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1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr>
5 // Copyright (C) 2010 Konstantinos Margaritis <markos@codex.gr>
6 // Heavily based on Gael's SSE version.
7 //
8 // This Source Code Form is subject to the terms of the Mozilla
9 // Public License v. 2.0. If a copy of the MPL was not distributed
10 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
11 
12 #ifndef EIGEN_PACKET_MATH_NEON_H
13 #define EIGEN_PACKET_MATH_NEON_H
14 
15 namespace Eigen {
16 
17 namespace internal {
18 
19 #ifndef EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD
20 #define EIGEN_CACHEFRIENDLY_PRODUCT_THRESHOLD 8
21 #endif
22 
23 // FIXME NEON has 16 quad registers, but since the current register allocator
24 // is so bad, it is much better to reduce it to 8
25 #ifndef EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS
26 #define EIGEN_ARCH_DEFAULT_NUMBER_OF_REGISTERS 8
27 #endif
28 
29 typedef float32x4_t Packet4f;
30 typedef int32x4_t   Packet4i;
31 typedef uint32x4_t  Packet4ui;
32 
33 #define _EIGEN_DECLARE_CONST_Packet4f(NAME,X) \
34   const Packet4f p4f_##NAME = pset1<Packet4f>(X)
35 
36 #define _EIGEN_DECLARE_CONST_Packet4f_FROM_INT(NAME,X) \
37   const Packet4f p4f_##NAME = vreinterpretq_f32_u32(pset1<int>(X))
38 
39 #define _EIGEN_DECLARE_CONST_Packet4i(NAME,X) \
40   const Packet4i p4i_##NAME = pset1<Packet4i>(X)
41 
42 #if defined(__llvm__) && !defined(__clang__)
43   //Special treatment for Apple's llvm-gcc, its NEON packet types are unions
44   #define EIGEN_INIT_NEON_PACKET2(X, Y)       {{X, Y}}
45   #define EIGEN_INIT_NEON_PACKET4(X, Y, Z, W) {{X, Y, Z, W}}
46 #else
47   //Default initializer for packets
48   #define EIGEN_INIT_NEON_PACKET2(X, Y)       {X, Y}
49   #define EIGEN_INIT_NEON_PACKET4(X, Y, Z, W) {X, Y, Z, W}
50 #endif
51 
52 #ifndef __pld
53 #define __pld(x) asm volatile ( "   pld [%[addr]]\n" :: [addr] "r" (x) : "cc" );
54 #endif
55 
56 template<> struct packet_traits<float>  : default_packet_traits
57 {
58   typedef Packet4f type;
59   enum {
60     Vectorizable = 1,
61     AlignedOnScalar = 1,
62     size = 4,
63 
64     HasDiv  = 1,
65     // FIXME check the Has*
66     HasSin  = 0,
67     HasCos  = 0,
68     HasLog  = 0,
69     HasExp  = 0,
70     HasSqrt = 0
71   };
72 };
73 template<> struct packet_traits<int>    : default_packet_traits
74 {
75   typedef Packet4i type;
76   enum {
77     Vectorizable = 1,
78     AlignedOnScalar = 1,
79     size=4
80     // FIXME check the Has*
81   };
82 };
83 
84 #if EIGEN_GNUC_AT_MOST(4,4) && !defined(__llvm__)
85 // workaround gcc 4.2, 4.3 and 4.4 compilatin issue
86 EIGEN_STRONG_INLINE float32x4_t vld1q_f32(const float* x) { return ::vld1q_f32((const float32_t*)x); }
87 EIGEN_STRONG_INLINE float32x2_t vld1_f32 (const float* x) { return ::vld1_f32 ((const float32_t*)x); }
88 EIGEN_STRONG_INLINE void        vst1q_f32(float* to, float32x4_t from) { ::vst1q_f32((float32_t*)to,from); }
89 EIGEN_STRONG_INLINE void        vst1_f32 (float* to, float32x2_t from) { ::vst1_f32 ((float32_t*)to,from); }
90 #endif
91 
92 template<> struct unpacket_traits<Packet4f> { typedef float  type; enum {size=4}; };
93 template<> struct unpacket_traits<Packet4i> { typedef int    type; enum {size=4}; };
94 
95 template<> EIGEN_STRONG_INLINE Packet4f pset1<Packet4f>(const float&  from) { return vdupq_n_f32(from); }
