kernel/timer.c

#include

volatile uint32_t timer_ticks = 0;

int timer_intr(int intr_no, void *arg, struct pt_regs *regs)

{

timer_ticks++;

return 0;

}

static void settimer(int hz)

{

/*设置定时器多长时间发送一个中断给cpu*/

uint32_t divisor = 1193180/hz;

/*二进制，工作模式为3，先写LSB再写MSB*/

outb(0x43, 0x36);

outb(0x40, divisor&0xff);

outb(0x40, divisor>>8);

}

static void timer_init()

{

KPRINTF("timer_init\n");

irq_attach(IRQ2INTR(IRQ_TIMER), timer_intr, NULL, "TIMER_INTERRUPT");

settimer(200);

enable_irq(IRQ_TIMER);

}

INITFUNC(timer_init, INIT_TIMER);