Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 | 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 136x 35773128x 35773128x 35773128x 35773128x 35773128x 35773128x 35773128x 35773128x 35773128x 35773128x 1044x 1044x 1044x 1044x 13x 13x 20x 18x 18x 18x 18x 18x 17x 17x 1x 17x 16x 2x 1x 1x 15x 15x 15x 15x 15x 15x 2x 2x 15x 20x 20x 20x 20x 20x 15x 15x 1044x 1044x 1044x 1044x 1044x 1044x 1044x 1487x 1487x 1487x 1487x 1487x 1487x 1487x 1487x 1487x 1487x 1487x 1487x 18595177x 18595177x 18595177x 18595177x 18595177x 1411x 1411x 1411x 18593766x 18593766x 18593766x 503270x 1408x 1408x 1411x 1411x 500451x 500451x 18590947x 148727576x 148727576x 148727576x 4647674x 4647674x 4647674x 4647674x 1487x 15x 15x 15x 15x 30x 2x 30x 17047936x 4261984x 4261984x 17047936x 17047936x 17047936x 1x 17047935x 17047936x 4261984x 1408x 1408x 1408x 1408x 1408x 1408x 4387774x 4387774x 125790x 125790x 4261984x 4261984x 4387774x 1408x 15x 15x 15x 15x 15x 1003x 1003x 1003x 1003x 1003x 1003x 1003x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 1003x 1003x 1003x 1003x 1003x 15x 15x 15x 15x 15x 1003x 1404x 1404x 1404x 1404x 1404x 1404x 1404x 68796x 68796x 68796x 68796x 68796x 68796x 68796x 1003x 15x | // HFE format implementation for disc image loading and saving
// Translated from beebjit by Chris Evans and expanded by Matt Godbolt.
import { IbmDiscFormat } from "./disc-format.js";
import { numberRuns } from "./disc.js";
import { hexbyte } from "./hex.js";
// HFE format constants
const HfeHeaderV1 = "HXCPICFE";
const HfeHeaderV3 = "HXCHFEV3";
const HfeV3OpcodeMask = 0xf0;
const HfeV3OpcodeNop = 0xf0;
const HfeV3OpcodeSetIndex = 0xf1;
const HfeV3OpcodeSetBitrate = 0xf2;
const HfeV3OpcodeSkipBits = 0xf3;
const HfeV3OpcodeRand = 0xf4;
const HfeTrackCountOffset = 9;
// SETBITRATE's argument is 72 for 250 kbit/s, the BBC's rate; these are as far from it as is believable.
const MinBitRate = 64;
const MaxBitRate = 80;
const HfeBlockSideSize = 256;
const HfeBlockSize = HfeBlockSideSize * 2;
const HfeShugartDdFloppyMode = 7;
const HfeIsoIbmFmEncoding = 2;
// 250kbit bitrate value per HFE format specification
const Bitrate250k = 72;
/**
* Flip the bits in a byte for HFE encoding
* @param {number} val - Byte value to flip
* @returns {number} - Flipped byte value
*/
function hfeByteFlip(val) {
let ret = 0;
if (val & 0x80) ret |= 0x01;
if (val & 0x40) ret |= 0x02;
if (val & 0x20) ret |= 0x04;
if (val & 0x10) ret |= 0x08;
if (val & 0x08) ret |= 0x10;
if (val & 0x04) ret |= 0x20;
if (val & 0x02) ret |= 0x40;
if (val & 0x01) ret |= 0x80;
return ret;
}
/**
* Get the track offset and length from HFE metadata
* @param {Uint8Array} metadata - HFE lookup table metadata
* @param {number} track - Track number
* @returns {{offset: number, length: number}} - Track offset and length
*/
function hfeGetTrackOffsetAndLength(metadata, track) {
const index = track << 2;
const offset = HfeBlockSize * (metadata[index] + (metadata[index + 1] << 8));
const length = metadata[index + 2] + (metadata[index + 3] << 8);
return { offset, length };
}
/**
* Whether an HFE image holds a 40 track format. A capture with no more tracks than half a surface
* cannot be one of an 80 track disc, whatever drive read it.
