L;
uint8_t H;
};
uint16_t HL;
};
uint16_t SP;
uint16_t PC;
};
struct GBCpuStateFlags
{
uint8_t IME : 1;
uint8_t halt : 1;
uint8_t stop : 1;
uint8_t dma : 1;
uint8_t haltBug : 1;
uint8_t pendingEI : 1;
};
struct GBCpuState
{
uint8_t* pIE;
uint8_t* pIF;
GBCpuRegisters registers;
uint32_t cycleCounter;
uint16_t dmaAddress;
uint8_t dmaCycleCounter;
GBCpuStateFlags flags; //FK: not to be confused with GBCpuRegisters::F
};
struct GBSerialState
{
uint8_t* pSerialTransferData = nullptr;
uint8_t* pSerialTransferControl = nullptr;
uint8_t shiftIndex = 0u;
uint8_t inByte = 0xFFu;
uint8_t initiateTransfer = 0u;
uint8_t useInternalClock = 0u;
uint32_t cycleCounter = 0u;
};
enum GBCartridgeType : uint8_t
{
ROM_ONLY = 0x00,
ROM_MBC1 = 0x01,
ROM_MBC1_RAM = 0x02,
ROM_MBC1_RAM_BATT = 0x03,
ROM_MBC2 = 0x05,
ROM_MBC2_BATT = 0x06,
ROM_RAM = 0x08,
ROM_RAM_BATT = 0x09,
ROM_MMMD1 = 0x0B,
ROM_MMMD1_SRAM = 0x0C,
ROM_MMMD1_SRAM_BATT = 0x0D,
ROM_MBC3_TIMER_BATT = 0x0F,
ROM_MBC3_TIMER_RAM_BATT = 0x10,
ROM_MBC3 = 0x11,
ROM_MBC3_RAM = 0x12,
ROM_MBC3_RAM_BATT = 0x13,
ROM_MBC5 = 0x19,
ROM_MBC5_RAM = 0x1A,
ROM_MBC5_RAM_BATT = 0x1B,
ROM_MBC5_RUMBLE = 0x1C,
ROM_MBC5_RUMBLE_SRAM = 0x1D,
ROM_MBC5_RUMBLE_SRAM_BATT = 0x1E,
POCKET_CAMERA = 0x1F,
BANDAI_TAMA5 = 0xFD,
HUDSON_HUC_3 = 0xFE,
};
enum GBCpuInterrupt : uint8_t
{
VBlankInterrupt = (1<<0),
LCDStatInterrupt = (1<<1),
TimerInterrupt = (1<<2),
SerialInterrupt = (1<<3),
JoypadInterrupt = (1<<4)
};
struct GBObjectAttributeFlags
{
uint8_t GBCpaletteNumber : 3;
uint8_t GBCtileVramBank : 1;
uint8_t paletteNumber : 1;
uint8_t xflip : 1;
uint8_t yflip : 1;
uint8_t bgOverObj : 1;
};
struct GBObjectAttributes
{
uint8_t y;
uint8_t x;
uint8_t tileIndex;
GBObjectAttributeFlags flags;
};
struct GBLcdControl
{
uint8_t bgEnable : 1;
uint8_t objEnable : 1;
uint8_t objSize : 1;
uint8_t bgTileMapArea : 1;
uint8_t bgAndWindowTileDataArea : 1;
uint8_t windowEnable : 1;
uint8_t windowTileMapArea : 1;
uint8_t enable : 1;
};
struct GBPalette
{
uint8_t color0 : 2;
uint8_t color1 : 2;
uint8_t color2 : 2;
uint8_t color3 : 2;
};
struct GBLcdStatus
{
uint8_t mode : 2;
uint8_t LycEqLyFlag : 1;
uint8_t enableMode0HBlankInterrupt : 1;
uint8_t enableMode1VBlankInterrupt : 1;
uint8_t enableMode2OAMInterrupt : 1;
uint8_t enableLycEqLyInterrupt : 1;
};
struct GBLcdRegisters
{
GBLcdStatus* pStatus;
uint8_t* pScy;
uint8_t* pScx;
uint8_t* pLy;
uint8_t* pLyc;
uint8_t* pWy;
uint8_t* pWx;
};
struct GBPpuFlags
{
uint8_t drawObjects : 1;
uint8_t drawBackground : 1;
uint8_t drawWindow : 1;
};
struct GBPpuState
{
GBPpuFlags flags;
GBLcdRegisters lcdRegisters;
GBObjectAttributes* pOAM;
GBLcdControl* pLcdControl;
GBPalette* pPalettes;
uint8_t* pBackgroundOrWindowTileIds[ 2 ];
uint8_t* pTileBlocks[ 3 ];
