Create initial scaffolding for JS WASM assembler
This commit is contained in:
258
asm.js
Normal file
258
asm.js
Normal file
@@ -0,0 +1,258 @@
|
||||
const HEADER = [
|
||||
0x00, 0x61, 0x73, 0x6d,
|
||||
0x01, 0x00, 0x00, 0x00
|
||||
];
|
||||
|
||||
const LINE_END = "\n"
|
||||
|
||||
class Tokenizer {
|
||||
constructor() {
|
||||
this.delims = new Set([" ", "\r", "\n", "\t"]);
|
||||
this.skips = new Set([" ", "\r", "\t"]);
|
||||
this.comment_start = ";"
|
||||
this.buffer = [];
|
||||
this.comment = false;
|
||||
}
|
||||
|
||||
skip() {
|
||||
const idx = this.buffer.findIndex((cp) => !this.skips.has(cp));
|
||||
this.buffer = idx == -1 ? [] : this.buffer.slice(idx);
|
||||
}
|
||||
|
||||
next() {
|
||||
this.skip();
|
||||
if (this.buffer[0] == LINE_END)
|
||||
return this.buffer.shift();
|
||||
|
||||
const idx = this.buffer.findIndex((cp) => this.delims.has(cp));
|
||||
if (idx != -1) {
|
||||
const token = this.buffer.slice(0, idx).join("");
|
||||
this.buffer = this.buffer.slice(idx);
|
||||
return token;
|
||||
}
|
||||
}
|
||||
|
||||
*handle(src) {
|
||||
this.buffer.push(...src);
|
||||
let token;
|
||||
while (token = this.next()) {
|
||||
if (token == this.comment_start)
|
||||
this.comment = true;
|
||||
else if (this.comment && token == LINE_END)
|
||||
this.comment = false;
|
||||
else if (!this.comment)
|
||||
yield token;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
const State = Object.freeze({
|
||||
TOP: 0,
|
||||
EXPORT: 1,
|
||||
FUNC: 2,
|
||||
RESULT: 3,
|
||||
});
|
||||
|
||||
const Action = Object.freeze({
|
||||
APPEND: 0,
|
||||
EXPORT: 1,
|
||||
FUNC: 2,
|
||||
RESULT: 3,
|
||||
});
|
||||
|
||||
const types = {
|
||||
"func": 0x60,
|
||||
"i32": 0x7f,
|
||||
};
|
||||
|
||||
const opcodes = {
|
||||
"end": 0x0b,
|
||||
"i32.const": 0x41,
|
||||
"i32.mul": 0x6c,
|
||||
};
|
||||
|
||||
class Parser {
|
||||
constructor() {
|
||||
this.tokens = [];
|
||||
this.tokenizer = new Tokenizer();
|
||||
this.state = State.TOP;
|
||||
this.directives = {
|
||||
".export": State.EXPORT,
|
||||
".func": State.FUNC,
|
||||
".result": State.RESULT,
|
||||
};
|
||||
this.handlers = {
|
||||
[State.TOP]: (token) => this.token_top(token),
|
||||
[State.EXPORT]: (token) => this.token_export(token),
|
||||
[State.FUNC]: (token) => this.token_func(token),
|
||||
[State.RESULT]: (token) => this.token_result(token),
|
||||
};
|
||||
|
||||
this.results = [];
|
||||
}
|
||||
|
||||
translate_code(token) {
|
||||
return opcodes[token] ?? parseInt(token);
|
||||
}
|
||||
|
||||
translate_type(token) {
|
||||
return types[token];
|
||||
}
|
||||
|
||||
token_top(token) {
|
||||
if (token == LINE_END)
|
||||
return;
|
||||
let state;
|
||||
if (state = this.directives[token]) {
|
||||
this.state = state;
|
||||
return;
|
||||
}
|
||||
const code = this.translate_code(token);
|
||||
return { type: Action.APPEND, code };
|
||||
}
|
||||
|
||||
token_export(token) {
|
||||
this.state = State.TOP;
|
||||
return { type: Action.EXPORT, name: token };
|
||||
}
|
||||
|
||||
token_func(token) {
|
||||
this.state = State.TOP;
|
||||
return { type: Action.FUNC, name: token };
|
||||
}
|
||||
|
||||
token_result(token) {
|
||||
if (token == LINE_END) {
|
||||
const action = { type: Action.RESULT, results: this.results };
|
||||
this.state = State.TOP;
|
||||
this.results = [];
|
||||
return action;
|
||||
} else {
|
||||
this.results.push(this.translate_type(token));
|
||||
}
|
||||
}
|
||||
|
||||
*handle(src) {
|
||||
let action;
|
||||
