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Unify Altivec/VSX's pexp with generic implementation

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This commit is contained in:
Gael Guennebaud 2018-11-26 16:47:13 +01:00
parent cf8b85d5c5
commit 5c8406babc
2 changed files with 11 additions and 39 deletions
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40
Eigen/src/Core/arch/AltiVec/MathFunctions.h
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@ -102,45 +102,7 @@ Packet4f plog<Packet4f>(const Packet4f& _x)
template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED
Packet4f pexp<Packet4f>(const Packet4f& _x)
{
Packet4f x = _x;
Packet4f tmp, fx;
Packet4i emm0;
// clamp x
x = pmax(pmin(x, p4f_exp_hi), p4f_exp_lo);
// express exp(x) as exp(g + n*log(2))
fx = pmadd(x, p4f_cephes_LOG2EF, p4f_half);
fx = pfloor(fx);
tmp = pmul(fx, p4f_cephes_exp_C1);
Packet4f z = pmul(fx, p4f_cephes_exp_C2);
x = psub(x, tmp);
x = psub(x, z);
z = pmul(x,x);
Packet4f y = p4f_cephes_exp_p0;
y = pmadd(y, x, p4f_cephes_exp_p1);
y = pmadd(y, x, p4f_cephes_exp_p2);
y = pmadd(y, x, p4f_cephes_exp_p3);
y = pmadd(y, x, p4f_cephes_exp_p4);
y = pmadd(y, x, p4f_cephes_exp_p5);
y = pmadd(y, z, x);
y = padd(y, p4f_1);
// build 2^n
emm0 = vec_cts(fx, 0);
emm0 = vec_add(emm0, p4i_0x7f);
emm0 = vec_sl(emm0, reinterpret_cast<Packet4ui>(p4i_23));
// Altivec's max & min operators just drop silent NaNs. Check NaNs in
// inputs and return them unmodified.
Packet4ui isnumber_mask = reinterpret_cast<Packet4ui>(vec_cmpeq(_x, _x));
return vec_sel(_x, pmax(pmul(y, reinterpret_cast<Packet4f>(emm0)), _x),
isnumber_mask);
return pexp_float(_x);
}
#ifndef EIGEN_COMP_CLANG

10
Eigen/src/Core/arch/AltiVec/PacketMath.h
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@ -576,6 +576,16 @@ template<> EIGEN_STRONG_INLINE Packet4f pfrexp<Packet4f>(const Packet4f& a, Pack
return pfrexp_float(a,exponent);
}
template<> EIGEN_STRONG_INLINE Packet4f pcast_and_shiftleft<Packet4f>(Packet4f v, int n)
{
Packet4i vi = vec_cts(v,0);
return reinterpret_cast<Packet4f>(vec_sl(vi, reinterpret_cast<Packet4ui>(pset1<Packet4i>(n))));
}
template<> EIGEN_STRONG_INLINE Packet4f pldexp<Packet4f>(const Packet4f& a, const Packet4f& exponent) {
return pldexp_float(a,exponent);
}
template<> EIGEN_STRONG_INLINE float predux<Packet4f>(const Packet4f& a)
{
Packet4f b, sum;