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0 pointsklelatti3y ago0 comments

Here is the JS reference in the article.

> For example, they added a lot of great JavaScript features, cognizant of the ton of online and semi-offline apps that are written in JavaScript. In contrast, Intel attempts to optimize a chip simultaneously for laptops, desktops, and servers, leading poorly optimizations for laptops.

Now there is a JS feature in the M1. It's the FJCVTZS instruction "Floating-point Javascript Convert to Signed fixed-point, rounding toward Zero" which ensures this conversion follows the JS specification. [1]

And this does indeed improve JS performance for Arm CPUs. But why does JS behave this way? Because it was specified to follow what x86 does!

So to say that 'M1 is optimised for JS but x86 isn't etc' is just plain wrong.

Also: - Apple didn't do it Arm did. - It has nothing whatsoever to do with memory management.

[1] https://stackoverflow.com/questions/50966676/why-do-arm-chip...

0 comments

masklinn3y ago

Indeed, the few things I do already know of what the article talks about (very much including the javascript feature of the M1 you outline) are completely wrong, that makes the entire thing extremely suspect.

An other banger:

> Apple also does crazy things like putting a high end GPU (graphics processor) on the same chip.

They’re good but they’re not especially high-end, unless compared to other embedded GPUs like the ones in AMD’s APU, which… are rather comparable overall, and also single-die.

klelattiOP3y ago

I find it very frustrating. There are nuggets of interesting and relevant historical info and the central message of 'ISA isn't the most important thing for high end CPUs' is something I'd broadly agree with.

But it's all mixed with factual errors and iffy opinions (the Patterson and Hennessy textbook really isn't 'horrible').

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