riscv-elf-psabi-doc VS picocli

Sure. It's the section here https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/ma...

It's that structs of two simple fields need to be passed in registers. And more specifically that this rule is relevant for mixed integer and floating point fields.

It's a very specific rule that requires a ton of code to implement compared to the integer calling convention. And again like the weird AMD64 convention likely invented to squeeze out a theoretical few cycles that never occur outside microbenchmarks

This one has more info on the ELF output, notably things like how things like relocations and special symbols like %pcrel_hi work: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc

This is a bit dense but that's what I referred to https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc. I'm not sure if there's a RISC-V specific assembly tutorial that talks about calling conventions.

The stack is defined by the ABI and it’s a purely software convention. It’s possible a program could use a different convention. FYI, the EBI is defined here: https://github.com/riscv-non-isa/riscv-elf-psabi-doc

It looks like people are starting to think somewhat along that direction in https://github.com/riscv-non-isa/riscv-elf-psabi-doc etc. but most CPUs that I can think of have basically a monolithic ISA with pretty much an expanding set of instructions as the versions increment and encoded in the -march argument to the linker.

Picocli allows using a compiler annotation processor to generate classes at compile time instead [0].

[0]: https://github.com/remkop/picocli/blob/main/picocli-codegen/...

Picocli is a pretty good one for writing CLI apps

"and there are simply no good command line input parsing libraries for Java."

Looks like author missed the most obvious and popular OSS one: https://picocli.info/

The command line example gave me the "ick". It is usually preferrable to parse the command line arguments into one instance of a custom "command class", rather than into a list of things. Like jcommander, picocli or jbock do.

Complex argument parsing needs to be auto-generated by libraries like picocli. Even if you need something custom, it'd be quicker to write an Annotation processor from scratch than editing that file.

https://github.com/remkop/picocli

"Picocli-based applications can be ahead-of-time compiled to a GraalVM native image, with extremely fast startup time and lower memory requirements, which can be distributed as a single executable file."

https://picocli.info/quick-guide.html

Using picocli to handle your command line options gives you the best chance to automatically generate an ArgumentCompleter script in the future, but won't help you today (other than possibly making your command line handling more standardized & easier).

Picocli

Then we released a JBang! and picocli based cli that would be, on any OS running a jvm runtime :

picocli : "a mighty tiny command line interface"