add: sleep

headers/drivers.h

@@ -6,4 +6,4 @@
 
 void load_drivers(void);
 void keyboard_handler(struct registers *regs);
-void clock_handler(struct registers *regs);
+void clock_init(struct registers *regs);

headers/interrupts.h

@@ -18,3 +18,13 @@ typedef void (*isr_t)(struct registers *);
 void isr_handler(struct registers *regs);
 void pic_send_eoi(uint8_t irq);
 void register_interrupt_handler(int index, isr_t handler);
+
+static inline void cli(void)
+{
+	__asm__ volatile("cli");
+}
+
+static inline void sti(void)
+{
+	__asm__ volatile("sti");
+}

headers/time.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <stdint.h>
+
+void sleep(uint64_t delay);

src/drivers/clock.c

@@ -1,6 +1,47 @@
-#include "interrupts.h"
+#include <stdint.h>
 
-void clock_handler(struct registers *regs)
+#include "debug.h"
+#include "drivers.h"
+#include "interrupts.h"
+#include "kprintf.h"
+#include "memory.h"
+#include "sys/io.h"
+
+#define PIT_CHANNEL0  0x40
+#define PIT_FREQUENCY 1193182
+#define PIT_COUNT     (65535 / 2)
+#define DELAY         (1000 / (PIT_FREQUENCY / PIT_COUNT))
+
+uint32_t counter = 0;
+
+static void clock_handler(struct registers *regs);
+
+static void set_pit_count(unsigned count)
+{
+	cli();
+
+	outb(0x40, count & 0xFF);          // Low byte
+	outb(0x40, (count & 0xFF00) >> 8); // High byte
+
+	sti();
+}
+
+void clock_init(struct registers *regs)
 {
 	(void)regs;
+	set_pit_count(PIT_COUNT);
+	register_interrupt_handler(0, clock_handler);
+}
+
+static void clock_handler(struct registers *regs)
+{
+	(void)regs;
+	counter--;
+}
+
+void sleep(uint64_t delay)
+{
+	counter = delay / DELAY;
+	while (counter)
+		;
 }

src/drivers/drivers.c

@@ -3,6 +3,6 @@
 
 void load_drivers(void)
 {
-	register_interrupt_handler(0, clock_handler);
+	register_interrupt_handler(0, clock_init);
 	register_interrupt_handler(1, keyboard_handler);
 }