for (const token of this.tokenizer.handle(src)) {
|
||||
if (action = this.handlers[this.state](token))
|
||||
yield action;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
const Section = Object.freeze({
|
||||
TYPE: 0x01,
|
||||
FUNC: 0x03,
|
||||
EXPORT: 0x07,
|
||||
CODE: 0x0a
|
||||
});
|
||||
|
||||
export class Assembler {
|
||||
constructor() {
|
||||
this.encoder = new TextEncoder("utf-8");
|
||||
this.decoder = new TextDecoder("utf-8");
|
||||
this.parser = new Parser();
|
||||
this.handlers = {
|
||||
[Action.APPEND]: (action) => this.action_append(action),
|
||||
[Action.EXPORT]: (action) => this.action_export(action),
|
||||
[Action.FUNC]: (action) => this.action_func(action),
|
||||
[Action.RESULT]: (action) => this.action_result(action),
|
||||
};
|
||||
|
||||
this.exports = [];
|
||||
this.funcs = {}
|
||||
}
|
||||
|
||||
action_append(action) {
|
||||
this.funcs[this.current_func].body.push(action.code);
|
||||
}
|
||||
|
||||
action_export(action) {
|
||||
const index = Object.keys(this.funcs).indexOf(action.name);
|
||||
this.exports[action.name] = { kind: 0x00, index };
|
||||
}
|
||||
|
||||
action_func(action) {
|
||||
this.funcs[action.name] = {
|
||||
params: {},
|
||||
results: [],
|
||||
locals: {},
|
||||
body: [],
|
||||
}
|
||||
this.current_func = action.name;
|
||||
}
|
||||
|
||||
action_result(action) {
|
||||
this.funcs[this.current_func].results.push(...action.results);
|
||||
}
|
||||
|
||||
push(chunk) {
|
||||
const text = this.decoder.decode(chunk, { stream: true });
|
||||
for (const action of this.parser.handle(text))
|
||||
this.handlers[action.type](action);
|
||||
}
|
||||
|
||||
wasm_section_type() {
|
||||
const funcs = Object.values(this.funcs);
|
||||
const contents = funcs.map(({ params, results }) => {
|
||||
const param_types = Object.values(params);
|
||||
return [
|
||||
types["func"],
|
||||
param_types.length,
|
||||
...param_types,
|
||||
results.length,
|
||||
...results,
|
||||
];
|
||||
});
|
||||
return [ contents.length ].concat(...contents);
|
||||
}
|
||||
|
||||
wasm_section_func() {
|
||||
const func_count = Object.entries(this.funcs).length;
|
||||
return [ func_count, ...Array(func_count).keys() ];
|
||||
}
|
||||
|
||||
wasm_section_export() {
|
||||
const exports = Object.entries(this.exports);
|
||||
const contents = exports.map(([ name, { kind, index }]) => {
|
||||
const name_utf8 = this.encoder.encode(name);
|
||||
return [
|
||||
name_utf8.length,
|
||||
...name_utf8,
|
||||
kind,
|
||||
index,
|
||||
];
|
||||
});
|
||||
return [ exports.length ].concat(...contents);
|
||||
}
|
||||
|
||||
wasm_section_code() {
|
||||
const funcs = Object.values(this.funcs);
|
||||
const contents = funcs.map(({ body, locals }) => {
|
||||
const local_count = Object.entries(locals).length;
|
||||
return [
|
||||
body.length + 2,
|
||||
local_count,
|
||||
...body,
|
||||
opcodes["end"]
|
||||
]
|
||||
});
|
||||
return [ contents.length ].concat(...contents);
|
||||
}
|
||||
|
||||
wasm() {
|
||||
const template = [
|
||||
[ Section.TYPE, () => this.wasm_section_type() ],
|
||||
[ Section.FUNC, () => this.wasm_section_func() ],
|
||||
[ Section.EXPORT, () => this.wasm_section_export() ],
|
||||
[ Section.CODE, () => this.wasm_section_code() ],
|
||||
];
|
||||
const sections = template.map(([ code, generator ]) => {
|
||||
const body = generator();
|
||||
return [ code, body.length, ...body ];
|
||||
});
|
||||
|
||||
return new Uint8Array(HEADER.concat(...sections));
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user