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Adds a genuine attempt to discern Pravetz disks from Apple.

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This commit is contained in:
Thomas Harte 2018-05-05 19:32:08 -04:00 committed by Thomas Harte
parent ba7fbc4032
commit 3e0055737e
1 changed files with 90 additions and 9 deletions
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99
Analyser/Static/DiskII/StaticAnalyser.cpp
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@ -7,16 +7,48 @@
//
#include "StaticAnalyser.hpp"
#include "../AppleII/Target.hpp"
#include "../Oric/Target.hpp"
#include "../Disassembler/6502.hpp"
#include "../Disassembler/AddressMapper.hpp"
#include "../../../Storage/Disk/Track/TrackSerialiser.hpp"
#include "../../../Storage/Disk/Encodings/AppleGCR/SegmentParser.hpp"
namespace {
Analyser::Static::Target *AppleTarget(const Storage::Encodings::AppleGCR::Sector *sector_zero) {
using Target = Analyser::Static::AppleII::Target;
auto *target = new Target;
target->machine = Analyser::Machine::AppleII;
if(sector_zero && sector_zero->encoding == Storage::Encodings::AppleGCR::Sector::Encoding::FiveAndThree) {
target->disk_controller = Target::DiskController::ThirteenSector;
} else {
target->disk_controller = Target::DiskController::SixteenSector;
}
return target;
}
Analyser::Static::Target *OricTarget(const Storage::Encodings::AppleGCR::Sector *sector_zero) {
using Target = Analyser::Static::Oric::Target;
auto *target = new Target;
target->machine = Analyser::Machine::Oric;
// TODO: configure the Oric as a Pravetz 8D with 8DOS.
return target;
}
}
Analyser::Static::TargetList Analyser::Static::DiskII::GetTargets(const Media &media, const std::string &file_name, TargetPlatform::IntType potential_platforms) {
// This analyser can comprehend disks only.
if(media.disks.empty()) return {};
// Grab track 0, sector 0.
// Grab track 0, sector 0: the boot sector.
auto track_zero = media.disks.front()->get_track_at_position(Storage::Disk::Track::Address(0, 0));
auto sector_map = Storage::Encodings::AppleGCR::sectors_from_segment(
Storage::Disk::track_serialisation(*track_zero, Storage::Time(1, 50000)));
@ -29,14 +61,63 @@ Analyser::Static::TargetList Analyser::Static::DiskII::GetTargets(const Media &m
}
}
using Target = Analyser::Static::AppleII::Target;
auto target = std::unique_ptr<Target>(new Target);
target->machine = Machine::AppleII;
target->media = media;
target->disk_controller = Target::DiskController::SixteenSector;
// If there's no boot sector then if there are also no sectors at all,
// decline to nominate a machine. Otherwise go with an Apple as the default.
TargetList targets;
targets.push_back(std::move(target));
if(!sector_zero) {
if(sector_map.empty()) {
return targets;
} else {
targets.push_back(std::unique_ptr<Analyser::Static::Target>(AppleTarget(nullptr)));
return targets;
}
}
// If the boot sector looks like it's intended for the Oric, create an Oric.
// Otherwise go with the Apple II.
auto disassembly = Analyser::Static::MOS6502::Disassemble(sector_zero->data, Analyser::Static::Disassembler::OffsetMapper(0xb800), {0xb800});
bool did_read_shift_register = false;
bool is_oric = false;
// Look for a tight BPL loop reading the Oric's shift register address of 0x31c. The Apple II just has RAM there,
// so the probability of such a loop is infinitesimal.
for(const auto &instruction: disassembly.instructions_by_address) {
// Is this a read of the shift register?
if(
(
(instruction.second.operation == Analyser::Static::MOS6502::Instruction::LDA) ||
(instruction.second.operation == Analyser::Static::MOS6502::Instruction::LDX) ||
(instruction.second.operation == Analyser::Static::MOS6502::Instruction::LDY)
) &&
instruction.second.addressing_mode == Analyser::Static::MOS6502::Instruction::Absolute &&
instruction.second.address == 0x031c) {
did_read_shift_register = true;
continue;
}
if(did_read_shift_register) {
if(
instruction.second.operation == Analyser::Static::MOS6502::Instruction::BPL &&
instruction.second.address == 0xfb) {
is_oric = true;
break;
}
did_read_shift_register = false;
}
}
// Check also for calls into the 0x3xx page above 0x320, as that's where the Oric's boot ROM is.
for(const auto address: disassembly.outward_calls) {
is_oric |= address >= 0x320 && address < 0x400;
}
if(is_oric) {
targets.push_back(std::unique_ptr<Analyser::Static::Target>(OricTarget(sector_zero)));
} else {
targets.push_back(std::unique_ptr<Analyser::Static::Target>(AppleTarget(sector_zero)));
}
return targets;
}