timer.c

См. документацию.

 
#include  "sys/timer.h"
#include  "sys/isr.h"
/* #include  "sys/scheduler.h" */
#include  "drv/fpu.h"
#include  "io/ports.h"
#include "sys/scheduler.h"
 
extern bool scheduler_working;
 
size_t tick = 0;                /* Количество тиков */
size_t frequency = CLOCK_FREQ;  /* Частота */
 
size_t getTicks(){
    return tick;
}
 
double getUptime() {
    if(getFrequency() == 0) {
        return 0.0;
    }else{
        return (double)tick / (double)frequency;
    }
}
 
size_t getFrequency(){
    return frequency;
}
 
void sleep_ticks(uint32_t delay){
    size_t current_ticks = getTicks();
    while (1){
        if (current_ticks + delay < getTicks()){
            break;
        } else {
            __asm__ volatile("hlt");
        }
    }
}
 
void sleep_ms(uint32_t milliseconds) {
    uint32_t needticks = milliseconds * frequency;
    sleep_ticks(needticks / 1000);
 
    /* (milliseconds * frequency + 500) / 1000 */
}
 
void timer_callback(__attribute__((unused)) registers_t regs){
    tick++;
 
    if (is_multitask() && scheduler_working) {
        task_switch_v2_wrapper(regs);
    }
}
 
void init_timer(uint32_t f){
    frequency = f;
 
    uint32_t divisor;
    uint8_t low;
    uint8_t high;
 
    divisor = BASE_FREQ / f;
 
    outb(0x43, 0x36);
 
    low = (uint8_t) (divisor & 0xFF);
    high = (uint8_t) ((divisor >> 8) & 0xFF);
 
    outb(0x40, low);
    outb(0x40, high);
 
    register_interrupt_handler(IRQ0, &timer_callback);
}