uint8_t* pGBFrameBuffers[ gbFrameBufferCount ];
uint32_t cycleCounter;
uint32_t dotCounter;
GBObjectAttributes scanlineSprites[ gbSpritesPerScanline ];
uint8_t objectMonochromePlatte[ 8 ];
uint8_t backgroundMonochromePalette[ 4 ];
uint8_t scanlineSpriteCounter;
uint8_t activeFrameBufferIndex;
};
enum GBMemoryAccess
{
GBMemoryAccess_None = 0,
GBMemoryAccess_Written = 1,
GBMemoryAccess_Read = 2
};
struct GBMemoryMapper
{
uint8_t* pBaseAddress;
uint8_t* pRom0Bank;
uint8_t* pRom1Bank;
uint8_t* pVideoRAM;
uint8_t* pRamBankSwitch;
uint8_t* pSpriteAttributes;
uint16_t lastAddressWrittenTo;
uint16_t lastAddressReadFrom;
uint8_t lastValueWritten;
GBMemoryAccess memoryAccess;
GBLcdStatus lcdStatus; //FK: Mirror lcd status to check whether we can read from VRAM and/or OAM
bool8_t lcdEnabled; //FK: Mirror lcd enabled flag to check whether we can read from VRAM and/or OAM
bool8_t dmaActive; //FK: Mirror dma flag to check whether we can read only from HRAM
bool8_t ramEnabled; //FK: Mirror ram enabled flag to check whether we can write to external RAM
};
struct GBRomHeader
{
uint8_t reserved[4]; //FK: Entry point
uint8_t nintendoLogo[48];
union
{
uint8_t gameTitle[16];
struct
{
uint8_t padding[11];
uint8_t manufactures[4];
uint8_t colorCompatibility;
};
};
uint8_t licenseHigh;
uint8_t licenseLow;
uint8_t superGameBoyCompatibility;
GBCartridgeType cartridgeType;
uint8_t romSize;
uint8_t ramSize;
uint8_t destinationCode;
uint8_t licenseCode;
uint8_t maskRomVersion;
uint8_t headerChecksum;
uint8_t checksumHigher;
uint8_t checksumLower;
};
#if K15_ENABLE_EMULATOR_DEBUG_FEATURES == 1
struct GBEmulatorDebugSettings
{
uint8_t enableBreakAtProgramCounter : 1;
uint8_t enableBreakAtOpcode : 1;
uint8_t enableBreakAtMemoryReadFromAddress : 1;
uint8_t enableBreakAtMemoryWriteToAddress : 1;
};
struct GBOpcodeHistoryElement
{
uint8_t opcode;
uint16_t address;
GBCpuRegisters registers;
};
struct GBEmulatorDebug
{
GBOpcodeHistoryElement opcodeHistory[ gbOpcodeHistoryBufferCapacity ];
uint8_t pauseExecution : 1;
uint8_t continueExecution : 1;
uint8_t runForOneInstruction : 1;
uint8_t runSingleFrame : 1;
uint8_t pauseAtBreakpoint : 1;
uint16_t breakpointAddress;
uint8_t opcodeHistorySize;
};
#endif
struct GBEmulatorInstanceFlags
{
union
{
struct
{
uint8_t vblank : 1;
uint8_t ramAccessed : 1;
};
uint8_t value;
};
};
struct GBTimerState
{
uint8_t* pDivider;
uint8_t* pCounter;
uint8_t* pModulo;
uint8_t* pControl;
uint16_t internalDivCounter;
uint8_t counterFrequencyBit : 4;
uint8_t enableCounter : 1;
uint8_t timerOverflow : 1;
uint8_t timerLoading : 1;
};
struct GBCartridge
{
const uint8_t* pRomBaseAddress;
uint8_t* pRamBaseAddress;
uint32_t romSizeInBytes;
uint32_t ramSizeInBytes;
uint16_t mappedRom0BankNumber;
uint16_t mappedRom1BankNumber;
