diff --git a/cutils.h b/cutils.h
index 63b94d3cb..72700e15c 100644
--- a/cutils.h
+++ b/cutils.h
@@ -148,7 +148,7 @@ static inline int clz32(unsigned int a)
 #ifdef _MSC_VER
     unsigned long idx;
     _BitScanReverse(&idx, a);
-    return 31 ^ idx;
+    return 31 - idx;
 #else
     return __builtin_clz(a);
 #endif
@@ -160,7 +160,7 @@ static inline int clz64(uint64_t a)
 #ifdef _MSC_VER
     unsigned long idx;
     _BitScanReverse64(&idx, a);
-    return 63 ^ idx;
+    return 63 - idx;
 #else
     return __builtin_clzll(a);
 #endif
@@ -172,7 +172,7 @@ static inline int ctz32(unsigned int a)
 #ifdef _MSC_VER
     unsigned long idx;
     _BitScanForward(&idx, a);
-    return 31 ^ idx;
+    return (int)idx;
 #else
     return __builtin_ctz(a);
 #endif
@@ -184,7 +184,7 @@ static inline int ctz64(uint64_t a)
 #ifdef _MSC_VER
     unsigned long idx;
     _BitScanForward64(&idx, a);
-    return 63 ^ idx;
+    return (int)idx;
 #else
     return __builtin_ctzll(a);
 #endif