#include #include #include static int pit_callback(void) { printk("tick"); return 0; } static irq_hook_t pit_irq_hook = { .irq_callback = pit_callback }; void pit_init(unsigned int hz) { unsigned int divisor = 1193180 / hz; outportb(0x43, 0x36); uint8_t lo = (uint8_t)(divisor & 0xFF); uint8_t hi = (uint8_t)((divisor >> 8) & 0xFF); outportb(0x40, lo); outportb(0x40, hi); hook_irq(IRQ0, &pit_irq_hook); printk("clock: 8253 PIT initialised at %uHz", hz); }