uint16_t romBankCount;
uint8_t highBankValue;
uint8_t lowBankValue;
GBRomHeader header;
uint8_t ramBankCount;
uint8_t mappedRamBankNumber;
uint8_t ramEnabled : 1;
uint8_t bankingMode : 1;
};
struct GBApuSquareWaveChannel1
{
uint8_t lengthTimer;
};
struct GBApuSquareWaveChannel2
{
uint8_t lengthTimer;
};
struct GBApuWaveChannel
{
uint8_t* pWavePattern;
uint8_t lengthTimer;
uint8_t currentSample;
uint16_t samplePosition;
uint16_t cycleCount;
uint16_t frequencyCycleCountTarget;
uint8_t channelEnabled : 1;
uint8_t volumeShift : 3;
};
struct GBApuNoiseChannel
{
uint8_t lengthTimer;
};
struct GBApuFrameSequencer
{
uint16_t cycleCounter;
uint8_t clockCounter;
};
struct GBApuState
{
GBApuSquareWaveChannel1 squareWaveChannel1;
GBApuSquareWaveChannel2 squareWaveChannel2;
GBApuWaveChannel waveChannel;
GBApuNoiseChannel noiseChannel;
GBApuFrameSequencer frameSequencer;
};
struct GBEmulatorInstance
{
GBCpuState* pCpuState;
GBPpuState* pPpuState;
GBApuState* pApuState;
GBTimerState* pTimerState;
GBMemoryMapper* pMemoryMapper;
GBSerialState* pSerialState;
GBCartridge* pCartridge;
GBEmulatorJoypadState joypadState;
GBEmulatorInstanceFlags flags;
#if K15_ENABLE_EMULATOR_DEBUG_FEATURES == 1
GBEmulatorDebug debug;
#endif
};
struct GBEmulatorState
{
GBCpuState cpuState;
GBPpuState ppuState;
GBApuState apuState;
GBTimerState timerState;
GBSerialState serialState;
GBCartridge cartridge;
uint16_t mappedRom0BankNumber;
uint16_t mappedRom1BankNumber;
uint8_t mappedRamBankNumber;
};
const uint8_t* getFontGlyphPixel( char glyph )
{
//FK: bitmap font starts with space
RuntimeAssert( glyph >= 32 );
const char glyphIndex = glyph - 32;
const uint8_t rowIndex = glyphIndex / glyphRowCount;
const uint8_t columnIndex = glyphIndex % glyphRowCount;
const uint8_t y = ( fontPixelDataHeightInPixels - 1 ) - ( rowIndex * glyphHeightInPixels );
const uint8_t x = columnIndex * glyphWidthInPixels;
return fontPixelData + (x + y * fontPixelDataWidthInPixels) * 3;
}
static inline uint32_t castSizeToUint32( const size_t value )
{
RuntimeAssert( value < 0xFFFFFFFF );
return ( uint32_t )value;
}
static inline int32_t castSizeToInt32( const size_t value )
{
RuntimeAssert( value < INT32_MAX && value > INT32_MIN );
return (int32_t)value;
}
bool8_t isInVideoRamAddressRange( const uint16_t address )
{
return address >= 0x8000 && address < 0xA000;
}
bool8_t isInOAMAddressRange( const uint16_t address )
{
return address >= 0xFE00 && address < 0xFEA0;
}
bool8_t isInCartridgeRomAddressRange( const uint16_t address )
{
return address >= 0x0000 && address < 0x8000;
}
bool8_t isInMBC1BankingModeSelectRegisterRange( const uint16_t address )
{
return address >= 0x6000 && address < 0x8000;
}
bool8_t isInMBC1RamBankNumberRegisterRange( const uint16_t address )
