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Merge pull request mattgodbolt#202 from scarybeasts/i8271-1
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Fix various i8271 bugs including the excessive seeking bug.
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@mattgodbolt
mattgodbolt authored Aug 6, 2019
2 parents 18a4b06 + 6bcb5f8 commit ad70851
Showing 1 changed file with 59 additions and 55 deletions.
114 changes: 59 additions & 55 deletions fdc.js
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Original file line number Diff line number Diff line change
Expand Up @@ -91,7 +91,7 @@ define(['./utils'], function (utils) {
this.sectorOffset = 0;
this.formatSector = 0;
this.rsector = 0;
this.track = -1;
this.track = 0;
this.side = -1;
this.notFoundTask = fdc.scheduler.newTask(function () {
this.fdc.notFound();
Expand Down Expand Up @@ -218,7 +218,6 @@ define(['./utils'], function (utils) {
self.status = 0;
self.result = 0;
self.data = 0;
self.driveSel = 0;
self.curDrive = 0;
self.drvout = 0;
self.curTrack = [0, 0];
Expand All @@ -237,22 +236,19 @@ define(['./utils'], function (utils) {
self.motorSpinDownTask = [
scheduler.newTask(function () {
self.motorOn[0] = false;
self.drvout &= ~0x40;
noise.spinDown(); // TODO multiple discs!
}),
scheduler.newTask(function () {
self.motorOn[1] = false;
self.drvout &= ~0x80;
noise.spinDown(); // TODO multiple discs!
})
];
self.written = false;
self.verify = false;
self.scheduler = scheduler;
self.drives = [emptySsd(this), emptySsd(this)];
self.pendingReady = false;
self.ready = true;
self.readyTask = scheduler.newTask(function () {
self.pendingReady = true;
});

self.NMI = function () {
cpu.NMI(self.status & 8);
Expand Down Expand Up @@ -319,8 +315,7 @@ define(['./utils'], function (utils) {
return self.data;
};
self.discFinishRead = function () {
self.callbackTask.cancel();
self.callbackTask.schedule(200);
self.callbackTask.reschedule(200);
};

var paramMap = {
Expand All @@ -338,47 +333,48 @@ define(['./utils'], function (utils) {
if (self.status & 0x80) return;
self.command = val & 0x3f;
if (self.command === 0x17) self.command = 0x13;
self.driveSel = val >>> 6;
self.curDrive = (val & 0x80) ? 1 : 0;
if (self.command < 0x2c) {
self.drvout &= ~(0x80 | 0x40);
self.drvout |= (val & (0x80 | 0x40));
}
self.paramNum = 0;
self.paramReq = numParams(self.command);
self.status = 0x80;
if (!self.paramReq) {
if (self.command === 0x2c) {
// read drive status
self.status = 0x10;
self.result = 0x88 | (self.curTrack[self.curDrive] ? 0 : 2);
if (self.ready) {
if (self.driveSel & 1) self.result |= 0x04;
if (self.driveSel & 2) self.result |= 0x40;
} else if (self.pendingReady) self.ready = true; // Ready for next time
self.result = 0x80;
self.result |= (self.realTrack[self.curDrive] ? 0 : 2);
self.result |= (self.drives[self.curDrive].writeProt ? 0x08 : 0);
if (self.drvout & 0x40) self.result |= 0x04;
if (self.drvout & 0x80) self.result |= 0x40;
} else {
self.result = 0x18;
self.status = 0x18;
self.NMI();
self.callbackTask.cancel();
}
}
}

function writeSpecial(reg, a, b) {
function writeSpecial(reg, val) {
self.status = 0;
switch (reg) {
case 0x17:
break; // apparently "mode register"
case 0x12:
self.curTrack[0] = b;
self.curTrack[0] = val;
break;
case 0x1a:
self.curTrack[1] = b;
self.curTrack[1] = val;
break;
case 0x23:
self.drvout = a;
self.drvout = val;
break;
default:
self.result = self.status = 0x18;
self.NMI();
self.callbackTask.cancel();
break;
}
}
Expand All @@ -401,51 +397,54 @@ define(['./utils'], function (utils) {
default:
self.result = self.status = 0x18;
self.NMI();
self.callbackTask.cancel();
break;
}
}

function spinup() {
// TODO: not sure where this should go, or for how long. This is a workaround for EliteA
self.ready = false;
self.pendingReady = false;
self.readyTask.cancel();
var time = 200;

if (!self.motorOn[self.curDrive]) {
self.readyTask.schedule((0.5 * cpu.peripheralCyclesPerSecond) | 0); // Apparently takes a half second to spin up
} else {
self.readyTask.schedule(1000); // little bit of time for each command (so, really, spinup is a bad place to put this)
// Half a second.
time = (0.5 * cpu.peripheralCyclesPerSecond) | 0;
self.motorOn[self.curDrive] = true;
noise.spinUp();
}
self.motorOn[self.curDrive] = true;

