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First step toward a unification of packet log implementation, currently only SSE and AVX are unified.

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To this end, I added the following functions: pzero, pcmp_*, pfrexp, pset1frombits functions.
This commit is contained in:
Gael Guennebaud
2018-11-26 14:21:24 +01:00
parent 5f6045077c
commit 2c44c40114
6 changed files with 220 additions and 183 deletions
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59
Eigen/src/Core/GenericPacketMath.h
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@@ -214,6 +214,38 @@ pxor(const Packet& a, const Packet& b) { return a ^ b; }
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pandnot(const Packet& a, const Packet& b) { return a & (!b); }
/** \internal \returns the significant and exponent of the underlying floating point numbers
* See https://en.cppreference.com/w/cpp/numeric/math/frexp
*/
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pfrexp(const Packet &a, Packet &exponent) { return std::frexp(a,&exponent); }
/** \internal \returns zeros */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pzero(const Packet& a) { return pxor(a,a); }
/** \internal \returns bits of \a or \b according to the input bit mask \a mask */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pselect(const Packet& mask, const Packet& a, const Packet& b) {
return por(pand(a,mask),pandnot(b,mask));
}
/** \internal \returns a <= b as a bit mask */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pcmp_le(const Packet& a, const Packet& b); /* { return a<=b ? pnot(pxor(a,a)) : pxor(a,a); } */
/** \internal \returns a < b as a bit mask */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pcmp_lt(const Packet& a, const Packet& b); /* { return a<b ? pnot(pxor(a,a)) : pxor(a,a); } */
/** \internal \returns a == b as a bit mask */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pcmp_eq(const Packet& a, const Packet& b); /* { return a==b ? pnot(pxor(a,a)) : pxor(a,a); } */
/** \internal \returns a < b or a==NaN or b==NaN as a bit mask */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pcmp_lt_or_nan(const Packet& a, const Packet& b); /* { return pnot(pcmp_le(b,a)); } */
/** \internal \returns a packet version of \a *from, from must be 16 bytes aligned */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pload(const typename unpacket_traits<Packet>::type* from) { return *from; }
@@ -226,6 +258,10 @@ ploadu(const typename unpacket_traits<Packet>::type* from) { return *from; }
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pset1(const typename unpacket_traits<Packet>::type& a) { return a; }
/** \internal \returns a packet with constant coefficients set from bits */
template<typename Packet,typename BitsType> EIGEN_DEVICE_FUNC inline Packet
pset1frombits(BitsType a);
/** \internal \returns a packet with constant coefficients \a a[0], e.g.: (a[0],a[0],a[0],a[0]) */
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pload1(const typename unpacket_traits<Packet>::type *a) { return pset1<Packet>(*a); }
@@ -597,6 +633,29 @@ pinsertlast(const Packet& a, typename unpacket_traits<Packet>::type b)
return pblend(mask, pset1<Packet>(b), a);
}
/***************************************************************************
* Some generic implementations to be used by implementors
***************************************************************************/
/** \internal shift the bits by n and cast the result to the initial type, i.e.:
* return float(reinterpret_cast<uint>(a) >> n)
*/
template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
pshiftright_and_cast(Packet a, int n);
/** Default implementation of pfrexp for float.
* It is expected to be called by implementers of template<> pfrexp,
* and the above pshiftright_and_cast function must be implemented.
*/
template<typename Packet> EIGEN_STRONG_INLINE Packet
pfrexp_float(const Packet& a, Packet& exponent) {
const Packet cst_126f = pset1<Packet>(126.0f);
const Packet cst_half = pset1<Packet>(0.5f);
const Packet cst_inv_mant_mask = pset1frombits<Packet>(~0x7f800000u);
exponent = psub(pshiftright_and_cast(a,23), cst_126f);
return por(pand(a, cst_inv_mant_mask), cst_half);
}
} // end namespace internal
} // end namespace Eigen