1                                  ;  hello.asm  a first program for nasm for Linux, Intel, gcc
     2                                  ;
     3                                  ; assemble:	nasm -f elf -l hello.lst  hello.asm
     4                                  ; link:		gcc -o hello  hello.o
     5                                  ; run:	        hello 
     6                                  ; output is:	Hello World 
     7                                  
     8                                  	SECTION .data		; data section
     9 00000000 48656C6C6F20576F72-     msg:	db "Hello World",10	; the string to print, 10=cr
    10 00000009 6C640A             
    11                                  len:	equ $-msg		; "$" means "here"
    12                                  				; len is a value, not an address
    13                                  
    14                                  	SECTION .text		; code section
    15                                          global main		; make label available to linker 
    16                                  main:				; standard  gcc  entry point
    17                                  	
    18 00000000 BA0C000000              	mov	edx,len		; arg3, length of string to print
    19 00000005 B9[00000000]            	mov	ecx,msg		; arg2, pointer to string
    20 0000000A BB01000000              	mov	ebx,1		; arg1, where to write, screen
    21 0000000F B804000000              	mov	eax,4		; write command to int 80 hex
    22 00000014 CD80                    	int	0x80		; interrupt 80 hex, call kernel
    23                                  	
    24 00000016 BB00000000              	mov	ebx,0		; exit code, 0=normal
    25 0000001B B801000000              	mov	eax,1		; exit command to kernel
    26 00000020 CD80                    	int	0x80		; interrupt 80 hex, call kernel