1 files changed, 101 insertions, 0 deletions
diff --git a/kernel/include/mux/sched.h b/kernel/include/mux/sched.h
new file mode 100644
index 0000000..de50f98
--- /dev/null
+++ b/kernel/include/mux/sched.h
@@ -0,0 +1,101 @@
+#ifndef MUX_SCHED_H
+#define MUX_SCHED_H
+
+#include "mux/list.h"
+
+/**
+ * Task control block, contains runtime
+ * information about tasks.
+ */
+struct tcb_t {
+  /** Stack pointer of this task. (must be first in structure) */
+  char* volatile sp;
+
+  /** Lowest address of this task's memory (inclusive). */
+  char* mem_low;
+
+  /** Highest address of this task's memory (inclusive). */
+  char* mem_high;
+
+  /** Entry function of this task. */
+  void (*entry)(char);
+
+  /** Current wait queue that this task is in.*/
+  struct list_head queue;
+
+  /** ID of task. */
+  char id;
+
+};
+
+/**
+ * Utility for declaring a task with statically allocated memory.
+ * Note: for a task to be scheduled, it must first be spawned (see spawn()).
+*/
+#define DECLARE_TASK(name, stack_size, entry_function) \
+  static char _declared_stack_##name[stack_size]; \
+  static struct tcb_t name = { \
+    .sp = 0, \
+    .mem_low = _declared_stack_##name, \
+    .mem_high = _declared_stack_##name + stack_size - 1, \
+    .entry = entry_function, \
+    .queue = {} \
+  };
+
+
+/**
+ * Points to currently executing task. If no scheduling has been enabled,
+ * this points to NULL
+ */
+extern struct tcb_t* volatile current;
+
+/**
+ * Queue that contains all tasks that are ready to be run, awaiting their
+ * turn from the scheduler.
+ */
+extern struct list_head ready;
+
+/** 
+ * Makes the current task sleep on a specific queue.
+ * This moves the current task to the given queue's tail.
+ */
+static inline void sleep_queue(struct list_head* queue) {
+  list_move_tail(&current->queue, queue);
+}
+
+/** 
+ * Wakes all tasks waiting in the given queue.
+ * This moves all tasks contained in the queue to the ready queue.
+ */
+static inline void wake_all_queue(struct list_head* queue) {
+  list_splice_init(queue, ready.prev);
+}
+
+/**
+ * Initializes a given task and adds it to the ready queue.
+ */
+void spawn(struct tcb_t* const tcb, char id);
+
+/**
+ * Spawns the idle task
+ */
+void spawn_idle(struct tcb_t* const tcb, char id);
+
+/**
+ * Voluntarily relinquishes control of the CPU from the current task to the scheduler.
+ */
+void yield() __attribute__ ( ( naked ) );
+
+
+/**
+ * Initializes the scheduler by setting up kstack, initializing the idle task
+ * and selecting the first task to run.
+ */
+void sched_init();
+
+/** 
+ * Enters the scheduler, setting current to the next runnable task.
+ */
+void schedule();
+
+#endif