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Merge pull request #873 from TomHarte/Mac128kb

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Fixes 400kb drive PWM interpretation; enables Mac 128kb and 512kb.
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Thomas Harte 2021-02-26 21:29:57 -05:00 committed by GitHub
commit e2b20568c6
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6 changed files with 77 additions and 26 deletions
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13
Analyser/Static/Macintosh/StaticAnalyser.cpp
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@ -19,6 +19,19 @@ Analyser::Static::TargetList Analyser::Static::Macintosh::GetTargets(const Media
using Target = Analyser::Static::Macintosh::Target;
auto *const target = new Target;
target->media = media;
// If this is a single-sided floppy disk, guess the Macintosh 512kb.
if(media.mass_storage_devices.empty()) {
bool has_800kb_disks = false;
for(const auto &disk: media.disks) {
has_800kb_disks |= disk->get_head_count() > 1;
}
if(!has_800kb_disks) {
target->model = Target::Model::Mac512k;
}
}
targets.push_back(std::unique_ptr<Analyser::Static::Target>(target));
return targets;

57
Machines/Apple/Macintosh/DriveSpeedAccumulator.cpp
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@ -8,6 +8,36 @@
#include "DriveSpeedAccumulator.hpp"
namespace {
/*
For knowledge encapsulate below, all credit goes to the MAME team. No original research here.
Per their investigation, the bytes collected for PWM output feed a 6-bit LFSR, which then keeps
output high until it eventually reaches a state of 0x20. The LFSR shifts rightward and taps bits
0 and 1 as the new input into bit 5.
I've therefore implemented the LFSR as below, feeding into a lookup table to calculate actual
pulse widths from the values stored into the PWM buffer.
*/
template<uint8_t value> constexpr uint8_t lfsr() {
if constexpr (value == 0x20 || !value) return 0;
return 1+lfsr<(((value ^ (value >> 1))&1) << 5) | (value >> 1)>();
}
constexpr uint8_t pwm_lookup[] = {
lfsr<0>(), lfsr<1>(), lfsr<2>(), lfsr<3>(), lfsr<4>(), lfsr<5>(), lfsr<6>(), lfsr<7>(),
lfsr<8>(), lfsr<9>(), lfsr<10>(), lfsr<11>(), lfsr<12>(), lfsr<13>(), lfsr<14>(), lfsr<15>(),
lfsr<16>(), lfsr<17>(), lfsr<18>(), lfsr<19>(), lfsr<20>(), lfsr<21>(), lfsr<22>(), lfsr<23>(),
lfsr<24>(), lfsr<25>(), lfsr<26>(), lfsr<27>(), lfsr<28>(), lfsr<29>(), lfsr<30>(), lfsr<31>(),
lfsr<32>(), lfsr<33>(), lfsr<34>(), lfsr<35>(), lfsr<36>(), lfsr<37>(), lfsr<38>(), lfsr<39>(),
lfsr<40>(), lfsr<41>(), lfsr<42>(), lfsr<43>(), lfsr<44>(), lfsr<45>(), lfsr<46>(), lfsr<47>(),
lfsr<48>(), lfsr<49>(), lfsr<50>(), lfsr<51>(), lfsr<52>(), lfsr<53>(), lfsr<54>(), lfsr<55>(),
lfsr<56>(), lfsr<57>(), lfsr<58>(), lfsr<59>(), lfsr<60>(), lfsr<61>(), lfsr<62>(), lfsr<63>(),
};
}
using namespace Apple::Macintosh;
void DriveSpeedAccumulator::post_sample(uint8_t sample) {
@ -17,40 +47,33 @@ void DriveSpeedAccumulator::post_sample(uint8_t sample) {
// the samples until there is a certain small quantity of them,
// then produce a new estimate of rotation speed and start the
// buffer afresh.
samples_[sample_pointer_] = sample;
++sample_pointer_;
if(sample_pointer_ == samples_.size()) {
sample_pointer_ = 0;
//
// Note the table lookup here; see text above.
sample_total_ += pwm_lookup[sample & 0x3f];
++sample_count_;
if(sample_count_ == samples_per_bucket) {
// The below fits for a function like `a + bc`; it encapsultes the following
// beliefs:
//
// (i) motor speed is proportional to voltage supplied;
// (ii) with pulse-width modulation it's therefore proportional to the duty cycle;
// (iii) the Mac pulse-width modulates whatever it reads from the disk speed buffer;
// (iii) the Mac pulse-width modulates whatever it reads from the disk speed buffer, as per the LFSR rules above;
// (iv) ... subject to software pulse-width modulation of that pulse-width modulation.
//
// So, I believe current motor speed is proportional to a low-pass filtering of
// the speed buffer. Which I've implemented very coarsely via 'large' bucketed-averages,
// noting also that exact disk motor speed is always a little approximate.
// Sum all samples.
// TODO: if the above is the correct test, do it on sample receipt rather than
// bothering with an intermediate buffer.
int sum = 0;
for(auto s: samples_) {
sum += s;
}
// The formula below was derived from observing values the Mac wrote into its
// disk-speed buffer. Given that it runs a calibration loop before doing so,
// I cannot guarantee the accuracy of these numbers beyond being within the
// range that the computer would accept.
const float normalised_sum = float(sum) / float(samples_.size());
const float rotation_speed = (normalised_sum * 27.08f) - 259.0f;
const float normalised_sum = float(sample_total_) / float(samples_per_bucket);
const float rotation_speed = (normalised_sum - 3.7f) * 17.6f;
delegate_->drive_speed_accumulator_set_drive_speed(this, rotation_speed);
sample_count_ = 0;
sample_total_ = 0;
}
}

