/* ============================================================================
 * Pactor64 — PIT Timer Driver (x86-64)
 * IRQ0 (INT 0x20), 100 Hz default, monotonic tick counter
 * ============================================================================ */
#include "../include/pactor64.h"

/* === Tick Counters === */
static volatile uint64_t timer_ticks    = 0;
static volatile uint64_t timer_seconds  = 0;

/* Forward declaration — defined in idt.c */
extern void irq_install(int irq, void (*handler)(registers_t *regs));

/* === Timer ISR (IRQ0) === */
static void timer_isr(registers_t *regs) {
    (void)regs;
    timer_ticks++;
    if (timer_ticks % 100 == 0) {
        timer_seconds++;
    }
}

/* === Initialize PIT at given frequency === */
void timer_init(uint32_t hz) {
    uint32_t divisor = 1193182 / hz;

    /* Channel 0, lobyte/hibyte, rate generator (mode 2) */
    outb(0x43, 0x34);
    outb(0x40, divisor & 0xFF);
    outb(0x40, (divisor >> 8) & 0xFF);

    /* Register our ISR for IRQ0 and unmask it */
    irq_install(0x20, timer_isr);
    pic_unmask_irq(0);
}

uint64_t timer_get_ticks(void) {
    return timer_ticks;
}

uint64_t timer_get_seconds(void) {
    return timer_seconds;
}