Hacker News Reader

Comment by danielvaughn | Hacker News Reader

Honest question - is there any language at all between C and Assembly? Because if there is, I haven't heard of it. For that reason alone, my mental model has always been "C is the lowest you can go before hitting direct instructions to the processor."

View on HN

I would say Forth is lower level than C. The mental model is a two stack machine plus memory, rather than a PDP-11.

And it is very reasonable if you are under 50 years of age, that you haven't heard of it.

Started programming 81 and technically I could have known it

https://www.timexsinclair.com/product/zx-forth/

Conceptually, you can consider LLVM IR to be such language, and there are people who use it that way.

There are some cleverer assemblers that allow to program in assembly while still being able to do stuff like loops without too much effort https://en.wikipedia.org/wiki/Assembly_language#Support_for_...

While staying portable across architectures, probably not. But you can make a little language that's nicer to jse than assembly for a particular CPU.

COMFY-65 is a compiler for a small Lisp language that provides all non-branching operations of the 6502 processor as primitives (e.g. tests for carries, overflows, zero, and negative; set decimal arithmetic mode; etc.). However, programs still consist of subroutines, loops, and tests, with no "go to label" construct provided. It's surprisingly simple and, I would say, elegant.

Here's the PDF that outlines it: https://dl.acm.org/doi/pdf/10.1145/270941.270947

C makes lots of things undefined behavior which are perfectly fine in assembler — read a stack without first writing to it, doing overflow signed internet arithmetic, treating the same memory location as different types.

Also there is quite a lot in modern assembler that you can’t really get to from C, like prefetch and cache flushing instructions.

That last bit is really interesting. Do newer languages make use of those features? Sorry I’m fairly ignorant of this level of the stack.

Newer languages don't make use of any of those features, to my knowledge. They're only available in assembly, and only on modern processors. Because C was made on and designed for hardware that was crappy even in the 1970s, which didn't have a cache or do out of order execution, C doesn't fully reflect the capabilities of modern processors. That's what they're implying with the last sentence, I'm pretty sure.

> is there any language at all between C and Assembly?

LLVM or QBE, for example.

Yes, WebAssembly is higher-level than machine code but lower than C.

Reply on news.ycombinator.com