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vm.js
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module('users.codefrau.St78.vm').requires().toRun(function() {
/*
* Copyright (c) 2013-2025 Vanessa Freudenberg and Dan Ingalls
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
// Alias for shorter class paths
St78 = users.codefrau.St78;
// Constants, accessible without path for brevity
NT = {
VM_DATE: "2025-02-12",
MAX_INSTSIZE: 0x100000, // arbitrary limit on instance size
largeOops: true, // automatically switch to 32 bit image format
OOP_NIL: 0,
OOP_FALSE: 2,
OOP_TRUE: 4,
OOP_THEPROCESS: 6,
OOP_SMALLTALK: 8,
// known classes
OOP_CLCLASS: 0x20,
OOP_CLINTEGER: 0x40, // class of SmallIntegers
OOP_CLSTRING: 0x60,
OOP_CLVECTOR: 0x80,
OOP_CLSTREAM: 0xa0,
OOP_CLFLOAT: 0xc0,
OOP_CLPROCESS: 0xe0,
OOP_CLREMOTECODE: 0x100,
OOP_CLPOINT: 0x120,
OOP_CLNATURAL: 0x140,
OOP_CLLARGEINTEGER: 0x160,
OOP_CLUNIQUESTRING: 0x1a0,
OOP_CLCOMPILEDMETHOD: 0x1e0,
OOP_CLRECTANGLE: 0x2a0,
OOP_CLVLENGTHCLASS: 0x9c0,
OOP_MASK: 0x1F, // mask for class oops
OOP_TAG_SMALL: 0x1E, // tag for 16 bit size header
OOP_TAG_LARGE: 0x1F, // tag for 32 bit size header
// CLCLASS layout:
PI_CLASS_TITLE: 0,
PI_CLASS_MYINSTVARS: 1,
PI_CLASS_INSTSIZE: 2,
PI_CLASS_MDICT: 3,
PI_CLASS_CLASSVARS: 4,
PI_CLASS_SUPERCLASS: 5,
PI_CLASS_ENVIRONMENT: 6,
// CLSTREAM layout:
PI_STREAM_ARRAY: 0,
PI_STREAM_POSITION: 1,
PI_STREAM_LIMIT: 2,
// CLPROCESS layout:
PI_PROCESS_MINSIZE: 0, // THEPROCESS: 128
PI_PROCESS_HWM: 1, // THEPROCESS: 0
PI_PROCESS_TOP: 2, // THEPROCESS: 7
PI_PROCESS_RESTARTCODE: 3, // THEPROCESS: NIL
PI_PROCESS_STACK: 4, // THEPROCESS: NIL
PN_PROCESS: 5, // number of fixed pointers
// CLREMOTECODE layout:
PI_RCODE_FRAMEOFFSET: 0,
PI_RCODE_STARTINGPC: 1,
PI_RCODE_PROCESS: 2,
PI_RCODE_STACKOFFSET: 3,
// CLHASHSET layout:
PI_HASHSET_OBJECTS: 0,
// CLDICTIONARY layout:
PI_DICTIONARY_OBJECTS: 0,
PI_DICTIONARY_VALUES: 1,
// CLSYMBOLTABLE layout:
PI_SYMBOLTABLE_OBJECTS: 0,
PI_SYMBOLTABLE_VALUES: 1,
// CLMESSAGEDICT layout:
PI_MESSAGEDICT_OBJECTS: 0,
PI_MESSAGEDICT_METHODS: 1,
// CLOBJECTREFERENCE layout:
PI_OBJECTREFERENCE_VALUE: 0,
// CLCOMPILEDMETHOD layout:
BI_COMPILEDMETHOD_FIRSTLITERAL: 2, // past method header
PC_BIAS: 2, // due to NT's shorter header format
// CLPOINT layout:
PI_POINT_X: 0,
PI_POINT_Y: 1,
// CLLARGEINTEGER layout:
PI_LARGEINTEGER_BYTES: 0,
PI_LARGEINTEGER_NEG: 1,
/* | i . (1 to: TextScanner instvars length) transform⦂ i to⦂ [(i-1),(TextScanner instvars◦i)] ==>
((0 'function' ) (1 'color' ) (2 'destbase' ) (3 'destraster' ) (4 'destx' ) (5 'desty' ) (6 'width' ) (7 'height' ) (8 'sourcebase' ) (9 'sourceraster' ) (10 'sourcex' ) (11 'sourcey' ) (12 'clipx' ) (13 'clipy' ) (14 'clipwidth' ) (15 'clipheight' ) (16 'sourcefield' ) (17 'destfield' ) (18 'source' ) (19 'dest' ) (20 'sstrike' ) (21 'dstrike' ) (22 'printing' ) (23 'chari' ) (24 'stopx' ) (25 'xtable' ) (26 'exceptions' ) (27 'spacecount' ) (28 'spacei' ) (29 'spacex' ) (30 'charpad' ) (31 'text' ) (32 'spacesize' ) (33 'style' ) (34 'para' ) (35 'font' ) (36 'fontno' ) (37 'minascii' ) (38 'maxascii' ) (39 'glyphs' ) (40 'frame' ) (41 'looktype' ) (42 'kern' ) ) */
// CLBITBLT layout:
PI_BITBLT_FUNCTION: 0,
PI_BITBLT_GRAY: 1,
PI_BITBLT_DESTBITS: 2,
PI_BITBLT_DESTRASTER: 3,
