x86/first_prog.s at master · fosres/x86 · GitHub

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#PURPOSE: Simple program that exits and returns a status code back to the Linux kernel
# 	  status code back to the Linux kernel
#

#INPUT:	  none
#

#OUTPUT:	returns a status code. This can be viewed
#		by typing.
#
#
#		echo $?
#

#		after running the program
#

#VARIABLES:
#		%eax holds the system call number
#		%ebx hodls the return status
#

.section .data

.section .text
.globl _start
_start:
movl $1, %eax	#this is the linux kernel command
		#number (system call) for exiting
		#a program.

movl $0, %ebx	#this is the status number we will
		#return to the operating system.
		#Change this around and it will
		#return different things to
		#echo $?
int $0x80 #this wakes up the kernel to run
	  #the exit command