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rwmjyesterday at 5:59 PM1 replyview on HN

Compressed is necessary to reduce code size which is important for performance.

A bunch of vendors have done high performance server chips which support compressed (Rivos, Ventana, some Chinese vendors), so in actual reality this was only a problem for Qualcomm. And that's only because Qualcomm bought Nuvia and they wanted to do the cheap thing (minimally change the front end) rather than the right thing.


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timhhyesterday at 8:00 PM

Of course you can make compressed work. E.g. you fetch 66 bytes instead of 64. Hell, Intel/AMD manage to make x86 fairly fast.

But it's definitely more awkward and has costs throughout the CPU.

I would be really surprised if the lower code density is worse than the improvement due to everything being nicely aligned. Especially because Qualcomm had actual data that it isn't (if you add new instructions with the extra coding space you free up).

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