diff --git a/src/move.c b/src/move.c
index f2780e5..ed252d9 100644
--- a/src/move.c
+++ b/src/move.c
@@ -3285,8 +3285,11 @@
 	{
 	    // Place cursor at top or bottom of window.
 	    validate_botline();
-	    curwin->w_cursor.lnum = (dir == FORWARD ? curwin->w_topline
+	    linenr_T lnum = (dir == FORWARD ? curwin->w_topline
 						    : curwin->w_botline - 1);
+	    // In silent Ex mode the value of w_botline - 1 may be 0,
+	    // but cursor lnum needs to be at least 1.
+	    curwin->w_cursor.lnum = MAX(lnum, 1);
 	}
     }