#define IO_PIC		0x20
#define IRQ_OFFSET	32
#define IO_PIT		0x40
#define TIMER_FREQ	1193182
#define TIMER_DIV(x)	((TIMER_FREQ+(x)/2)/(x))

#define TEST_COUNT	0x0200

	.code16gcc
	.text
	.globl	_start
	.type	_start, @function
_start:
/*
 * fill up noop handlers
 */
	xorw	%ax, %ax
	xorw	%di, %di
	movw	%ax, %es
	movw	$256, %cx
fill_noop_idt:
	movw	$noop_handler, %es:(%di)
	movw	%cs, %es:2(%di)
	add	$4, %di
	loop	fill_noop_idt

set_idt:
	movw	$timer_isr, %es:(IRQ_OFFSET*4)
	movw	%cs, %es:(IRQ_OFFSET*4+2)

set_pic:
	# ICW1
	mov	$0x11, %al
	mov	$(IO_PIC), %dx
	out	%al,%dx
	# ICW2
	mov	$(IRQ_OFFSET), %al
	mov	$(IO_PIC+1), %dx
	out	%al, %dx
	# ICW3
	mov	$0x00, %al
	mov	$(IO_PIC+1), %dx
	out	%al, %dx
	# ICW4
	mov	$0x3, %al
	mov	$(IO_PIC+1), %dx
	out	%al, %dx

set_pit:
	# set 8254 mode
	mov	$(IO_PIT+3), %dx
	mov	$0x34, %al
	outb	%al, %dx
	# set 8254 freq 1KHz
	mov	$(IO_PIT), %dx
	movb	$(TIMER_DIV(1000) % 256), %al
	outb	%al, %dx
	movb	$(TIMER_DIV(1000) / 256), %al
	outb	%al, %dx

enable_irq0:
	mov	$0xfe, %al
	mov	$(IO_PIC+1), %dx
	out	%al, %dx
	sti
loop:
	1:
	jmp	1b

test_ok:
	mov	$0x3f8,%dx
	cs lea	msg2, %si
	mov	$(msg2_end-msg2), %cx
	cs rep/outsb

	/* Reboot by using the i8042 reboot line */
	mov	$0xfe, %al
	outb	%al, $0x64

timer_isr:
	cli
	pushaw
	pushfw
	mov	$0x3f8,%dx
	mov	$0x2e, %al	# .
	out	%al,%dx
	decw	count
	jz	test_ok
	popfw
	popaw
	iretw

noop_handler:
	iretw

count:
	.word	TEST_COUNT

msg2:
	.asciz "\nTest OK\n"
msg2_end: