bsnes/sfc/chip/obc1/obc1.cpp

81 lines
2.0 KiB
C++

#include <sfc/sfc.hpp>
#define OBC1_CPP
namespace SuperFamicom {
#include "serialization.cpp"
OBC1 obc1;
void OBC1::init() {
}
void OBC1::load() {
}
void OBC1::unload() {
ram.reset();
}
void OBC1::power() {
}
void OBC1::reset() {
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;
switch(addr) {
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);
}
return ram_read(addr);
}
void OBC1::write(unsigned addr, uint8 data) {
addr &= 0x1fff;
switch(addr) {
case 0x1ff0: ram_write(status.baseptr + (status.address << 2) + 0, data); return;
case 0x1ff1: ram_write(status.baseptr + (status.address << 2) + 1, data); return;
case 0x1ff2: ram_write(status.baseptr + (status.address << 2) + 2, data); return;
case 0x1ff3: ram_write(status.baseptr + (status.address << 2) + 3, data); return;
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);
} return;
case 0x1ff5:
status.baseptr = (data & 1) ? 0x1800 : 0x1c00;
ram_write(addr, data);
return;
case 0x1ff6:
status.address = (data & 0x7f);
status.shift = (data & 3) << 1;
ram_write(addr, data);
return;
case 0x1ff7:
ram_write(addr, data);
return;
}
return ram_write(addr, data);
}
uint8 OBC1::ram_read(unsigned addr) {
return ram.read(addr & 0x1fff);
}
void OBC1::ram_write(unsigned addr, uint8 data) {
ram.write(addr & 0x1fff, data);
}
}