apple2js/js/formats/woz.ts

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import { debug, toHex } from '../util';
import { bit, byte, word } from '../types';
import { grabNibble } from './format_utils';
import { DiskOptions, ENCODING_BITSTREAM, WozDisk } from './types';
const WOZ_HEADER_START = 0;
const WOZ_HEADER_SIZE = 12;
const WOZ1_SIGNATURE = 0x315A4F57;
const WOZ2_SIGNATURE = 0x325A4F57;
const WOZ_INTEGRITY_CHECK = 0x0a0d0aff;
/**
* Converts a range of bytes from a DataView into an ASCII string
*
* @param data DataView containing string
* @param start start index of string
* @param end end index of string
* @returns ASCII string
*/
function stringFromBytes(data: DataView, start: number, end: number): string {
const byteArray = new Uint8Array(
data.buffer.slice(data.byteOffset + start, data.byteOffset + end)
);
return String.fromCharCode(...byteArray);
}
export class InfoChunk {
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version: byte;
// Version 1
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diskType: byte;
writeProtected: byte;
synchronized: byte;
cleaned: byte;
creator: string;
// Version 2
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sides: byte = 0;
bootSector: byte = 0;
bitTiming: byte = 0;
compatibleHardware: word = 0;
requiredRAM: word = 0;
largestTrack: word = 0;
constructor(data: DataView) {
this.version = data.getUint8(0);
this.diskType = data.getUint8(1);
this.writeProtected = data.getUint8(2);
this.synchronized = data.getUint8(3);
this.cleaned = data.getUint8(4);
this.creator = stringFromBytes(data, 5, 37);
if (this.version > 1) {
this.sides = data.getUint8(37);
this.bootSector = data.getUint8(38);
this.bitTiming = data.getUint8(39);
this.compatibleHardware = data.getUint16(40, true);
this.requiredRAM = data.getUint16(42, true);
this.largestTrack = data.getUint16(44, true);
}
}
}
export class TMapChunk {
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trackMap: byte[];
constructor(data: DataView) {
this.trackMap = [];
for (let idx = 0; idx < 160; idx++) {
this.trackMap.push(data.getUint8(idx));
}
}
}
const WOZ_TRACK_SIZE = 6656;
const WOZ_TRACK_INFO_BITS = 6648;
export class TrksChunk {
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rawTracks: Uint8Array[];
tracks: Uint8Array[];
}
export class TrksChunk1 extends TrksChunk {
constructor(data: DataView) {
super();
this.rawTracks = [];
this.tracks = [];
for (let trackNo = 0, idx = 0; idx < data.byteLength; idx += WOZ_TRACK_SIZE, trackNo++) {
let track = [];
const rawTrack: bit[] = [];
const slice = data.buffer.slice(data.byteOffset + idx, data.byteOffset + idx + WOZ_TRACK_SIZE);
const trackData = new Uint8Array(slice);
const trackInfo = new DataView(slice);
const trackBitCount = trackInfo.getUint16(WOZ_TRACK_INFO_BITS, true);
for (let jdx = 0; jdx < trackBitCount; jdx++) {
const byteIndex = jdx >> 3;
const bitIndex = 7 - (jdx & 0x07);
rawTrack[jdx] = (trackData[byteIndex] >> bitIndex) & 0x01 ? 1 : 0;
}
track = [];
let offset = 0;
while (offset < rawTrack.length) {
const result = grabNibble(rawTrack, offset);
if (!result.nibble) { break; }
track.push(result.nibble);
offset = result.offset + 1;
}
this.tracks[trackNo] = new Uint8Array(track);
this.rawTracks[trackNo] = new Uint8Array(rawTrack);
}
}
}
export interface Trk {
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startBlock: word;
blockCount: word;
bitCount: number;
}
export class TrksChunk2 extends TrksChunk {
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trks: Trk[];
constructor (data: DataView) {
super();
let trackNo;
this.trks = [];
for (trackNo = 0; trackNo < 160; trackNo++) {
const startBlock = data.getUint16(trackNo * 8, true);
const blockCount = data.getUint16(trackNo * 8 + 2, true);
const bitCount = data.getUint32(trackNo * 8 + 4, true);
if (bitCount === 0) { break; }
this.trks.push({
startBlock: startBlock,
blockCount: blockCount,
bitCount: bitCount
});
}
this.tracks = [];
this.rawTracks = [];
const bits = data.buffer;
for (trackNo = 0; trackNo < this.trks.length; trackNo++) {
const trk = this.trks[trackNo];
let track = [];
const rawTrack: bit[] = [];
const start = trk.startBlock * 512;
const end = start + trk.blockCount * 512;
const slice = bits.slice(start, end);
const trackData = new Uint8Array(slice);
if (trackNo === 0) {
// debug(`First bytes: ${toHex(trackData[0])} ${toHex(trackData[1])} ${toHex(trackData[2])} ${toHex(trackData[3])}`);
}
for (let jdx = 0; jdx < trk.bitCount; jdx++) {
const byteIndex = jdx >> 3;
const bitIndex = 7 - (jdx & 0x07);
rawTrack[jdx] = (trackData[byteIndex] >> bitIndex) & 0x01 ? 1 : 0;
}
track = [];
let offset = 0;
