diff --git a/include/boost/multiprecision/cpp_int.hpp b/include/boost/multiprecision/cpp_int.hpp
index de26540f..a9ebeac7 100644
--- a/include/boost/multiprecision/cpp_int.hpp
+++ b/include/boost/multiprecision/cpp_int.hpp
@@ -1511,7 +1511,8 @@ void divide_unsigned_helper(cpp_int_backend<MinBits, Signed, Allocator>* result,
    {
       result->resize(r_order + 1);
       pres = result->limbs();
-      pres[r_order] = 0;  // just in case we don't set the most significant limb below.
+      if(result->size() > r_order)
+         pres[r_order] = 0;  // just in case we don't set the most significant limb below.
    }
 
    do
diff --git a/include/boost/multiprecision/tommath.hpp b/include/boost/multiprecision/tommath.hpp
index cc32fcd9..5f2c3db6 100644
--- a/include/boost/multiprecision/tommath.hpp
+++ b/include/boost/multiprecision/tommath.hpp
@@ -200,7 +200,7 @@ struct tommath_int
             unsigned shift = radix == 8 ? 3 : 4;
             unsigned block_count = DIGIT_BIT / shift;
             unsigned block_shift = shift * block_count;
-            boost::uint32_t val, block;
+            unsigned long long val, block;
             while(*s)
             {
                block = 0;
diff --git a/performance/miller_rabin_performance.cpp b/performance/miller_rabin_performance.cpp
index 458c14b2..9667aa51 100644
--- a/performance/miller_rabin_performance.cpp
+++ b/performance/miller_rabin_performance.cpp
@@ -138,7 +138,7 @@ int main()
 #ifdef TEST_CPP_INT
    test_miller_rabin<mp_number<cpp_int_backend<>, false> >("cpp_int (no Expression templates)");
    test_miller_rabin<cpp_int>("cpp_int");
-   test_miller_rabin<mp_number<cpp_int_backend<64> > >("cpp_int (64-bit cache)");
+   test_miller_rabin<mp_number<cpp_int_backend<128> > >("cpp_int (128-bit cache)");
    test_miller_rabin<mp_number<cpp_int_backend<256> > >("cpp_int (256-bit cache)");
    test_miller_rabin<mp_number<cpp_int_backend<512> > >("cpp_int (512-bit cache)");
    test_miller_rabin<mp_number<cpp_int_backend<1024> > >("cpp_int (1024-bit cache)");