blob: 8ed0be85b821df535aaf206f3154c15159db56ce [file] [log] [blame]
swissChilidefeb0d2021-02-18 15:28:36 -08001#include "timer.h"
swissChilidefeb0d2021-02-18 15:28:36 -08002#include "io.h"
swissChili825d46b2021-02-21 10:14:16 -08003#include "log.h"
4#include "pic.h"
5#include "registers.h"
swissChilief97c262021-04-04 10:20:21 -07006#include "task.h"
swissChilidefeb0d2021-02-18 15:28:36 -08007
8static ulong tick = 0;
9
swissChili19ef4182021-02-21 17:45:51 -080010static void timer_cb(struct registers *regs)
swissChilidefeb0d2021-02-18 15:28:36 -080011{
swissChilief97c262021-04-04 10:20:21 -070012 // Preemptive multitasking!
13 switch_task();
swissChilidefeb0d2021-02-18 15:28:36 -080014}
15
16void init_timer(uint hz)
17{
18 add_interrupt_handler(IRQ_TO_INT(0), timer_cb);
19
20 uint divisor = TIMER_FREQ / hz;
21
swissChilidefeb0d2021-02-18 15:28:36 -080022 outb(0x43, 0x36);
swissChili825d46b2021-02-21 10:14:16 -080023 uchar l = divisor & 0xff, h = (divisor >> 8) & 0xff;
swissChilidefeb0d2021-02-18 15:28:36 -080024
25 outb(0x40, l);
swissChilidefeb0d2021-02-18 15:28:36 -080026 outb(0x40, h);
swissChilidefeb0d2021-02-18 15:28:36 -080027}