bsnes/icarus/heuristics/mega-drive.cpp

88 lines
2.7 KiB
C++

namespace Heuristics {
struct MegaDrive {
MegaDrive(vector<uint8_t>& data, string location);
explicit operator bool() const;
auto manifest() const -> string;
private:
vector<uint8_t>& data;
string location;
};
MegaDrive::MegaDrive(vector<uint8_t>& data, string location) : data(data), location(location) {
}
MegaDrive::operator bool() const {
return data.size() >= 0x200;
}
auto MegaDrive::manifest() const -> string {
if(!operator bool()) return {};
string ramMode = "none";
uint32_t ramFrom = 0;
ramFrom |= data[0x01b4] << 24;
ramFrom |= data[0x01b5] << 16;
ramFrom |= data[0x01b6] << 8;
ramFrom |= data[0x01b7] << 0;
uint32_t ramTo = 0;
ramTo |= data[0x01b8] << 24;
ramTo |= data[0x01b9] << 16;
ramTo |= data[0x01ba] << 8;
ramTo |= data[0x01bb] << 0;
if(!(ramFrom & 1) && !(ramTo & 1)) ramMode = "hi";
if( (ramFrom & 1) && (ramTo & 1)) ramMode = "lo";
if(!(ramFrom & 1) && (ramTo & 1)) ramMode = "word";
if(data[0x01b0] != 'R' || data[0x01b1] != 'A') ramMode = "none";
uint32_t ramSize = ramTo - ramFrom + 1;
if(ramMode == "hi") ramSize = (ramTo >> 1) - (ramFrom >> 1) + 1;
if(ramMode == "lo") ramSize = (ramTo >> 1) - (ramFrom >> 1) + 1;
if(ramMode == "word") ramSize = ramTo - ramFrom + 1;
if(ramMode != "none") ramSize = bit::round(min(0x20000, ramSize));
if(ramMode == "none") ramSize = 0;
string_vector regions;
string region = slice((const char*)&data[0x1f0], 0, 16).trimRight(" ");
if(!regions) {
if(region == "JAPAN" ) regions.append("NTSC-J");
if(region == "EUROPE") regions.append("PAL");
}
if(!regions) {
if(region.find("J")) regions.append("NTSC-J");
if(region.find("U")) regions.append("NTSC-U");
if(region.find("E")) regions.append("PAL");
if(region.find("W")) regions.append("NTSC-J", "NTSC-U", "PAL");
}
if(!regions && region.size() == 1) {
uint8_t field = region.hex();
if(field & 0x01) regions.append("NTSC-J");
if(field & 0x04) regions.append("NTSC-U");
if(field & 0x08) regions.append("PAL");
}
if(!regions) {
regions.append("NTSC-J");
}
string output;
output.append("game\n");
output.append(" sha256: ", Hash::SHA256(data).digest(), "\n");
output.append(" label: ", Location::prefix(location), "\n");
output.append(" name: ", Location::prefix(location), "\n");
output.append(" region: ", regions.left(), "\n");
output.append(" board\n");
output.append(Memory{}.type("ROM").size(data.size()).category("Program").text());
if(ramSize && ramMode != "none") {
output.append(Memory{}.type("RAM").size(ramSize).category("Save").text());
output.append(" mode: ", ramMode, "\n");
output.append(" offset: 0x", hex(ramFrom), "\n");
}
return output;
}
}