CppCon
13 HN recommenders · recommended in 14 months, 2016–2024
1:19:52 · 264K views · Sep 24, 2016
Jason Turner's CppCon 2016 talk builds a simple Commodore 64 game using C++17, showing how constexpr and const let a modern compiler produce tight 6502 code. He walks through assembly output to show abstractions being optimized away.
A perennial favorite, recommended as proof that expressive modern C++ can compile to efficient code even on tiny retro hardware.
20 comments from Hacker News
Absolutely. There was a fantastic talk at CppCon last year, using C++17 to program a game for the Commodore 64. Using standard C++ idioms, the optimizer was easily able to make it compile down to efficient machine code. [1] this video
For those who haven't seen it, there is a wonderful talk by Jason Turner about writing a simple Pong clone for the Commodore 64 in modern C++: this video
I think this way of looking at it old. Even if the const-ness is somehow subverted without generating an error then most compilers (or at least GCC and Clang) will presume the code is compliant and make optimizations following what the standard allows. This potentially results in undefined behavior when that pointer you mentioned is used to modified a thing that ought to be const. Consider the amount of optimizations seen in the video from CppCon 2016: this video Jason Turner, the presenter, is writing code a few lines at a time and cross compiling for the Commodore 64. He shows his assembly at many steps of the way and shows how many functions are completely elided when const (and later constexpr) are used correctly. There are a ton of other good talks from CppCon 2016 including one about const and what optimizations it makes possible and several about how compilers are more willing to "break" code that is non-compliant by making its behavior undefined. None of it really shocking or new, unless you have been writing to one compiler implementation instead of to the standard.
> Nor does it have any concern for the elegance of its design. It has a lot of inelegant facilities, which, when used under the hood, allow you to express your elegant abstractions. > Hence the common practice of using a small subset C++ and pretending it's just C with Extras. That's mostly failure to use C++. Since C++11, and especially with later updates to the standard, idiomatic C++ is very different from C - even if you're not using a lot of the standard library. I'll link to a talk already linked-to in another comment in this discussion: Rich code for tiny computers / Jason Turner, CppCon 2016 this video
This talk proves this point exactly: this video Watch from 27:00 where he talks about using const wherever possible so the compiler can optimise. It reduces a full function call to work out a colour in 3D space from thousands of instructions to one. After watching this and a few others particularly dynamic dispatch in Swift, I find myself adding as many hints as I can and applying the most restrictions / scoping possible. Final, const, Private etc. [LINK] Even though actually it can work this out in your module!