EightBit/LR35902/inc/IoRegisters.h

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#pragma once
#include <cstdint>
#include <Ram.h>
#include <Processor.h>
#include <Register.h>
#include <Signal.h>
namespace EightBit {
namespace GameBoy {
class Bus;
class IoRegisters final : public EightBit::Ram {
public:
enum {
BASE = 0xFF00,
// Port/Mode Registers
P1 = 0x0, // R/W Mask5
SB = 0x1, // R/W Mask8
SC = 0x2, // R/W Bit7 | Bit0
// Timer control
DIV = 0x4, // R/W Mask8
TIMA = 0x5, // R/W Mask8
TMA = 0x6, // R/W Mask8
TAC = 0x7, // R/W Mask3
// Interrupt Flags
IF = 0xF, // R/W Mask5
IE = 0xFF, // R/W Mask5
// Sound Registers
NR10 = 0x10, // R/W Mask7
NR11 = 0x11, // R/W Bit7 | Bit6
NR12 = 0x12, // R/W Mask8
NR13 = 0x13, // W 0
NR14 = 0x14, // R/W Bit6
NR21 = 0x16, // R/W Bit7 | Bit6
NR22 = 0x17, // R/W Mask8
NR23 = 0x18, // W 0
NR24 = 0x19, // R/W Bit6
NR30 = 0x1A, // R/W Bit7
NR31 = 0x1B, // R/W Mask8
NR32 = 0x1C, // R/W Bit6 | Bit5
NR33 = 0x1D, // W 0
NR34 = 0x1E, // R/W Bit6
NR41 = 0x20, // R/W Mask6
NR42 = 0x21, // R/W Mask8
NR43 = 0x22, // R/W Mask8
NR44 = 0x23, // R/W Bit6
NR50 = 0x24, // R/W Mask8
NR51 = 0x25, // R/W Mask8
NR52 = 0x26, // R/W Mask8 Mask8
WAVE_PATTERN_RAM_START = 0x30,
WAVE_PATTERN_RAM_END = 0x3F,
// LCD Display Registers
LCDC = 0x40, // R/W Mask8
STAT = 0x41, // R/W Mask7
SCY = 0x42, // R/W Mask8
SCX = 0x43, // R/W Mask8
LY = 0x44, // R Mask8 zeroed
LYC = 0x45, // R/W Mask8
DMA = 0x46, // W 0
BGP = 0x47, // R/W Mask8
OBP0 = 0x48, // R/W Mask8
OBP1 = 0x49, // R/W Mask8
WY = 0x4A, // R/W Mask8
WX = 0x4B, // R/W Mask8
// Boot rom control
BOOT_DISABLE = 0x50,
};
// IF and IE flags
enum Interrupts {
VerticalBlank = Chip::Bit0, // VBLANK
DisplayControlStatus = Chip::Bit1, // LCDC Status
TimerOverflow = Chip::Bit2, // Timer Overflow
SerialTransfer = Chip::Bit3, // Serial Transfer
KeypadPressed = Chip::Bit4 // Hi-Lo transition of P10-P13
};
enum LcdcControl {
DisplayBackground = Chip::Bit0,
ObjectEnable = Chip::Bit1,
ObjectBlockCompositionSelection = Chip::Bit2,
BackgroundCodeAreaSelection = Chip::Bit3,
BackgroundCharacterDataSelection = Chip::Bit4,
WindowEnable = Chip::Bit5,
WindowCodeAreaSelection = Chip::Bit6,
LcdEnable = Chip::Bit7
};
enum LcdStatusMode {
HBlank = 0b00,
VBlank = 0b01,
SearchingOamRam = 0b10,
TransferringDataToLcd = 0b11
};
IoRegisters(Bus& bus);
Signal<int> DisplayStatusModeUpdated;
void reset();
void transferDma();
void triggerInterrupt(const int cause) {
poke(IF, peek(IF) | cause);
}
void checkTimers(int cycles);
int timerClockTicks();
int timerClock();
bool timerEnabled();
bool timerDisabled();
void incrementDIV(int cycles);
void incrementTIMA();
void incrementLY();
void resetLY();
void updateLcdStatusMode(int mode);
void disableBootRom() { m_disableBootRom = true; }
void enableBootRom() { m_disableBootRom = false; }
auto bootRomDisabled() const { return m_disableBootRom; }
auto bootRomEnabled() const { return !bootRomDisabled(); }
void pressRight() { m_p14 = m_p10 = false; triggerKeypadInterrupt(); }
void releaseRight() { m_p14 = m_p10 = true; }
void pressLeft() { m_p14 = m_p11 = false, triggerKeypadInterrupt(); }
void releaseLeft() { m_p14 = m_p11 = true; }
void pressUp() { m_p14 = m_p12 = false, triggerKeypadInterrupt(); }
void releaseUp() { m_p14 = m_p12 = true; }
void pressDown() { m_p14 = m_p13 = false, triggerKeypadInterrupt(); }
void releaseDown() { m_p14 = m_p13 = true; }
void pressA() { m_p15 = m_p10 = false, triggerKeypadInterrupt(); }
void releaseA() { m_p15 = m_p10 = true; }
void pressB() { m_p15 = m_p11 = false, triggerKeypadInterrupt(); }
void releaseB() { m_p15 = m_p11 = true; }
void pressSelect() { m_p15 = m_p12 = false, triggerKeypadInterrupt(); }
void releaseSelect() { m_p15 = m_p12 = true; }
void pressStart() { m_p15 = m_p13 = false, triggerKeypadInterrupt(); }
void releaseStart() { m_p15 = m_p13 = true; }
private:
Bus& m_bus;
bool m_disableBootRom = false;
register16_t m_divCounter = { 0xab, 0xcc };
int m_timerCounter = 0;
int m_timerRate = 0;
register16_t m_dmaAddress;
bool m_dmaTransferActive = false;
bool m_scanP15 = false;
bool m_scanP14 = false;
bool m_p15 = true; // misc keys
bool m_p14 = true; // direction keys
bool m_p13 = true; // down/start
bool m_p12 = true; // up/select
bool m_p11 = true; // left/b
bool m_p10 = true; // right/a
void checkTimer(int cycles);
void mask(const uint16_t address, const uint8_t masking) {
poke(address, peek(address) | ~masking);
}
void triggerKeypadInterrupt() {
triggerInterrupt(Interrupts::KeypadPressed);
}
void Bus_WrittenByte(EightBit::EventArgs);
void Bus_ReadingByte(EightBit::EventArgs);
};
}
}