96 template<> EIGEN_STRONG_INLINE Packet4i pset1<Packet4i>(const int&    from)   { return vdupq_n_s32(from); }
97 
98 template<> EIGEN_STRONG_INLINE Packet4f plset<float>(const float& a)
99 {
100   Packet4f countdown = EIGEN_INIT_NEON_PACKET4(0, 1, 2, 3);
101   return vaddq_f32(pset1<Packet4f>(a), countdown);
102 }
103 template<> EIGEN_STRONG_INLINE Packet4i plset<int>(const int& a)
104 {
105   Packet4i countdown = EIGEN_INIT_NEON_PACKET4(0, 1, 2, 3);
106   return vaddq_s32(pset1<Packet4i>(a), countdown);
107 }
108 
109 template<> EIGEN_STRONG_INLINE Packet4f padd<Packet4f>(const Packet4f& a, const Packet4f& b) { return vaddq_f32(a,b); }
110 template<> EIGEN_STRONG_INLINE Packet4i padd<Packet4i>(const Packet4i& a, const Packet4i& b) { return vaddq_s32(a,b); }
111 
112 template<> EIGEN_STRONG_INLINE Packet4f psub<Packet4f>(const Packet4f& a, const Packet4f& b) { return vsubq_f32(a,b); }
113 template<> EIGEN_STRONG_INLINE Packet4i psub<Packet4i>(const Packet4i& a, const Packet4i& b) { return vsubq_s32(a,b); }
114 
115 template<> EIGEN_STRONG_INLINE Packet4f pnegate(const Packet4f& a) { return vnegq_f32(a); }
116 template<> EIGEN_STRONG_INLINE Packet4i pnegate(const Packet4i& a) { return vnegq_s32(a); }
117 
118 template<> EIGEN_STRONG_INLINE Packet4f pmul<Packet4f>(const Packet4f& a, const Packet4f& b) { return vmulq_f32(a,b); }
119 template<> EIGEN_STRONG_INLINE Packet4i pmul<Packet4i>(const Packet4i& a, const Packet4i& b) { return vmulq_s32(a,b); }
120 
121 template<> EIGEN_STRONG_INLINE Packet4f pdiv<Packet4f>(const Packet4f& a, const Packet4f& b)
122 {
123   Packet4f inv, restep, div;
124 
125   // NEON does not offer a divide instruction, we have to do a reciprocal approximation
126   // However NEON in contrast to other SIMD engines (AltiVec/SSE), offers
127   // a reciprocal estimate AND a reciprocal step -which saves a few instructions
128   // vrecpeq_f32() returns an estimate to 1/b, which we will finetune with
129   // Newton-Raphson and vrecpsq_f32()
130   inv = vrecpeq_f32(b);
131 
132   // This returns a differential, by which we will have to multiply inv to get a better
133   // approximation of 1/b.
134   restep = vrecpsq_f32(b, inv);
135   inv = vmulq_f32(restep, inv);
136 
137   // Finally, multiply a by 1/b and get the wanted result of the division.
138   div = vmulq_f32(a, inv);
139 
140   return div;
141 }
142 template<> EIGEN_STRONG_INLINE Packet4i pdiv<Packet4i>(const Packet4i& /*a*/, const Packet4i& /*b*/)
143 { eigen_assert(false && "packet integer division are not supported by NEON");
144   return pset1<Packet4i>(0);
145 }
146 
147 // for some weird raisons, it has to be overloaded for packet of integers
148 template<> EIGEN_STRONG_INLINE Packet4f pmadd(const Packet4f& a, const Packet4f& b, const Packet4f& c) { return vmlaq_f32(c,a,b); }
149 template<> EIGEN_STRONG_INLINE Packet4i pmadd(const Packet4i& a, const Packet4i& b, const Packet4i& c) { return vmlaq_s32(c,a,b); }
150 
151 template<> EIGEN_STRONG_INLINE Packet4f pmin<Packet4f>(const Packet4f& a, const Packet4f& b) { return vminq_f32(a,b); }
152 template<> EIGEN_STRONG_INLINE Packet4i pmin<Packet4i>(const Packet4i& a, const Packet4i& b) { return vminq_s32(a,b); }
153 
154 template<> EIGEN_STRONG_INLINE Packet4f pmax<Packet4f>(const Packet4f& a, const Packet4f& b) { return vmaxq_f32(a,b); }
