AltiVec/PacketMath.h
1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008 Konstantinos Margaritis <markos@codex.gr>
5 //
6 // This Source Code Form is subject to the terms of the Mozilla
7 // Public License v. 2.0. If a copy of the MPL was not distributed
8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9 
10 #ifndef EIGEN_PACKET_MATH_ALTIVEC_H
11 #define EIGEN_PACKET_MATH_ALTIVEC_H
12 
13 namespace Eigen {
14 
15 namespace internal {
16 
17 #ifndef EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD
18 #define EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD 4
19 #endif
20 
21 #ifndef EIGEN_HAS_FUSE_CJMADD
22 #define EIGEN_HAS_FUSE_CJMADD 1
23 #endif
24 
25 // NOTE Altivec has 32 registers, but Eigen only accepts a value of 8 or 16
26 #ifndef EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS
27 #define EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS 16
28 #endif
29 
30 typedef __vector float Packet4f;
31 typedef __vector int Packet4i;
32 typedef __vector unsigned int Packet4ui;
33 typedef __vector __bool int Packet4bi;
34 typedef __vector short int Packet8i;
35 typedef __vector unsigned char Packet16uc;
36 
37 // We don't want to write the same code all the time, but we need to reuse the constants
38 // and it doesn't really work to declare them global, so we define macros instead
39 
40 #define _EIGEN_DECLARE_CONST_FAST_Packet4f(NAME,X) \
41  Packet4f p4f_##NAME = (Packet4f) vec_splat_s32(X)
42 
43 #define _EIGEN_DECLARE_CONST_FAST_Packet4i(NAME,X) \
44  Packet4i p4i_##NAME = vec_splat_s32(X)
45 
46 #define _EIGEN_DECLARE_CONST_Packet4f(NAME,X) \
47  Packet4f p4f_##NAME = pset1<Packet4f>(X)
48 
49 #define _EIGEN_DECLARE_CONST_Packet4f_FROM_INT(NAME,X) \
50  Packet4f p4f_##NAME = vreinterpretq_f32_u32(pset1<int>(X))
51 
52 #define _EIGEN_DECLARE_CONST_Packet4i(NAME,X) \
53  Packet4i p4i_##NAME = pset1<Packet4i>(X)
54 
55 #define DST_CHAN 1
56 #define DST_CTRL(size, count, stride) (((size) << 24) | ((count) << 16) | (stride))
57 
58 // Define global static constants:
59 static Packet4f p4f_COUNTDOWN = { 3.0, 2.0, 1.0, 0.0 };
60 static Packet4i p4i_COUNTDOWN = { 3, 2, 1, 0 };
61 static Packet16uc p16uc_REVERSE = {12,13,14,15, 8,9,10,11, 4,5,6,7, 0,1,2,3};
62 static Packet16uc p16uc_FORWARD = vec_lvsl(0, (float*)0);
63 static Packet16uc p16uc_DUPLICATE = {0,1,2,3, 0,1,2,3, 4,5,6,7, 4,5,6,7};
64 
65 static _EIGEN_DECLARE_CONST_FAST_Packet4f(ZERO, 0);
66 static _EIGEN_DECLARE_CONST_FAST_Packet4i(ZERO, 0);
67 static _EIGEN_DECLARE_CONST_FAST_Packet4i(ONE,1);
68 static _EIGEN_DECLARE_CONST_FAST_Packet4i(MINUS16,-16);
69 static _EIGEN_DECLARE_CONST_FAST_Packet4i(MINUS1,-1);
70 static Packet4f p4f_ONE = vec_ctf(p4i_ONE, 0);
71 static Packet4f p4f_ZERO_ = (Packet4f) vec_sl((Packet4ui)p4i_MINUS1, (Packet4ui)p4i_MINUS1);
72 
73 template<> struct packet_traits<float> : default_packet_traits
74 {
75  typedef Packet4f type;
76  enum {
77  Vectorizable = 1,
78  AlignedOnScalar = 1,
79  size=4,
80 
81  // FIXME check the Has*
82  HasSin = 0,
83  HasCos = 0,
84  HasLog = 0,
85  HasExp = 0,
86  HasSqrt = 0
87  };
88 };
89 template<> struct packet_traits<int> : default_packet_traits
90 {
91  typedef Packet4i type;
92  enum {
93  // FIXME check the Has*
94  Vectorizable = 1,
95  AlignedOnScalar = 1,
96  size=4
97  };
98 };
99 
100 template<> struct unpacket_traits<Packet4f> { typedef float type; enum {size=4}; };
