diff --git a/lib/base64.c b/lib/base64.c
index dea74de9e..1820302a1 100644
--- a/lib/base64.c
+++ b/lib/base64.c
@@ -70,11 +70,11 @@ static void decodeQuantum(unsigned char *dest, const char *src)
       x = (x << 6);
   }
 
-  dest[2] = (unsigned char)(x & 0xFFUL);
+  dest[2] = Curl_ultouc(x);
   x >>= 8;
-  dest[1] = (unsigned char)(x & 0xFFUL);
+  dest[1] = Curl_ultouc(x);
   x >>= 8;
-  dest[0] = (unsigned char)(x & 0xFFUL);
+  dest[0] = Curl_ultouc(x);
 }
 
 /*
diff --git a/lib/warnless.c b/lib/warnless.c
index 83a1c68ab..94e77de46 100644
--- a/lib/warnless.c
+++ b/lib/warnless.c
@@ -38,3 +38,17 @@ unsigned short Curl_ultous(unsigned long ulnum)
 #  pragma warning(pop)
 #endif
 }
+
+unsigned char Curl_ultouc(unsigned long ulnum)
+{
+#ifdef __INTEL_COMPILER
+#  pragma warning(push)
+#  pragma warning(disable:810) /* conversion may lose significant bits */
+#endif
+
+  return (unsigned char)(ulnum & 0xFFUL);
+
+#ifdef __INTEL_COMPILER
+#  pragma warning(pop)
+#endif
+}
diff --git a/lib/warnless.h b/lib/warnless.h
index cd257d3ed..d8734910a 100644
--- a/lib/warnless.h
+++ b/lib/warnless.h
@@ -25,4 +25,6 @@
 
 unsigned short Curl_ultous(unsigned long ulnum);
 
+unsigned char Curl_ultouc(unsigned long ulnum);
+
 #endif /* HEADER_CURL_WARNLESS_H */