*
* @param {Uint8Array} data
* @returns {{is40Track: boolean, reason: string}}
*/
export function sniffHfeLayout(data) {
const numTracks = data.length > HfeTrackCountOffset ? data[HfeTrackCountOffset] : 0;
return {
is40Track: numTracks > 0 && numTracks * 2 <= IbmDiscFormat.tracksPerDisc,
reason: `its header declares ${numTracks} tracks`,
};
}
/**
* Load a disc image in HFE format (v1 or v3)
* @param {import("./disc.js").Disc} disc - The disc object to load into
* @param {Uint8Array} data - The HFE file data
* @param {function(Uint8Array): void} onChange - Optional callback when disc content changes
* @returns {import("./disc.js").Disc} - The loaded disc object
*/
export function loadHfe(disc, data, onChange) {
if (data.length < HfeBlockSize) throw new Error("HFE file missing header");
const header = new TextDecoder("ascii").decode(data.slice(0, 8));
let isV3 = false;
let hfeVersion = 1;
Iif (header === HfeHeaderV1) {
// HFE v1 format
} else if (header === HfeHeaderV3) {
hfeVersion = 3;
isV3 = true;
} else {
throw new Error(`HFE file bad header '${header}'`);
}
if (data[8] !== 0) throw new Error("HFE file revision not 0");
if (data[11] !== 2 && data[11] !== 0) {
if (data[11] === 0xff) {
disc.loadNotes.push({ text: `unknown encoding &${hexbyte(data[11])}, read as FM or MFM`, isOdd: true });
} else {
throw new Error(`HFE encoding not ISOIBM_(M)FM_ENCODING: ${data[11]}`);
}
}
const numSides = data[10];
Iif (numSides < 1 || numSides > 2) throw new Error(`Invalid number of sides: ${numSides}`);
const numTracks = data[HfeTrackCountOffset];
Iif (numTracks > IbmDiscFormat.tracksPerDisc) throw new Error(`Too many tracks: ${numTracks}`);
let expandShift = 0;
if (disc.config.expandTo80 && numTracks * 2 <= IbmDiscFormat.tracksPerDisc) {
expandShift = 1;
disc.is40Track = true;
}
const spread = expandShift ? " spread over 80" : "";
disc.loadNotes.push({
text: `HFE v${hfeVersion}, ${numSides} ${numSides === 1 ? "side" : "sides"}, ${numTracks} tracks${spread}`,
isOdd: false,
});
const wildBitRateTracks = new Set();
const lateIndexTracks = new Set();
const lutOffset = HfeBlockSize * (data[18] + (data[19] << 8));
Iif (lutOffset + HfeBlockSize > data.length) throw new Error("HFE LUT doesn't fit");
const metadata = data.slice(lutOffset, lutOffset + HfeBlockSize);
for (let trackNum = 0; trackNum < numTracks; ++trackNum) {
let actualTrackNum = trackNum;
Iif (disc.config.isSkipOddTracks) {
if (trackNum & 1) continue;
actualTrackNum = trackNum >>> 1;
}
actualTrackNum = actualTrackNum << expandShift;
const { offset, length } = hfeGetTrackOffsetAndLength(metadata, trackNum);
Iif (offset + length > data.length)
throw new Error(
`HFE track ${trackNum} doesn't fit (length ${length} offset ${offset} file length ${data.length})`,
);
const trackData = data.slice(offset, offset + length);
for (let sideNum = 0; sideNum < numSides; ++sideNum) {
const bufLen = length >> 1;
let bytesWritten = 0;
Iif (disc.config.isSkipUpperSide && sideNum === 1) continue;
let isSetBitRate = false;
let isSkipBits = false;
let skipBitsLength = 0;
let pulses = 0;
let shiftCounter = 0;
const trackObj = disc.getTrack(sideNum === 1, actualTrackNum);
disc.setTrackUsed(sideNum === 1, actualTrackNum);
const rawPulses = trackObj.pulses2Us;
for (let byteIndex = 0; byteIndex < bufLen; ++byteIndex) {
Iif (bytesWritten === rawPulses.length) {
throw new Error(`HFE track ${trackNum} truncated`);
}
const index = ((byteIndex >>> 8) << 9) + (sideNum << 8) + (byteIndex & 0xff);
let byte = hfeByteFlip(trackData[index]);
let numBits = 8;
if (isSetBitRate) {
isSetBitRate = false;
if (byte < MinBitRate || byte > MaxBitRate) wildBitRateTracks.add(trackNum);
continue;
} else Iif (isSkipBits) {
isSkipBits = false;
if (byte === 0 || byte >= 8) {
throw new Error(`HFE v3 invalid skipbits ${byte}`);
}
skipBitsLength = byte;
continue;
} else Iif (skipBitsLength) {
byte = (byte << (8 - skipBitsLength)) & 0xff;
numBits = skipBitsLength;
skipBitsLength = 0;
} else if (isV3 && (byte & HfeV3OpcodeMask) === HfeV3OpcodeMask) {
switch (byte) {
case HfeV3OpcodeNop:
continue; // NB continue
case HfeV3OpcodeSetIndex:
if (bytesWritten !== 0) lateIndexTracks.add(trackNum);
continue; // NB continue
case HfeV3OpcodeSetBitrate:
isSetBitRate = true;
continue; // NB continue
case HfeV3OpcodeSkipBits:
isSkipBits = true;
continue; // NB continue
case HfeV3OpcodeRand:
// internally we represent weak bits on disc as a no flux area.