101 template<> struct unpacket_traits<Packet4i> { typedef int type; enum {size=4}; };
102 /*
103 inline std::ostream & operator <<(std::ostream & s, const Packet4f & v)
104 {
105  union {
106  Packet4f v;
107  float n[4];
108  } vt;
109  vt.v = v;
110  s << vt.n[0] << ", " << vt.n[1] << ", " << vt.n[2] << ", " << vt.n[3];
111  return s;
112 }
113 
114 inline std::ostream & operator <<(std::ostream & s, const Packet4i & v)
115 {
116  union {
117  Packet4i v;
118  int n[4];
119  } vt;
120  vt.v = v;
121  s << vt.n[0] << ", " << vt.n[1] << ", " << vt.n[2] << ", " << vt.n[3];
122  return s;
123 }
124 
125 inline std::ostream & operator <<(std::ostream & s, const Packet4ui & v)
126 {
127  union {
128  Packet4ui v;
129  unsigned int n[4];
130  } vt;
131  vt.v = v;
132  s << vt.n[0] << ", " << vt.n[1] << ", " << vt.n[2] << ", " << vt.n[3];
133  return s;
134 }
135 
136 inline std::ostream & operator <<(std::ostream & s, const Packetbi & v)
137 {
138  union {
139  Packet4bi v;
140  unsigned int n[4];
141  } vt;
142  vt.v = v;
143  s << vt.n[0] << ", " << vt.n[1] << ", " << vt.n[2] << ", " << vt.n[3];
144  return s;
145 }
146 */
147 template<> EIGEN_STRONG_INLINE Packet4f pset1<Packet4f>(const float& from) {
148  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
149  float EIGEN_ALIGN16 af[4];
150  af[0] = from;
151  Packet4f vc = vec_ld(0, af);
152  vc = vec_splat(vc, 0);
153  return vc;
154 }
155 
156 template<> EIGEN_STRONG_INLINE Packet4i pset1<Packet4i>(const int& from) {
157  int EIGEN_ALIGN16 ai[4];
158  ai[0] = from;
159  Packet4i vc = vec_ld(0, ai);
160  vc = vec_splat(vc, 0);
161  return vc;
162 }
163 
164 template<> EIGEN_STRONG_INLINE Packet4f plset<float>(const float& a) { return vec_add(pset1<Packet4f>(a), p4f_COUNTDOWN); }
165 template<> EIGEN_STRONG_INLINE Packet4i plset<int>(const int& a) { return vec_add(pset1<Packet4i>(a), p4i_COUNTDOWN); }
166 
167 template<> EIGEN_STRONG_INLINE Packet4f padd<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_add(a,b); }
168 template<> EIGEN_STRONG_INLINE Packet4i padd<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_add(a,b); }
169 
170 template<> EIGEN_STRONG_INLINE Packet4f psub<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_sub(a,b); }
171 template<> EIGEN_STRONG_INLINE Packet4i psub<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_sub(a,b); }
172 
173 template<> EIGEN_STRONG_INLINE Packet4f pnegate(const Packet4f& a) { return psub<Packet4f>(p4f_ZERO, a); }
174 template<> EIGEN_STRONG_INLINE Packet4i pnegate(const Packet4i& a) { return psub<Packet4i>(p4i_ZERO, a); }
175 
176 template<> EIGEN_STRONG_INLINE Packet4f pmul<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_madd(a,b,p4f_ZERO); }
177 /* Commented out: it's actually slower than processing it scalar
178  *
179 template<> EIGEN_STRONG_INLINE Packet4i pmul<Packet4i>(const Packet4i& a, const Packet4i& b)
180 {
181  // Detailed in: http://freevec.org/content/32bit_signed_integer_multiplication_altivec
182  //Set up constants, variables
183  Packet4i a1, b1, bswap, low_prod, high_prod, prod, prod_, v1sel;
184 
185  // Get the absolute values
186  a1 = vec_abs(a);
187  b1 = vec_abs(b);
188 
189  // Get the signs using xor
190  Packet4bi sgn = (Packet4bi) vec_cmplt(vec_xor(a, b), p4i_ZERO);
191 
192  // Do the multiplication for the asbolute values.
