Feat: kernel thread done

lib/string.c

@@ -59,6 +59,15 @@ void *memcpy(void *dest, const void *src, size_t count)
   return ret;
 }
 
+void *memset(void *dest, int ch, size_t count)
+{
+  void *ret = dest;
+  for (; count > 0; --count, ++dest)
+    *(uint8_t *)dest = ch & 0xff;
+
+  return ret;
+}
+
 void *memzero(void *start, void *end)
 {
   void *ret = start;