{
return address >= 0x4000 && address < 0x6000;
}
bool8_t isInMBC1RomBankNumberRegisterRange( const uint16_t address )
{
return address >= 0x2000 && address < 0x4000;
}
bool8_t isInMBC5LowRomBankNumberRegisterRange( const uint16_t address )
{
return address >= 0x2000 && address < 0x3000;
}
bool8_t isInMBC5HighRomBankNumberRegisterRange( const uint16_t address )
{
return address >= 0x3000 && address < 0x4000;
}
bool8_t isInMBC5RamBankNumberRegisterRange( const uint16_t address )
{
return address >= 0x4000 && address < 0x6000;
}
bool8_t isInRamEnableRegisterRange( const uint16_t address )
{
return address >= 0x0000 && address < 0x2000;
}
bool8_t isInExternalRamRange( const uint16_t address )
{
return address >= 0xA000 && address < 0xC000;
}
bool8_t isInIORegisterRange( const uint16_t address )
{
return address >= 0xFF00 && address < 0xFF80;
}
bool8_t isInHighRamAddressRange( const uint16_t address )
{
return address >= 0xFF80 && address < 0xFFFF;
}
bool8_t isInWorkRamRange( const uint16_t address )
{
return address >= 0xC000 && address < 0xCFFF;
}
bool8_t isInEchoRamRange( const uint16_t address )
{
return address >= 0xE000 && address < 0xFDFF;
}
void patchIOCartridgeMappedMemoryPointer( GBMemoryMapper* pMemoryMapper, GBCartridge* pCartridge )
{
pCartridge->pRomBaseAddress = pMemoryMapper->pBaseAddress;
}
void patchIOCpuMappedMemoryPointer( GBMemoryMapper* pMemoryMapper, GBCpuState* pState )
{
pState->pIE = pMemoryMapper->pBaseAddress + 0xFFFF;
pState->pIF = pMemoryMapper->pBaseAddress + 0xFF0F;
}
void patchIOTimerMappedMemoryPointer( GBMemoryMapper* pMemoryMapper, GBTimerState* pTimerState )
{
pTimerState->pDivider = pMemoryMapper->pBaseAddress + 0xFF04;
pTimerState->pCounter = pMemoryMapper->pBaseAddress + 0xFF05;
pTimerState->pModulo = pMemoryMapper->pBaseAddress + 0xFF06;
pTimerState->pControl = pMemoryMapper->pBaseAddress + 0xFF07;
}
void patchIOSerialMappedMemoryPointer( GBMemoryMapper* pMemoryMapper, GBSerialState* pSerialState )
{
pSerialState->pSerialTransferData = pMemoryMapper->pBaseAddress + 0xFF01;
pSerialState->pSerialTransferControl = pMemoryMapper->pBaseAddress + 0xFF02;
}
void patchIOPpuMappedMemoryPointer( GBMemoryMapper* pMemoryMapper, GBPpuState* pPpuState )
{
pPpuState->pOAM = (GBObjectAttributes*)(pMemoryMapper->pBaseAddress + 0xFE00);
pPpuState->pLcdControl = (GBLcdControl*)(pMemoryMapper->pBaseAddress + 0xFF40);
pPpuState->pPalettes = (GBPalette*)(pMemoryMapper->pBaseAddress + 0xFF47);
pPpuState->pTileBlocks[0] = pMemoryMapper->pBaseAddress + 0x8000;
pPpuState->pTileBlocks[1] = pMemoryMapper->pBaseAddress + 0x8080;
pPpuState->pTileBlocks[2] = pMemoryMapper->pBaseAddress + 0x9000;
pPpuState->pBackgroundOrWindowTileIds[0] = pMemoryMapper->pBaseAddress + 0x9800;
