Re: [eigen] some problems with building with AltiVec enabled

[Konstantinos Margaritis <markos@xxxxxxxx>]

Thanks to Gael and Benoit, I managed to fix AltiVec/PacketMath.h so that 
everything compiles again now, I attach the file to be commited to the 
repository :)
Some tests seem to fail, and this may or may not be related to Altivec, that 
will have to examined closer.

Konstantinos

Στις Wednesday 20 August 2008 16:31:28 ο/η Konstantinos Margaritis έγραψε:
> Hi all,
>
> I'd like to bring the AltiVec support back to life :) and I did some tests.
> For some reason, template specialization doesn't seem to work for
> AltiVec and the following errors occur (while compiling adjoint.cpp):
>
> Any help appreciated. I also attach my current AltiVec/PacketMath.h
> (note that it will not compile cleanly due to ei_palign() not properly
> implemented, apparently offset is a runtime value and vec_sld() needs
> values known at compile time, anyway, this is irrelevant for the problem,
> I hed the same problems even before).
>

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2008 Konstantinos Margaritis <markos@xxxxxxxx>
// Copyright (C) 2008 Gael Guennebaud <g.gael@xxxxxxx>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.

#ifndef EIGEN_PACKET_MATH_ALTIVEC_H
#define EIGEN_PACKET_MATH_ALTIVEC_H

#ifndef EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD
#define EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD 4
#endif

typedef vector float v4f;
typedef vector int   v4i;

static const v4i   v0i   = vec_splat_s32(0);
static const v4i   v16i_ = vec_splat_s32(-16);
static const v4f   v0f   = (v4f) v0i;

template<> struct ei_packet_traits<float>  { typedef v4f type; enum {size=4}; };
template<> struct ei_packet_traits<int>    { typedef v4i type; enum {size=4}; };

template<> struct ei_unpacket_traits<v4f>  { typedef float  type; enum {size=4}; };
template<> struct ei_unpacket_traits<v4i>  { typedef int    type; enum {size=4}; };

template<> inline v4f  ei_padd(const v4f&   a, const v4f&   b) { return vec_add(a,b); }
template<> inline v4i  ei_padd(const v4i&   a, const v4i&   b) { return vec_add(a,b); }

template<> inline v4f  ei_psub(const v4f&   a, const v4f&   b) { return vec_sub(a,b); }
template<> inline v4i  ei_psub(const v4i&   a, const v4i&   b) { return vec_sub(a,b); }

template<> inline v4f  ei_pmul(const v4f&   a, const v4f&   b) { return vec_madd(a,b, v0f); }
template<> inline v4i  ei_pmul(const v4i&   a, const v4i&   b)
{
  // Taken from http://developer.apple.com/hardwaredrivers/ve/algorithms.html#Multiply32
  //Set up constants
  v4i bswap, lowProduct, highProduct;

  // Do real work
  bswap = (v4i)vec_rl( (vector unsigned int)b, (vector unsigned int)v16i_ );
  lowProduct = vec_mulo( (vector short)a,(vector short)b );
  highProduct = vec_msum((vector short)a,(vector short)bswap, v0i);
  highProduct = (v4i) vec_sl( (vector unsigned int)highProduct, (vector unsigned int)v16i_ );
  return vec_add( lowProduct, highProduct );
}

template<> inline v4f  ei_pdiv(const v4f&   a, const v4f&   b) {
  // Altivec does not offer a divide instruction, we have to do a reciprocal approximation
  v4f y = vec_re(b);

