58 lines
No EOL
1 KiB
C++
58 lines
No EOL
1 KiB
C++
#include "stdafx.h"
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enum PPURegisters
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{
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Control = 0x00,
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Control2 = 0x01,
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Status = 0x02,
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SpriteAddr = 0x03,
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SpriteData = 0x04,
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ScrollOffsets = 0x05,
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VideoMemoryAddr = 0x06,
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VideoMemoryData = 0x07
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};
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struct PPUState
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{
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uint16_t Control;
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uint8_t Status;
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uint8_t SpriteRamAddr;
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uint16_t VideoRamAddr;
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};
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class PPU : public IMemoryHandler
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{
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private:
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PPUState _state;
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uint8_t _spriteRAM[256];
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uint8_t _videoRAM[16*1024];
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PPURegisters GetRegisterID(uint16_t addr) {
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return (PPURegisters)(addr & 0x07);
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}
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public:
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PPU() {
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_state = {};
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_state.Status |= 0xFF;
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}
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uint8_t MemoryRead(uint16_t addr) {
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switch(GetRegisterID(addr)) {
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case PPURegisters::Control:
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return (uint8_t)_state.Control;
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case PPURegisters::Control2:
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return (uint8_t)(_state.Control >> 8);
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case PPURegisters::Status:
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return _state.Status;
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case PPURegisters::SpriteData:
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return _spriteRAM[_state.SpriteRamAddr];
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case PPURegisters::VideoMemoryData:
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return _videoRAM[_state.VideoRamAddr];
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}
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}
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void MemoryWrite(uint16_t addr, uint8_t value) {
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}
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}; |