tick.s

这是一个符合posix.13 pse51的实时内核

/* Tick interrupt handler */

#include "sel.h"

.data
.globl		_tick_num
_tick_num: 	.long	 	0

.text
.globl _tick

_tick:	pushal
	pushw	%ds
	pushw	%es
	pushw	%fs
	pushw	%gs
	
	incl	_tick_num
	movw	$(X_FLATDATA_SEL),%ax
	movw	%ax,%ds
	movl	$0xB8000,%edi
	addl	$158,%edi
	movb	%ds:(%edi),%al
	xorb	$'*',%al
	movb	%al,%ds:(%edi)	
	
	movb	$0x20,%al
	movl	$0x20,%edx
	outb	%al,%dx
	
	popw	%gs
	popw	%fs
	popw	%es
	popw	%ds
	popal
	iret