Accessing multiboot data

[oli2]

I know that you can specify what data you want a multiboot compliant bootloader to return, but I don’t understand how to do this. Also, where would this data be returned?

[Octocontrabass]

You specify it in your Multiboot or Multiboot2 header. The specifics depend on which version of Multiboot you're using.

When the bootloader jumps to your kernel's entry point, the EBX register will contain a pointer to the Multiboot information structure. You can parse that structure to get the information you requested in your Multiboot header.