pPpuState->pBackgroundOrWindowTileIds[1] = pMemoryMapper->pBaseAddress + 0x9C00;
pPpuState->dotCounter = 0;
pPpuState->cycleCounter = 0;
pPpuState->lcdRegisters.pStatus = (GBLcdStatus*)(pMemoryMapper->pBaseAddress + 0xFF41);
pPpuState->lcdRegisters.pScy = pMemoryMapper->pBaseAddress + 0xFF42;
pPpuState->lcdRegisters.pScx = pMemoryMapper->pBaseAddress + 0xFF43;
pPpuState->lcdRegisters.pLy = pMemoryMapper->pBaseAddress + 0xFF44;
pPpuState->lcdRegisters.pLyc = pMemoryMapper->pBaseAddress + 0xFF45;
pPpuState->lcdRegisters.pWy = pMemoryMapper->pBaseAddress + 0xFF4A;
pPpuState->lcdRegisters.pWx = pMemoryMapper->pBaseAddress + 0xFF4B;
}
void patchIOApuMappedMemoryPointer( GBMemoryMapper* pMemoryMapper, GBApuState* pApuState )
{
pApuState->waveChannel.pWavePattern = pMemoryMapper->pBaseAddress + 0xFF30;
}
uint8_t calculateGBRomHeaderChecksum( const uint8_t* pRomData )
{
const uint8_t* pData = pRomData + 0x0134;
const uint8_t* pDataEnd = pRomData + 0x014C;
uint8_t checksum = 0u;
while( pData <= pDataEnd )
{
checksum = checksum - *pData - 1;
++pData;
}
return checksum;
}
bool8_t isGBRomData( const uint8_t* pRomData, const size_t romDataSizeInBytes )
{
if( romDataSizeInBytes < gbMinRomSizeInBytes || romDataSizeInBytes > gbMaxRomSizeInBytes )
{
return 0u;
}
GBRomHeader header;
memcpy(&header, pRomData + 0x0100, sizeof(GBRomHeader));
//FK: TODO calculate complete rom checksum eventually...
const uint8_t headerChecksum = calculateGBRomHeaderChecksum( pRomData );
return headerChecksum == header.headerChecksum;
}
GBRomHeader getGBRomHeader(const uint8_t* pRomData)
{
GBRomHeader header;
memcpy(&header, pRomData + 0x0100, sizeof(GBRomHeader));
return header;
}
struct ZipEndOfCentralDirectory
{
uint32_t signature;
uint16_t diskNumber;
uint16_t centralDirDisk;
uint16_t centralDirRecordCount;
uint32_t centralDirectorySizeInBytes;
uint32_t centralDirectoryAbsoluteOffset;
};
struct ZipArchive
{
const uint8_t* restrict_modifier pData;
const ZipEndOfCentralDirectory* restrict_modifier pEocd;
uint32_t dataSizeInBytes;
};
struct GZipDataFlags
{
union
{
struct
{
uint8_t FTEXT : 1;
uint8_t FHCRC : 1;
uint8_t FEXTRA : 1;
uint8_t FNAME : 1;
uint8_t FCOMMENT : 1;
uint8_t reserved : 3;
};
uint8_t value;
};
};
struct GZipFooter
{
uint32_t crc32Checksum;
uint32_t uncompressedSizeInBytes;
};
struct GZipData
{
const uint8_t* pData;
const GZipFooter* pFooter;
uint32_t dataSizeInBytes;
uint8_t compressionMethod;
GZipDataFlags flags;
};
enum class UncompressResult : uint8_t
{
Success,
UnsupportedCompressionMethod,
ChecksumError,
TargetBufferTooSmall
};
struct BitStream
{
const uint8_t* pDataStart;
const uint8_t* pDataEnd;
const uint8_t* pDataCurrent;
uint8_t bitMask;
};
struct MemoryWriteStream
{
uint8_t* pTargetData;
