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Learning about the miracle of boot
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pantonshire 1974163db6 use hlt for padding of stage 2 data section 12 months ago
.cargo cargo xtask alias 12 months ago
boot1 print to vga on panic 1 year ago
buildtools library-ify nasm helper 1 year ago
docs more refactoring 12 months ago
elf fix hexdump alignment for non-multiple-of-16 size 2 years ago
include update layout macros 12 months ago
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stage_1 more refactoring 12 months ago
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xtask more refactoring 12 months ago
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Cargo.toml workspace for build tools 12 months ago
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readme.md enable a20 2 years ago
resources.md update resouces 12 months ago
rust-toolchain.toml default to nightly compiler 12 months ago

readme.md

Overview

Currently we boot from BIOS on a GPT-partitioned disk.

boot0.s is the first-stage bootloader. It lives in the MBR bootstrap field, and must therefore fit into 440 bytes. Its tasks are:

  • Set up a stack etc.
  • Get the boot drive geometry
  • Load and parse the GPT
  • Find the partition of the second stage
  • Load and jump to the first sector of the second stage

boot1.s is the second-stage bootloader. Its tasks are:

  • Load its own sectors not loaded by the first stage
  • Enable A20
  • Detect available memory
  • Enter unreal mode
  • Read the kernel ELF from disk (don't have to parse the ELF just yet)
  • Get all the useful information we can from the BIOS before we leave unreal mode
  • Enter long mode (possibly via protected mode?)
  • Load the kernel ELF
  • Initialise stack etc. for the kernel
  • Jump to kernel