(timer): basic start

src/kernel/interrupts.c

@@ -6,6 +6,7 @@
 #include <kernel/plic.h>
 #include <kernel/interrupts.h>
 #include <kernel/memory.h>
+#include <kernel/timer.h>
 
 void interrupt_init()
 {
@@ -115,9 +116,7 @@ void handle_interrupt(unsigned long code)
     switch (code)
     {
     case 7:
-        static volatile uint64_t *mtime = (uint64_t *)CLINT_MTIME;
-        static volatile uint64_t *mtimecmp = (uint64_t *)CLINT_MTIMECMP(0);
-        *mtimecmp = *mtime + 100000;
+        timer_handle_interrupt();
 
         break;
     case 11:

src/kernel/timer.c

@@ -0,0 +1,12 @@
+#include <stdint.h>
+#include <kernel/interrupts.h>
+#include <kernel/plic.h>
+#include <kernel/timer.h>
+
+void timer_handle_interrupt()
+{
+	static volatile uint64_t *mtime = (uint64_t *)CLINT_MTIME;
+	static volatile uint64_t *mtimecmp = (uint64_t *)CLINT_MTIMECMP(0);
+
+    *mtimecmp = *mtime + TIMER_FREQ;
+}

src/kernel/timer.h

@@ -0,0 +1,8 @@
+#ifndef KTIMER_H
+#define KTIMER_H
+
+#define TIMER_FREQ 100000
+
+void timer_handle_interrupt();
+
+#endif