math_util: speed up rescaling on 64-bit platforms by using native 128-bit types

common/math/math_util.cpp

@@ -27,20 +27,24 @@
 #include <cstdlib>
 #include <climits>
 #include <math/math_util.h>
+#include <stdint.h>
 
-template <>
+template<>
 int rescale( int aNumerator, int aValue, int aDenominator )
 {
     return (int) ( (int64_t) aNumerator * (int64_t) aValue / (int64_t) aDenominator );
 }
 
 
-template <>
+template<>
 int64_t rescale( int64_t aNumerator, int64_t aValue, int64_t aDenominator )
 {
+#ifdef __x86_64__
+    return ( (__int128_t) aNumerator * (__int128_t) aValue ) / aDenominator;
+#else
     int64_t r = 0;
     int64_t sign = ( ( aNumerator < 0 ) ? -1 : 1 ) * ( aDenominator < 0 ? -1 : 1 ) *
-                                                    ( aValue < 0 ? -1 : 1 );
+                                                     ( aValue < 0 ? -1 : 1 );
 
     int64_t a = std::abs( aNumerator );
     int64_t b = std::abs( aValue );
@@ -84,4 +88,5 @@ int64_t rescale( int64_t aNumerator, int64_t aValue, int64_t aDenominator )
 
         return t1 * sign;
     }
+#endif
 }