while (offset < rawTrack.length) {
const result = grabNibble(rawTrack, offset);
if (!result.nibble) { break; }
track.push(result.nibble);
offset = result.offset + 1;
}
this.tracks[trackNo] = new Uint8Array(track);
this.rawTracks[trackNo] = new Uint8Array(rawTrack);
}
}
}
export class MetaChunk {
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values: Record<string, string>;
constructor (data: DataView) {
const infoStr = stringFromBytes(data, 0, data.byteLength);
const parts = infoStr.split('\n');
this.values = parts.reduce(function(acc: Record<string, string>, part) {
const subParts = part.split('\t');
acc[subParts[0]] = subParts[1];
return acc;
}, {});
}
}
interface Chunks {
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[key: string]: unknown;
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info?: InfoChunk;
tmap?: TMapChunk;
trks?: TrksChunk;
meta?: MetaChunk;
}
/**
* Returns a `Disk` object from Woz image data.
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* @param options the disk image and options
* @returns A bitstream disk
*/
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export default function createDiskFromWoz(options: DiskOptions): WozDisk {
const { rawData } = options;
if (!rawData) {
throw new Error('Requires rawData');
}
const dv = new DataView(rawData, 0);
let dvOffset = 0;
let wozVersion;
const chunks: Chunks = {};
function readHeader() {
const wozSignature = dv.getUint32(WOZ_HEADER_START + 0, true);
switch (wozSignature) {
case WOZ1_SIGNATURE:
wozVersion = 1;
break;
case WOZ2_SIGNATURE:
wozVersion = 2;
break;
default:
return false;
}
if (dv.getUint32(WOZ_HEADER_START + 4, true) !== WOZ_INTEGRITY_CHECK) {
return false;
}
return true;
}
function readChunk() {
if (dvOffset >= dv.byteLength) {
return null;
}
const type = dv.getUint32(dvOffset, true);
const size = dv.getUint32(dvOffset + 4, true);
const data = new DataView(dv.buffer, dvOffset + 8, size);
dvOffset += size + 8;
return {
type: type,
size: size,
data: data
};
}
if (readHeader()) {
dvOffset = WOZ_HEADER_SIZE;
let chunk = readChunk();
while (chunk) {
switch (chunk.type) {
case 0x4F464E49: // INFO
chunks.info = new InfoChunk(chunk.data);
break;
case 0x50414D54: // TMAP
chunks.tmap = new TMapChunk(chunk.data);
break;
case 0x534B5254: // TRKS
if (wozVersion === 1) {
chunks.trks = new TrksChunk1(chunk.data);
} else {
chunks.trks = new TrksChunk2(chunk.data);
}
break;
case 0x4154454D: // META
chunks.meta = new MetaChunk(chunk.data);
break;
case 0x54495257: // WRIT
// Ignore
break;
default:
debug('Unsupported chunk', toHex(chunk.type, 8));
}
chunk = readChunk();
}
} else {
debug('Invalid woz header');
}
// debug(chunks);
const { meta, tmap, trks, info } = chunks;
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const disk: WozDisk = {
encoding: ENCODING_BITSTREAM,
Split disk data out into its own record (#158) * Harmonize drive and disk type hierarchies Before, the `XXXDrive` and `XXXDisk` type hierarchies were similar, but not exactly the same. For example, `encoding` and `format` were missing on some `XXXDisk` types where they existed on the `XXXDrive` type. This change attempts to bring the hierarchies closer together. However, the biggest visible consequence is the introduction of the `FLOPPY_FORMATS` array and its associated `FloppyFormat` type. This replaces `NIBBLE_FORMATS` in most places. A couple of new type guards for disk formats and disks have been added as well. All tests pass, everything compiles with no errors, and both WOZ and nibble format disks load in the emulator. * Move disk data to a `disk` field in the drive Before, disk data was mixed in with state about the drive itself (like track, motor phase, etc.). This made it hard to know exactly what data was necessary for different image formats. Now, the disk data is in a `disk` field whose type depends on the drive type. This makes responisbility a bit easier. One oddity, though, is that the `Drive` has metadata _and_ the `Disk` has metadata. When a disk is in the drive, these should be `===`, but when there is no disk in the drive, obviously only the drive metadata is set. All tests pass, everything compiles, and both WOZ and nibble disks work in the emulator (both preact and classic). * Squash the `Drive` type hierarchy Before, the type of the drive depended on the type of the disk in the drive. Thus, `NibbleDrive` contained a `NibbleDisk` and a `WozDrive` contained a `WozDisk`. With the extraction of the disk data to a single field, this type hierarchy makes no sense. Instead, it suffices to check the type of the disk. This change removes the `NibbleDrive` and `WozDrive` types and type guards, checking the disk type where necessary. This change also introduces the `NoFloppyDisk` type to represent the lack of a disk. This allows the drive to have metadata, for one. All tests pass, everything compiles, and both WOZ and nibble disks work locally. * Use more destructuring assignment Now, more places use constructs like: ```TypeScript const { metadata, readOnly, track, head, phase, dirty } = drive; return { disk: getDiskState(drive.disk), metadata: {...metadata}, readOnly, track, head, phase, dirty, }; ``` * Remove the `Disk` object from the `Drive` object This change splits out the disk objects into a record parallel to the drive objects. The idea is that the `Drive` structure becomes a representation of the state of the drive that is separate from the disk image actually in the drive. This helps in an upcoming refactoring. This also changes the default empty disks to be writable. While odd, the write protect switch should be in the "off" position since there is no disk pressing on it. Finally, `insertDisk` now resets the head position to 0 since there is no way of preserving the head position across disks. (Even in the real world, the motor-off delay plus spindle spin-down would make it impossible to know the disk head position with any accuracy.)
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format: 'woz',
trackMap: tmap?.trackMap || [],
rawTracks: trks?.rawTracks || [],
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readOnly: true, //chunks.info.writeProtected === 1;
Floppy controller refactorings 1 (#155) * Add `DiskMetada` to the `Disk` interface Before, metadata about the image, such as name, side, etc. was mixed in with actual disk image information. This change breaks that information into a separate structure called `DiskMetadata`. Currently, the only two fields are `name` and `side`, but the idea is that more fields could be added as necessary, like a description, a scan of the disk or label, etc. In a follow-on change, the default write-protection status will come from the metadata as well. The current implementation copies the metadata when saving/restoring state, loading disk images, etc. In the future, the metadata should passed around until the format is required to change (like saving one disk image format as another). Likewise, in the future, in may be desirable to be able to override the disk image metadata with user-supplied metadata. This could be use, for example, to temporarily add or remove write-protection from a disk image. All existing tests pass and the emulator builds with no errors. * Rename `writeMode` to `q7` Before, nibble disk emulation used the `writeMode` field to keep track of whether the drive should be read from or written to, but the WOZ emulation used `q7` to keep track of the same state. This change renames `writeMode` to `q7` because it more accurately reflects the state of the Disk II controller as specified in the manuals, DOS source, and, especially, _Understanding the Apple //e_ by Jim Sather. * Remove the coil state Before, `q` captured the state of the coils. But it was never read. This change just deletes it. * Use the bootstrap and sequencer ROMs with indirection Before, the contents of the bootstrap ROM and sequencer ROM were set directly on fields of the controller. These were not saved or restored with the state in `getState` and `setState`. (It would have been very space inefficient if they had). Now, these ROMs are used from constants indexed by the number of sectors the card supports. This, in turn, means that if the number of sectors is saved with the state, it can be easily restored. * Split out the Disk II controller state This change factors the emulated hardware state into a separate structure in the Disk II controller. The idea is that this hardware state will be able to be shared with the WOZ and nibble disk code instead of sharing _all_ of the controller state (like callbacks and so forth). * Factor out disk insertion Before, several places in the code essentially inserted a new disk image into the drive, which similar—but not always exactly the same—code. Now there is an `insertDisk` method that is responsible for inserting a new `FloppyDisk`. All tests pass, everything compiles, manually tested nibble disks and WOZ disks.
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metadata: {
name: meta?.values['title'] || options.name,
side: meta?.values['side_name'] || meta?.values['side']
},
info
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};
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return disk;
}