Thread switching (one thread)

src/kernel/include/proc.h

@@ -0,0 +1,16 @@
+#pragma once
+#include <stdint.h>
+
+struct thread
+{
+    struct thread *q_next;
+    uint64_t tid;
+    void *stack;
+    uint64_t state;
+};
+
+// proc/swtch.S
+void *switch_stack(void *out, void *in);
+
+// proc/thread.c
+void start_scheduler();