mirror of
https://github.com/pkimpel/retro-b5500.git
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1c430583cd
2. Fully implement Double Precision Add/Subtract (DLA/DLS), Multiply (DLM), and Divide (DLD) syllables. 3. Replace standard setTimeout() by redesigned setCallback() mechanism throughout the emulator for scheduling timing delays and other callbacks on the Javascript thread. Delete obsolete setImmediate() mechanism. 4. Replace "new Date().getTime()" by "performance.now()" calls for greater timer precision. 5. Minor tweaks to Single Precision arithmetic operators. 6. Replace Javascript postfix operators by prefix operators wherever feasible (e.g., x++ becomes ++x). 8. Attempt to correct character translation and keyboard filtering in DatacomUnit for CANDE. 9. Minor changes to button colors and illumination behavior for I/O devices and Console. 10. Suppress I/O device classes in B5500SyllableDebugger by default (uncomment in source to enable). . Drop support for webkitIndexedDB and mozIndexedDB (for now). . Configure four tape drives (MTA-MTD) by default.
486 lines
23 KiB
JavaScript
486 lines
23 KiB
JavaScript
/***********************************************************************
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* retro-b5500/emulator B5500DiskUnit.js
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************************************************************************
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* Copyright (c) 2013, Nigel Williams and Paul Kimpel.
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* Licensed under the MIT License, see
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* http://www.opensource.org/licenses/mit-license.php
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************************************************************************
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* B5500 Disk File Control Unit module.
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*
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* Defines a peripheral unit type for the Disk File Control Unit used with
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* Burroughs Model I and Model IB Head-per-Track disk units. The DFCU is the
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* addressable unit to the B5500. This module manages the Electronic Units (EU)
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* and Storage Units (SU) that make up the physical disk storage facility.
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*
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* Physical storage in this implementation is provided by a W3C IndexedDB
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* database local to the browser in which the emulator is running. This database
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* must have been previously initialized; see tools/B5500ColdLoader.html.
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*
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* The database consists of a CONFIG object store and some number of EUn object
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* stores, where n is in 0..9. The CONFIG store contains an "eus" member that
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* specifies the total number of EU objects, plus an "EUn" member that specifies
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* the size of that EU in 240-character segments. There may be gaps in the EU
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* numbering, but the EU sizes should be specified in increments of 40,000 up to
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* a maximum of 200,000 (for Model I) or 400,000 (for Model IB "slow" disks).
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*
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* Within an EU, segments are represented in the database as 240-byte Uint8Array
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* objects, each with a database key corresponding to its numeric segment address.
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* The segments in an EU are not pre-allocated, but are created as they are
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* written to by IDB put() methods. When reading, any unallocated segments are
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* returned with their bytes set to 0x23 (#), which will be translated by the
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* IOU to BIC "0" for alpha mode and BIC "#" for binary mode.
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*
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* At present, disk write lockout is not supported. When there are two DFCUs in
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* the system, the presence of a Disk File Exchange is assumed, allowing either
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* DFCU to access any EU. Thus this implementation is currently limited to a
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* maximum of 10 EUs (480 million characters).
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*
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* Note that all disk I/O is done in units of 240-character segments. The
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* interface with the I/O Unit uses lengths in terms of characters, however.
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* All lengths SHOULD be multiples of 240 characters; any other values will be
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* rounded up to the next multiple of 240. The I/O Unit is responsible for any
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* padding or truncation to account for differences between the segment count
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* and word count in the IOD. This implementation ignores binary vs. alpha mode
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* and assumes the IOU does any necessary translation.
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*
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* The starting disk segment address for an I/O is passed in the "control"
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* parameter to each of the I/O methods. This is an an alphanumeric value in
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* the B5500 memory and I/O Unit. The I/O unit translates this value to binary
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* for the "control" parameter. The low-order six decimal digits of the value
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* comprise the segment address within the EU. The seventh decimal digit is the
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* EU number. Any other portion of the value is ignored.
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*
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* The DFCU's "read check" operation is asynchronous with respect to the IOU, and
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* the I/O operation itself completes almost immediately. Because of this, any
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* error reporting for the read check is deferred until the next I/O operation
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* (typically an interrogate) against the unit. Therefore, the error mask is
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* cleared at the end of each disk I/O operation (except for read check) instead
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* of at the beginning, and new errors are OR-ed with any errors persisting from
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* the prior operation.
