--- /n/sources/plan9/sys/src/libmp/port/dat.h	Sat Jan 10 10:00:05 2015
+++ /sys/src/libmp/port/dat.h	Sun Jun 28 00:00:00 2026
@@ -1,4 +1,4 @@
-#define	mpdighi  (mpdigit)(1<<(Dbits-1))
+#define	mpdighi  (mpdigit)(1ull<<(Dbits-1))
 #define DIGITS(x) ((Dbits - 1 + (x))/Dbits)
 
 // for converting between int's and mpint's