193  bswap = (Packet4i) vec_rl((Packet4ui) b1, (Packet4ui) p4i_MINUS16 );
194  low_prod = vec_mulo((Packet8i) a1, (Packet8i)b1);
195  high_prod = vec_msum((Packet8i) a1, (Packet8i) bswap, p4i_ZERO);
196  high_prod = (Packet4i) vec_sl((Packet4ui) high_prod, (Packet4ui) p4i_MINUS16);
197  prod = vec_add( low_prod, high_prod );
198 
199  // NOR the product and select only the negative elements according to the sign mask
200  prod_ = vec_nor(prod, prod);
201  prod_ = vec_sel(p4i_ZERO, prod_, sgn);
202 
203  // Add 1 to the result to get the negative numbers
204  v1sel = vec_sel(p4i_ZERO, p4i_ONE, sgn);
205  prod_ = vec_add(prod_, v1sel);
206 
207  // Merge the results back to the final vector.
208  prod = vec_sel(prod, prod_, sgn);
209 
210  return prod;
211 }
212 */
213 template<> EIGEN_STRONG_INLINE Packet4f pdiv<Packet4f>(const Packet4f& a, const Packet4f& b)
214 {
215  Packet4f t, y_0, y_1, res;
216 
217  // Altivec does not offer a divide instruction, we have to do a reciprocal approximation
218  y_0 = vec_re(b);
219 
220  // Do one Newton-Raphson iteration to get the needed accuracy
221  t = vec_nmsub(y_0, b, p4f_ONE);
222  y_1 = vec_madd(y_0, t, y_0);
223 
224  res = vec_madd(a, y_1, p4f_ZERO);
225  return res;
226 }
227 
228 template<> EIGEN_STRONG_INLINE Packet4i pdiv<Packet4i>(const Packet4i& /*a*/, const Packet4i& /*b*/)
229 { eigen_assert(false && "packet integer division are not supported by AltiVec");
230  return pset1<Packet4i>(0);
231 }
232 
233 // for some weird raisons, it has to be overloaded for packet of integers
234 template<> EIGEN_STRONG_INLINE Packet4f pmadd(const Packet4f& a, const Packet4f& b, const Packet4f& c) { return vec_madd(a, b, c); }
235 template<> EIGEN_STRONG_INLINE Packet4i pmadd(const Packet4i& a, const Packet4i& b, const Packet4i& c) { return padd(pmul(a,b), c); }
236 
237 template<> EIGEN_STRONG_INLINE Packet4f pmin<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_min(a, b); }
238 template<> EIGEN_STRONG_INLINE Packet4i pmin<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_min(a, b); }
239 
240 template<> EIGEN_STRONG_INLINE Packet4f pmax<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_max(a, b); }
241 template<> EIGEN_STRONG_INLINE Packet4i pmax<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_max(a, b); }
242 
243 // Logical Operations are not supported for float, so we have to reinterpret casts using NEON intrinsics
244 template<> EIGEN_STRONG_INLINE Packet4f pand<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_and(a, b); }
245 template<> EIGEN_STRONG_INLINE Packet4i pand<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_and(a, b); }
246 
247 template<> EIGEN_STRONG_INLINE Packet4f por<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_or(a, b); }
248 template<> EIGEN_STRONG_INLINE Packet4i por<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_or(a, b); }
249 
250 template<> EIGEN_STRONG_INLINE Packet4f pxor<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_xor(a, b); }
251 template<> EIGEN_STRONG_INLINE Packet4i pxor<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_xor(a, b); }
252 
253 template<> EIGEN_STRONG_INLINE Packet4f pandnot<Packet4f>(const Packet4f& a, const Packet4f& b) { return vec_and(a, vec_nor(b, b)); }
