mirror of https://github.com/bsnes-emu/bsnes.git
110 lines
2.5 KiB
C++
110 lines
2.5 KiB
C++
//BANDAI-FCG
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struct BandaiFCG : Board {
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BandaiFCG(Markup::Node& document) : Board(document) {
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}
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auto main() -> void {
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if(irq_counter_enable) {
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if(--irq_counter == 0xffff) {
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cpu.set_irq_line(1);
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irq_counter_enable = false;
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}
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}
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tick();
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}
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auto ciram_addr(uint addr) const -> uint {
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switch(mirror) {
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case 0: return ((addr & 0x0400) >> 0) | (addr & 0x03ff);
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case 1: return ((addr & 0x0800) >> 1) | (addr & 0x03ff);
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case 2: return 0x0000 | (addr & 0x03ff);
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case 3: return 0x0400 | (addr & 0x03ff);
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}
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}
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auto prg_read(uint addr) -> uint8 {
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if(addr & 0x8000) {
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bool region = addr & 0x4000;
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uint bank = (region == 0 ? prg_bank : (uint8)0x0f);
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return prgrom.read((bank << 14) | (addr & 0x3fff));
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}
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return cpu.mdr();
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}
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auto prg_write(uint addr, uint8 data) -> void {
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if(addr >= 0x6000) {
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switch(addr & 15) {
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case 0x00: case 0x01: case 0x02: case 0x03:
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case 0x04: case 0x05: case 0x06: case 0x07:
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chr_bank[addr & 7] = data;
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break;
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case 0x08:
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prg_bank = data & 0x0f;
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break;
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case 0x09:
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mirror = data & 0x03;
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break;
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case 0x0a:
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cpu.set_irq_line(0);
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irq_counter_enable = data & 0x01;
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irq_counter = irq_latch;
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break;
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case 0x0b:
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irq_latch = (irq_latch & 0xff00) | (data << 0);
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break;
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case 0x0c:
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irq_latch = (irq_latch & 0x00ff) | (data << 8);
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break;
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case 0x0d:
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//TODO: serial EEPROM support
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break;
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}
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}
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}
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auto chr_read(uint addr) -> uint8 {
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if(addr & 0x2000) return ppu.ciram_read(ciram_addr(addr));
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addr = (chr_bank[addr >> 10] << 10) | (addr & 0x03ff);
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return Board::chr_read(addr);
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}
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auto chr_write(uint addr, uint8 data) -> void {
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if(addr & 0x2000) return ppu.ciram_write(ciram_addr(addr), data);
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addr = (chr_bank[addr >> 10] << 10) | (addr & 0x03ff);
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return Board::chr_write(addr, data);
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}
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auto power() -> void {
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reset();
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}
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auto reset() -> void {
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for(auto &n : chr_bank) n = 0;
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prg_bank = 0;
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mirror = 0;
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irq_counter_enable = 0;
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irq_counter = 0;
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irq_latch = 0;
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}
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auto serialize(serializer& s) -> void {
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Board::serialize(s);
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s.array(chr_bank);
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s.integer(prg_bank);
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s.integer(mirror);
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s.integer(irq_counter_enable);
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s.integer(irq_counter);
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s.integer(irq_latch);
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}
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uint8 chr_bank[8];
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uint8 prg_bank;
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uint2 mirror;
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bool irq_counter_enable;
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uint16 irq_counter;
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uint16 irq_latch;
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};
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