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Provide expected wave lengths.

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This commit is contained in:
Thomas Harte
2025-12-04 23:15:10 -05:00
parent 1a7e0bd6a5
commit bdfb9c0684
2 changed files with 37 additions and 6 deletions
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Storage/Tape/Parsers/Commodore.cpp
+23 -5
View File
@@ -235,6 +235,14 @@ uint16_t Parser::get_next_short(Storage::Tape::TapeSerialiser &serialiser) {
return value;
}
float Parser::expected_length(const WaveType type) {
const size_t index = size_t(type);
if(index >= 0 && index < timing_records_.size()) {
return timing_records_[index].total / float(timing_records_[index].count);
}
return 0.0f;
}
/*!
Per the contract with Analyser::Static::TapeParser; sums time across pulses. If this pulse
indicates a high to low transition, inspects the time since the last transition, to produce
@@ -251,6 +259,16 @@ void Parser::process_pulse(const Storage::Tape::Pulse &pulse) {
// medium: 480us => 0.000960s cycle
// long: 960us => 0.001920s cycle
const auto classify_as = [&](const WaveType type) {
push_wave(type);
const size_t index = size_t(type);
if(index >= 0 && index < timing_records_.size() && timing_records_[index].count < 10) {
++timing_records_[index].count;
timing_records_[index].total += wave_period_;
}
};
const bool is_high = pulse.type == Storage::Tape::Pulse::High;
if(!is_high && previous_was_high_) {
const bool is_plus4 = target_platform_ == TargetPlatform::Plus4;
@@ -264,11 +282,11 @@ void Parser::process_pulse(const Storage::Tape::Pulse &pulse) {
const float medium_threshold = ((medium_ms + short_ms) * 0.5f) * to_s;
const float short_threshold = (short_ms * 0.5f) * to_s;
if(wave_period_ >= overlong_threshold) push_wave(WaveType::Unrecognised);
else if(wave_period_ >= long_threshold) push_wave(WaveType::Long);
else if(wave_period_ >= medium_threshold) push_wave(WaveType::Medium);
else if(wave_period_ >= short_threshold) push_wave(WaveType::Short);
else push_wave(WaveType::Unrecognised);
if(wave_period_ >= overlong_threshold) classify_as(WaveType::Unrecognised);
else if(wave_period_ >= long_threshold) classify_as(WaveType::Long);
else if(wave_period_ >= medium_threshold) classify_as(WaveType::Medium);
else if(wave_period_ >= short_threshold) classify_as(WaveType::Short);
else classify_as(WaveType::Unrecognised);
wave_period_ = 0.0f;
}
Storage/Tape/Parsers/Commodore.hpp
+14 -1
View File
@@ -10,6 +10,8 @@
#include "TapeParser.hpp"
#include "Storage/TargetPlatforms.hpp"
#include <array>
#include <memory>
#include <string>
@@ -72,6 +74,11 @@ public:
*/
std::unique_ptr<Data> get_next_data(Storage::Tape::TapeSerialiser &);
/*!
Returns an average length for encountered waves that were bucketed as the specified type.
*/
float expected_length(WaveType);
private:
TargetPlatform::Type target_platform_;
@@ -123,10 +130,16 @@ private:
indicates a high to low transition, inspects the time since the last transition, to produce
a long, medium, short or unrecognised wave period.
*/
void process_pulse(const Storage::Tape::Pulse &pulse) override;
void process_pulse(const Storage::Tape::Pulse &) override;
bool previous_was_high_ = false;
float wave_period_ = 0.0f;
struct WaveTiming {
float total;
int count = 0;
};
std::array<WaveTiming, 5> timing_records_{};
/*!
Per the contract with Analyser::Static::TapeParser; produces any of a word marker, an end-of-block marker,
a zero, a one or a lead-in symbol based on the currently captured waves.