src/gromacs/legacyheaders/gmx_math_x86_avx_128_fma_double.h

   1 /* -*- mode: c; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; c-file-style: "stroustrup"; -*-
   2  *
   3  *
   4  * This file is part of GROMACS.
   5  * Copyright (c) 2012-
   6  *
   7  * Written by the Gromacs development team under coordination of
   8  * David van der Spoel, Berk Hess, and Erik Lindahl.
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * To help us fund GROMACS development, we humbly ask that you cite
  16  * the research papers on the package. Check out http://www.gromacs.org
  17  *
  18  * And Hey:
  19  * Gnomes, ROck Monsters And Chili Sauce
  20  */
  21 #ifndef _gmx_math_x86_avx_128_fma_double_h_
  22 #define _gmx_math_x86_avx_128_fma_double_h_
  23
  24 #include <math.h>
  25
  26 #include "gmx_x86_avx_128_fma.h"
  27
  28
  29 #ifndef M_PI
  30 #  define M_PI 3.14159265358979323846264338327950288
  31 #endif
  32
  33
  34 /************************
  35  *                      *
  36  * Simple math routines *
  37  *                      *
  38  ************************/
  39
  40 /* 1.0/sqrt(x) */
  41 static gmx_inline __m128d
  42 gmx_mm_invsqrt_pd(__m128d x)
  43 {
  44     const __m128d half  = _mm_set1_pd(0.5);
  45     const __m128d three = _mm_set1_pd(3.0);
  46
  47     /* Lookup instruction only exists in single precision, convert back and forth... */
  48     __m128d lu = _mm_cvtps_pd(_mm_rsqrt_ps( _mm_cvtpd_ps(x)));
  49
  50     lu = _mm_mul_pd(_mm_mul_pd(half,lu),_mm_nmacc_pd(_mm_mul_pd(lu,lu),x,three));
  51     return _mm_mul_pd(_mm_mul_pd(half,lu),_mm_nmacc_pd(_mm_mul_pd(lu,lu),x,three));
  52 }
  53
  54 /* 1.0/sqrt(x), done for a pair of arguments to improve throughput */
  55 static void
  56 gmx_mm_invsqrt_pair_pd(__m128d x1, __m128d x2, __m128d *invsqrt1, __m128d *invsqrt2)
  57 {
  58     const __m128d half   = _mm_set1_pd(0.5);
  59     const __m128d three  = _mm_set1_pd(3.0);
  60     const __m128  halff  = _mm_set1_ps(0.5f);
  61     const __m128  threef = _mm_set1_ps(3.0f);
  62
  63     __m128 xf,luf;
  64     __m128d lu1,lu2;
  65
  66     /* Do first N-R step in float for 2x throughput */
  67     xf  = _mm_shuffle_ps(_mm_cvtpd_ps(x1),_mm_cvtpd_ps(x2),_MM_SHUFFLE(1,0,1,0));
  68     luf = _mm_rsqrt_ps(xf);
  69
  70     luf = _mm_mul_ps(_mm_mul_ps(halff,luf),_mm_nmacc_ps(_mm_mul_ps(luf,luf),xf,threef));
  71
  72
  73     lu2 = _mm_cvtps_pd(_mm_shuffle_ps(luf,luf,_MM_SHUFFLE(3,2,3,2)));
  74     lu1 = _mm_cvtps_pd(luf);
  75
  76     *invsqrt1 = _mm_mul_pd(_mm_mul_pd(half,lu1),_mm_nmacc_pd(_mm_mul_pd(lu1,lu1),x1,three));
  77     *invsqrt2 = _mm_mul_pd(_mm_mul_pd(half,lu2),_mm_nmacc_pd(_mm_mul_pd(lu2,lu2),x2,three));
  78 }
  79
  80 /* sqrt(x) - Do NOT use this (but rather invsqrt) if you actually need 1.0/sqrt(x) */
  81 static gmx_inline __m128d
  82 gmx_mm_sqrt_pd(__m128d x)
  83 {
  84     __m128d mask;
  85     __m128d res;
  86