PI_BITBLT_DESTX: 4,
PI_BITBLT_DESTY: 5,
PI_BITBLT_WIDTH: 6,
PI_BITBLT_HEIGHT: 7,
PI_BITBLT_SOURCEBITS: 8,
PI_BITBLT_SOURCERASTER: 9,
PI_BITBLT_SOURCEX: 10,
PI_BITBLT_SOURCEY: 11,
PI_BITBLT_CLIPX: 12,
PI_BITBLT_CLIPY: 13,
PI_BITBLT_CLIPWIDTH: 14,
PI_BITBLT_CLIPHEIGHT: 15,
PI_BITBLT_SOURCEFIELD: 16,
PI_BITBLT_DESTFIELD: 17,
PI_BITBLT_SOURCE: 18,
PI_BITBLT_DEST: 19,
PI_BITBLT_PRINTING: 22,
PI_BITBLT_CHARI: 23,
PI_BITBLT_STOPX: 24,
PI_BITBLT_XTABLE: 25,
PI_BITBLT_EXCEPTIONS: 26,
PI_BITBLT_CHARPAD: 30,
PI_BITBLT_TEXT: 31,
PI_BITBLT_MINASCII: 37,
PI_BITBLT_MAXASCII: 38,
PI_BITBLT_KERN: 42,
// CLFORM layout:
PI_FORM_EXTENT: 0,
PI_FORM_BITS: 1,
// also: offset figure ground
// CLCURSOR layout:
PI_CURSOR_BITSTR: 0,
PI_CURSOR_OFFSET: 1,
// runtime indices and offsets:
// process frame layout (off BP):
FI_FIRST_TEMP: -1,
// nominal stack frame contains six items, as follow:
FI_SAVED_BP: 0,
FI_CALLER_PC: 1,
FI_NUMARGS: 2,
FI_METHOD: 3,
FI_MCLASS: 4,
FI_RECEIVER: 5, // top stack item in previous frame
//
FI_LAST_ARG: 6, // stack item in previous frame
//
F_FRAMESIZE: 5, // don't count args nor receiver...
// Class instSize format (assuming untagged integer!):
FMT_HASPOINTERS: 0x4000,
FMT_HASWORDS: 0x2000,
FMT_ISVARIABLE: 0x1000,
FMT_BYTELENGTH: 0x07ff,
// Ints
MAX_INT: 0x3FFF,
MIN_INT: -0x4000,
NON_INT: -0x5000, // non-small and neg (so non pos16 too)
// Display colors
BLACK: 0xFF000000,
WHITE: 0xFFFFFFFF,
// Event constants
Mouse_Blue: 1,
Mouse_Yellow: 2,
Mouse_Red: 4,
Key_Shift: 8,
Key_Ctrl: 16,
Key_Meta: 32, // Cmd on Mac, Alt on PC
// original keyboard map used inside the image
// set to vm.image.globalNamed('NTkbMap').bytes on startup
kbMap: [
255, 91, 255, 110, 104, 103, 114, 255, 25, 61, 32, 109, 56, 121, 116, 173,
13, 46, 122, 106, 255, 9, 49, 255, 95, 59, 255, 98, 99, 102, 160, 29,
39, 108, 120, 57, 115, 119, 51, 158, 93, 44, 111, 105, 97, 113, 50, 30,
47, 45, 48, 117, 55, 54, 53, 8, 92, 112, 107, 118, 100, 101, 52, 29,
255, 123, 255, 78, 72, 71, 82, 255, 25, 43, 32, 77, 42, 89, 84, 173,
13, 62, 90, 74, 255, 9, 33, 255, 94, 58, 255, 66, 67, 70, 160, 29,
34, 76, 88, 40, 83, 87, 35, 22, 125, 60, 79, 73, 65, 81, 90, 30,
63, 21, 41, 85, 38, 126, 37, 8, 124, 80, 75, 86, 68, 69, 36, 255,
255, 91, 255, 78, 72, 71, 82, 255, 25, 61, 32, 77, 56, 89, 84, 173,
13, 46, 90, 74, 255, 9, 49, 255, 95, 59, 255, 66, 67, 70, 160, 29,
39, 76, 88, 57, 83, 87, 51, 158, 93, 44, 79, 73, 65, 81, 90, 30,
47, 45, 48, 85, 55, 54, 53, 8, 92, 80, 75, 86, 68, 69, 52, 255,
255, 7, 255, 14, 179, 7, 18, 255, 25, 6, 32, 182, 180, 25, 6, 173,
13, 18, 167, 165, 255, 9, 159, 255, 17, 3, 255, 166, 3, 6, 160, 29,
15, 153, 151, 149, 19, 145, 143, 255, 23, 1, 15, 150, 1, 17, 167, 30,
27, 137, 135, 21, 131, 129, 127, 8, 14, 138, 136, 134, 132, 130, 128, 255,
255, 249, 255, 245, 243, 30, 239, 255, 25, 14, 32, 246, 244, 242, 240, 173,
13, 233, 231, 229, 255, 9, 223, 255, 246, 3, 255, 230, 228, 226, 160, 24,
219, 217, 215, 213, 211, 209, 207, 22, 220, 218, 226, 214, 212, 210, 231, 30,
203, 201, 199, 197, 195, 193, 191, 8, 204, 202, 200, 198, 196, 194, 192, 192],
// symbolic NT keycodes (it uses ASCII for 32-126)
kbSymbolic: {
tab: 9,
cr: 13,
// Dispframe>>kbd
ctld: 132,
ctlw: 145,
ctlx: 151,
// TextImage>>classInit, kbd
bs: 8,
ctlw: 145, // delete word?
cut: 173,
paste: 158,
esc: 160,