const uint8_t* pTargetDataEnd;
};
struct DeflateBlockHeader
{
uint8_t isFinal : 1;
uint8_t compressionMethod : 2;
};
MemoryWriteStream createMemoryWriteStream( uint8_t* pTargetBuffer, const uint32_t targetBufferCapacityInBytes )
{
MemoryWriteStream writeStream;
writeStream.pTargetData = pTargetBuffer;
writeStream.pTargetDataEnd = pTargetBuffer + targetBufferCapacityInBytes;
return writeStream;
}
bool8_t pushData( MemoryWriteStream* pWriteStream, const uint8_t* pData, const uint32_t dataSizeInBytes )
{
if( pWriteStream->pTargetData + dataSizeInBytes < pWriteStream->pTargetDataEnd )
{
return 0u;
}
memcpy( pWriteStream->pTargetData, pData, dataSizeInBytes );
pWriteStream->pTargetData += dataSizeInBytes;
return 1u;
}
BitStream createBitStream( const uint8_t* pData, uint32_t dataSizeInBytes )
{
BitStream bitStream;
bitStream.pDataStart = pData;
bitStream.pDataCurrent = pData;
bitStream.pDataEnd = pData + dataSizeInBytes;
bitStream.bitMask = 1;
return bitStream;
}
void advanceToNextByte( BitStream* pBitStream )
{
RuntimeAssert( ( pBitStream->pDataCurrent + 1 ) < pBitStream->pDataEnd );
++pBitStream->pDataCurrent;
pBitStream->bitMask = 1;
}
uint8_t reverseBitsInByte( uint8_t value )
{
//FK: https://developer.squareup.com/blog/reversing-bits-in-c/
return (uint8_t)(((value * 0x0802LU & 0x22110LU) |
(value * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
}
uint8_t readBit( BitStream* pBitStream )
{
const uint8_t bit = ( *pBitStream->pDataCurrent & pBitStream->bitMask ) > 0;
pBitStream->bitMask <<= 1;
if( pBitStream->bitMask == 0u )
{
advanceToNextByte( pBitStream );
}
return bit;
}
uint8_t readBits( BitStream* pBitStream, uint8_t bitsToRead )
{
RuntimeAssert( bitsToRead <= 8 );
uint8_t value = 0u;
while( true )
{
value |= readBit( pBitStream );
if( ( --bitsToRead ) == 0u )
{
break;
}
value <<= 1u;
}
return value;
}
uint8_t readBitsInverse( BitStream* pBitStream, uint8_t bitsToRead )
{
RuntimeAssert( bitsToRead <= 8 );
uint8_t value = 0u;
for( uint8_t bitIndex = 0u; bitIndex < bitsToRead; ++bitIndex )
{
value |= ( readBit( pBitStream ) << bitIndex );
}
return value;
}
void moveToNextByteBoundary( BitStream* pBitStream )
{
if( pBitStream->bitMask == 1u )
{
return;
}
advanceToNextByte( pBitStream );
}
void skipBytes( BitStream* pBitStream, const uint32_t bytesToSkip )
{
RuntimeAssert( pBitStream->bitMask == 1u );
RuntimeAssert( pBitStream->pDataCurrent + bytesToSkip < pBitStream->pDataEnd );
pBitStream->pDataCurrent += bytesToSkip;
}
const ZipEndOfCentralDirectory* findZipArchiveEndOfCentralDirectory( const uint8_t* pZipData, const uint32_t zipDataSizeInBytes )
{
uint32_t eocdPos = zipDataSizeInBytes - 20;
while( eocdPos != 0 )
{
if( pZipData[ eocdPos + 3 ] == 0x06 &&
pZipData[ eocdPos + 2 ] == 0x05 &&