arno/linux-insides
1
0
Fork 0
mirror of https://github.com/0xAX/linux-insides.git synced 2024-12-22 22:58:08 +00:00
Code Issues Releases Wiki Activity

Update linux-bootstrap-1.md

Browse Source
This commit is contained in:
0xAX 2015-02-10 22:58:32 +06:00
parent eca46a8a8a
commit 4f87dd7be0
1 changed files with 8 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
Booting/linux-bootstrap-1.md
View File

@ -133,7 +133,14 @@ We will see:
![Simple bootloader which prints only `!`](http://oi60.tinypic.com/2qbwup0.jpg) ![Simple bootloader which prints only `!`](http://oi60.tinypic.com/2qbwup0.jpg)
In this example we can see that this code will be executed in 16 bit real mode and will start at 0x7c00 in memory. After the start it calls the [0x10](http://www.ctyme.com/intr/rb-0106.htm) interrupt which just prints `!` symbol. It fills rest of 510 bytes with zeros and finish with two magic bytes 0xaa and 0x55. In this example we can see that this code will be executed in 16 bit real mode and will start at 0x7c00 in memory. After the start it calls the [0x10](http://www.ctyme.com/intr/rb-0106.htm) interrupt which just prints `!` symbol. It fills rest of 510 bytes with zeros and finish with two magic bytes `0xaa` and `0x55`.
Although you can see binary dump of it with `objdump` util:
```
nasm -f binary boot.nasm
objdump -D -b binary -mi386 -Maddr16,data16,intel boot
```
A real-world boot sector has code for continuing the boot process and the partition table... instead of a bunch of 0's and an exclamation point :) Ok, so, from this moment BIOS handed control to the bootloader and we can go ahead. A real-world boot sector has code for continuing the boot process and the partition table... instead of a bunch of 0's and an exclamation point :) Ok, so, from this moment BIOS handed control to the bootloader and we can go ahead.