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The C23 edition of Modern C

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515 points bwidlar | 2 comments | 15 Oct 24 16:06 UTC | HN request time: 1.912s | source
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eqvinox ◴[16 Oct 24 12:54 UTC] No.41858531[source]▶
> The storage order, the endianness, as given for my machine, is called little-endian. A system that has high-order representation digits first is called big-endian. Both orders are commonly used by modern processor types. Some processors are even able to switch between the two orders on the fly.

Calling big endian "commonly used by modern processor types" when s390x is really the only one left is a bit of a stretch ;D

(Comments about everyone's favorite niche/dead BE architecture in 3… 2… 1…)

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throwaway19972 ◴[16 Oct 24 13:08 UTC] No.41858658[source]▶
"Modern" doesn't mean "currently widespread".
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eqvinox ◴[16 Oct 24 13:24 UTC] No.41858788[source]▶
Indeed, if it meant "currently widespread" there'd be a stronger argument for Big Endian with a lot of MIPS and PPC chugging away silently. But interpreting "modern" as recent development, BE is close to gone.
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throwaway19972 ◴[16 Oct 24 13:27 UTC] No.41858814[source]▶
Is there some end to this criticism or do you have some stake in dismissing big endian architectures?
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eqvinox ◴[16 Oct 24 13:33 UTC] No.41858872[source]▶
Uh, why so serious? I called it "a bit of a stretch ;D" - there was a reason for that smiley. I'm well aware BE is alive enough to be around.

If you can't live without knowing, sure, my stake in dismissing big endian architectures is that I can't in fact dismiss BE architectures because I have users on it. And it's incredibly painful to test because while my users have such hardware, actually buying a good test platform or CI system is close to impossible. (It ended up being Freescale T4240-QDS devkits off eBay. Not a good sign when the best system you can get is from a company that doesn't exist anymore.)

And at some point it's a question about network protocols/encodings being designed to a "network byte order" determined in the 80s to be big endian. When almost everything is LE, maybe new protocols should just stick with LE as well.

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1. throwaway19972 ◴[16 Oct 24 15:21 UTC] No.41860156[source]▶
> there was a reason for that smiley

Fair—my bad, I can fail at reading tone sometimes.

Would you propose the C abstract machine abstracting away endianness entirely as an alternative? My understanding is that deprecating support for existing architectures is discouraged to every practical extent.

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2. eqvinox ◴[16 Oct 24 16:26 UTC] No.41860983[source]▶
Maybe we failed to communicate because our brains have different endianness? :D

To be honest, I don't think this is a solvable problem. (Changing the C machine concept doesn't do much if you need to process network traffic that uses both (e.g. IP packet [big endian] carrying protobuf [little endian]). It's already mostly a question of data ingress/egress.)

What is solvable though is making sure people are sufficiently aware. And the people who read a book like "Modern C" are probably a very good target audience, building low-level bindings and abstractions. They should know that LE and BE are technically a free-floating design choice, but practically the vast majority of systems is LE now. But at the same time, yes, BE isn't extinct, and won't be any time soon… and it's left to them to make their best possible design given their environments.