byte = 0;
break; // NB a break
default:
throw new Error(`Unknown HFE v3 opcode ${byte}`);
}
}
for (let bitIndex = 0; bitIndex < numBits; ++bitIndex) {
pulses = ((pulses << 1) & 0xffffffff) | (byte & 0x80 ? 1 : 0);
byte = (byte << 1) & 0xff;
if (++shiftCounter === 32) {
rawPulses[bytesWritten] = pulses;
bytesWritten++;
pulses = 0;
shiftCounter = 0;
}
}
}
trackObj.length = bytesWritten;
}
}
noteTracks(disc, wildBitRateTracks, "a bit rate far from 250 kbit/s");
noteTracks(disc, lateIndexTracks, "the index part way round");
Iif (onChange) {
disc.addTrackWriteListener((_side, _trackNum, _trackObj) => {
// Generate a complete HFE image from the current disc state
const hfeData = toHfe(disc);
// Call the onChange handler with the updated HFE data
onChange(hfeData);
}, true);
}
return disc;
}
function noteTracks(disc, trackNums, what) {
if (!trackNums.size) return;
const tracks = trackNums.size === 1 ? "track" : "tracks";
disc.loadNotes.push({ text: `${what} on ${tracks} ${numberRuns([...trackNums])}`, isOdd: true });
}
/**
* Check if a byte could be mistakenly interpreted as a v3 opcode
* @param {number} byte - The byte to check after bit flipping
* @returns {boolean} - True if the byte could be interpreted as a v3 opcode
*/
function isHfeV3OpcodeCollision(byte) {
// After bit flipping, check if the lower 4 bits are all 1s (0x0F)
return (byte & 0x0f) === 0x0f;
}
/**
* Encode a single 32-bit pulse value to 4 bytes in HFE v3 format
* Handles opcode collisions by replacing with RAND opcode if needed
* @param {number} pulsesWord - The 32-bit pulse value
* @returns {Uint8Array} - 4 bytes of HFE v3 encoded data
*/
function encodeHfeV3Pulses(pulsesWord) {
const result = new Uint8Array(4);
for (let i = 0; i < 4; i++) {
const byte = (pulsesWord >>> 24) & 0xff;
const flippedByte = hfeByteFlip(byte);
// Check if the byte could be mistakenly interpreted as a v3 opcode
if (isHfeV3OpcodeCollision(flippedByte)) {
// Replace with bit-flipped RAND opcode
result[i] = hfeByteFlip(HfeV3OpcodeRand);
} else {
result[i] = flippedByte;
}
pulsesWord <<= 8;
}
return result;
}
/**
* Convert track data to HFE v3 format, handling weak pulses and opcode collisions
* @param {Uint32Array|Array<number>} pulses - Array of 32-bit pulse values for the track
* @returns {Uint8Array} - The track data in HFE v3 format
*/
export function convertTrackToHfeV3(pulses) {
// Calculate the max potential size (4 bytes per pulse value + 3 bytes header)
const buffer = new Uint8Array(pulses.length * 4 + 3);
let bufferIndex = 0;
// Add HFE v3 header opcodes (SETINDEX, SETBITRATE, Bitrate250k)
buffer[bufferIndex++] = hfeByteFlip(HfeV3OpcodeSetIndex);
buffer[bufferIndex++] = hfeByteFlip(HfeV3OpcodeSetBitrate);
buffer[bufferIndex++] = hfeByteFlip(Bitrate250k);
// Process each pulse
for (let i = 0; i < pulses.length; i++) {
const pulse = pulses[i];
if (pulse === 0) {
// Handle weak bits explicitly in HFEv3 with RAND opcode
const randOpcode = hfeByteFlip(HfeV3OpcodeRand);
buffer.fill(randOpcode, bufferIndex, bufferIndex + 4);
} else {
// Encode normal pulses, handling potential opcode collisions
const encodedPulses = encodeHfeV3Pulses(pulse);
buffer.set(encodedPulses, bufferIndex);
}
bufferIndex += 4;
}
// Return only the used part of the buffer
return buffer.slice(0, bufferIndex);
}
/**
* Convert disc to HFE v3 format
* HFE is a format used by the HxC Floppy Emulator for storing disk images.
