iiinova — where your digital self keeps evolving

eliassjogreen @xn--sjgreen-b1a.se · 24/04/2025

The string it creates seems to be truncated and rounded to around ~32 chars when dealing with radix 3, but the bug exists for all radixes which aren't a power of 2. This makes sense because v8 doesn't use the faulty `DoubleToRadixStringView` when stringifying 2, 4, 8, 16 and 32.

> BigInt(Number.MAX_VALUE).toString(3);
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
> Number.MAX_VALUE.toString(3);
'10020200012020012100112000100111212000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000'
> BigInt(Number.MAX_VALUE).toString(3).substring(0, 32) === Number.MAX_VALUE.toString(3).substring(0, 32);
true

$> for (let i = 2; i <= 36; i++) console.log(`${i}: ${BigInt(Number.MAX_VALUE).toString(i) === Number.MAX_VALUE.toString(i)}`); 2: true 3: false 4: true 5: false 6: false 7: false 8: true 9: false 10: false 11: false 12: false 13: false 14: false 15: false 16: true 17: false 18: false 19: false 20: false 21: false 22: false 23: false 24: false 25: false 26: false 27: false 28: false 29: false 30: false 31: false 32: true 33: false 34: false 35: false 36: false$

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eliassjogreen @xn--sjgreen-b1a.se · 24/04/2025

We found a bug in v8 while developing the @trynova.dev JavaScript engine. I was implementing the Number.prototype.toString method when @aapoalas.trynova.dev found that v8 doesn't properly handle Number.MAX_VALUE.toString()!

> BigInt(Number.MAX_VALUE).toString(3) === Number.MAX_VALUE.toString(3);
false

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eliassjogreen @xn--sjgreen-b1a.se · 05/12/2024

The major problem of course is my rather simple and stupid algorithm which could be heavily optimized but it's still quite fast in all other modern and optimized JS engines. I also can't find any single major performance bottleneck engine-wise like I did for day 4 when profiling though.

A callstack generated from the profiling of the execution. Shown are the most called symbols ordered descending.

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eliassjogreen @xn--sjgreen-b1a.se · 05/12/2024

Profiling the run 97% of the calls are just resolving and checking if bindings exist in the environment. Something which could be greatly sped up by some rather simple caching.

A table of the five most called symbols where 87% of calls are for a symbol named "has_binding" and 10% are for a symbol named "resolve_binding". The last three symbols are "execute_instruction", "get_instruction" and "inner_execute": all three of which combined take less than a 1% of calls.

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eliassjogreen @xn--sjgreen-b1a.se · 22/11/2024

My computer got a bit too hot when running the test262 suite for Nova last night 😅 #javascript

A 2019 MacBook Pro 16" sitting outside on my balcony on a stool in the snow. On the display a terminal running the Nova test262 runner.

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