  87     mask = _mm_cmpeq_pd(x,_mm_setzero_pd());
  88     res  = _mm_andnot_pd(mask,gmx_mm_invsqrt_pd(x));
  89
  90     res  = _mm_mul_pd(x,res);
  91
  92     return res;
  93 }
  94
  95 /* 1.0/x */
  96 static gmx_inline __m128d
  97 gmx_mm_inv_pd(__m128d x)
  98 {
  99     const __m128d two  = _mm_set1_pd(2.0);
 100
 101     /* Lookup instruction only exists in single precision, convert back and forth... */
 102     __m128d lu = _mm_cvtps_pd(_mm_rcp_ps( _mm_cvtpd_ps(x)));
 103
 104     /* Perform two N-R steps for double precision */
 105     lu         = _mm_mul_pd(lu,_mm_nmacc_pd(lu,x,two));
 106     return _mm_mul_pd(lu,_mm_nmacc_pd(lu,x,two));
 107 }
 108
 109 static gmx_inline __m128d
 110 gmx_mm_abs_pd(__m128d x)
 111 {
 112     const __m128d signmask  = gmx_mm_castsi128_pd( _mm_set_epi32(0x7FFFFFFF, 0xFFFFFFFF, 0x7FFFFFFF, 0xFFFFFFFF) );
 113
 114     return _mm_and_pd(x,signmask);
 115 }
 116
 117
 118 /*
 119  * 2^x function.
 120  *
 121  * The 2^w term is calculated from a (6,0)-th order (no denominator) Minimax polynomia on the interval
 122  * [-0.5,0.5].
 123  *
 124  * The approximation on [-0.5,0.5] is a rational Padé approximation, 1+2*P(x^2)/(Q(x^2)-P(x^2)),
 125  * according to the same algorithm as used in the Cephes/netlib math routines.
 126  */
 127 static __m128d
 128 gmx_mm_exp2_pd(__m128d x)
 129 {
 130     /* Lower bound: We do not allow numbers that would lead to an IEEE fp representation exponent smaller than -126. */
 131     const __m128d arglimit = _mm_set1_pd(1022.0);
 132     const __m128i expbase  = _mm_set1_epi32(1023);
 133
 134     const __m128d P2       = _mm_set1_pd(2.30933477057345225087e-2);
 135     const __m128d P1       = _mm_set1_pd(2.02020656693165307700e1);
 136     const __m128d P0       = _mm_set1_pd(1.51390680115615096133e3);
 137     /* Q2 == 1.0 */
 138     const __m128d Q1       = _mm_set1_pd(2.33184211722314911771e2);
 139     const __m128d Q0       = _mm_set1_pd(4.36821166879210612817e3);
 140     const __m128d one      = _mm_set1_pd(1.0);
 141     const __m128d two      = _mm_set1_pd(2.0);
 142
 143     __m128d valuemask;
 144     __m128i iexppart;
 145     __m128d fexppart;
 146     __m128d intpart;
 147     __m128d z,z2;
 148     __m128d PolyP,PolyQ;
 149
 150     iexppart  = _mm_cvtpd_epi32(x);
 151     intpart   = _mm_round_pd(x,_MM_FROUND_TO_NEAREST_INT);
 152
 153     /* The two lowest elements of iexppart now contains 32-bit numbers with a correctly biased exponent.
 154      * To be able to shift it into the exponent for a double precision number we first need to
 155      * shuffle so that the lower half contains the first element, and the upper half the second.
 156      * This should really be done as a zero-extension, but since the next instructions will shift
 157      * the registers left by 52 bits it doesn't matter what we put there - it will be shifted out.
 158      * (thus we just use element 2 from iexppart).
