Latest ARM Instruction Set Includes Specific Optimizations for JavaScript: Daring Fireball

It looks like the latest revisions to ARM’s instruction set includes specific optimizations for JavaScript.

That’s according to a new blog post from Daring Fireball‘s John Gruber, who notes that the newest version of the family of reduced instruction set computing architectures for computer processors screams on the newest A12 Bionic systems-on-a-chip (SoC).

“More precisely: ARMv8.3 adds a new float-to-int instruction with errors and out-of-range values handled the way that JavaScript wants,” reads a tweet from developer Greg Parker quoted in the post. “The previous insns to get JavaScript’s semantics were much slower. JavaScript’s numbers are double by default so it needs this conversion a lot.”

Gruber also notes that the iPhone XS, when first shipped, performed incredibly well on JavaScript benchmarks, quoting Basecamp founder and CTO David Heinemeier Hansson:

Interestingly, Gruber notes that the Cupertino company claims the A12 SoC is “only” 15 percent faster than its predecessor, the A11, in regards to CPU tasks. In the case of JavaScript, which is “mostly (entirely?) CPU-bound,” Apple is far surpassing that number.

Gruber notes that the A12 is performing better than an iMac Pro desktop computer in this regard, certainly no tame feat.