diff --git a/library/bignum.c b/library/bignum.c
index 0008748..5d68520 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -1087,7 +1087,7 @@
 
     n = X.n - 1;
     t = Y.n - 1;
-    mpi_shift_l( &Y, biL * (n - t) );
+    MPI_CHK( mpi_shift_l( &Y, biL * (n - t) ) );
 
     while( mpi_cmp_mpi( &X, &Y ) >= 0 )
     {