  // Set up some constants for inverse reciprocals
  vector unsigned int v1_;
  v4f v1, v0_;
  v1 = (v4f) vec_splat_u32(1);
  v1_ = vec_splat_u32(-1);
  v0_ = (v4f) vec_sl(v1_, v1_);
  // Do a Newton-Raphson iteration to get the needed accuracy
  y = vec_madd(vec_nmsub( y, b, v1 ), y, y);
  v4f res = vec_madd(a, y, v0_);
  return res;
}

template<> inline v4f  ei_pmadd(const v4f&  a, const v4f&   b, const v4f&  c) { return vec_madd(a, b, c); }

template<> inline v4f  ei_pmin(const v4f&   a, const v4f&   b) { return vec_min(a,b); }
template<> inline v4i  ei_pmin(const v4i&   a, const v4i&   b) { return vec_min(a,b); }

template<> inline v4f  ei_pmax(const v4f&   a, const v4f&   b) { return vec_max(a,b); }
template<> inline v4i  ei_pmax(const v4i&   a, const v4i&   b) { return vec_max(a,b); }

template<> inline v4f  ei_pload(const float* from) { return vec_ld(0, from); }
template<> inline v4i  ei_pload(const int*   from) { return vec_ld(0, from); }

template<> inline v4f  ei_ploadu(const float*  from)
{
  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
  vector unsigned char MSQ, LSQ;
  vector unsigned char mask;
  MSQ = vec_ld(0, (unsigned char *)from);          // most significant quadword
  LSQ = vec_ld(15, (unsigned char *)from);         // least significant quadword
  mask = vec_lvsl(0, from);                        // create the permute mask
  return (v4f) vec_perm(MSQ, LSQ, mask);  // align the data
}

template<> inline v4i    ei_ploadu(const int*    from)
{
  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
  vector unsigned char MSQ, LSQ;
  vector unsigned char mask;
  MSQ = vec_ld(0, (unsigned char *)from);          // most significant quadword
  LSQ = vec_ld(15, (unsigned char *)from);         // least significant quadword
  mask = vec_lvsl(0, from);                        // create the permute mask
  return (v4i) vec_perm(MSQ, LSQ, mask);    // align the data
}

template<> inline v4f  ei_pset1(const float&  from)
{
  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
  float __attribute__(aligned(16)) af[4];
  af[0] = from;
  v4f vc = vec_ld(0, af);
  vc = vec_splat(vc, 0);
  return vc;
}

template<> inline v4i    ei_pset1(const int&    from)
{
  int __attribute__(aligned(16)) ai[4];
  ai[0] = from;
  v4i vc = vec_ld(0, ai);
  vc = vec_splat(vc, 0);
  return vc;
}

template<> inline void ei_pstore(float*   to, const v4f&   from) { vec_st(from, 0, to); }
template<> inline void ei_pstore(int*     to, const v4i&   from) { vec_st(from, 0, to); }

template<> inline void ei_pstoreu(float*  to, const v4f&   from)
{
  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
  // Warning: not thread safe!
  vector unsigned char MSQ, LSQ, edges;
  vector unsigned char edgeAlign, align;

  MSQ = vec_ld(0, (unsigned char *)to);                     // most significant quadword
  LSQ = vec_ld(15, (unsigned char *)to);                    // least significant quadword
  edgeAlign = vec_lvsl(0, to);                              // permute map to extract edges
  edges=vec_perm(LSQ,MSQ,edgeAlign);                        // extract the edges
  align = vec_lvsr( 0, to );                                // permute map to misalign data
  MSQ = vec_perm(edges,(vector unsigned char)from,align);   // misalign the data (MSQ)
  LSQ = vec_perm((vector unsigned char)from,edges,align);   // misalign the data (LSQ)
  vec_st( LSQ, 15, (unsigned char *)to );                   // Store the LSQ part first
  vec_st( MSQ, 0, (unsigned char *)to );                    // Store the MSQ part
}

template<> inline void ei_pstoreu(int*    to , const v4i&    from )
{
  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
  // Warning: not thread safe!
  vector unsigned char MSQ, LSQ, edges;
  vector unsigned char edgeAlign, align;

