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CLK/StaticAnalyser/MSX/StaticAnalyser.cpp
Thomas Harte 999a0c22d4 Adds superficial support for MSX .DSK.
In the sense that the file format itself is properly parsed, but the MSX doesn't actually yet have disk hardware.
2018-01-07 16:35:57 -05:00

225 lines
8.5 KiB
C++

//
// StaticAnalyser.cpp
// Clock Signal
//
// Created by Thomas Harte on 25/11/2017.
// Copyright © 2017 Thomas Harte. All rights reserved.
//
#include "StaticAnalyser.hpp"
#include "Tape.hpp"
#include "../Disassembler/Z80.hpp"
#include "../Disassembler/AddressMapper.hpp"
#include <algorithm>
/*
Expected standard cartridge format:
DEFB "AB" ; expansion ROM header
DEFW initcode ; start of the init code, 0 if no initcode
DEFW callstat; pointer to CALL statement handler, 0 if no such handler
DEFW device; pointer to expansion device handler, 0 if no such handler
DEFW basic ; pointer to the start of a tokenized basicprogram, 0 if no basicprogram
DEFS 6,0 ; room reserved for future extensions
*/
static std::list<std::shared_ptr<Storage::Cartridge::Cartridge>>
MSXCartridgesFrom(const std::list<std::shared_ptr<Storage::Cartridge::Cartridge>> &cartridges, StaticAnalyser::Target &target) {
std::list<std::shared_ptr<Storage::Cartridge::Cartridge>> msx_cartridges;
for(const auto &cartridge : cartridges) {
const auto &segments = cartridge->get_segments();
// Only one mapped item is allowed.
if(segments.size() != 1) continue;
// Which must be a multiple of 16 kb in size.
Storage::Cartridge::Cartridge::Segment segment = segments.front();
const size_t data_size = segment.data.size();
if(data_size < 0x2000 || data_size & 0x3fff) continue;
// Check for a ROM header at address 0; if it's not found then try 0x4000
// and adjust the start address;
uint16_t start_address = 0;
bool found_start = false;
if(segment.data[0] == 0x41 && segment.data[1] == 0x42) {
start_address = 0x4000;
found_start = true;
} else if(segment.data.size() >= 0x8000 && segment.data[0x4000] == 0x41 && segment.data[0x4001] == 0x42) {
start_address = 0;
found_start = true;
}
// Reject cartridge if the ROM header wasn't found.
if(!found_start) continue;
uint16_t init_address = static_cast<uint16_t>(segment.data[2] | (segment.data[3] << 8));
// TODO: check for a rational init address?
// If this ROM is greater than 48kb in size then some sort of MegaROM scheme must
// be at play; disassemble to try to figure it out.
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::None;
if(data_size > 0xc000) {
std::vector<uint8_t> first_16k;
first_16k.insert(first_16k.begin(), segment.data.begin(), segment.data.begin() + 8192);
StaticAnalyser::Z80::Disassembly disassembly =
StaticAnalyser::Z80::Disassemble(
first_16k,
StaticAnalyser::Disassembler::OffsetMapper(start_address),
{ init_address }
);
// Look for a indirect store followed by an unconditional JP or CALL into another
// segment, that's a fairly explicit sign where found.
