diff --git a/libc/src/__support/FPUtil/dyadic_float.h b/libc/src/__support/FPUtil/dyadic_float.h
index 6c3e1520e5af..4c77d3c541cd 100644
--- a/libc/src/__support/FPUtil/dyadic_float.h
+++ b/libc/src/__support/FPUtil/dyadic_float.h
@@ -465,7 +465,10 @@ template <size_t Bits> struct DyadicFloat {
         // exponents coming in to this function _shouldn't_ be that large). The
         // result should always end up as a positive size_t.
         size_t shift = -static_cast<size_t>(exponent);
-        new_mant >>= shift;
+        if (shift >= Bits)
+          new_mant = 0;
+        else
+          new_mant >>= shift;
         round_dir = rounding_direction(mantissa, shift, sign);
         if (round_dir > 0)
           ++new_mant;