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> The market can sort it out for themselves

Because nobody will write software for 300 unique hardware variations of a platform that have inconsistent capabilities. Consistency is one of the reasons why x86-64 with extensions like like SSE, AVX2 etc is popular.

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Noone uses an 8051 because it's elegant. Billions are still still sold every year because no matter if you learned it in the 70s or last week and no matter who made it, the basics are exactly alike. Software matters; ISAs don't.

Every time I've seen someone use an 8051 in the past twenty years, it's had new, bespoke software written for it. They were more used because they were a known quantity with the patents obviously dead rather than support for existing codebases.

Interesting comment. I suspect without solid facts that new bespoke stuff is mostly either 1) some ARM variant, or 2) some rando US$0.001 Chinese uproc. I think 8051 survives because there's many decades of experience using it, but as I understand the cool kids going into embedded don't think the boomers 8051 is fun and the pool of talent is shrinking fast. SO we'll see what the future holds.

Those aren't mutually exclusive. Some of the sophgo and bouffalo chips have 8051s for always on cores, and riscv for the main cores.

They didn't choose 8051 there for experience, but because it was a tiny core with a decent IPC they could license for a small part, then focus on the main cores. I wouldn't be surprised if they eventually switch to riscv there too.

Also, these 8051 cores tend to be extremely diverse. I don't think I've come across cores from different manufacturers that were actually compatible for real code. They all seem to want to handle accessing 16/32 bit memory differently, have different interrupt details, etc.

Interesting...I don't know much about sophgo and bouffalo chips. Not surprising since the 8051 is patent-free these days. Something I found crazy is how many places someone embedded an 8051 core. Like the tire pressure monitor in every tire these days. Fun stuff.

>You learned it in the 70s [emphasis mine]

I really don't know anything about this space, but you just said that 8051 is dominant because it has one dominant architecture since the 70s. It has hundreds of manufacturers making identical parts.

As you say, software matters. If the Software can't run because of hundreds of extensions that can't be checked for, then you're going to pick a target that works, no? So in fact the ISA matters most: which ISA has the most software? Which ISA means my software runs on the most devices?

I really don't know anything about this space

And yet you couldn't help yourself...

but you just said that 8051 is dominant

I said absolutely no such thing.

If the Software can't run because of hundreds of extensions

The software in the x86 world runs because there aren't hundreds of mutually incompatible extensions. I think the last time there was a major completely incompatible x86 ISA divergence was AMD "3DNow" vs other SIMD extensions. AFAIK the rest were "processor X got feature Y later than competitor Z".

Which ISA means my software runs on the most devices?

Easiest question evah: x86.

Yeah, I completely misinterpreted you post. Apologies.

I believe the market will standardize on certain extensions for specific solutions. No one is going to make a mobile phone with only RV32I, for example.

Yeah, that's the point of the profiles. A curated set of extensions for common use cases like application cores for generic software to target.

How can you use consistency and SSE/AVX in the same sentence?

SSE has inconsistencies like SSE4.x vs SSE4a. AVX is an even more mixed bag. There are some 19 AVX-512 extensions and ZERO chips support all of them.

The situation is so bad that AMD and Intel got together to make AVX10 to unify everything. That seemed great, but Intel now has AVX 10.1 and 10.2 in addition to the base set, so there we go again...

x86 is a massive battleground with tons of competing extensions like FMA3 vs FMA4 (why did FMA3 win???) and in cases where one of the competing variants didn't win, we get something like virtualization extensions being completely different between Intel and AMD. There's also the rash of security extensions that have gone through various support and dropped support (not to mention using some of this stuff for market segmentation and further fragmenting the ecosystem).

x86 is anything but consistent if you look into its history (or even it's present).

> but Intel now has AVX 10.1 and 10.2 in addition to the base set

Intel committed to not slicing and dicing the AVX instruction set going forward. AVX 10.(n+1) will not remove instructions that were in AVX 10.n. Feature testing is also easier: a single feature bit and a single version number.

I bet Intel's management will find some new counterproductive way of segmenting the market but AVX-10 (and therefore AVX-512) should be safe now.

> Because nobody will write software for 300 unique hardware variations

Who said they have to? One can select a RISC-V configuration for a baseline for a particular purpose. Desktop? Choose the one that's most powerful.

ARM is more popular than x86 and is less consistent than it.