> From a bystanderʼs POV it is excessively hard to memorize all the mess with multiple different extensions

It's the same for other ISAs.

> What Iʼm slightly confused for is that all these extensions, useful for a minor part of applications, arenʼt moved to longer instructions (6-byte).

Because these instructions don't need it. There will be future >4-byte instructions, for things thay can't resonably be done in 4-bytes, e.g. much larger immediates.

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wg0 32 minutes ago | parent | next [-]

> It's the same for other ISAs.

No they are not. See the Intel Software Programmer Volumes. Highly detailed, highly structured and highly specific.

	▲	Joker_vD 27 minutes ago \| parent [-]
		You're joking, right?

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pclmulqdq an hour ago | parent | prev [-]

It's way worse on RISC-V. There are maybe 5 x86 or ARM variants to care about at any given time, even if you want to hyper-optimize your code. RISC-V has a soup of literally 100s of extensions with non-uniform use and support.

	▲	benj111 25 minutes ago \| parent [-]
		What are you imagining? If this is desktop then most of the extensions are going to be standard. The only reason they're optional is because I'm using the same instruction set on my Pico, so no it doesn't have floating point, and I believe it has integer divide but I wouldn't be surprised if it didn't. And the extensions are in groups, a good chunk of which are compressed instructions, which unless you're writing assembly, you don't need to worry about. In fact most of this you don't need to worry about unless youre writing assembly.