 159      */
 160     iexppart  = _mm_shuffle_epi32(iexppart,_MM_SHUFFLE(2,1,2,0));
 161
 162     /* Do the shift operation on the 64-bit registers */
 163     iexppart  = _mm_add_epi32(iexppart,expbase);
 164     iexppart  = _mm_slli_epi64(iexppart,52);
 165
 166     valuemask = _mm_cmpge_pd(arglimit,gmx_mm_abs_pd(x));
 167     fexppart  = _mm_and_pd(valuemask,gmx_mm_castsi128_pd(iexppart));
 168
 169     z         = _mm_sub_pd(x,intpart);
 170     z2        = _mm_mul_pd(z,z);
 171
 172     PolyP     = _mm_macc_pd(P2,z2,P1);
 173     PolyQ     = _mm_add_pd(z2,Q1);
 174     PolyP     = _mm_macc_pd(PolyP,z2,P0);
 175     PolyQ     = _mm_macc_pd(PolyQ,z2,Q0);
 176     PolyP     = _mm_mul_pd(PolyP,z);
 177
 178     z         = _mm_mul_pd(PolyP,gmx_mm_inv_pd(_mm_sub_pd(PolyQ,PolyP)));
 179     z         = _mm_macc_pd(two,z,one);
 180
 181     z         = _mm_mul_pd(z,fexppart);
 182
 183     return  z;
 184 }
 185
 186 /* Exponential function. This could be calculated from 2^x as Exp(x)=2^(y), where y=log2(e)*x,
 187  * but there will then be a small rounding error since we lose some precision due to the
 188  * multiplication. This will then be magnified a lot by the exponential.
 189  *
 190  * Instead, we calculate the fractional part directly as a Padé approximation of
 191  * Exp(z) on [-0.5,0.5]. We use extended precision arithmetics to calculate the fraction
 192  * remaining after 2^y, which avoids the precision-loss.
 193  */
 194 static __m128d
 195 gmx_mm_exp_pd(__m128d exparg)
 196 {
 197     const __m128d argscale = _mm_set1_pd(1.4426950408889634073599);
 198     /* Lower bound: We do not allow numbers that would lead to an IEEE fp representation exponent smaller than -126. */
 199     const __m128d arglimit = _mm_set1_pd(1022.0);
 200     const __m128i expbase  = _mm_set1_epi32(1023);
 201
 202     const __m128d invargscale0  = _mm_set1_pd(6.93145751953125e-1);
 203     const __m128d invargscale1  = _mm_set1_pd(1.42860682030941723212e-6);
 204
 205     const __m128d P2       = _mm_set1_pd(1.26177193074810590878e-4);
 206     const __m128d P1       = _mm_set1_pd(3.02994407707441961300e-2);
 207     /* P0 == 1.0 */
 208     const __m128d Q3       = _mm_set1_pd(3.00198505138664455042E-6);
 209     const __m128d Q2       = _mm_set1_pd(2.52448340349684104192E-3);
 210     const __m128d Q1       = _mm_set1_pd(2.27265548208155028766E-1);
 211     /* Q0 == 2.0 */
 212     const __m128d one      = _mm_set1_pd(1.0);
 213     const __m128d two      = _mm_set1_pd(2.0);
 214
 215     __m128d valuemask;
 216     __m128i iexppart;
 217     __m128d fexppart;
 218     __m128d intpart;
 219     __m128d x,z,z2;
 220     __m128d PolyP,PolyQ;
 221
 222     x             = _mm_mul_pd(exparg,argscale);
 223
 224     iexppart  = _mm_cvtpd_epi32(x);
 225     intpart   = _mm_round_pd(x,_MM_FROUND_TO_NEAREST_INT);
 226
 227     /* The two lowest elements of iexppart now contains 32-bit numbers with a correctly biased exponent.
 228      * To be able to shift it into the exponent for a double precision number we first need to
 229      * shuffle so that the lower half contains the first element, and the upper half the second.
 230      * This should really be done as a zero-extension, but since the next instructions will shift
 231      * the registers left by 52 bits it doesn't matter what we put there - it will be shifted out.
 232      * (thus we just use element 2 from iexppart).
