www.pudn.com > LFYOS.zip > timer.s

TIME_LENGTH	=	1190 
.global setup_timer 
setup_timer: 
 
/*	init 8259 for interruption */ 
 
	movb $(0x11),%al 
	outb %al,$(0x20) 
	movb $(0x20),%al 
	outb %al,$(0x21) 
	movb $(0x04),%al 
	outb %al,$(0x21) 
	movb $(0x03),%al 
	outb %al,$(0x21) 
 
	movb $(0xfe),%al 
	outb %al,$(0x21) 
 
	 
	movb $(0x11),%al 
	outb %al,$(0xa0) 
	movb $(0x70),%al 
	outb %al,$(0xa1) 
	movb $(0x02),%al 
	outb %al,$(0xa1) 
	movb $(0x01),%al 
	outb %al,$(0xa1) 
	 
	movb $(0x04),%al 
	outb %al,$(0xa1) 
 
/*	init 8259 end 	*/ 
 
 
/*	init 8254 for timer ,thus for time-sharing */ 
 
	movb $(0x34),%al 
	outb %al,$(0x43) 
 
	movl $(TIME_LENGTH),%eax 
	outb %al,$(0x40) 
	movb %ah,%al 
	outb %al,$(0x40) 
 
/*	init 8254 end  */ 
 
	ret