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- #include <../base.hpp>
- #include <../cart/cart.hpp>
- #include "obc1.hpp"
- void OBC1::init() {}
- void OBC1::enable() {}
- void OBC1::power() {
- reset();
- }
- void OBC1::reset() {
- for(unsigned i = 0x0000; i <= 0x1fff; i++) ram_write(i, 0xff);
- status.baseptr = (ram_read(0x1ff5) & 1) ? 0x1800 : 0x1c00;
- status.address = (ram_read(0x1ff6) & 0x7f);
- status.shift = (ram_read(0x1ff6) & 3) << 1;
- }
- uint8 OBC1::read(unsigned addr) {
- addr &= 0x1fff;
- if((addr & 0x1ff8) != 0x1ff0) return ram_read(addr);
- switch(addr) { default: //never used, avoids compiler warning
- case 0x1ff0: return ram_read(status.baseptr + (status.address << 2) + 0);
- case 0x1ff1: return ram_read(status.baseptr + (status.address << 2) + 1);
- case 0x1ff2: return ram_read(status.baseptr + (status.address << 2) + 2);
- case 0x1ff3: return ram_read(status.baseptr + (status.address << 2) + 3);
- case 0x1ff4: return ram_read(status.baseptr + (status.address >> 2) + 0x200);
- case 0x1ff5: case 0x1ff6: case 0x1ff7: return ram_read(addr);
- }
- }
- void OBC1::write(unsigned addr, uint8 data) {
- addr &= 0x1fff;
- if((addr & 0x1ff8) != 0x1ff0) return ram_write(addr, data);
- switch(addr) {
- case 0x1ff0: ram_write(status.baseptr + (status.address << 2) + 0, data); break;
- case 0x1ff1: ram_write(status.baseptr + (status.address << 2) + 1, data); break;
- case 0x1ff2: ram_write(status.baseptr + (status.address << 2) + 2, data); break;
- case 0x1ff3: ram_write(status.baseptr + (status.address << 2) + 3, data); break;
- case 0x1ff4: {
- uint8 temp = ram_read(status.baseptr + (status.address >> 2) + 0x200);
- temp = (temp & ~(3 << status.shift)) | ((data & 3) << status.shift);
- ram_write(status.baseptr + (status.address >> 2) + 0x200, temp);
- } break;
- case 0x1ff5: {
- status.baseptr = (data & 1) ? 0x1800 : 0x1c00;
- ram_write(addr, data);
- } break;
- case 0x1ff6: {
- status.address = (data & 0x7f);
- status.shift = (data & 3) << 1;
- ram_write(addr, data);
- } break;
- case 0x1ff7: {
- ram_write(addr, data);
- } break;
- }
- }
- uint8 OBC1::ram_read(unsigned addr) {
- return memory::cartram.read(addr & 0x1fff);
- }
- void OBC1::ram_write(unsigned addr, uint8 data) {
- memory::cartram.write(addr & 0x1fff, data);
- }
- OBC1::OBC1() {}
- OBC1::~OBC1() {}
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