millfork VS compiler-explorer

Well from the pov of machine or assembly code, C is without a doubt a high level language.

But at the same time it's the lowest-level high-level language.

(there are a couple of interesting 'mid-level' languages for 8-bit processors though, like Millfork: https://github.com/KarolS/millfork)

Take a look at millfork, it's similar to what you're trying to do

There are no doubt some systems still running under emulation doing the same thing as they were 40 years ago. But the truth is CP/M is dead. Long live CP/M!

It's just hobbyists now. One hacker ported his game to a Kaypro under CP/M a couple years ago: http://www.chrisfenton.com/dd9-kaypro-edition/

Much of the focus is on porting CP/M to whatever new or old Z80 system someone has built or found. I can't think of anything particularly dazzling besides the above, in terms of recent new programs, but here are some pointers if you wanted to write something yourself!

RunCPM is a CP/M Z80 virtual machine under modern OSes for development etc. https://github.com/MockbaTheBorg/RunCPM

CP/Mish is an attempt to bring all the free software CP/M tools together. It is to CP/M as Linux is to UNIX, or FreeDOS is to MS-DOS. A mostly complete, improved, libre reimplementation: https://github.com/davidgiven/cpmish

Also from David Given (and not CP/M specific) is Cowgol. Alpha quality. But it's a self-hosted Pascal/Ada-like language with compiler. Runs on 8-bit systems, at least theoretically. It is written, of course, entirely in Cowgol: https://github.com/davidgiven/cowgol

Millfork is a language which targets CP/M systems, among others. It's a whole-program optimizing compiler for a language somewhat lower level than C, with properties that make it very nice to compile for 8-bit systems like no recursion, and no automatic promotion to 16-bit integers in type handling: https://github.com/KarolS/millfork

SDCC supports the platform with C surprisingly well. I wouldn't call it rock-solid but compared to the above toys it is an industrial quality compiler for the Z80. In fact, C seems to be the most common actual language for hobbyist and the little remaining serious Z80 development, probably ahead of assembly.

If it just reads and writes the terminal and can fit in 64 KB, then a port is probably straightforward.

At least on android arm64, looks like a `dmb ishst` is emitted after the constructor, which allows future loads to not need an explicit barrier. Removing `final` from the field causes that barrier to not be emitted.

https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename...

You said You won't get "extreme performance" from C++ because it is buried under the weight of decades of compatibility hacks.

Now your whole comment is about vector behavior. You haven't talked about what 'decades of compatibility hacks' are holding back performance. Whatever behavior you want from a vector is not a language limitation.

You could write your own vector and be done with it, although I'm still not sure what you mean, since once you reserve capacity a vector still doubles capacity when you overrun it. The reason this is never a performance obstacle is that if you're going to use more memory anyway, you reserve more up front. This is what any normal programmer does and they move on.

Show what you mean here:

https://godbolt.org/

I've never used ISPC. It's somewhat interesting although since it's Intel focused of course it's not actually portable.

I guess now the goal posts are shifting. First it was that "C++ as a language has performance limitations" now it's "rust has a vector that has a function I want and also I want SIMD stuff that doesn't exist. It does exist? not like that!"

Try to stay on track. You said there were "decades of compatibility hacks" holding back C++ performance then you went down a rabbit hole that has nothing to do with supporting that.

C++ Insights is available online at https://cppinsights.io/

It is also available at a touch of a button within the most excellent https://godbolt.org/

along side the button that takes your code sample to https://quick-bench.com/

Those sites and https://cppreference.com/ are what I'm using constantly while coding.

I recently discovered https://whitebox.systems/ It's a local app with a $69 one-time charge. And, it only really works with "C With Classes" style functions. But, it looks promising as another productivity boost.

[P&H RISC] https://www.google.com/books/edition/_/e8DvDwAAQBAJ

Compiler Explorer by Matt Godbolt [Godbolt] can help better understand what code a compiler generates under different circumstances.

[Godbolt] https://godbolt.org

The official CPU architecture manuals from CPU vendors are surprisingly readable and information-rich. I only read the fragments that I need or that I am interested in and move on. Here is the Intel’s one [Intel]. I use the Combined Volume Set, which is a huge PDF comprising all the ten volumes. It is easier to search in when it’s all in one file. I can open several copies on different pages to make navigation easier.

Intel also has a whole optimization reference manual [Intel] (scroll down, it’s all on the same page). The manual helps understand what exactly the CPU is doing.

[Intel] https://www.intel.com/content/www/us/en/developer/articles/t...

Personally, I believe in automated benchmarks that measure end-to-end what is actually important and notify you when a change impacts performance for the worse.

Let's compile it with https://godbolt.org/, turn on some optimisations and inspect the IR (-O2 -emit-llvm). Copying out the part that corresponds to the while loop:

  4:

resources were extra useful when building deeper intuitions about GPU performance for ML models at work and in graduate school.

- CMU's "Deep Learning Systems" Course is hosted online and has YouTube lectures online. While not generally relevant to software performance, it is especially useful for engineers interested in building strong fundamentals that will serve them well when taking ML models into production environments: https://dlsyscourse.org/

- Compiler Explorer is a tool that allows you easily input some code in and check how the assembly output maps to the source. I think this is exceptionally useful for beginner/intermediate programmers who are familiar with one compiled high-level language and have not been exposed to reading lots of assembly. It is also great for testing how different compiler flags affect assembly output. Many people used to coding in C and C++ probably know about this, but I still run into people who haven't so I share it whenever performance comes up: https://godbolt.org/

To really understand what's going on here we can look at the compiled assembly code. I'm working on a Mac and can do this using the objdump tool. Compiler Explorer is also a handy tool but doesn't seem to support Arm assembly which is what Rust will use when compiling on Apple Silicon.

Play around with it in godbolt if you're really curious: https://godbolt.org/