 233      */
 234     iexppart  = _mm_shuffle_epi32(iexppart,_MM_SHUFFLE(2,1,2,0));
 235
 236     /* Do the shift operation on the 64-bit registers */
 237     iexppart  = _mm_add_epi32(iexppart,expbase);
 238     iexppart  = _mm_slli_epi64(iexppart,52);
 239
 240     valuemask = _mm_cmpge_pd(arglimit,gmx_mm_abs_pd(x));
 241     fexppart  = _mm_and_pd(valuemask,gmx_mm_castsi128_pd(iexppart));
 242
 243     z         = _mm_sub_pd(exparg,_mm_mul_pd(invargscale0,intpart));
 244     z         = _mm_sub_pd(z,_mm_mul_pd(invargscale1,intpart));
 245
 246     z2        = _mm_mul_pd(z,z);
 247
 248     PolyQ     = _mm_macc_pd(Q3,z2,Q2);
 249     PolyP     = _mm_macc_pd(P2,z2,P1);
 250     PolyQ     = _mm_macc_pd(PolyQ,z2,Q1);
 251
 252     PolyP     = _mm_macc_pd(PolyP,z2,one);
 253     PolyQ     = _mm_macc_pd(PolyQ,z2,two);
 254
 255     PolyP     = _mm_mul_pd(PolyP,z);
 256
 257     z         = _mm_mul_pd(PolyP,gmx_mm_inv_pd(_mm_sub_pd(PolyQ,PolyP)));
 258     z         = _mm_macc_pd(two,z,one);
 259
 260     z         = _mm_mul_pd(z,fexppart);
 261
 262     return  z;
 263 }
 264
 265
 266
 267 static __m128d
 268 gmx_mm_log_pd(__m128d x)
 269 {
 270     /* Same algorithm as cephes library */
 271     const __m128d expmask    = gmx_mm_castsi128_pd( _mm_set_epi32(0x7FF00000, 0x00000000, 0x7FF00000, 0x00000000) );
 272
 273     const __m128i expbase_m1 = _mm_set1_epi32(1023-1); /* We want non-IEEE format */
 274
 275     const __m128d half       = _mm_set1_pd(0.5);
 276     const __m128d one        = _mm_set1_pd(1.0);
 277     const __m128d two        = _mm_set1_pd(2.0);
 278     const __m128d invsq2     = _mm_set1_pd(1.0/sqrt(2.0));
 279
 280     const __m128d corr1      = _mm_set1_pd(-2.121944400546905827679e-4);
 281     const __m128d corr2      = _mm_set1_pd(0.693359375);
 282
 283     const __m128d P5         = _mm_set1_pd(1.01875663804580931796e-4);
 284     const __m128d P4         = _mm_set1_pd(4.97494994976747001425e-1);
 285     const __m128d P3         = _mm_set1_pd(4.70579119878881725854e0);
 286     const __m128d P2         = _mm_set1_pd(1.44989225341610930846e1);
 287     const __m128d P1         = _mm_set1_pd(1.79368678507819816313e1);
 288     const __m128d P0         = _mm_set1_pd(7.70838733755885391666e0);
 289
 290     const __m128d Q4         = _mm_set1_pd(1.12873587189167450590e1);
 291     const __m128d Q3         = _mm_set1_pd(4.52279145837532221105e1);
 292     const __m128d Q2         = _mm_set1_pd(8.29875266912776603211e1);
 293     const __m128d Q1         = _mm_set1_pd(7.11544750618563894466e1);
 294     const __m128d Q0         = _mm_set1_pd(2.31251620126765340583e1);
 295
 296     const __m128d R2         = _mm_set1_pd(-7.89580278884799154124e-1);
 297     const __m128d R1         = _mm_set1_pd(1.63866645699558079767e1);
 298     const __m128d R0         = _mm_set1_pd(-6.41409952958715622951e1);
 299
 300     const __m128d S2         = _mm_set1_pd(-3.56722798256324312549E1);
