addind more important kernel files and also fixing bugs

kernel/scheduler.c

@@ -1,5 +1,62 @@
 #include "scheduler.h"
+#include <stddef.h>
+
+static task_t tasks[MAX_TASKS];
+static uint32_t task_stacks[MAX_TASKS][STACK_SIZE / sizeof(uint32_t)];
+
+static int task_count = 0;
+static task_t *task_list = NULL;
+static task_t *current_task = NULL;
 
 void scheduler_init() {
-    // Scheduler initialization code
+    // Initialize task list, etc.
+    task_list = NULL;
+    current_task = NULL;
+    task_count = 0;
+}
+
+void scheduler_add_task(void (*entry)(void)) {
+    if (task_count >= MAX_TASKS || entry == NULL) return;
+
+    task_t *new_task = &tasks[task_count];
+    new_task->id = task_count;
+    new_task->entry = entry;
+
+    // Simulate a stack pointer pointing to the "top" of the stack
+    new_task->stack_ptr = &task_stacks[task_count][STACK_SIZE / sizeof(uint32_t) - 1];
+
+    new_task->next = NULL;
+
+    // Add to task list
+    if (task_list == NULL) {
+        task_list = new_task;
+    } else {
+        task_t *tail = task_list;
+        while (tail->next) {
+            tail = tail->next;
+        }
+        tail->next = new_task;
+    }
+
+    task_count++;
+}
+
+void scheduler_schedule() {
+    // Very basic round-robin switch
+    if (current_task && current_task->next) {
+        current_task = current_task->next;
+    } else {
+        current_task = task_list; // Loop back
+    }
+
+    // Call context switch or simulate yielding to current_task
+    // In real system: context_switch_to(current_task)
+    if (current_task && current_task->entry) {
+        current_task->entry();  // Simulate switching by calling
+    }
+}
+
+void scheduler_yield() {
+    // Stub: manually call schedule for cooperative multitasking
+    scheduler_schedule();
 }