mirror of https://github.com/bsnes-emu/bsnes.git
93 lines
2.0 KiB
C++
93 lines
2.0 KiB
C++
struct VRC3 : Chip {
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VRC3(Board& board) : Chip(board) {
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}
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auto main() -> void {
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if(irqEnable) {
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if(irqMode == 0) { //16-bit
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if(++irqCounter.w == 0) {
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irqLine = 1;
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irqEnable = irqAcknowledge;
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irqCounter.w = irqLatch;
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}
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}
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if(irqMode == 1) { //8-bit
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if(++irqCounter.l == 0) {
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irqLine = 1;
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irqEnable = irqAcknowledge;
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irqCounter.l = irqLatch;
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}
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}
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}
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cpu.irqLine(irqLine);
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tick();
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}
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auto addrPRG(uint addr) const -> uint {
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uint bank = (addr < 0xc000 ? (uint)prgBank : 0x0f);
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return (bank * 0x4000) + (addr & 0x3fff);
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}
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auto writeIO(uint addr, uint8 data) -> void {
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switch(addr & 0xf000) {
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case 0x8000: irqLatch = (irqLatch & 0xfff0) | ((data & 0x0f) << 0); break;
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case 0x9000: irqLatch = (irqLatch & 0xff0f) | ((data & 0x0f) << 4); break;
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case 0xa000: irqLatch = (irqLatch & 0xf0ff) | ((data & 0x0f) << 8); break;
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case 0xb000: irqLatch = (irqLatch & 0x0fff) | ((data & 0x0f) << 12); break;
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case 0xc000:
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irqMode = data & 0x04;
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irqEnable = data & 0x02;
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irqAcknowledge = data & 0x01;
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if(irqEnable) irqCounter.w = irqLatch;
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break;
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case 0xd000:
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irqLine = 0;
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irqEnable = irqAcknowledge;
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break;
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case 0xf000:
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prgBank = data & 0x0f;
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break;
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}
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}
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auto power() -> void {
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}
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auto reset() -> void {
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prgBank = 0;
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irqMode = 0;
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irqEnable = 0;
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irqAcknowledge = 0;
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irqLatch = 0;
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irqCounter.w = 0;
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irqLine = 0;
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}
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auto serialize(serializer& s) -> void {
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s.integer(prgBank);
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s.integer(irqMode);
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s.integer(irqEnable);
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s.integer(irqAcknowledge);
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s.integer(irqLatch);
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s.integer(irqCounter.w);
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s.integer(irqLine);
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}
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uint4 prgBank;
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bool irqMode;
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bool irqEnable;
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bool irqAcknowledge;
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uint16 irqLatch;
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struct {
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union {
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uint16_t w;
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struct { uint8_t order_lsb2(l, h); };
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};
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} irqCounter;
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bool irqLine;
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};
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