254 template<> EIGEN_STRONG_INLINE Packet4i pandnot<Packet4i>(const Packet4i& a, const Packet4i& b) { return vec_and(a, vec_nor(b, b)); }
255 
256 template<> EIGEN_STRONG_INLINE Packet4f pload<Packet4f>(const float* from) { EIGEN_DEBUG_ALIGNED_LOAD return vec_ld(0, from); }
257 template<> EIGEN_STRONG_INLINE Packet4i pload<Packet4i>(const int* from) { EIGEN_DEBUG_ALIGNED_LOAD return vec_ld(0, from); }
258 
259 template<> EIGEN_STRONG_INLINE Packet4f ploadu<Packet4f>(const float* from)
260 {
261  EIGEN_DEBUG_ALIGNED_LOAD
262  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
263  Packet16uc MSQ, LSQ;
264  Packet16uc mask;
265  MSQ = vec_ld(0, (unsigned char *)from); // most significant quadword
266  LSQ = vec_ld(15, (unsigned char *)from); // least significant quadword
267  mask = vec_lvsl(0, from); // create the permute mask
268  return (Packet4f) vec_perm(MSQ, LSQ, mask); // align the data
269 
270 }
271 template<> EIGEN_STRONG_INLINE Packet4i ploadu<Packet4i>(const int* from)
272 {
273  EIGEN_DEBUG_ALIGNED_LOAD
274  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
275  Packet16uc MSQ, LSQ;
276  Packet16uc mask;
277  MSQ = vec_ld(0, (unsigned char *)from); // most significant quadword
278  LSQ = vec_ld(15, (unsigned char *)from); // least significant quadword
279  mask = vec_lvsl(0, from); // create the permute mask
280  return (Packet4i) vec_perm(MSQ, LSQ, mask); // align the data
281 }
282 
283 template<> EIGEN_STRONG_INLINE Packet4f ploaddup<Packet4f>(const float* from)
284 {
285  Packet4f p;
286  if((ptrdiff_t(&from) % 16) == 0) p = pload<Packet4f>(from);
287  else p = ploadu<Packet4f>(from);
288  return vec_perm(p, p, p16uc_DUPLICATE);
289 }
290 template<> EIGEN_STRONG_INLINE Packet4i ploaddup<Packet4i>(const int* from)
291 {
292  Packet4i p;
293  if((ptrdiff_t(&from) % 16) == 0) p = pload<Packet4i>(from);
294  else p = ploadu<Packet4i>(from);
295  return vec_perm(p, p, p16uc_DUPLICATE);
296 }
297 
298 template<> EIGEN_STRONG_INLINE void pstore<float>(float* to, const Packet4f& from) { EIGEN_DEBUG_ALIGNED_STORE vec_st(from, 0, to); }
299 template<> EIGEN_STRONG_INLINE void pstore<int>(int* to, const Packet4i& from) { EIGEN_DEBUG_ALIGNED_STORE vec_st(from, 0, to); }
300 
301 template<> EIGEN_STRONG_INLINE void pstoreu<float>(float* to, const Packet4f& from)
302 {
303  EIGEN_DEBUG_UNALIGNED_STORE
304  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
305  // Warning: not thread safe!
306  Packet16uc MSQ, LSQ, edges;
307  Packet16uc edgeAlign, align;
308 
309  MSQ = vec_ld(0, (unsigned char *)to); // most significant quadword
310  LSQ = vec_ld(15, (unsigned char *)to); // least significant quadword
311  edgeAlign = vec_lvsl(0, to); // permute map to extract edges
312  edges=vec_perm(LSQ,MSQ,edgeAlign); // extract the edges
313  align = vec_lvsr( 0, to ); // permute map to misalign data
314  MSQ = vec_perm(edges,(Packet16uc)from,align); // misalign the data (MSQ)
315  LSQ = vec_perm((Packet16uc)from,edges,align); // misalign the data (LSQ)
316  vec_st( LSQ, 15, (unsigned char *)to ); // Store the LSQ part first
317  vec_st( MSQ, 0, (unsigned char *)to ); // Store the MSQ part
318 }
319 template<> EIGEN_STRONG_INLINE void pstoreu<int>(int* to, const Packet4i& from)
320 {
321  EIGEN_DEBUG_UNALIGNED_STORE
322  // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
323  // Warning: not thread safe!
