Getting what they want

IE and Chrome set to support asm.js

Natali Vlatko
Browser image via Shutterstock

Support for asm.js has made it into the next version of Windows, following a collaboration between Mozilla and Microsoft to satisfy a long-standing hunger of users. This marks a giant step forward for Internet Explorer, with Chrome to follow suit.

Microsoft has recently announced that the upcoming Windows 10 is set to support Mozilla’s asm.js optimisations in the next version of its Chakra JavaScript engine. The IE team has been collaborating with Mozilla in order to implement it faster and have now updated its status to ‘In Development‘.

Community push

The addition of asm.js support evolved from the IE Platform Suggestion Box, which saw users requesting the inclusion for better overall performance. Gaurav Seth and Ed Maurer of the Microsoft Chakra team stated that they’ve taken a closer look at asm.js as a technology and what it means for the Web at large, recognising that it is a “clear step towards enabling near-native performance for the Web platform”.

Seth and Maurer went on to share the technology characteristics they’re most interested in, and other than the boost to JavaScript execution speed, they’re loving the fact that asm.js is a pure subset of JavaScript and guarantees interoperability across platforms and browsers:

This means that engines that support asm.js light up the new features, while engines that don’t will simply run with degraded performance. Since the beginning of Chakra, our team’s focus has always been to prioritize this approach to new functionality.

Chrome’s TurboFan

Chrome’s asm.js support will come via TurboFan, a new optimizing compiler for V8. A Chromium team member created Issue #2599 “Implement ‘use asm'” back in 2013, which has only recently been listed as Assigned and is now being worked on by the V8 team. Ben Titzer from the TurboFan gang recently updated members with what’s been happening:

We’re already beta testing TurboFan in Chrome 41, which significantly improves the performance of numeric code like asm.js. There are additional heuristics and optimizations that are coming, so we are hesitant to close this issue as “Fixed”, but one could consider this issue “Mostly fixed”. We are actively experimenting with the policy to activate TurboFan, and one signal is the “use asm” directive.

With this latest news, support for asm.js will eventually appear across all three major browsers used today: Firefox, Chrome, and IE.

Natali Vlatko
An Australian who calls Berlin home, via a two year love affair with Singapore. Natali was an Editorial Assistant for (S&S Media Group).

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