  MSQ = vec_ld(0, (unsigned char *)to);                     // most significant quadword
  LSQ = vec_ld(15, (unsigned char *)to);                    // least significant quadword
  edgeAlign = vec_lvsl(0, to);                              // permute map to extract edges
  edges=vec_perm(LSQ,MSQ,edgeAlign);                        // extract the edges
  align = vec_lvsr( 0, to );                                // permute map to misalign data
  MSQ = vec_perm(edges,(vector unsigned char)from,align);   // misalign the data (MSQ)
  LSQ = vec_perm((vector unsigned char)from,edges,align);   // misalign the data (LSQ)
  vec_st( LSQ, 15, (unsigned char *)to );                   // Store the LSQ part first
  vec_st( MSQ, 0, (unsigned char *)to );                    // Store the MSQ part
}

template<> inline float  ei_pfirst(const v4f&  a)
{
  float __attribute__(aligned(16)) af[4];
  vec_st(a, 0, af);
  return af[0];
}

template<> inline int    ei_pfirst(const v4i&  a)
{
  int __attribute__(aligned(16)) ai[4];
  vec_st(a, 0, ai);
  return ai[0];
}

inline v4f ei_preduxp(const v4f* vecs)
{
  v4f v[4], sum[4];

  // It's easier and faster to transpose then add as columns
  // Check: http://www.freevec.org/function/matrix_4x4_transpose_floats for explanation
  // Do the transpose, first set of moves
  v[0] = vec_mergeh(vecs[0], vecs[2]);
  v[1] = vec_mergel(vecs[0], vecs[2]);
  v[2] = vec_mergeh(vecs[1], vecs[3]);
  v[3] = vec_mergel(vecs[1], vecs[3]);
  // Get the resulting vectors
  sum[0] = vec_mergeh(v[0], v[2]);
  sum[1] = vec_mergel(v[0], v[2]);
  sum[2] = vec_mergeh(v[1], v[3]);
  sum[3] = vec_mergel(v[1], v[3]);

  // Now do the summation:
  // Lines 0+1
  sum[0] = vec_add(sum[0], sum[1]);
  // Lines 2+3
  sum[1] = vec_add(sum[2], sum[3]);
  // Add the results
  sum[0] = vec_add(sum[0], sum[1]);
  return sum[0];
}

inline float ei_predux(const v4f& a)
{
  v4f b, sum;
  b = (v4f)vec_sl((vector unsigned char)a, vec_splat_u8(8));
  sum = vec_add(a, b);
  b = (v4f)vec_sl((vector unsigned char)a, vec_splat_u8(4));
  sum = vec_add(a, b);
  return ei_pfirst(sum);
}

inline v4i  ei_preduxp(const v4i* vecs)
{
  v4i v[4], sum[4];

  // It's easier and faster to transpose then add as columns
  // Check: http://www.freevec.org/function/matrix_4x4_transpose_floats for explanation
  // Do the transpose, first set of moves
  v[0] = vec_mergeh(vecs[0], vecs[2]);
  v[1] = vec_mergel(vecs[0], vecs[2]);
  v[2] = vec_mergeh(vecs[1], vecs[3]);
  v[3] = vec_mergel(vecs[1], vecs[3]);
  // Get the resulting vectors
  sum[0] = vec_mergeh(v[0], v[2]);
  sum[1] = vec_mergel(v[0], v[2]);
  sum[2] = vec_mergeh(v[1], v[3]);
  sum[3] = vec_mergel(v[1], v[3]);

  // Now do the summation:
  // Lines 0+1
  sum[0] = vec_add(sum[0], sum[1]);
  // Lines 2+3
  sum[1] = vec_add(sum[2], sum[3]);
  // Add the results
  sum[0] = vec_add(sum[0], sum[1]);
  return sum[0];
}

inline int ei_predux(const v4i& a)
{
  v4i sum, v0 = vec_splat_s32(0);
  sum = vec_sums(a, v0);
  sum = vec_sld(sum, v0, 12);
  return ei_pfirst(sum);
}

template<int Offset>
struct ei_palign_impl<Offset, v4f>
{
  inline static void run(v4f& first, const v4f& second)
  {
    first = vec_sld(first, second, Offset*4);
  }
};

template<int Offset>
struct ei_palign_impl<Offset, v4i>
{
  inline static void run(v4i& first, const v4i& second)
  {
    first = vec_sld(first, second, Offset*4);
  }
};

#endif // EIGEN_PACKET_MATH_ALTIVEC_H