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*
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* This module attempts to simulate actual disk activity times by delaying the
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* finish() call by an amount of time computed from the numbers of sectors
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* requested and the Model I SU's average 96KC transfer rate, plus a random
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* distribution across its 40ms max rotational latency time.
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************************************************************************
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* 2013-01-19 P.Kimpel
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* Original version, cloned from B5500DummyUnit.js.
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***********************************************************************/
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"use strict";
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/**************************************/
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function B5500DiskUnit(mnemonic, index, designate, statusChange, signal) {
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/* Constructor for the DiskUnit object */
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this.mnemonic = mnemonic; // Unit mnemonic
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this.index = index; // Ready-mask bit number
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this.designate = designate; // IOD unit designate number
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this.statusChange = statusChange; // external function to call for ready-status change
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this.signal = signal; // external function to call for special signals (e.g,. SPO input request)
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this.timer = 0; // setCallback() token
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this.initiateStamp = 0; // timestamp of last initiation (set by IOUnit)
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this.clear();
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}
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B5500DiskUnit.prototype.dbName = "B5500DiskUnit"; // IndexedDB database name
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B5500DiskUnit.prototype.dbVersion = 1; // current IDB database version
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B5500DiskUnit.prototype.configName = "CONFIG"; // database configuration store name
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B5500DiskUnit.prototype.euPrefix = "EU"; // prefix for EU object store names
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B5500DiskUnit.prototype.charXferRate = 96000; // avg. transfer rate, characters/sec (Model I SU)
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B5500DiskUnit.prototype.maxLatency = 0.040; // max rotational latency, sec (Model I SU)
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/**************************************/
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B5500DiskUnit.prototype.clear = function clear() {
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/* Initializes (and if necessary, creates) the processor state */
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this.ready = false; // ready status
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this.busy = false; // busy status
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this.errorMask = 0; // error mask for finish()
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this.finish = null; // external function to call for I/O completion
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this.startStamp = null; // I/O starting timestamp
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this.config = null; // copy of CONFIG store contents
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this.disk = null; // the IDB database object
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this.openDatabase(); // attempt to open the IDB database
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};
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/**************************************/
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B5500DiskUnit.genericDBError = function genericDBError(ev) {
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/* Formats a generic alert when otherwise-unhandled database errors occur */
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var disk = ev.currentTarget.result;
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this.errorMask |= 0x20; // set a generic disk-parity error
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alert("Database for \"" + this.mnemonic + "\" error: " + ev.target.result.error);
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this.finish(this.errorMask, 0);
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this.errorMask = 0;
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};
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/**************************************/
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B5500DiskUnit.prototype.copySegment = function copySegment(seg, buffer, offset) {
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/* Copies the bytes from a single segment Uint8Array object to "buffer" starting
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at "offset" for 240 bytes. If "seg" is undefined, copies zero bytes instead */
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var x;
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if (seg) {
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for (x=0; x<240; x++) {
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buffer[offset+x] = seg[x];
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}
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} else {
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for (x=offset+239; x>=offset; x--) {
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buffer[x] = 0x23; // ASCII "#", translates as alpha to BIC "0" = @00
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}
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}
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};
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/**************************************/
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B5500DiskUnit.prototype.openDatabase = function openDataBase() {
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/* Attempts to open the disk subsystem database specified by this.dbName and
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this.dbVersion. If successful, sets this.disk to the IDB object and sets the
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DFCU to ready status */
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var req;
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var db = null;
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var that = this;
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this.statusChange(0); // initially force DFCU status to not ready
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req = indexedDB.open(this.dbName, this.dbVersion);
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req.onerror = function idbOpenOnerror(ev) {
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alert("Cannot open " + that.mnemonic + " database: " + ev.target.error);
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};
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req.onblocked = function idbOpenOnblocked(ev) {
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alert("Database.open is blocked -- cannot continue");
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};
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req.onupgradeneeded = function idbOpenOnupgradeneeded(ev) {
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alert("Database requires version upgrade -- cannot continue");