// TextImage>>checkLooks
ctlb: 166, // bold
ctli: 150, // italic
ctlminus: 137,
ctlx: 151, // reset emph
ctlB: 230, // non-bold
ctlI: 214, // non-italic
ctlMinus: 201,
ctlX: 215, // reset emph
ctl0: 135, // font 0
ctl1: 159, // font 1
ctl2: 144, // font 2
ctl3: 143, // font 3
ctl4: 128, // font 4
ctl5: 127, // font 5
ctl6: 129, // font 6
ctl7: 131, // font 7
ctl8: 180, // font 8
ctl9: 149, // font 9
ctlShift0: 199, // font 10
ctlShift1: 223, // font 11
ctlShift2: 208, // font 12
ctlShift3: 207, // font 13
ctlShift4: 192, // font 14
ctlShift5: 191, // font 15
ctlt: 240, // toBravo
ctlf: 226, // fromBravo
// newly assigned
smaller: 228,
larger: 229,
doit: 130,
prompt: 167,
again: 134,
selectAll: 136,
compile: 138,
undo: 153,
cancel: 165,
left: 193,
right: 194,
up: 195,
down: 196,
pageUp: 197,
pageDown: 198,
home: 202,
end: 203,
search: 204,
},
// key bindings: html keydown code to NT symbolic
kbCommands: {
'.': "interrupt",
'd': "doit",
'p': "doit", // printit
'D': "prompt",
'j': "again",
'a': "selectAll",
's': "compile",
'z': "undo",
'l': "cancel",
'f': "search",
'b': "ctlb", // bold
'i': "ctli", // italic
'u': "ctlminus", // underline
'x': "ctlx", // reset emph
'B': "ctlB", // bold
'I': "ctlI", // italic
'U': "ctlMinus", // underline
'X': "ctlX", // reset emph
'0': "ctl0", // font change
'1': "ctl1",
'2': "ctl2",
'3': "ctl3",
'4': "ctl4",
'5': "ctl5",
'6': "ctl6",
'7': "ctl7",
'8': "ctl8",
'9': "ctl9",
'-': "smaller",
'_': "smaller",
'+': "larger",
'=': "larger",
},
// key bindings: html keypress code to unicode
// var 31 = 31;
kbSpecial: {
35: '↪', // #: Unique string
64: '⌾', // @: make point
94: '⇑', // ^: return
95: '←', // _: assignment
96: 'ⓢ', // `: 's operator
1: '◦', // ^A: At
3: '⦂', // ^C: open Colon
4: 'ctld', // ^D
5: '∢', // ^E: Eye
6: '⇒', // ^F: iF
7: '≥', // ^G: Greater or equal
// 8: ^H = backspace
// 9: ^I = tab
12: '≤', // ^L: Lesser or equal
// 13: ^M = return
14: '≠', // ^N: Not equal
16: '◣', // ^P: Prompt
17: '◻', // ^Q: sQuare
19: 'ⓢ', // ^S: 's operator
20: '≡', // ^T: Triple equal
21: '↪', // ^U: Unique string
22: '➲', // ^V: inVerse arrow
23: 'ctlw', // ^W: delete word
24: '▱', // ^X
29: '◢', // ^]: doit
30: '↑', // ^^: single up arrow
31: '¬', // ^_: unary minus
},
// encoding of notetaker glyphs as printable unicode chars
toUnicode: {
'\x00': "␀",
'\x01': "≤",
'\x02': "␂",
'\x03': "⦂",
'\x04': "␄",
'\x05': "√",
'\x06': "≡",
'\x07': "◦",
'\x08': "␈",
//'\x09': "␉", // keep TAB
'\x0a': "␊",
'\x0b': "␋",
'\x0c': "␌",
'\x0d': "\n", // CR becomes LF
'\x0e': "≠",
'\x0f': "↪",
'\x10': "␐",
'\x11': "⇑",
'\x12': "≥",
'\x13': "ⓢ",
'\x14': "◣",
'\x15': "¬",
'\x16': "∢",
'\x17': "⌾",
'\x18': "▱",
'\x19': "➲",
'\x1a': "␚",
'\x1b': "⇒",
'\x1c': "␜",
'\x1d': "◻︎",
'\x1e': "◢",
'\x1f': "␟",
'\x7f': "␡",
'_' : "←",
'^' : "↑",
},
};
Object.subclass('St78.vm.ObjectTableReader',
'about', {
about: function() {
/*
ot is the object table, a sequence of 4-byte entries, retrievable by this.otAt(oop), where oop is an object pointer with the bottom two bits = 0. The entry encodes the data address, along with some other bits including a reference count that we can now ignore. The method dataAddress(oop) will retrieve the address, also taking into account the "dataBias" which I won't explain.