 301     const __m128d S1         = _mm_set1_pd(3.12093766372244180303E2);
 302     const __m128d S0         = _mm_set1_pd(-7.69691943550460008604E2);
 303
 304     __m128d fexp;
 305     __m128i iexp;
 306
 307     __m128d mask1,mask2;
 308     __m128d corr,t1,t2,q;
 309     __m128d zA,yA,xA,zB,yB,xB,z;
 310     __m128d polyR,polyS;
 311     __m128d polyP1,polyP2,polyQ1,polyQ2;
 312
 313     /* Separate x into exponent and mantissa, with a mantissa in the range [0.5..1[ (not IEEE754 standard!) */
 314     fexp   = _mm_and_pd(x,expmask);
 315     iexp   = gmx_mm_castpd_si128(fexp);
 316     iexp   = _mm_srli_epi64(iexp,52);
 317     iexp   = _mm_sub_epi32(iexp,expbase_m1);
 318     iexp   = _mm_shuffle_epi32(iexp, _MM_SHUFFLE(1,1,2,0) );
 319     fexp   = _mm_cvtepi32_pd(iexp);
 320
 321     x      = _mm_andnot_pd(expmask,x);
 322     x      = _mm_or_pd(x,one);
 323     x      = _mm_mul_pd(x,half);
 324
 325     mask1     = _mm_cmpgt_pd(gmx_mm_abs_pd(fexp),two);
 326     mask2     = _mm_cmplt_pd(x,invsq2);
 327
 328     fexp   = _mm_sub_pd(fexp,_mm_and_pd(mask2,one));
 329
 330     /* If mask1 is set ('A') */
 331     zA     = _mm_sub_pd(x,half);
 332     t1     = _mm_blendv_pd( zA,x,mask2 );
 333     zA     = _mm_sub_pd(t1,half);
 334     t2     = _mm_blendv_pd( x,zA,mask2 );
 335     yA     = _mm_mul_pd(half,_mm_add_pd(t2,one));
 336
 337     xA     = _mm_mul_pd(zA,gmx_mm_inv_pd(yA));
 338     zA     = _mm_mul_pd(xA,xA);
 339
 340     /* EVALUATE POLY */
 341     polyR  = _mm_macc_pd(R2,zA,R1);
 342     polyR  = _mm_macc_pd(polyR,zA,R0);
 343
 344     polyS  = _mm_add_pd(zA,S2);
 345     polyS  = _mm_macc_pd(polyS,zA,S1);
 346     polyS  = _mm_macc_pd(polyS,zA,S0);
 347
 348     q      = _mm_mul_pd(polyR,gmx_mm_inv_pd(polyS));
 349     zA     = _mm_mul_pd(_mm_mul_pd(xA,zA),q);
 350
 351     zA     = _mm_macc_pd(corr1,fexp,zA);
 352     zA     = _mm_add_pd(zA,xA);
 353     zA     = _mm_macc_pd(corr2,fexp,zA);
 354
 355     /* If mask1 is not set ('B') */
 356     corr   = _mm_and_pd(mask2,x);
 357     xB     = _mm_add_pd(x,corr);
 358     xB     = _mm_sub_pd(xB,one);
 359     zB     = _mm_mul_pd(xB,xB);
 360
 361     polyP1 = _mm_macc_pd(P5,zB,P3);
 362     polyP2 = _mm_macc_pd(P4,zB,P2);
 363     polyP1 = _mm_macc_pd(polyP1,zB,P1);
 364     polyP2 = _mm_macc_pd(polyP2,zB,P0);
 365     polyP1 = _mm_macc_pd(polyP1,xB,polyP2);
 366
 367     polyQ2 = _mm_macc_pd(Q4,zB,Q2);
 368     polyQ1 = _mm_add_pd(zB,Q3);
 369     polyQ1 = _mm_macc_pd(polyQ1,zB,Q1);
 370     polyQ2 = _mm_macc_pd(polyQ2,zB,Q0);
 371     polyQ1 = _mm_macc_pd(polyQ1,xB,polyQ2);
 372
 373     fexp   = _mm_and_pd(fexp,_mm_cmpneq_pd(fexp,_mm_setzero_pd()));
 374
 375     q      = _mm_mul_pd(polyP1,gmx_mm_inv_pd(polyQ1));
 376     yB     = _mm_macc_pd(_mm_mul_pd(xB,zB),q,_mm_mul_pd(corr1,fexp));
 377
 378     yB     = _mm_nmacc_pd(half,zB,yB);
 379     zB     = _mm_add_pd(xB,yB);
 380     zB     = _mm_macc_pd(corr2,fexp,zB);