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};
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req.onsuccess = function idbOpenOnsuccess(ev) {
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that.disk = ev.target.result; // save the object reference globally for later use
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that.disk.onerror = function idbCONFIGGetOnerror(ev) {
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alert("Database for \"" + that.mnemonic + "\" CONFIG get error: " + ev.target.result.error);
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};
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that.disk.transaction("CONFIG").objectStore("CONFIG").get(0).onsuccess = function idbCONFIGGetOnsuccess(ev) {
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that.config = ev.target.result;
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that.statusChange(1); // report the DFCU as ready to Central Control
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// Set up the generic error handler
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that.disk.onerror = function idbGenericOnError(ev) {
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that.genericIDBError(ev);
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};
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};
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};
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};
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/**************************************/
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B5500DiskUnit.prototype.read = function read(finish, buffer, length, mode, control) {
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/* Initiates a read operation on the unit. "length" is in characters; segment address
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is in "control". "mode" is ignored (any translation would have been done by IOU) */
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var bx = 0; // current buffer offset
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var euSize; // max seg size for EU
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var finishTime; // predicted time of I/O completion, ms
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var range; // key range for multi-segment read
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var req; // IDB request object
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var that = this; // local object context
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var txn; // IDB transaction object
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this.finish = finish; // for global error handler
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var segs = Math.floor((length+239)/240);
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var segAddr = control % 1000000; // starting seg address
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var euNumber = (control % 10000000 - segAddr)/1000000;
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var euName = this.euPrefix + euNumber;
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var endAddr = segAddr+segs-1; // ending seg address
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euSize = this.config[euName];
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if (!euSize) { // EU does not exist
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finish(this.errorMask | 0x20, 0); // set D27F for EU not ready/not present
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this.errorMask = 0;
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} else if (segAddr < 0) {
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finish(this.errorMask | 0x20, 0); // set D27F for invalid starting seg address
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this.errorMask = 0;
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} else {
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if (endAddr >= euSize) { // if read is past end of disk
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this.errorMask |= 0x20; // set D27F for invalid seg address
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segs = euSize-segAddr; // compute number of segs possible to read
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length = segs*240; // recompute length and ending seg address
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endAddr = euSize-1;
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}
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finishTime = this.initiateStamp +
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(Math.random()*this.maxLatency + segs*240/this.charXferRate)*1000;
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if (segs < 1) { // No length specified, so just finish the I/O
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finish(this.errorMask, 0);
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this.errorMask = 0;
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} else if (segs < 2) { // A single-segment read
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req = this.disk.transaction(euName).objectStore(euName).get(segAddr);
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req.onsuccess = function singleReadOnsuccess(ev) {
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that.copySegment(ev.target.result, buffer, 0);
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this.timer = setCallback(this.mnemonic, this, finishTime - performance.now(),
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function singleReadTimeout() {
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finish(this.errorMask, length);
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this.errorMask = 0;
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});
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}
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} else { // A multi-segment read
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range = IDBKeyRange.bound(segAddr, endAddr);
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txn = this.disk.transaction(euName);
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req = txn.objectStore(euName).openCursor(range);
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req.onsuccess = function rangeReadOnsuccess(ev) {
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var cursor = ev.target.result;
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if (cursor) { // found a segment at some address in range
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// fill buffer with zeroes for any unallocated segments
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while (cursor.key > segAddr) {
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that.copySegment(null, buffer, bx);
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bx += 240;
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segAddr++;
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}
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// copy the segment data to the buffer and request next seg
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that.copySegment(cursor.value, buffer, bx);
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bx += 240;
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segAddr++;
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cursor.continue();
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} else { // at end of range
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// fill buffer with zeroes for any remaining segments in range
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while (endAddr > segAddr) {
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that.copySegment(null, buffer, bx);
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bx += 240;
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segAddr++;
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}
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this.timer = setCallback(this.mnemonic, this, finishTime - performance.now(),
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function rangeReadTimeout() {