* This implementation supports variable track lengths without truncation.
* Reference: https://hxc2001.com/download/floppy_drive_emulator/SDCard_HxC_Floppy_Emulator_HFE_file_format.pdf
* @param {import("./disc.js").Disc} disc - The disc to convert to HFE
* @returns {Uint8Array} - The HFE file data
*/
export function toHfe(disc) {
const numSides = disc.isDoubleSided ? 2 : 1;
const numTracks = disc.tracksUsed;
// Pre-calculate sizes for each track to properly support variable track lengths
const trackSizes = [];
const trackOffsetDeltas = [];
for (let trackNum = 0; trackNum < numTracks; trackNum++) {
const track0 = disc.getTrack(false, trackNum);
const track1 = numSides > 1 ? disc.getTrack(true, trackNum) : { length: 0 };
// Calculate the actual size needed for this specific track
// From C code: 4 bytes per 32-bit word, 3 "header" HFEv3 bytes, 2 sides
const trackLen = Math.max(track0.length, track1.length);
const hfeTrackLen = (trackLen * 4 + 3) * 2;
const hfeOffsetDelta = Math.floor(hfeTrackLen / HfeBlockSize) + 1;
trackSizes.push(hfeTrackLen);
trackOffsetDeltas.push(hfeOffsetDelta);
}
// Build header
const header = new Uint8Array(512);
header.fill(0xff);
// Write HFE v3 signature
const encoder = new TextEncoder();
header.set(encoder.encode("HXCHFEV3"), 0);
header[8] = 0; // Revision 0
header[9] = numTracks;
header[10] = numSides;
header[11] = HfeIsoIbmFmEncoding; // IBM FM/MFM encoding
header[12] = 250; // Bit rate (nb we use the set bitrate command per track)
header[13] = 0;
header[14] = 0; // RPM (unused)
header[15] = 0;
header[16] = HfeShugartDdFloppyMode; // Mode: Shugart DD
header[17] = 0xff; // Unused
header[18] = 1; // LUT offset at block 1 (512 bytes)
header[19] = 0;
header[20] = 0xff; // Write allowed
header[21] = 0xff; // Single step
header[22] = 0xff; // No alternate track options
header[23] = 0xff;
header[24] = 0xff;
header[25] = 0xff;
const headerSize = HfeBlockSize;
// Assume everything will fit into one block.
const lutSize = 1 * HfeBlockSize;
// Build LUT (Lookup Table) for track offsets
const lut = new Uint8Array(lutSize);
const lutDataView = new DataView(lut.buffer);
let hfeOffset = 2; // Start at block 2 (after header and LUT)
// Calculate total file size and build LUT
let totalSize = headerSize + lutSize;
for (let trackNum = 0; trackNum < numTracks; trackNum++) {
const byteOffset = trackNum * 4;
lutDataView.setUint16(byteOffset, hfeOffset, true); // Offset in 512-byte blocks
lutDataView.setUint16(byteOffset + 2, trackSizes[trackNum], true); // Track-specific length in bytes
// Add this track's size to the total and advance offset
totalSize += trackOffsetDeltas[trackNum] * HfeBlockSize;
hfeOffset += trackOffsetDeltas[trackNum];
}
const hfeData = new Uint8Array(totalSize);
// Write header
hfeData.set(header, 0);
// Write LUT
hfeData.set(lut, headerSize);
// Write track data
let trackOffset = 1024; // Start after header and LUT
for (let trackNum = 0; trackNum < numTracks; trackNum++) {
// Process each side separately
for (let side = 0; side < numSides; side++) {
const track = disc.getTrack(side === 1, trackNum);
const pulses = track.pulses2Us;
const trackBuffer = convertTrackToHfeV3(pulses.slice(0, track.length));
let bufferIndex = trackBuffer.length;
// Write track data in per-side sized chunks, interleaved according to HFE format
let writePos = trackOffset + (side === 1 ? HfeBlockSideSize : 0);
let iByte = 0;
while (iByte < bufferIndex) {
const chunkLen = Math.min(HfeBlockSideSize, bufferIndex - iByte);
const chunk = new Uint8Array(HfeBlockSideSize);
Eif (chunkLen > 0) {
chunk.set(trackBuffer.slice(iByte, iByte + chunkLen));
}
hfeData.set(chunk, writePos);
writePos += HfeBlockSize;
iByte += chunkLen;
}
}
// Move to the next track after processing all sides
trackOffset += trackOffsetDeltas[trackNum] * HfeBlockSize;
}
return hfeData;
}
|