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

This commit is contained in:
Tomasz Wlostowski 2014-05-22 15:07:28 +02:00 committed by Maciej Suminski
parent 655721d9ae
commit b688f9bc20
1 changed files with 8 additions and 3 deletions

View File

@ -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
}