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finish(this.errorMask, length);
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this.errorMask = 0;
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});
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}
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};
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}
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}
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};
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/**************************************/
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B5500DiskUnit.prototype.space = function space(finish, length, control) {
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/* Initiates a space operation on the unit */
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finish(0x04, 0); // report unit not ready
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};
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/**************************************/
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B5500DiskUnit.prototype.write = function write(finish, buffer, length, mode, control) {
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/* Initiates a write operation on the unit. "length" is in characters; segment address
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is in "control". "mode" is ignored (any translation will done by the IOU) */
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var bx = 0; // current buffer offset
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var eu; // IDB object store for EU
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var euSize; // max seg size for EU
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var finishTime; // predicted time of I/O completion, ms
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var req; // IDB request object
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var txn; // IDB transaction object
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this.finish = finish; // for global error handler
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var segs = Math.floor((length+239)/240);
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var segAddr = control % 1000000; // starting seg address
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var euNumber = (control % 10000000 - segAddr)/1000000;
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var euName = this.euPrefix + euNumber;
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var endAddr = segAddr+segs-1; // ending seg address
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euSize = this.config[euName];
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if (!euSize) { // EU does not exist
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finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
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this.errorMask = 0;
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} else if (segAddr < 0) {
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finish(this.errorMask | 0x20, 0); // set D27F for invalid starting seg address
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this.errorMask = 0;
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} else {
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if (endAddr >= euSize) { // if read is past end of disk
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this.errorMask |= 0x20; // set D27F for invalid seg address
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segs = euSize-segAddr; // compute number of segs possible to read
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length = segs*240; // recompute length and ending seg address
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endAddr = euSize-1;
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}
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finishTime = this.initiateStamp +
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(Math.random()*this.maxLatency + segs*240/this.charXferRate)*1000;
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// No length specified, so just finish the I/O
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if (segs < 1) {
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finish(this.errorMask, 0);
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this.errorMask = 0;
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// Do the write
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} else {
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txn = this.disk.transaction(euName, "readwrite")
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txn.oncomplete = function writeComplete(ev) {
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this.timer = setCallback(this.mnemonic, this, finishTime - performance.now(),
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function writeTimeout() {
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finish(this.errorMask, length);
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this.errorMask = 0;
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});
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};
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eu = txn.objectStore(euName);
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for (; segAddr<=endAddr; segAddr++) {
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eu.put(buffer.subarray(bx, bx+240), segAddr);
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bx += 240;
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}
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}
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}
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};
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/**************************************/
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B5500DiskUnit.prototype.erase = function erase(finish, length) {
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/* Initiates an erase operation on the unit */
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finish(0x04, 0); // report unit not ready
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};
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/**************************************/
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B5500DiskUnit.prototype.rewind = function rewind(finish) {
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/* Initiates a rewind operation on the unit */
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finish(0x04, 0); // report unit not ready
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};
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/**************************************/
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B5500DiskUnit.prototype.readCheck = function readCheck(finish, length, control) {
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/* Initiates a read check operation on the unit. "length" is in characters;
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segment address is in "control". "mode" is ignored. This is essentially a
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read without any data transfer to memory. Note that the errorMask is NOT
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zeroed at the end of the I/O -- it will be reported with the next I/O */
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var euSize; // max seg size for EU
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var finishTime; // predicted time of I/O completion, ms
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var range; // key range for multi-segment read
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var req; // IDB request object
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var txn; // IDB transaction object
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this.finish = finish; // for global error handler
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var segs = Math.floor((length+239)/240);
