Shutdown the computer using assembly

Question

How can I shutdown the computer using only assembly code?

Answer 1

You need to say what processor family it is and which OS you're using. Also what privileges your code is running under - if it's kernel code then it has more privileges than user code.

Assuming you're using some member of the Windows NT family (including XP or Vista) on an Intel x86 family CPU, and your code is normal (userspace) code, then... you need to call the Windows built-in function to do this. You can't just execute some magic sequence of assembly.

Even if you could just execute some magic sequence of assembly, you wouldn't want to - you almost certainly want to give the OS chance to write data from the disk cache to disk, and do other graceful-shutdown stuff.

If you're writing your own OS for x86, then you need to look at the ACPI (or APM) specs. If GPL code is OK, then the relevent Linux kernel routines are here (ACPI) and here (APM).