data is the object data space, a sequence of 2-byte words, retrievable by this.fieldOfObject(i, oop), where oop is an object pointer with the bottom two bits = 0, and i is the instance field number, with 1 being the index of the first field. An index of 0 would retrieve the class pointer of an object, but this must be masked by 0xFFC0 because the bottom 6 bits of the class word are used for the object's size in bytes. The method classOfOop will do this for you. This implies that all class oops have zero in the bottom 6 bits. This worked out nicely for OOZE's zones, but we will drop all that and go to the Squeak object format or whatever Vanessa is using internally. Note that if the size field is zero, then there is a word before the class with a 16-bit length. The method lengthBitsAt decodes this for you. It appears that the size field is the size in bytes, including the class(and size), so a string of length 1 has size=3, and a Point would have a size = 6.
The format of classes is (quoting from the system itself...
title "<String> for identification, printing"
myinstvars "<String> partnames for compiling, printing"
instsize "<Integer> for storage management"
messagedict "<MessageDict> for communication, compiling"
classvars "<Dictionary/nil> compiler checks here"
superclass "<Class> for execution of inherited behavior"
environment "<Vector of SymbolTables> for external refs"
fieldtype
The instsize is an integer (ie low bit = 1) with the following interpretation:
0x8000 - fields are pointers, else not
0x4000 - fields are words, else bytes
0x2000 - instances are variable length
0x0FFE - instance size in words including class
Thus Point has instsize = 0x8006 and Float has instsize = 04008 (nasty 3-word binary format)
*/
},
},
'initialize', {
initialize: function(objTable, objSpace, bias) {
this.ot = objTable;
this.data = objSpace;
this.dataBias = bias;
}
},
'reading', {
readObjects: function() {
// create js objects for the st78 objects in ot+data
var oopMap = {};
for (var oti = 0; oti < this.ot.length; oti += 4) {
var oop = oti / 2; // 1 more bit for our oops so we get up to 32 K objects
if (this.refCountOf(oop)) {
oopMap[oop] = new St78.vm.Object(oop);
}
}
return oopMap;
}
},
'object access', {
otAt: function(oop) {
// Return the OT entry for the oop
// Decode two two-byte numbers into one 32-bit number
var i = oop * 2,
val = 0;
val = this.ot[i+1];
val = val*256 + this.ot[i];
val = val*256 + this.ot[i+3];
val = val*256 + this.ot[i+2];
return val;
},
dataAddress: function(oop) {
var entry = this.otAt(oop);
return (entry&0xFFFF) * 16 + ((entry>>16)&0x1E) - this.dataBias;
},
fieldOfObject: function(i, oop) {
// i = 1 for first field after class
var addr = this.dataAddress(oop);
var a = addr+(2*i);
return this.data[a+1]*256 + this.data[a];
},
classOfOop: function(oop) {
return (this.fieldOfObject(0, oop) & 0xFFC0) / 2; // our oops are half the original
},
refCountOf: function (oop) {
return this.otAt(oop) >>> 24;
},
isInteger: function(oop) {
return oop & 1;
},
lengthBitsAtAddr: function(addr) {
var len = this.data[addr] & 0x3F;
if (len > 0) return len;
return this.data[addr-1] * 256 + this.data[addr-2];
},
});
Object.subclass('St78.vm.Image',
'about', {
about: function() {
/*
Object Format
=============
Each St78 object is a St78.vm.Object, only SmallIntegers are JS numbers.
