Shutdown the computer using assembly

Question

How can I shutdown the computer using only assembly code?

Answer 1

This is the 29 byte program that I have been using to turn the computer off in DOS mode for years.

;Connect to APM API
MOV     AX,5301
XOR     BX,BX
INT     15

;Try to set APM version (to 1.2)
MOV     AX,530E
XOR     BX,BX
MOV     CX,0102
INT     15

;Turn off the system
MOV     AX,5307
MOV     BX,0001
MOV     CX,0003
INT     15

;Exit (for good measure and in case of failure)
RET

You can lookup more functions with Ralf Brown’s Interrupt List at DJGPP.