155 template<> EIGEN_STRONG_INLINE Packet4i pmax<Packet4i>(const Packet4i& a, const Packet4i& b) { return vmaxq_s32(a,b); }
156 
157 // Logical Operations are not supported for float, so we have to reinterpret casts using NEON intrinsics
158 template<> EIGEN_STRONG_INLINE Packet4f pand<Packet4f>(const Packet4f& a, const Packet4f& b)
159 {
160   return vreinterpretq_f32_u32(vandq_u32(vreinterpretq_u32_f32(a),vreinterpretq_u32_f32(b)));
161 }
162 template<> EIGEN_STRONG_INLINE Packet4i pand<Packet4i>(const Packet4i& a, const Packet4i& b) { return vandq_s32(a,b); }
163 
164 template<> EIGEN_STRONG_INLINE Packet4f por<Packet4f>(const Packet4f& a, const Packet4f& b)
165 {
166   return vreinterpretq_f32_u32(vorrq_u32(vreinterpretq_u32_f32(a),vreinterpretq_u32_f32(b)));
167 }
168 template<> EIGEN_STRONG_INLINE Packet4i por<Packet4i>(const Packet4i& a, const Packet4i& b) { return vorrq_s32(a,b); }
169 
170 template<> EIGEN_STRONG_INLINE Packet4f pxor<Packet4f>(const Packet4f& a, const Packet4f& b)
171 {
172   return vreinterpretq_f32_u32(veorq_u32(vreinterpretq_u32_f32(a),vreinterpretq_u32_f32(b)));
173 }
174 template<> EIGEN_STRONG_INLINE Packet4i pxor<Packet4i>(const Packet4i& a, const Packet4i& b) { return veorq_s32(a,b); }
175 
176 template<> EIGEN_STRONG_INLINE Packet4f pandnot<Packet4f>(const Packet4f& a, const Packet4f& b)
177 {
178   return vreinterpretq_f32_u32(vbicq_u32(vreinterpretq_u32_f32(a),vreinterpretq_u32_f32(b)));
179 }
180 template<> EIGEN_STRONG_INLINE Packet4i pandnot<Packet4i>(const Packet4i& a, const Packet4i& b) { return vbicq_s32(a,b); }
181 
182 template<> EIGEN_STRONG_INLINE Packet4f pload<Packet4f>(const float* from) { EIGEN_DEBUG_ALIGNED_LOAD return vld1q_f32(from); }
183 template<> EIGEN_STRONG_INLINE Packet4i pload<Packet4i>(const int*   from) { EIGEN_DEBUG_ALIGNED_LOAD return vld1q_s32(from); }
184 
185 template<> EIGEN_STRONG_INLINE Packet4f ploadu<Packet4f>(const float* from) { EIGEN_DEBUG_UNALIGNED_LOAD return vld1q_f32(from); }
186 template<> EIGEN_STRONG_INLINE Packet4i ploadu<Packet4i>(const int* from)   { EIGEN_DEBUG_UNALIGNED_LOAD return vld1q_s32(from); }
187 
188 template<> EIGEN_STRONG_INLINE Packet4f ploaddup<Packet4f>(const float*   from)
189 {
190   float32x2_t lo, hi;
191   lo = vdup_n_f32(*from);
192   hi = vdup_n_f32(*(from+1));
193   return vcombine_f32(lo, hi);
194 }
195 template<> EIGEN_STRONG_INLINE Packet4i ploaddup<Packet4i>(const int*     from)
196 {
197   int32x2_t lo, hi;
198   lo = vdup_n_s32(*from);
199   hi = vdup_n_s32(*(from+1));
200   return vcombine_s32(lo, hi);
201 }
202 
203 template<> EIGEN_STRONG_INLINE void pstore<float>(float*   to, const Packet4f& from) { EIGEN_DEBUG_ALIGNED_STORE vst1q_f32(to, from); }
204 template<> EIGEN_STRONG_INLINE void pstore<int>(int*       to, const Packet4i& from) { EIGEN_DEBUG_ALIGNED_STORE vst1q_s32(to, from); }
205 
206 template<> EIGEN_STRONG_INLINE void pstoreu<float>(float*  to, const Packet4f& from) { EIGEN_DEBUG_UNALIGNED_STORE vst1q_f32(to, from); }
207 template<> EIGEN_STRONG_INLINE void pstoreu<int>(int*      to, const Packet4i& from) { EIGEN_DEBUG_UNALIGNED_STORE vst1q_s32(to, from); }
208 
209 template<> EIGEN_STRONG_INLINE void prefetch<float>(const float* addr) { __pld(addr); }
210 template<> EIGEN_STRONG_INLINE void prefetch<int>(const int*     addr) { __pld(addr); }
211 
212 // FIXME only store the 2 first elements ?