Instance variables/fields reference other objects directly via the "pointers" property.
{
stClass: reference to class object
pointers: (optional) Array referencing inst vars + indexable fields
words: (optional) Array of numbers (words)
bytes: (optional) Array of numbers (bytes)
float: (optional) float value if this is a Float object
isNil: (optional) true if this is the nil object
isTrue: (optional) true if this is the true object
isFalse: (optional) true if this is the false object
isFloat: (optional) true if this is a Float object
oop: unique integer (16 bits, lsb is 0, in classes 5 lower bits are 0)
mark: boolean (used only during GC, otherwise false)
nextObject: linked list of objects in old space (new space objects do not have this yet)
}
Object Table
============
Unlike the original Notetaker implementation, there is no object table.
Objects use direct references. We have immediate untagged ints (+/-16K).
The snapshot image format uses 16 bit words for oops (even) and tags the ints (odd).
If there are more than 32K objects, and NT.largeOops is true, we us snapshot image format 2.0
with 32 bit words for oops. SmallIntegers are still only +/-16K but stored as 32 bit words.
*/
}
},
'initializing', {
initialize: function(oopMap, process, display, name, convertTaggedInts, largeOops) {
this.name = name;
this.largeOops = largeOops || 0;
this.maxTenuresBeforeGC = 1000;
this.tenuresSinceLastGC = 0;
this.gcCount = 0;
this.newSpaceCount = 0;
this.oldSpaceCount = 0;
this.oldSpaceBytes = 0;
this.nextTempOop = -2; // new objects get negative preliminary oops
this.freeOops = []; // pool for real oops
this.freeClassOops = []; // pool for real class oops (lower bits 0)
// link all objects into oldspace
var prevObj,
large = !!this.largeOops,
maxOop = Math.max(this.largeOops, 0xFFFE);
for (var oop = 0; oop <= maxOop; oop += 2)
if (oopMap[oop]) {
this.oldSpaceCount++;
this.oldSpaceBytes += oopMap[oop].totalBytes(large);
if (prevObj) prevObj.nextObject = oopMap[oop];
prevObj = oopMap[oop];
} else if (oop < 0x10000) {
(oop & NT.OOP_MASK ? this.freeOops : this.freeClassOops).push(oop);
}
this.firstOldObject = oopMap[0];
this.lastOldObject = prevObj;
this.userProcess = process;
this.userDisplay = display;
this.initKnownObjects(oopMap);
this.initCompiledMethods(oopMap, convertTaggedInts);
console.log("Loaded image " + this.name);
},
initKnownObjects: function(oopMap) {
oopMap[NT.OOP_NIL].isNil = true;
oopMap[NT.OOP_TRUE].isTrue = true;
oopMap[NT.OOP_FALSE].isFalse = true;
this.globals = oopMap[NT.OOP_SMALLTALK];
this.specialOopsVector = this.globalNamed('SpecialOops');
},
initCompiledMethods: function(oopMap, convertTaggedInts) {
// make proper pointer objects for literals encoded in bytes
var cmClass = this.objectFromOop(NT.OOP_CLCOMPILEDMETHOD, oopMap),
cm = this.someInstanceOf(cmClass);
while (cm) {
cm.methodInitLits(this, oopMap, convertTaggedInts);
cm = this.nextInstanceAfter(cm);
}
},
globalRefNamed: function(name) {
var ref = this.globals.symbolTableRefNamed(name);
if (!ref) {
// try other symbol tables
var tableClass = this.globals.stClass,
table = this.firstOldObject;
while ((table = table.nextObject) && !ref) {
if (table.stClass !== tableClass) continue;
if (table !== this.globals)
ref = table.symbolTableRefNamed(name);
}
}
return ref;
},
selectorNamed: function(name) {
var symbolClass = this.objectFromOop(NT.OOP_CLUNIQUESTRING),
symbol = this.someInstanceOf(symbolClass);
while (symbol) {
if (name.length === symbol.bytes.length && name === symbol.bytesAsUnicode())
return symbol;
symbol = this.nextInstanceAfter(symbol);
}
},
globalNamed: function(name) {
return this.globalRefNamed(name).pointers[NT.PI_OBJECTREFERENCE_VALUE];
},
smallifyLargeInts: function() {
// visit every pointer field of every object, converting smallable LargeInts to Integers
// We do this because the normal ST-76 range is +-32K
var lgIntClass = this.objectFromOop(NT.OOP_CLLARGEINTEGER),
obj = this.firstOldObject;
while (obj) {
var body = obj.pointers;
if (body) {
for (var i=0; i<body.length; i++) {
if (body[i].stClass === lgIntClass) {
var value = body[i].largeIntegerValue();
if (value <= 32767 && value >= -32768) body[i] = value
}
}
}
obj = obj.nextObject;
}
},
},
'garbage collection', {
fullGC: function() {
// Old space is a linked list of objects - each object has an "nextObject" reference.
