1. asm.js begins
Andrei Palchys
andrei@palchys.com
@apalchys

2. 2008
TraceMonkey
V8
Nitro

3. Just-In-Time

4. 2011
Emscripten

5. Emscripten

6. 2013
asm.js

7. asm.js
an extraordinarily
optimizable, low-level
subset of JavaScript

8. Compatibility
Backward compatible with
vanilla* JavaScript
* vanilla-js.com – the best JS framework ever

9. Memory
Manual Memory
Management

10. Type System
- Type system:
integer
double
- Typed Functions

11. function ArithmeticModule(global, foreign, heap) {
"use asm";
function square(x) {
x = x|0;
return (x * x)|0;
}
function multiply(x, y) {
x = +x;
y = +y;
return +(x * y);
}
return {square: square, multiply: multiply};
}

12. var _ = 0, N = 0, M = 0, final = 0, buf = 0, t = 0, i = 0, $SP = 0;
U4[1] = (U4[1] | 0) - 32768;
$SP = U4[1] | 0;
N = 16384;
M = 200;
final = 0;
_;
for (t = 0; (t | 0) < (M | 0); t = (t | 0) + 1 | 0) {
for (i = 0; (i | 0) < (N | 0); i = (i | 0) + 1 | 0) {
U1[((($SP) >> 0) + i) >> 0] = (((i | 0) + (final | 0) | 0 |
0) % 256 | 0) & 255;
}
for (i = 0; (i | 0) < (N | 0); i = (i | 0) + 1 | 0) {
final = ((final | 0) + (U1[((($SP) >> 0) + i) >> 0] >>> 0) |
0) & 1;
}
https://github.com/jlongster/LLJS/blob/asm.js/test/asm/bench2.js

13. Supported browsers
Firefox 22
OdinMonkey

14. Performance

15. Future
- LLJS
- Extended Type System
- Other JS Engines(Chrome ?)
- Improve performance

16. Andrei Palchys
andrei@palchys.com
@apalchys