That's how they did it indeed. They have also fallback code for when this the double-width integer type is not available. https://github.com/v8/v8/blob/6.8.137

That's how they did it indeed. They have also fallback code for when this the double-width integer type is not available. https://github.com/v8/v8/blob/6.8.137/src/objects/bigint.cc#L2289 https://github.com/v8/v8/blob/6.8.137/src/objects/bigint.cc#...