213 template<> EIGEN_STRONG_INLINE float  pfirst<Packet4f>(const Packet4f& a) { float EIGEN_ALIGN16 x[4]; vst1q_f32(x, a); return x[0]; }
214 template<> EIGEN_STRONG_INLINE int    pfirst<Packet4i>(const Packet4i& a) { int   EIGEN_ALIGN16 x[4]; vst1q_s32(x, a); return x[0]; }
215 
216 template<> EIGEN_STRONG_INLINE Packet4f preverse(const Packet4f& a) {
217   float32x2_t a_lo, a_hi;
218   Packet4f a_r64;
219 
220   a_r64 = vrev64q_f32(a);
221   a_lo = vget_low_f32(a_r64);
222   a_hi = vget_high_f32(a_r64);
223   return vcombine_f32(a_hi, a_lo);
224 }
225 template<> EIGEN_STRONG_INLINE Packet4i preverse(const Packet4i& a) {
226   int32x2_t a_lo, a_hi;
227   Packet4i a_r64;
228 
229   a_r64 = vrev64q_s32(a);
230   a_lo = vget_low_s32(a_r64);
231   a_hi = vget_high_s32(a_r64);
232   return vcombine_s32(a_hi, a_lo);
233 }
234 template<> EIGEN_STRONG_INLINE Packet4f pabs(const Packet4f& a) { return vabsq_f32(a); }
235 template<> EIGEN_STRONG_INLINE Packet4i pabs(const Packet4i& a) { return vabsq_s32(a); }
236 
237 template<> EIGEN_STRONG_INLINE float predux<Packet4f>(const Packet4f& a)
238 {
239   float32x2_t a_lo, a_hi, sum;
240   float s[2];
241 
242   a_lo = vget_low_f32(a);
243   a_hi = vget_high_f32(a);
244   sum = vpadd_f32(a_lo, a_hi);
245   sum = vpadd_f32(sum, sum);
246   vst1_f32(s, sum);
247 
248   return s[0];
249 }
250 
251 template<> EIGEN_STRONG_INLINE Packet4f preduxp<Packet4f>(const Packet4f* vecs)
252 {
253   float32x4x2_t vtrn1, vtrn2, res1, res2;
254   Packet4f sum1, sum2, sum;
255 
256   // NEON zip performs interleaving of the supplied vectors.
257   // We perform two interleaves in a row to acquire the transposed vector
258   vtrn1 = vzipq_f32(vecs[0], vecs[2]);
259   vtrn2 = vzipq_f32(vecs[1], vecs[3]);
260   res1 = vzipq_f32(vtrn1.val[0], vtrn2.val[0]);
261   res2 = vzipq_f32(vtrn1.val[1], vtrn2.val[1]);
262 
263   // Do the addition of the resulting vectors
264   sum1 = vaddq_f32(res1.val[0], res1.val[1]);
265   sum2 = vaddq_f32(res2.val[0], res2.val[1]);
266   sum = vaddq_f32(sum1, sum2);
267 
268   return sum;
269 }
270 
271 template<> EIGEN_STRONG_INLINE int predux<Packet4i>(const Packet4i& a)
272 {
273   int32x2_t a_lo, a_hi, sum;
274   int32_t s[2];
275 
276   a_lo = vget_low_s32(a);
277   a_hi = vget_high_s32(a);
278   sum = vpadd_s32(a_lo, a_hi);
279   sum = vpadd_s32(sum, sum);
280   vst1_s32(s, sum);
281 
282   return s[0];
283 }
284 
285 template<> EIGEN_STRONG_INLINE Packet4i preduxp<Packet4i>(const Packet4i* vecs)
286 {
287   int32x4x2_t vtrn1, vtrn2, res1, res2;
288   Packet4i sum1, sum2, sum;
289 
290   // NEON zip performs interleaving of the supplied vectors.