324  Packet16uc MSQ, LSQ, edges;
325  Packet16uc edgeAlign, align;
326 
327  MSQ = vec_ld(0, (unsigned char *)to); // most significant quadword
328  LSQ = vec_ld(15, (unsigned char *)to); // least significant quadword
329  edgeAlign = vec_lvsl(0, to); // permute map to extract edges
330  edges=vec_perm(LSQ, MSQ, edgeAlign); // extract the edges
331  align = vec_lvsr( 0, to ); // permute map to misalign data
332  MSQ = vec_perm(edges, (Packet16uc) from, align); // misalign the data (MSQ)
333  LSQ = vec_perm((Packet16uc) from, edges, align); // misalign the data (LSQ)
334  vec_st( LSQ, 15, (unsigned char *)to ); // Store the LSQ part first
335  vec_st( MSQ, 0, (unsigned char *)to ); // Store the MSQ part
336 }
337 
338 template<> EIGEN_STRONG_INLINE void prefetch<float>(const float* addr) { vec_dstt(addr, DST_CTRL(2,2,32), DST_CHAN); }
339 template<> EIGEN_STRONG_INLINE void prefetch<int>(const int* addr) { vec_dstt(addr, DST_CTRL(2,2,32), DST_CHAN); }
340 
341 template<> EIGEN_STRONG_INLINE float pfirst<Packet4f>(const Packet4f& a) { float EIGEN_ALIGN16 x[4]; vec_st(a, 0, x); return x[0]; }
342 template<> EIGEN_STRONG_INLINE int pfirst<Packet4i>(const Packet4i& a) { int EIGEN_ALIGN16 x[4]; vec_st(a, 0, x); return x[0]; }
343 
344 template<> EIGEN_STRONG_INLINE Packet4f preverse(const Packet4f& a) { return (Packet4f)vec_perm((Packet16uc)a,(Packet16uc)a, p16uc_REVERSE); }
345 template<> EIGEN_STRONG_INLINE Packet4i preverse(const Packet4i& a) { return (Packet4i)vec_perm((Packet16uc)a,(Packet16uc)a, p16uc_REVERSE); }
346 
347 template<> EIGEN_STRONG_INLINE Packet4f pabs(const Packet4f& a) { return vec_abs(a); }
348 template<> EIGEN_STRONG_INLINE Packet4i pabs(const Packet4i& a) { return vec_abs(a); }
349 
350 template<> EIGEN_STRONG_INLINE float predux<Packet4f>(const Packet4f& a)
351 {
352  Packet4f b, sum;
353  b = (Packet4f) vec_sld(a, a, 8);
354  sum = vec_add(a, b);
355  b = (Packet4f) vec_sld(sum, sum, 4);
356  sum = vec_add(sum, b);
357  return pfirst(sum);
358 }
359 
360 template<> EIGEN_STRONG_INLINE Packet4f preduxp<Packet4f>(const Packet4f* vecs)
361 {
362  Packet4f v[4], sum[4];
363 
364  // It's easier and faster to transpose then add as columns
365  // Check: http://www.freevec.org/function/matrix_4x4_transpose_floats for explanation
366  // Do the transpose, first set of moves
367  v[0] = vec_mergeh(vecs[0], vecs[2]);
368  v[1] = vec_mergel(vecs[0], vecs[2]);
369  v[2] = vec_mergeh(vecs[1], vecs[3]);
370  v[3] = vec_mergel(vecs[1], vecs[3]);
371  // Get the resulting vectors
372  sum[0] = vec_mergeh(v[0], v[2]);
373  sum[1] = vec_mergel(v[0], v[2]);
374  sum[2] = vec_mergeh(v[1], v[3]);
375  sum[3] = vec_mergel(v[1], v[3]);
376 
377  // Now do the summation:
378  // Lines 0+1
379  sum[0] = vec_add(sum[0], sum[1]);
380  // Lines 2+3
381  sum[1] = vec_add(sum[2], sum[3]);
382  // Add the results
383  sum[0] = vec_add(sum[0], sum[1]);
384 
385  return sum[0];
386 }
387 
388 template<> EIGEN_STRONG_INLINE int predux<Packet4i>(const Packet4i& a)
389 {
390  Packet4i sum;
