diff --git a/utils/TSZ/sz/inc/transcode.h b/utils/TSZ/sz/inc/transcode.h
index faff487a50..27b3aa79b7 100644
--- a/utils/TSZ/sz/inc/transcode.h
+++ b/utils/TSZ/sz/inc/transcode.h
@@ -17,6 +17,13 @@
 extern "C" {
 #endif
 
+
+#ifdef WINDOWS
+int32_t BUILDIN_CLZ(uint32_t val);
+#else
+#define BUILDIN_CLZ(val)  __builtin_clz(val)
+#endif
+
 /**
  *  dict = {
         0: [0,0], 1:[1,0], 2:[2,0], 3:[3,0],
@@ -53,10 +60,10 @@ MEM_STATIC int Int2code(int factor)
                                          24, 24, 24, 24, 24, 24, 24, 24,
                                          24, 24, 24, 24, 24, 24, 24, 24 };
     if (factor >= 0)
-        return (factor > 63) ? 50 - __builtin_clz(factor) : Ft_Code[factor];
+        return (factor > 63) ? 50 - BUILDIN_CLZ(factor) : Ft_Code[factor];
     else {
         factor = -factor;
-        return (factor > 63) ? 17 + __builtin_clz(factor) : 67 - Ft_Code[factor];
+        return (factor > 63) ? 17 + BUILDIN_CLZ(factor) : 67 - Ft_Code[factor];
     }
 }
 
diff --git a/utils/TSZ/sz/src/transcode.c b/utils/TSZ/sz/src/transcode.c
index 4046b088f3..abd015515f 100644
--- a/utils/TSZ/sz/src/transcode.c
+++ b/utils/TSZ/sz/src/transcode.c
@@ -13,6 +13,15 @@
 #include "bitstream.h"
 #include <stdlib.h>
 
+
+#ifdef WINDOWS
+int32_t BUILDIN_CLZ(uint32_t val) {
+  unsigned long r = 0;
+  _BitScanReverse(&r, val);
+  return (int)(31 - r);
+}
+#endif
+
 /**
  * @brief transform type array to FseCode & tranCodeBits
  * [type] ---minus md---> [factor] ---transcode---> [tp_code] + [bitstream of diff]