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Extend the generic psin_float code to handle cosine and make SSE and AVX use it (-> this adds pcos for AVX)

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Gael Guennebaud
2018-11-30 11:26:30 +01:00
parent e19ece822d
commit b477d60bc6
4 changed files with 41 additions and 105 deletions
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38
Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
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@@ -245,14 +245,23 @@ Packet pexp_double(const Packet _x)
// Construct the result 2^n * exp(g) = e * x. The max is used to catch
// non-finite values in the input.
//return pmax(pmul(x, _mm256_castsi256_pd(e)), _x);
return pmax(pldexp(x,fx), _x);
}
template<typename Packet>
/* The code is the rewriting of the cephes sinf/cosf functions.
Precision is excellent as long as x < 8192 (I did not bother to
take into account the special handling they have for greater values
-- it does not return garbage for arguments over 8192, though, but
the extra precision is missing).
Note that it is such that sinf((float)M_PI) = 8.74e-8, which is the
surprising but correct result.
*/
template<bool ComputeSine,typename Packet>
EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
EIGEN_UNUSED
Packet psin_float(const Packet& _x)
Packet psincos_float(const Packet& _x)
{
typedef typename unpacket_traits<Packet>::integer_packet PacketI;
const Packet cst_1 = pset1<Packet>(1.0f);
@@ -261,6 +270,7 @@ Packet psin_float(const Packet& _x)
const PacketI csti_1 = pset1<PacketI>(1);
const PacketI csti_not1 = pset1<PacketI>(~1);
const PacketI csti_2 = pset1<PacketI>(2);
const PacketI csti_3 = pset1<PacketI>(3);
const Packet cst_sign_mask = pset1frombits<Packet>(0x80000000u);
@@ -290,7 +300,8 @@ Packet psin_float(const Packet& _x)
// Compute the sign to apply to the polynomial.
// sign = third_bit(y_int1) xor signbit(_x)
Packet sign_bit = pxor(_x, preinterpret<Packet>(pshiftleft<29>(y_int1)));
Packet sign_bit = ComputeSine ? pxor(_x, preinterpret<Packet>(pshiftleft<29>(y_int1)))
: preinterpret<Packet>(pshiftleft<29>(padd(y_int1,csti_3)));
sign_bit = pand(sign_bit, cst_sign_mask); // clear all but left most bit
// Get the polynomial selection mask from the second bit of y_int1
@@ -323,11 +334,28 @@ Packet psin_float(const Packet& _x)
y2 = pmadd(y2, x, x);
// Select the correct result from the two polynoms.
y = pselect(poly_mask,y2,y1);
y = ComputeSine ? pselect(poly_mask,y2,y1)
: pselect(poly_mask,y1,y2);
// Update the sign
return pxor(y, sign_bit);
}
template<typename Packet>
EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
EIGEN_UNUSED
Packet psin_float(const Packet& x)
{
return psincos_float<true>(x);
}
template<typename Packet>
EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
EIGEN_UNUSED
Packet pcos_float(const Packet& x)
{
return psincos_float<false>(x);
}
} // end namespace internal
} // end namespace Eigen