Real mode assembly I: Difference between revisions

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{{Warning|Please see the [[Real Mode OS Warning]] page before continuing.}}

 

''In this tutorial we will assemble a small 16-bit [[assembly|assembly language]] kernel with [[NASM]] and boot it.''

Here you go, go wild.

 

org 0x7C00 ; add 0x7C00 to label addresses

bits 16 ; tell the assembler we want 16 bit code

times 510-($-$$) db 0

dw 0AA55h ; some BIOSes require this signature

 

To assemble on Windows:

 

nasm kernel.asm -f bin -o kernel.bin

partcopy kernel.bin 0 200 -f0

 

Or on Linux:

nasm kernel.asm -f bin -o kernel.bin

dd if=kernel.bin of=/dev/sda

 

Those commands assemble your kernel binary and write them to the first disk (sda might be your system disk, so use sdb, sdc etc. according to your configuration. USB-sticks also appear as one of the "sd" devices). Go ahead and test out your operating system now!

'''EDIT on December 12 2008: I've written a second part to this tutorial at [[Real mode assembly II]]. This and future parts will have less code to copy and paste and more theory!'''

 

[[Category:Real mode assembly]]

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