1 files changed, 9 insertions, 3 deletions
diff --git a/bignum.c b/bignum.c
index 766677a7ab..209b03e3e2 100644
--- a/bignum.c
+++ b/bignum.c
@@ -1445,7 +1445,9 @@ bary_add_one(BDIGIT *ds, size_t n)
 {
     size_t i;
     for (i = 0; i < n; i++) {
-	ds[i] = BIGLO(ds[i]+1);
+        BDIGIT_DBL n = ds[i];
+        n += 1;
+        ds[i] = BIGLO(n);
         if (ds[i] != 0)
             return 0;
     }
@@ -5271,8 +5273,12 @@ big2dbl(VALUE x)
 		    }
 		}
 		if (carry) {
-		    dl &= BDIGMAX << bits;
-		    dl = BIGLO(dl + ((BDIGIT)1 << bits));
+                    BDIGIT mask = BDIGMAX;
+                    BDIGIT bit = 1;
+                    mask <<= bits;
+                    bit <<= bits;
+                    dl &= mask;
+                    dl |= bit;
 		    if (!dl) d += 1;
 		}
 	    }