391  sum = vec_sums(a, p4i_ZERO);
392  sum = vec_sld(sum, p4i_ZERO, 12);
393  return pfirst(sum);
394 }
395 
396 template<> EIGEN_STRONG_INLINE Packet4i preduxp<Packet4i>(const Packet4i* vecs)
397 {
398  Packet4i v[4], sum[4];
399 
400  // It's easier and faster to transpose then add as columns
401  // Check: http://www.freevec.org/function/matrix_4x4_transpose_floats for explanation
402  // Do the transpose, first set of moves
403  v[0] = vec_mergeh(vecs[0], vecs[2]);
404  v[1] = vec_mergel(vecs[0], vecs[2]);
405  v[2] = vec_mergeh(vecs[1], vecs[3]);
406  v[3] = vec_mergel(vecs[1], vecs[3]);
407  // Get the resulting vectors
408  sum[0] = vec_mergeh(v[0], v[2]);
409  sum[1] = vec_mergel(v[0], v[2]);
410  sum[2] = vec_mergeh(v[1], v[3]);
411  sum[3] = vec_mergel(v[1], v[3]);
412 
413  // Now do the summation:
414  // Lines 0+1
415  sum[0] = vec_add(sum[0], sum[1]);
416  // Lines 2+3
417  sum[1] = vec_add(sum[2], sum[3]);
418  // Add the results
419  sum[0] = vec_add(sum[0], sum[1]);
420 
421  return sum[0];
422 }
423 
424 // Other reduction functions:
425 // mul
426 template<> EIGEN_STRONG_INLINE float predux_mul<Packet4f>(const Packet4f& a)
427 {
428  Packet4f prod;
429  prod = pmul(a, (Packet4f)vec_sld(a, a, 8));
430  return pfirst(pmul(prod, (Packet4f)vec_sld(prod, prod, 4)));
431 }
432 
433 template<> EIGEN_STRONG_INLINE int predux_mul<Packet4i>(const Packet4i& a)
434 {
435  EIGEN_ALIGN16 int aux[4];
436  pstore(aux, a);
437  return aux[0] * aux[1] * aux[2] * aux[3];
438 }
439 
440 // min
441 template<> EIGEN_STRONG_INLINE float predux_min<Packet4f>(const Packet4f& a)
442 {
443  Packet4f b, res;
444  b = vec_min(a, vec_sld(a, a, 8));
445  res = vec_min(b, vec_sld(b, b, 4));
446  return pfirst(res);
447 }
448 
449 template<> EIGEN_STRONG_INLINE int predux_min<Packet4i>(const Packet4i& a)
450 {
451  Packet4i b, res;
452  b = vec_min(a, vec_sld(a, a, 8));
453  res = vec_min(b, vec_sld(b, b, 4));
454  return pfirst(res);
455 }
456 
457 // max
458 template<> EIGEN_STRONG_INLINE float predux_max<Packet4f>(const Packet4f& a)
459 {
460  Packet4f b, res;
461  b = vec_max(a, vec_sld(a, a, 8));
462  res = vec_max(b, vec_sld(b, b, 4));
463  return pfirst(res);
464 }
465 
466 template<> EIGEN_STRONG_INLINE int predux_max<Packet4i>(const Packet4i& a)
467 {
468  Packet4i b, res;
469  b = vec_max(a, vec_sld(a, a, 8));
470  res = vec_max(b, vec_sld(b, b, 4));
471  return pfirst(res);
472 }
473 
474 template<int Offset>
475 struct palign_impl<Offset,Packet4f>
476 {
477  static EIGEN_STRONG_INLINE void run(Packet4f& first, const Packet4f& second)
478  {
479  if (Offset!=0)
480  first = vec_sld(first, second, Offset*4);
481  }
482 };
483 
484 template<int Offset>
485 struct palign_impl<Offset,Packet4i>
486 {
487  static EIGEN_STRONG_INLINE void run(Packet4i& first, const Packet4i& second)
488  {
489  if (Offset!=0)
490  first = vec_sld(first, second, Offset*4);
491  }
492 };
493 
494 } // end namespace internal
495 
496 } // end namespace Eigen
497 
498 #endif // EIGEN_PACKET_MATH_ALTIVEC_H