self.callbackTask.reschedule(time);
self.motorSpinDownTask[self.curDrive].cancel();
noise.spinUp();
self.phase = 0;
}

function setspindown() {
if (self.motorOn[self.curDrive]) {
self.motorSpinDownTask[self.curDrive].reschedule(40000 * 128);
self.motorSpinDownTask[self.curDrive].reschedule(cpu.peripheralCyclesPerSecond * 2);
}
}

function seek(track) {
spinup();
self.realTrack[self.curDrive] += track - self.curTrack[self.curDrive];
var diff = self.drives[self.curDrive].seek(self.realTrack[self.curDrive]);
var realTrack = self.realTrack[self.curDrive];
realTrack += (track - self.curTrack[self.curDrive]);
if (realTrack < 0)
realTrack = 0;
if (realTrack > 79) {
realTrack = 79;
}
self.realTrack[self.curDrive] = realTrack;
var diff = self.drives[self.curDrive].seek(realTrack);
// Let disc noises overlap by ~10%
var seekLen = (noise.seek(diff) * 0.9 * cpu.peripheralCyclesPerSecond) | 0;
self.callbackTask.cancel();
self.callbackTask.schedule(Math.max(200, seekLen));
self.callbackTask.reschedule(Math.max(200, seekLen));
self.phase = 1;
}

var debugByte = 0;

function prepareSectorIO(track, sector, numSectors) {
if (numSectors !== undefined) self.sectorsLeft = numSectors & 31;
if (sector !== undefined) self.curSector = sector;
spinup();
self.phase = 0;
seek(track);
debugByte = 0;
spinup(); // State: spinup -> seek.
}

function parameter(val) {
Expand All @@ -456,7 +455,7 @@ define(['./utils'], function (utils) {
self.status = 0;
break;
case 0x29: // Seek
seek(self.params[0]);
spinup(); // State: spinup -> seek.
break;
case 0x1f: // Verify
case 0x13: // Read
Expand All @@ -470,7 +469,7 @@ define(['./utils'], function (utils) {
prepareSectorIO(self.params[0]);
break;
case 0x3a: // Special register write
writeSpecial(self.params[0], self.params[1], self.params[2]);
writeSpecial(self.params[0], self.params[1]);
break;
case 0x3d: // Special register read
readSpecial(self.params[0]);
Expand All @@ -479,7 +478,6 @@ define(['./utils'], function (utils) {
self.result = 0x18;
self.status = 0x18;
self.NMI();
self.callbackTask.cancel();
break;
}
}
Expand Down Expand Up @@ -528,16 +526,22 @@ define(['./utils'], function (utils) {
}

function callback() {
if (self.phase == 0) {
// Spinup complete.
seek(self.params[0]);
return;
}

switch (self.command) {
case 0x29: // Seek
self.curTrack[self.curDrive] = self.params[0];
update(0x18);
done();
break;

case 0x0b: // Write
if (!self.phase) {
if (self.phase == 1) {
self.curTrack[self.curDrive] = self.params[0];
self.phase = 1;
self.phase = 2;
self.drives[self.curDrive].write(self.curSector, self.params[0], density(), 0);
update(0x8c);
return;
Expand All @@ -554,9 +558,9 @@ define(['./utils'], function (utils) {

case 0x13: // Read
case 0x1f: // Verify
if (!self.phase) {
if (self.phase == 1) {
self.curTrack[self.curDrive] = self.params[0];
self.phase = 1;
self.phase = 2;
self.drives[self.curDrive].read(self.curSector, self.params[0], density(), 0);
return;
}
Expand All @@ -569,9 +573,9 @@ define(['./utils'], function (utils) {
break;

case 0x1b: // Read ID
if (!self.phase) {
if (self.phase == 1) {
self.curTrack[self.curDrive] = self.params[0];
self.phase = 1;
self.phase = 2;
self.drives[self.curDrive].address(self.params[0], density(), 0);
return;
}
Expand All @@ -584,17 +588,17 @@ define(['./utils'], function (utils) {

case 0x23: // Format
switch (self.phase) {
case 0:
case 1:
self.curTrack[self.curDrive] = self.params[0];
self.drives[self.curDrive].write(self.curSector, self.params[0], density(), 0);
update(0x8c);
self.phase = 1;
break;
case 1:
self.drives[self.curDrive].format(self.params[0], density(), 0);
self.phase = 2;
break;
case 2:
self.drives[self.curDrive].format(self.params[0], density(), 0);
self.phase = 3;
break;
case 3:
done();
break;
}
Expand Down

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