diff --git a/FixedPointTests.cpp b/FixedPointTests.cpp
index c3e01da..ea150d7 100644
--- a/FixedPointTests.cpp
+++ b/FixedPointTests.cpp
@@ -612,12 +612,12 @@ SUITE(MultiwordInteger) {
       CHECK_EQUAL(FixedPointHelpers::nlz(uint32_t(1)), 31);
       CHECK_EQUAL(FixedPointHelpers::nlz(uint16_t(1)), 15);
       CHECK_EQUAL(FixedPointHelpers::nlz(uint8_t(1)), 7);
-      CHECK_EQUAL(FixedPointHelpers::ilogb(0), INT_MIN);
+      CHECK_EQUAL(FixedPointHelpers::ilogb(0), std::numeric_limits<int>::min());
       CHECK_EQUAL(FixedPointHelpers::ilogb(0.5), -1);
       CHECK_EQUAL(FixedPointHelpers::ilogb(2), 1);
       CHECK_EQUAL(FixedPointHelpers::ilogb(-2), 1);
       CHECK_EQUAL(FixedPointHelpers::ilogb(NAN), 0);
-      CHECK_EQUAL(FixedPointHelpers::ilogb(INFINITY), INT_MAX);
+      CHECK_EQUAL(FixedPointHelpers::ilogb(INFINITY), std::numeric_limits<int>::max());
   }
 }
 
diff --git a/include/FixedPoint/FixedPointHelpers.hpp b/include/FixedPoint/FixedPointHelpers.hpp
index 1e35c0d..9c019c8 100644
--- a/include/FixedPoint/FixedPointHelpers.hpp
+++ b/include/FixedPoint/FixedPointHelpers.hpp
@@ -4,7 +4,7 @@
 #ifndef FIXEDPOINTHELPERS_HPP
 #define FIXEDPOINTHELPERS_HPP
 #include <cmath>
-#include <limits.h>
+#include <limits>
 #include <algorithm>
 #include <stdint.h>
 
@@ -60,9 +60,9 @@ namespace FixedPointHelpers {
 
     constexpr int ilogb(double v) {
         return v < 0         ? ilogb(-v) :
-               std::isnan(v) ? 0 :
-               std::isinf(v) ? INT_MAX :
-               v == 0        ? INT_MIN :
+               !(v == v)     ? 0 : // NAN check
+               v > std::numeric_limits<double>::max() ? std::numeric_limits<int>::max() :
+               v == 0        ? std::numeric_limits<int>::min() :
                v < 1         ? ilogb(v*2)-1 :
                v >= 2        ? ilogb(v/2) + 1 :
                                0;
diff --git a/include/FixedPoint/MultiwordIntegerSpecialization.hpp b/include/FixedPoint/MultiwordIntegerSpecialization.hpp
index 7551c4f..79143fe 100644
--- a/include/FixedPoint/MultiwordIntegerSpecialization.hpp
+++ b/include/FixedPoint/MultiwordIntegerSpecialization.hpp
@@ -63,7 +63,7 @@ class MultiwordInteger<1, _storageType> {
     constexpr MultiwordInteger<size, storageType>& operator--() { s[0]--; return *this; }
     constexpr MultiwordInteger<size, storageType>  operator--(int) { MultiwordInteger<size, storageType> r(*this); --*this; return r; }
 
-    constexpr MultiwordInteger<size, storageType> operator-() const { return MultiwordInteger<size, storageType>(storageType(-s[0])); }
+    constexpr MultiwordInteger<size, storageType> operator-() const { return MultiwordInteger<size, storageType>(storageType(-signedType(s[0]))); }
 
     constexpr MultiwordInteger<size, storageType>& operator &=(MultiwordInteger<size, storageType> const &o) { s[0] &= o.s[0]; return *this; }
     constexpr MultiwordInteger<size, storageType>& operator |=(MultiwordInteger<size, storageType> const &o) { s[0] |= o.s[0]; return *this; }