Hacktical C: practical hacker's guide to the C programming language

C lacks sympathy with nearly all additions to hardware capabilities since the late 80s. And it's only with the addition of atomics that it earns the qualification of "nearly". The only thing that makes it appear as lower level than other languages is the lack of high-level abstraction capabilities, not any special affinity for the hardware.

For one, would expect that a low level language wouldn't be so completely worthless at bit twiddling. Another thing, if C is so low level, why can't I define a new calling convention optimized for my use case? Why doesn't C have a rich library for working with SIMD types that has been ubiquitous in processors for 25 years?

Like, say I have a data structure that is four bits wide (consisting of a couple of flags or something) and I want to make an array of them and access them randomly. What help do I get from C to do this? C says "fuck you".

It also has pointers which are absent from most languages but essential to instruction sets.

Lots of languages since the 1950's have pointers.

It puts less obstacles in the way of dealing with hardware than almost any other language for sure.

What's standardized was never as important in C land, at least traditionally, which I guess partly explains why it's trailing so far behind. But the stability of the language is also one of its features.

Only if you don't know C.

Otherwise is says, do whatever you feel like.

simd doesnt make much sense as a standard feature/library for a general purpose language. If you're doing simd its because you're doing something particular for a particular machine and you want to leverage platform specific instructions, so thats why intrinsics (or hell, even externally linked blobs written in asm) is the way to go and C supports that just fine.

But sure, if all youre doing is dot products I guess you can write a standard function that will work on most simd platforms, but who cares, use a linalg library instead.

Pick an appropriate base type (uintN_t) for a bitset, make an array of those (K * N/4) and write a couple inline functions or macros to set and clear those bits.