// New space objects do not have that pointer, they are garbage-collected by JavaScript.
// But they have an allocation id so the survivors can be ordered on tenure.
// The "nextObject" references are created by collecting all new objects,
// and then linking them into old space.
// Note: after an old object is released, its "nextObject" ref must still allow traversal
// of all remaining objects. This is so enumeration works despite GC.
var newObjects = this.markReachableObjects();
var removedObjects = this.removeUnmarkedOldObjects();
if (this.largeOops) this.compactLargeOops(); // possibly sets largeOops to false
this.appendToOldObjects(newObjects);
if (this.largeOops) this.updateOldSpaceBytes();
/*
this.spaceReport(newObjects, removedObjects, function(line){console.log(line)});
console.log(Strings.format("GC: %s allocations, %s unchecked tenures, %s released, %s tenured, now %s total (%s bytes)",
this.newSpaceCount, this.tenuresSinceLastGC, removedObjects.length, newObjects.length, this.oldSpaceCount, this.oldSpaceBytes));
*/
this.tenuresSinceLastGC = 0;
this.newSpaceCount = 0;
this.nextTempOop = -2;
this.gcCount++;
return this.availableOops();
},
allocateOopFor: function(anObj) {
// get an oop from the pool of unused oops
var isClass = anObj.isClass(),
pool = isClass ? this.freeClassOops : this.freeOops;
if (pool.length > 0) {
return anObj.oop = pool.pop();
}
// support for more than 32 K objects
if (!this.largeOops && NT.largeOops) {
this.largeOops = 0xFFFE; // so first large oop is 0x10000
console.log("Too many oops - switching from 16 to 32 bits");
}
if (this.largeOops >= 0xFFFE && this.largeOops <= 0xFFFFFFF0) {
return anObj.oop = this.largeOops += 2;
}
this.vm.primHandler.filePut('spacereport.txt', this.spaceReport());
throw isClass ? "too many classes" : "too many objects";
},
freeOopFor: function(anObj) {
if (anObj.oop > 0) {
if (anObj.oop < 0x10000) {
(anObj.oop & NT.OOP_MASK ? this.freeOops : this.freeClassOops).push(anObj.oop);
}
anObj.oop = null;
} else throw "attempt to free invalid oop";
},
markReachableObjects: function() {
// Visit all reachable objects and mark them.
// Return surviving new objects
if (this.vm) {
this.userProcess = this.vm.activeProcess;
this.userDisplay = this.vm.primHandler.displayBlt;
}
var todo = [this.globals, this.userProcess];
if (this.userDisplay) // stored in image header so must be retained
todo.push(this.userDisplay);
var newObjects = [];
while (todo.length > 0) {
var object = todo.pop();
if (object.mark) continue; // objects are added to todo more than once
if (object.oop < 0) // it's a new object
newObjects.push(object);
object.mark = true; // mark it
if (!object.stClass.mark) // trace class if not marked
todo.push(object.stClass);
var body = object.pointers;
if (body) // trace all unmarked pointers
for (var i = 0; i < body.length; i++)
if (typeof body[i] === "object" && !body[i].mark) // except SmallInts
todo.push(body[i]);
}
return newObjects;
},
removeUnmarkedOldObjects: function() {
// Unlink unmarked old objects from the nextObject linked list
// Reset marks of remaining objects
// Set this.lastOldObject to last old object
// Return removed old objects
var removed = [];
var obj = this.firstOldObject;
while (true) {
var next = obj.nextObject;
if (!next) {// we're done
this.lastOldObject = obj;
return removed;
}
// if marked, continue with next object
if (next.mark) {
next.mark = false; // unmark for next GC
obj = next;
} else { // otherwise, remove it
var corpse = next;
obj.nextObject = corpse.nextObject; // drop from list
this.oldSpaceCount--;
this.oldSpaceBytes -= corpse.totalBytes(!!this.largeOops);
this.freeOopFor(corpse);
removed.push(corpse);
}
}
},
appendToOldObjects: function(newObjects) {
// append new objects to linked list of old objects
// and unmark them. Also, assign a real oop.
