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Optimized bitfieldReverse

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This commit is contained in:
Christophe Riccio
2014-11-02 20:48:59 +01:00
parent 41c00872a1
commit afb1f6d152
2 changed files with 391 additions and 51 deletions
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47
glm/detail/func_integer.inl
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@@ -46,6 +46,26 @@ namespace detail
{
return ~((~0) << Bits);
}
template <bool EXEC = false>
struct compute_bitfieldReverseStep
{
template <typename T, glm::precision P, template <class, glm::precision> class vecType>
GLM_FUNC_QUALIFIER static vecType<T, P> call(vecType<T, P> const & v, T, T)
{
return v;
}
};
template <>
struct compute_bitfieldReverseStep<true>
{
template <typename T, glm::precision P, template <class, glm::precision> class vecType>
GLM_FUNC_QUALIFIER static vecType<T, P> call(vecType<T, P> const & v, T Mask, T Shift)
{
return (v & Mask) << Shift | (v & (~Mask)) >> Shift;
}
};
}//namespace detail
// uaddCarry
@@ -167,26 +187,23 @@ namespace detail
}
// bitfieldReverse
template <typename T>
GLM_FUNC_QUALIFIER T bitfieldReverse(T v)
template <typename genType>
GLM_FUNC_QUALIFIER genType bitfieldReverse(genType x)
{
return bitfieldReverse(tvec1<T>(v)).x;
return bitfieldReverse(glm::tvec1<genType, glm::defaultp>(x)).x;
}
template <typename T, precision P, template <typename, precision> class vecType>
template <typename T, glm::precision P, template <typename, glm::precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> bitfieldReverse(vecType<T, P> const & v)
{
GLM_STATIC_ASSERT(std::numeric_limits<T>::is_integer, "'bitfieldReverse' only accept integer values");
vecType<T, P> Result(0);
T const BitSize = static_cast<T>(sizeof(T) * 8);
for(T i = 0; i < BitSize; ++i)
{
vecType<T, P> const BitSet(v & (static_cast<T>(1) << i));
vecType<T, P> const BitFirst(BitSet >> i);
Result |= BitFirst << (BitSize - 1 - i);
}
return Result;
vecType<T, P> x(v);
x = detail::compute_bitfieldReverseStep<sizeof(T) * 8 >= 2>::call<T, P, vecType>(x, T(0x5555555555555555ull), static_cast<T>( 1));
x = detail::compute_bitfieldReverseStep<sizeof(T) * 8 >= 4>::call<T, P, vecType>(x, T(0x3333333333333333ull), static_cast<T>( 2));
x = detail::compute_bitfieldReverseStep<sizeof(T) * 8 >= 8>::call<T, P, vecType>(x, T(0x0F0F0F0F0F0F0F0Full), static_cast<T>( 4));
x = detail::compute_bitfieldReverseStep<sizeof(T) * 8 >= 16>::call<T, P, vecType>(x, T(0x00FF00FF00FF00FFull), static_cast<T>( 8));
x = detail::compute_bitfieldReverseStep<sizeof(T) * 8 >= 32>::call<T, P, vecType>(x, T(0x0000FFFF0000FFFFull), static_cast<T>(16));
x = detail::compute_bitfieldReverseStep<sizeof(T) * 8 >= 64>::call<T, P, vecType>(x, T(0x00000000FFFFFFFFull), static_cast<T>(32));
return x;
}
// bitCount