Mints

Cli utils for the Atari Mint in no_std Rust.

This crate defines a custom rust target (m68k-atari-mintelf.json) that allows you to create elf binaries with the crossmint toolchain. You'll need the m68k-atari-mintelf toolchain instead of the old a.out toolchain (m68k-atari-mint).

This crate links to Mintbox, although you can remove the link lines to link to Mintlib as your libc. This will make your binaries larger -- by default C and Rust binaries that link to mintlib are >100KB. I wanted a smaller size so I wrote my own libc with just enough to bootstrap Rust but still keep small binaries.

Currently, the allocator uses libc_alloc to defer to libc's malloc and friends -- that means that memalign is required to use alloc in rust. Libcmini could be used as a replacement libc for smaller binaries, but it currently doesn't implement memalign, so until then you'll have to use mintlib or mintbox.

Size footguns to keep in mind

• Any language feature that brings in compiler builtins will bloat the binary to 300KB. This apparently includes derives (thiserror + noshell seems to do this), as well as formatting certain things. If an i32 is printed, then it doesn't pull in compiler-builtins, but if you debug print it, it pulls in compiler-builtins, and the binary will go up to 300KB. It also seems like using a Box<dyn Error> causes the same issue, probably due to accessing formatting code indirectly. An impl Error doesn't seem to have the same issue.

• To handle printing, The print macro calls format_args.as_str() which returns a Some(s) if the string itself can be folded into a string without requiring trait dispatch, otherwise, just panicking. It would be preferable to do this at compile time, so that code like println!("{:?}", vec![1]); would be compiler errors instead of panics at runtime. As is, this code will panic and then sigabort.

In Progress:

• rm