bootloader/README.md

# bootloader

A tiny 32-bit x86 operating system kernel

http://3zanders.co.uk/2017/10/13/writing-a-bootloader/

## Real Mode Boot 1

16-bit mode.

Assemble with

``` shell
nasm -f bin boot1.asm -o boot1.bin
```

Run with

``` shell
qemu-system-x86_64 -fda boot1.bin
```

## Protected Mode Boot 2

32-bit mode.

Assemble with

``` shell
nasm -f bin boot2.asm -o bin2.bin
```

Run with

``` shell
qemu-system-x86_64 -fda boot2.bin
```

## Extended Boot 3

32-bit, 1024 byte.

Assemble with

``` shell
nasm -f bin boot3.asm -o boot3.bin
```

Run with

``` shell
qemu-system-x86_64 -fda boot3.bin
```

## Linking with Zig

32-bit, 1024 byte, building and linking in Zig code.

Build with

``` shell
zig build-exe boot4.o fun.zig -T linker.ld -nostdlib -target x86-freestanding
```

Convert to raw binary (strip ELF)

```shell
objcopy -Obinary fun fun.bin
```


Run with

``` shell
qemu-system-x86_64 -fda fun.bin
```