peel

intro

this is the userland portion of a smol os called citrusos. the plan is to first develop a programming language called yuzu and write a bootstrap compiler. then I'm going to write userland stuff in yuzu. finally, i'll write the kernel in yuzu. this document is a roadmap of the things that need to be done.

requirements

• gcc
• nasm
• a 64 bit linux kernel

bootstrapping sequence

1. assemble libpith with nasm. link with ld.
2. compile byc with gcc and libpith with nasm. link with ld.
3. compile zest with byc/nasm and libpith with nasm. link with ld.
4. compile yuzu with byc/zest and libpith with zest

now we have a compiler frontend (yuzu), assembler (zest), library (libpith) that are togther capable of building themselves.

phase 1: userland environment using linux kernel

/ (userland)

1. byc: program to compile yuzu to assembly (nasm) - bootstrap yuzu compiler (C) DONE!
2. zest: final compiler backend (assembler - produces object files) (yuzu)
3. yuzu: final compiler frontend (yuzu)
4. bergamot: shell (yuzu)
5. various utilities (yuzu)

notes: zest will support multiple output formats. We will start with an elf64 object file output format and binary format for testing and ultimately move to a custom executable format for phase 2. bz only need support elf64 object file output.

/lib/libpith.asm (standard library)

1. execv: needed for shell
2. argv: needed for shell
3. env: needed for shell

phase 2: pulp (kernel)

this is so far down the road i can't imagine getting here yet. it will be unix like and will basically support the syscalls used by pith.