// Note: also called outside GC to quickly tenure an object
var oldObj = this.lastOldObject;
for (var i = 0; i < newObjects.length; i++) {
var newObj = newObjects[i];
if (newObj.oop >= 0) {debugger; throw "attempt to tenure old object"}
newObj.mark = false;
this.allocateOopFor(newObj);
oldObj.nextObject = newObj;
oldObj = newObj;
this.oldSpaceCount++;
this.oldSpaceBytes += newObj.totalBytes(!!this.largeOops);
}
this.lastOldObject = oldObj;
},
compactLargeOops: function() {
if (this.freeOops.length > 0) {
// if we have free small oops, maybe we can fall back to 16 bits
return this.compactLargeOopsToSmall();
}
// otherwise just reassign oops in sequence
var nextOop = 0xFFFE; // so the first large oop is 0x10000
var obj = this.firstOldObject;
while (obj) {
if (obj.oop >= 0x10000) obj.oop = nextOop += 2;
obj = obj.nextObject;
}
this.largeOops = nextOop;
},
compactLargeOopsToSmall: function() {
// we had some free small oops, use those first, then large ones
this.largeOops = 0xFFFE; // so the first large oop is 0x10000
var obj = this.firstOldObject;
while (obj) {
if (obj.oop >= 0x10000) obj.oop = this.allocateOopFor(obj);
obj = obj.nextObject;
}
// if we did not use any large oops, switch back to 16 bits
if (this.largeOops === 0xFFFE) {
this.largeOops = 0;
this.updateOldSpaceBytes();
console.log("Freed oops - switching from 32 to 16 bits");
}
},
updateOldSpaceBytes: function() {
// with large oops, object size can change depending on the oops it holds
var large = !!this.largeOops,
obj = this.firstOldObject,
bytes = 0;
while (obj) {
bytes += obj.totalBytes(large);
obj = obj.nextObject;
}
this.oldSpaceBytes = bytes;
},
},
'creating', {
tempOop: function() {
// new objects get a temporary oop
this.newSpaceCount++;
return this.nextTempOop -= 2;
},
instantiateClass: function(aClass, indexableSize, nilObj) {
var newObject = new St78.vm.Object(this.tempOop());
newObject.initInstanceOf(aClass, indexableSize, nilObj);
return newObject;
},
},
'operations', {
bulkBecome: function(fromArray, toArray, twoWay) {
var n = fromArray.length;
if (n !== toArray.length)
return false;
var mutations = {};
for (var i = 0; i < n; i++) {
var obj = fromArray[i];
if (!obj.stClass) return false; //non-objects in from array
if (mutations[obj.oop]) return false; //repeated oops in from array
else mutations[obj.oop] = toArray[i];
}
if (twoWay) for (var i = 0; i < n; i++) {
var obj = toArray[i];
if (!obj.stClass) return false; //non-objects in to array
if (mutations[obj.oop]) return false; //repeated oops in to array
else mutations[obj.oop] = fromArray[i];
}
// ensure new objects have nextObject pointers
if (this.newSpaceCount > 0)
this.fullGC();
// Now, for every object...
var obj = this.firstOldObject;
while (obj) {
// mutate the class
var mut = mutations[obj.stClass.oop];
if (mut) obj.stClass = mut;
// and mutate body pointers
var body = obj.pointers;
if (body) for (var j = 0; j < body.length; j++) {
mut = mutations[body[j].oop];
if (mut) body[j] = mut;
}
obj = obj.nextObject;
}
// finally, swap the oops so they stay with the pointer, not the object
for (var i = 0; i < n; i++) {
var temp = fromArray[i].oop;
fromArray[i].oop = toArray[i].oop;
toArray[i].oop = temp;
}
this.vm.flushMethodCacheAfterBecome(mutations);
return true;
},
diffFrom: function(base) {
// assumes both images have ordered oops
// which is the case right after loading them
var thisObj = this.firstOldObject,
baseObj = base.firstOldObject,
delta = [];
while (thisObj) {
if (!thisObj.sameAs(baseObj)) {
if (!baseObj || thisObj.oop <= baseObj.oop) {
// after end of base, or modified, or new
delta.push(thisObj);
if (baseObj && thisObj.oop < baseObj.oop) {
thisObj = thisObj.nextObject;
continue;
}
} else { // baseObj.oop < thisObj.oop
baseObj = baseObj.nextObject;
continue;
}
}
// same oops, or after end of base image
if (baseObj) baseObj = baseObj.nextObject;
thisObj = thisObj.nextObject;
}
return delta;
},
writeDiffToBuffer: function(baseImage) {
// write only objects in this image that are not in baseImage
// assumes both images are freshly loaded, not run
if (this.largeOops) throw new Error("32 bit image deltas not supported");
var delta = this.diffFrom(baseImage),
deltaBytes = 0;
for (var i = 0; i < delta.length; i++)