using Instruction = StaticAnalyser::Z80::Instruction;
std::map<uint16_t, Instruction> &instructions = disassembly.instructions_by_address;
bool is_ascii = false;
auto iterator = instructions.begin();
while(iterator != instructions.end()) {
auto next_iterator = iterator;
next_iterator++;
if(next_iterator == instructions.end()) break;
if( iterator->second.operation == Instruction::Operation::LD &&
iterator->second.destination == Instruction::Location::Operand_Indirect &&
(
iterator->second.operand == 0x5000 ||
iterator->second.operand == 0x6000 ||
iterator->second.operand == 0x6800 ||
iterator->second.operand == 0x7000 ||
iterator->second.operand == 0x77ff ||
iterator->second.operand == 0x7800 ||
iterator->second.operand == 0x8000 ||
iterator->second.operand == 0x9000 ||
iterator->second.operand == 0xa000
) &&
(
next_iterator->second.operation == Instruction::Operation::CALL ||
next_iterator->second.operation == Instruction::Operation::JP
) &&
((next_iterator->second.operand >> 13) != (0x4000 >> 13))
) {
const uint16_t address = static_cast<uint16_t>(next_iterator->second.operand);
switch(iterator->second.operand) {
case 0x6000:
if(address >= 0x6000 && address < 0x8000) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::KonamiWithSCC;
}
break;
case 0x6800:
if(address >= 0x6000 && address < 0x6800) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::ASCII8kb;
}
break;
case 0x7000:
if(address >= 0x6000 && address < 0x8000) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::KonamiWithSCC;
}
if(address >= 0x7000 && address < 0x7800) {
is_ascii = true;
}
break;
case 0x77ff:
if(address >= 0x7000 && address < 0x7800) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::ASCII16kb;
}
break;
case 0x7800:
if(address >= 0xa000 && address < 0xc000) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::ASCII8kb;
}
break;
case 0x8000:
if(address >= 0x8000 && address < 0xa000) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::KonamiWithSCC;
}
break;
case 0x9000:
if(address >= 0x8000 && address < 0xa000) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::KonamiWithSCC;
}
break;
case 0xa000:
if(address >= 0xa000 && address < 0xc000) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::Konami;
}
break;
case 0xb000:
if(address >= 0xa000 && address < 0xc000) {
target.msx.cartridge_type = StaticAnalyser::MSXCartridgeType::KonamiWithSCC;
}
break;
}
}
iterator = next_iterator;
}
if(target.msx.cartridge_type == StaticAnalyser::MSXCartridgeType::None) {
// Look for LD (nnnn), A instructions, and collate those addresses.
std::map<uint16_t, int> address_counts;
for(const auto &instruction_pair : instructions) {
if( instruction_pair.second.operation == Instruction::Operation::LD &&
instruction_pair.second.destination == Instruction::Location::Operand_Indirect &&
instruction_pair.second.source == Instruction::Location::A) {
address_counts[static_cast<uint16_t>(instruction_pair.second.operand)]++;
}
}
// Sort possible cartridge types.
using Possibility = std::pair<StaticAnalyser::MSXCartridgeType, int>;
std::vector<Possibility> possibilities;
// Add to list in order of declining probability, so that stable_sort below prefers
// the more likely option in a tie.
possibilities.push_back(std::make_pair(StaticAnalyser::MSXCartridgeType::ASCII8kb, address_counts[0x6000] + address_counts[0x6800] + address_counts[0x7000] + address_counts[0x7800]));
possibilities.push_back(std::make_pair(StaticAnalyser::MSXCartridgeType::ASCII16kb, address_counts[0x6000] + address_counts[0x7000] + address_counts[0x77ff]));
if(!is_ascii) possibilities.push_back(std::make_pair(StaticAnalyser::MSXCartridgeType::Konami, address_counts[0x6000] + address_counts[0x8000] + address_counts[0xa000]));
if(!is_ascii) possibilities.push_back(std::make_pair(StaticAnalyser::MSXCartridgeType::KonamiWithSCC, address_counts[0x5000] + address_counts[0x7000] + address_counts[0x9000] + address_counts[0xb000]));
std::stable_sort(possibilities.begin(), possibilities.end(), [](const Possibility &a, const Possibility &b) {
return a.second > b.second;
});
target.msx.cartridge_type = possibilities[0].first;
}
}
// Apply the standard MSX start address.
msx_cartridges.emplace_back(new Storage::Cartridge::Cartridge({
Storage::Cartridge::Cartridge::Segment(start_address, segment.data)
}));
}
return msx_cartridges;
}
void StaticAnalyser::MSX::AddTargets(const Media &media, std::list<Target> &destination) {
Target target;
// Obtain only those cartridges which it looks like an MSX would understand.
target.media.cartridges = MSXCartridgesFrom(media.cartridges, target);
// Check tapes for loadable files.
for(const auto &tape : media.tapes) {
std::vector<File> files_on_tape = GetFiles(tape);
if(!files_on_tape.empty()) {
switch(files_on_tape.front().type) {
case File::Type::ASCII: target.loading_command = "RUN\"CAS:\r"; break;
case File::Type::TokenisedBASIC: target.loading_command = "CLOAD\rRUN\r"; break;
case File::Type::Binary: target.loading_command = "BLOAD\"CAS:\",R\r"; break;
default: break;
}
target.media.tapes.push_back(tape);
}
}
// Blindly accept disks for now.
target.media.disks = media.disks;
if(!target.media.empty()) {
target.machine = Target::MSX;
target.probability = 1.0;
destination.push_back(target);
}
}