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var segAddr = control % 1000000; // starting seg address
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var euNumber = (control % 10000000 - segAddr)/1000000;
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var euName = this.euPrefix + euNumber;
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var endAddr = segAddr+segs-1; // ending seg address
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this.errorMask = 0; // clear any prior error mask
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euSize = this.config[euName];
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if (!euSize) { // EU does not exist
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finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
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this.signal();
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// DO NOT clear the error mask
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} else if (segAddr < 0) {
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finish(this.errorMask | 0x20, 0); // set D27F for invalid starting seg address
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this.signal();
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// DO NOT clear the error mask
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} else {
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if (endAddr >= euSize) { // if read is past end of disk
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this.errorMask |= 0x20; // set D27F for invalid seg address
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segs = euSize-segAddr; // compute number of segs possible to read
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length = segs*240; // recompute length and ending seg address
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endAddr = euSize-1;
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}
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finishTime = this.initiateStamp +
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(Math.random()*this.maxLatency + segs*240/this.charXferRate)*1000;
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if (segs < 1) { // No length specified, so just finish the I/O
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finish(this.errorMask, 0);
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this.signal();
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// DO NOT clear the error mask -- will return it on the next interrogate
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} else { // A multi-segment read
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range = IDBKeyRange.bound(segAddr, endAddr);
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txn = this.disk.transaction(euName);
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finish(this.errorMask, length); // post I/O complete now -- DFCU will signal when check finished
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req = txn.objectStore(euName).openCursor(range);
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req.onsuccess = function readCheckOnsuccess(ev) {
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var cursor = ev.target.result;
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if (cursor) { // found a segment at some address in range
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cursor.continue();
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} else { // at end of range
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this.timer = setCallback(this.mnemonic, this, finishTime - performance.now(),
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function readCheckTimeout() {
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this.signal();
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// DO NOT clear the error mask
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});
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}
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};
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}
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}
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};
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/**************************************/
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B5500DiskUnit.prototype.readInterrogate = function readInterrogate(finish, control) {
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/* Initiates a read interrogate operation on the unit. This serves only to
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check the addresss for validity and to return any errorMask from a prior
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read check operation. This implementation assumes completion will be delayed
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by a random amount of time based on rotational latency for the EU to search for
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the address */
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var euSize; // max seg size for EU
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var segAddr = control % 1000000; // starting seg address
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var euNumber = (control % 10000000 - segAddr)/1000000;
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var euName = this.euPrefix + euNumber;
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this.finish = finish; // for global error handler
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euSize = this.config[euName];
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if (!euSize) { // EU does not exist
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finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
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this.errorMask = 0;
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} else {
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if (segAddr < 0 || segAddr >= euSize) { // if read is past end of disk
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this.errorMask |= 0x20; // set D27F for invalid seg address
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}
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this.timer = setCallback(this.mnemonic, this,
|
|
Math.random()*this.maxLatency*1000 + this.initiateStamp - performance.now(),
|
|
function readInterrogateTimeout() {
|
|
finish(this.errorMask, length);
|
|
this.errorMask = 0;
|
|
});
|
|
}
|
|
};
|
|
|
|
/**************************************/
|
|
B5500DiskUnit.prototype.writeInterrogate = function writeInterrogate(finish, control) {
|
|
/* Initiates a write interrogate operation on the unit. This serves only to
|
|
check the addresss for validity and to return any errorMask from a prior
|
|
read check operation. This implementation assumes completion will be delayed
|
|
by a random amount of time based on rotational latency for the EU to search for
|
|
the address */
|
|
|
|
/* Note: until disk write lockout is implemented, this operation is identical
|
|
to readInterrogate() */
|
|
|
|
var euSize; // max seg size for EU
|
|
var segAddr = control % 1000000; // starting seg address
|
|
var euNumber = (control % 10000000 - segAddr)/1000000;
|
|
var euName = this.euPrefix + euNumber;
|
|
|
|
this.finish = finish; // for global error handler
|
|
euSize = this.config[euName];
|
|
if (!euSize) { // EU does not exist
|
|
finish(this.errorMask | 0x20, 0); // set D27F for EU not ready
|
|
this.errorMask = 0;
|
|
} else {
|
|
if (segAddr < 0 || segAddr >= euSize) { // if read is past end of disk
|
|
this.errorMask |= 0x20; // set D27F for invalid seg address
|
|
}
|
|
this.timer = setCallback(this.mnemonic, this,
|
|
Math.random()*this.maxLatency*1000 + this.initiateStamp - performance.now(),
|
|
function writeInterrogateTimeout() {
|
|
finish(this.errorMask, length);
|
|
this.errorMask = 0;
|
|
});
|
|
}
|
|
};
|
|
|
|
/**************************************/
|
|
B5500DiskUnit.prototype.shutDown = function shutDown() {
|
|
/* Shuts down the device */
|
|
|
|
if (this.timer) {
|
|
clearCallback(this.timer);
|
|
}
|
|
// this device has no window to close
|
|
};
|