"zig cc" Cross-Compiler

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If you want to write an operating system in C, you'll need a cross-compiler. However, building a GCC cross-compiler can be painful. If you just want to write C (not C++), you can use zig cc - a C cross-compiler that comes with the Zig programming language. There are pre-compiled binaries for Windows, Linux, MacOS, and FreeBSD.

Bare-Bones with zig cc

This section describes how to build Bare Bones using zig cc. First off, install the following software:

  • Zig (tested with version 0.6.0)
  • GNU binutils (we just care about the linker - if ld --version reports "GNU ld", you're good to go)
  • NASM

Start off with the standard Bare Bones setup, but use the boot.asm file provided in Bare Bones with NASM instructions (since Zig does not come with an assembler, just a C compiler). At that point, you can continue with Bare Bones, but instead of using i686-elf-gcc, use the following command to build kernel.c:

zig build-obj --c-source kernel.c -target i386-freestanding

This should create a kernel.o file, just the same as if you had used gcc.

When you get to the linking step, we won't be able to use i686-elf-gcc, but luckily, modern versions of GNU ld are able to emulate almost any other linker, so we can use the system ld like so:

ld -m elf_i386 -T linker.ld -o myos.bin boot.o kernel.o

And at that point, you can carry on with Bare Bones, and you should have an operating system, compiled without having to compile your own cross-compiler!

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