/* main kernel routine	*/
	.text			  # section declaration (code)
	.globl main	 	  

main:
	call cls
 	call clc
 	call printstr
	ret
	
	.size main,.-main

	/* print string */
printstr:	
        movl $0xb8000,%ebx        # set video address (text mode)
	movl $len,%ecx
	movl $msg,%esi
loop:	movb (%esi),%al	          
        movb $2,%ah               # set green color
        movw %ax,(%ebx)           # print it
	addl $2,%ebx		  # next video address
	addl $1,%esi 		  # next char in string
	subl $1,%ecx		  # len--
	jne loop
	ret
	
	/* clear screen	*/
cls:	
	movl $0xb8000,%edi
	movw $0x0720,%ax
	movl $80*25,%ecx
        cld
	rep stosw
	ret
 
	/* clear cursor */
clc:	
        movw $0x3d4,%dx
        movb $0xa,%al
        outb %al,%dx
        movw $0x3d5,%dx
        inb %dx,%al
        andb $0xc0,%al
        orb  $0x1f,%al
        outb %al,%dx
	ret

	.data			  # section declaration (data)	
msg:	.ascii "Hello world!"     # our famous string
	len = . - msg             # string length