5
Machines/Apple/Macintosh/DriveSpeedAccumulator.hpp
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@ -34,8 +34,9 @@ class DriveSpeedAccumulator {
}
private:
std::array<uint8_t, 20> samples_;
std::size_t sample_pointer_ = 0;
static constexpr int samples_per_bucket = 20;
int sample_count_ = 0;
int sample_total_ = 0;
Delegate *delegate_ = nullptr;
};

12
OSBindings/Mac/Clock Signal/MachinePicker/Base.lproj/MachinePicker.xib
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@ -238,11 +238,11 @@ Gw
</tabViewItem>
<tabViewItem label="Macintosh" identifier="mac" id="lmR-z3-xSm">
<view key="view" id="7Yf-vi-Q0W">
<rect key="frame" x="10" y="33" width="674" height="94"/>
<rect key="frame" x="10" y="33" width="679" height="95"/>
<autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
<subviews>
<textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ZOY-4E-Cfl">
<rect key="frame" x="15" y="73" width="46" height="16"/>
<rect key="frame" x="15" y="74" width="46" height="16"/>
<textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Model:" id="h9r-i6-66j">
<font key="font" metaFont="system"/>
<color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@ -250,13 +250,15 @@ Gw
</textFieldCell>
</textField>
<popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="xa6-NA-JY5">
<rect key="frame" x="65" y="67" width="74" height="25"/>
<popUpButtonCell key="cell" type="push" title="Plus" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="3" imageScaling="proportionallyDown" inset="2" selectedItem="R6T-hg-rOF" id="1Kb-Q2-BGM">
<rect key="frame" x="64" y="68" width="75" height="25"/>
<popUpButtonCell key="cell" type="push" title="128k" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" borderStyle="borderAndBezel" imageScaling="proportionallyDown" inset="2" selectedItem="WCG-6u-ANQ" id="1Kb-Q2-BGM">
<behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
<font key="font" metaFont="menu"/>
<menu key="menu" id="ofy-j9-YnU">
<items>
<menuItem title="512ke" tag="2" id="WCG-6u-ANQ"/>
<menuItem title="128k" id="WCG-6u-ANQ"/>
<menuItem title="512k" tag="1" id="FlG-je-OOM"/>
<menuItem title="512ke" tag="2" id="xaj-em-oZa"/>
<menuItem title="Plus" state="on" tag="3" id="R6T-hg-rOF"/>
</items>
</menu>

6
OSBindings/Qt/mainwindow.cpp
View File

@ -1175,8 +1175,10 @@ void MainWindow::start_macintosh() {
auto target = std::make_unique<Target>();
switch(ui->macintoshModelComboBox->currentIndex()) {
default: target->model = Target::Model::Mac512ke; break;
case 1: target->model = Target::Model::MacPlus; break;
default: target->model = Target::Model::Mac128k; break;
case 1: target->model = Target::Model::Mac512k; break;
case 2: target->model = Target::Model::Mac512ke; break;
case 3: target->model = Target::Model::MacPlus; break;
}
launchTarget(std::move(target));

10
OSBindings/Qt/mainwindow.ui
View File

@ -248,6 +248,16 @@
</item>
<item row="0" column="1">
<widget class="QComboBox" name="macintoshModelComboBox">
<item>
<property name="text">
<string>128k</string>
</property>
</item>
<item>
<property name="text">
<string>512k</string>
</property>
</item>
<item>
<property name="text">
<string>512ke</string>