291   // We perform two interleaves in a row to acquire the transposed vector
292   vtrn1 = vzipq_s32(vecs[0], vecs[2]);
293   vtrn2 = vzipq_s32(vecs[1], vecs[3]);
294   res1 = vzipq_s32(vtrn1.val[0], vtrn2.val[0]);
295   res2 = vzipq_s32(vtrn1.val[1], vtrn2.val[1]);
296 
297   // Do the addition of the resulting vectors
298   sum1 = vaddq_s32(res1.val[0], res1.val[1]);
299   sum2 = vaddq_s32(res2.val[0], res2.val[1]);
300   sum = vaddq_s32(sum1, sum2);
301 
302   return sum;
303 }
304 
305 // Other reduction functions:
306 // mul
307 template<> EIGEN_STRONG_INLINE float predux_mul<Packet4f>(const Packet4f& a)
308 {
309   float32x2_t a_lo, a_hi, prod;
310   float s[2];
311 
312   // Get a_lo = |a1|a2| and a_hi = |a3|a4|
313   a_lo = vget_low_f32(a);
314   a_hi = vget_high_f32(a);
315   // Get the product of a_lo * a_hi -> |a1*a3|a2*a4|
316   prod = vmul_f32(a_lo, a_hi);
317   // Multiply prod with its swapped value |a2*a4|a1*a3|
318   prod = vmul_f32(prod, vrev64_f32(prod));
319   vst1_f32(s, prod);
320 
321   return s[0];
322 }
323 template<> EIGEN_STRONG_INLINE int predux_mul<Packet4i>(const Packet4i& a)
324 {
325   int32x2_t a_lo, a_hi, prod;
326   int32_t s[2];
327 
328   // Get a_lo = |a1|a2| and a_hi = |a3|a4|
329   a_lo = vget_low_s32(a);
330   a_hi = vget_high_s32(a);
331   // Get the product of a_lo * a_hi -> |a1*a3|a2*a4|
332   prod = vmul_s32(a_lo, a_hi);
333   // Multiply prod with its swapped value |a2*a4|a1*a3|
334   prod = vmul_s32(prod, vrev64_s32(prod));
335   vst1_s32(s, prod);
336 
337   return s[0];
338 }
339 
340 // min
341 template<> EIGEN_STRONG_INLINE float predux_min<Packet4f>(const Packet4f& a)
342 {
343   float32x2_t a_lo, a_hi, min;
344   float s[2];
345 
346   a_lo = vget_low_f32(a);
347   a_hi = vget_high_f32(a);
348   min = vpmin_f32(a_lo, a_hi);
349   min = vpmin_f32(min, min);
350   vst1_f32(s, min);
351 
352   return s[0];
353 }
354 template<> EIGEN_STRONG_INLINE int predux_min<Packet4i>(const Packet4i& a)
355 {
356   int32x2_t a_lo, a_hi, min;
357   int32_t s[2];
358 
359   a_lo = vget_low_s32(a);
360   a_hi = vget_high_s32(a);
361   min = vpmin_s32(a_lo, a_hi);
362   min = vpmin_s32(min, min);
363   vst1_s32(s, min);
364 
365   return s[0];
366 }
367 
368 // max
369 template<> EIGEN_STRONG_INLINE float predux_max<Packet4f>(const Packet4f& a)
370 {
371   float32x2_t a_lo, a_hi, max;
372   float s[2];
373 
374   a_lo = vget_low_f32(a);
375   a_hi = vget_high_f32(a);
376   max = vpmax_f32(a_lo, a_hi);
377   max = vpmax_f32(max, max);
378   vst1_f32(s, max);
379 
380   return s[0];
381 }
382 template<> EIGEN_STRONG_INLINE int predux_max<Packet4i>(const Packet4i& a)
383 {
384   int32x2_t a_lo, a_hi, max;
385   int32_t s[2];
386 
387   a_lo = vget_low_s32(a);
388   a_hi = vget_high_s32(a);
389   max = vpmax_s32(a_lo, a_hi);
390   max = vpmax_s32(max, max);
391   vst1_s32(s, max);
392 
393   return s[0];
394 }
395 
396 // this PALIGN_NEON business is to work around a bug in LLVM Clang 3.0 causing incorrect compilation errors,
397 // see bug 347 and this LLVM bug: http://llvm.org/bugs/show_bug.cgi?id=11074
398 #define PALIGN_NEON(Offset,Type,Command) \
399 template<>\
400 struct palign_impl<Offset,Type>\
401 {\
402     EIGEN_STRONG_INLINE static void run(Type& first, const Type& second)\
403     {\
404         if (Offset!=0)\
405             first = Command(first, second, Offset);\
406     }\
407 };\
408 
409 PALIGN_NEON(0,Packet4f,vextq_f32)
410 PALIGN_NEON(1,Packet4f,vextq_f32)
411 PALIGN_NEON(2,Packet4f,vextq_f32)
412 PALIGN_NEON(3,Packet4f,vextq_f32)
413 PALIGN_NEON(0,Packet4i,vextq_s32)
414 PALIGN_NEON(1,Packet4i,vextq_s32)
415 PALIGN_NEON(2,Packet4i,vextq_s32)
416 PALIGN_NEON(3,Packet4i,vextq_s32)
417 
418 #undef PALIGN_NEON
419 
420 } // end namespace internal
421 
422 } // end namespace Eigen
423 
424 #endif // EIGEN_PACKET_MATH_NEON_H
425