Add base code

os/alloc.c

@@ -0,0 +1,14 @@
+#include "alloc.h"
+#include "stdint.h"
+
+void* *first_mem_avail = (void*) 0x20000000;
+
+void init_allocator() {
+    *first_mem_avail = (void*) 0x20000000 +sizeof(void*);
+}
+
+void* malloc(size_t size) {
+    void* block = *first_mem_avail;
+    *first_mem_avail += size;
+    return block;
+}