deltaBytes += delta[i].totalBytes(false);
var magic = 'Sd78',
version = 0x0100, // 1.0
headerSize = 18,
data = new DataView(new ArrayBuffer(headerSize + deltaBytes)),
pos = 0;
// magic bytes
for (var i = 0; i < 4; i++)
data.setUint8(pos++, magic.charCodeAt(i));
// version
data.setUint16(pos, version); pos += 2;
// header size
data.setUint16(pos, headerSize); pos += 2;
// delta size
data.setUint16(pos, delta.length); pos += 2;
data.setUint32(pos, deltaBytes); pos += 4;
// current process and display
data.setUint16(pos, this.userProcess.oop); pos += 2;
data.setUint16(pos, this.userDisplay.oop); pos += 2;
if (pos !== headerSize) throw "wrong header size";
// objects
for (var i = 0; i < delta.length; i++)
pos = delta[i].writeTo(data, pos, this);
if (pos !== headerSize + deltaBytes) throw "wrong image size";
return data.buffer;
},
writeToBuffer: function() {
this.fullGC(); // collect all objects
if (this.largeOops) return this.writeToBufferLarge();
var magic = 'St78',
version = 0x0100, // 1.0: 16 bit oops
headerSize = 18,
data = new DataView(new ArrayBuffer(headerSize + this.oldSpaceBytes)),
pos = 0;
// magic bytes
for (var i = 0; i < 4; i++)
data.setUint8(pos++, magic.charCodeAt(i));
// version
data.setUint16(pos, version); pos += 2;
// header size
data.setUint16(pos, headerSize); pos += 2;
// image size
data.setUint16(pos, this.oldSpaceCount); pos += 2;
data.setUint32(pos, this.oldSpaceBytes); pos += 4;
// current process and display
data.setUint16(pos, this.vm.activeProcess.oop); pos += 2;
data.setUint16(pos,this.vm.primHandler.displayBlt.oop); pos += 2;
if (pos !== headerSize) throw "wrong header size";
// objects
var obj = this.firstOldObject,
n = 0;
while (obj) {
pos = obj.writeTo(data, pos, this);
obj = obj.nextObject;
n++;
}
if (pos !== headerSize + this.oldSpaceBytes) throw "wrong image size";
if (n !== this.oldSpaceCount) throw "wrong object count";
return data.buffer;
},
writeToBufferLarge: function() {
// this.fullGC(); // happened already
var magic = 'St78',
version = 0x0200, // 2.0: 32 bit oops
headerSize = 28,
data = new DataView(new ArrayBuffer(headerSize + this.oldSpaceBytes)),
pos = 0;
// magic bytes
for (var i = 0; i < 4; i++)
data.setUint8(pos++, magic.charCodeAt(i));
// version
data.setUint16(pos, version); pos += 2;
// header size
data.setUint16(pos, headerSize); pos += 2;
// image size
data.setUint32(pos, this.oldSpaceCount); pos += 4;
data.setUint32(pos, this.oldSpaceBytes); pos += 4;
data.setUint32(pos, this.largeOops); pos += 4;
// current process and display
data.setUint32(pos, this.vm.activeProcess.oop); pos += 4;
data.setUint32(pos,this.vm.primHandler.displayBlt.oop); pos += 4;
if (pos !== headerSize) throw "wrong header size";
// objects
var obj = this.firstOldObject,
n = 0;
while (obj) {
pos = obj.writeToLarge(data, pos, this);
obj = obj.nextObject;
n++;
}
if (pos !== headerSize + this.oldSpaceBytes) throw "wrong image size";
if (n !== this.oldSpaceCount) throw "wrong object count";
return data.buffer;
},
objectFromOop: function(oop, optionalOopMap) {
if (oop & 1) {
var val = oop >> 1;
return (val & 0x3FFF) - (val & 0x4000);
}
if (optionalOopMap) return optionalOopMap[oop]; // only available at startup
// find the object with the given oop - looks only in oldSpace for now!
var obj = this.firstOldObject;
do {
if (oop === obj.oop) return obj;
obj = obj.nextObject;
} while (obj);
debugger;
throw "oop not found";
},
objectToOop: function(anObject) {
// newly created objects have a temporary oop, so assign a real one
if (typeof anObject === "number")
return (anObject * 2 + 0x10001) & 0xFFFF; // add tag bit, make unsigned
if (anObject.oop < 0) { // it's a temp oop
if (this.tenuresSinceLastGC++ > this.maxTenuresBeforeGC) {
console.log("Forcing GC after " + this.maxTenuresBeforeGC + " unchecked tenures");
this.fullGC(); // force a GC since we tenured many objects already
if (!(anObject.oop > 0))
throw "attempt to tenure unreachable object";
} else {
this.appendToOldObjects([anObject]); // just tenure the object
console.log("Tenuring " + anObject.stInstName(32));
}
}
return anObject.oop;
},
someInstanceOf: function(clsObj) {
var obj = this.firstOldObject;
while (true) {
if (obj.stClass === clsObj)
return obj;
if (!obj.nextObject) {