diff --git a/sources/nix13/extra/clock.c b/sources/nix13/extra/clock.c
new file mode 100644
index 0000000..e0efe0e
--- /dev/null
+++ b/sources/nix13/extra/clock.c
@@ -0,0 +1,20 @@
+#include <time.h>
+#include <limits.h>
+#include <dos/dos.h>
+#include <proto/dos.h>
+#include "stabs.h"
+
+static struct DateStamp ds;
+
+void __initclock(void)
+{ DateStamp(&ds); }
+
+ADD2INIT(__initclock,-10);
+
+clock_t clock(void)
+{ struct DateStamp ds2;
+  DateStamp(&ds2);
+  return (((ds2.ds_Days-ds.ds_Days)*(24*60)+
+           ds2.ds_Minute-ds.ds_Minute)*(60*TICKS_PER_SECOND)+
+           ds2.ds_Tick-ds.ds_Tick)*CLOCKS_PER_SEC/TICKS_PER_SECOND;
+}
diff --git a/sources/nix/time/clock.c b/sources/nix20/extra/clock.c
similarity index 100%
rename from sources/nix/time/clock.c
rename to sources/nix20/extra/clock.c