 381
 382     z      = _mm_blendv_pd( zB,zA,mask1 );
 383
 384     return z;
 385 }
 386
 387
 388
 389 static __m128d
 390 gmx_mm_erf_pd(__m128d x)
 391 {
 392     /* Coefficients for minimax approximation of erf(x)=x*(CAoffset + P(x^2)/Q(x^2)) in range [-0.75,0.75] */
 393     const __m128d CAP4      = _mm_set1_pd(-0.431780540597889301512e-4);
 394     const __m128d CAP3      = _mm_set1_pd(-0.00578562306260059236059);
 395     const __m128d CAP2      = _mm_set1_pd(-0.028593586920219752446);
 396     const __m128d CAP1      = _mm_set1_pd(-0.315924962948621698209);
 397     const __m128d CAP0      = _mm_set1_pd(0.14952975608477029151);
 398
 399     const __m128d CAQ5      = _mm_set1_pd(-0.374089300177174709737e-5);
 400     const __m128d CAQ4      = _mm_set1_pd(0.00015126584532155383535);
 401     const __m128d CAQ3      = _mm_set1_pd(0.00536692680669480725423);
 402     const __m128d CAQ2      = _mm_set1_pd(0.0668686825594046122636);
 403     const __m128d CAQ1      = _mm_set1_pd(0.402604990869284362773);
 404     /* CAQ0 == 1.0 */
 405     const __m128d CAoffset  = _mm_set1_pd(0.9788494110107421875);
 406
 407     /* Coefficients for minimax approximation of erfc(x)=exp(-x^2)*x*(P(x-1)/Q(x-1)) in range [1.0,4.5] */
 408     const __m128d CBP6      = _mm_set1_pd(2.49650423685462752497647637088e-10);
 409     const __m128d CBP5      = _mm_set1_pd(0.00119770193298159629350136085658);
 410     const __m128d CBP4      = _mm_set1_pd(0.0164944422378370965881008942733);
 411     const __m128d CBP3      = _mm_set1_pd(0.0984581468691775932063932439252);
 412     const __m128d CBP2      = _mm_set1_pd(0.317364595806937763843589437418);
 413     const __m128d CBP1      = _mm_set1_pd(0.554167062641455850932670067075);
 414     const __m128d CBP0      = _mm_set1_pd(0.427583576155807163756925301060);
 415     const __m128d CBQ7      = _mm_set1_pd(0.00212288829699830145976198384930);
 416     const __m128d CBQ6      = _mm_set1_pd(0.0334810979522685300554606393425);
 417     const __m128d CBQ5      = _mm_set1_pd(0.2361713785181450957579508850717);
 418     const __m128d CBQ4      = _mm_set1_pd(0.955364736493055670530981883072);
 419     const __m128d CBQ3      = _mm_set1_pd(2.36815675631420037315349279199);
 420     const __m128d CBQ2      = _mm_set1_pd(3.55261649184083035537184223542);
 421     const __m128d CBQ1      = _mm_set1_pd(2.93501136050160872574376997993);
 422     /* CBQ0 == 1.0 */
 423
 424     /* Coefficients for minimax approximation of erfc(x)=exp(-x^2)/x*(P(1/x)/Q(1/x)) in range [4.5,inf] */
 425     const __m128d CCP6      = _mm_set1_pd(-2.8175401114513378771);
 426     const __m128d CCP5      = _mm_set1_pd(-3.22729451764143718517);
 427     const __m128d CCP4      = _mm_set1_pd(-2.5518551727311523996);
 428     const __m128d CCP3      = _mm_set1_pd(-0.687717681153649930619);
 429     const __m128d CCP2      = _mm_set1_pd(-0.212652252872804219852);
 430     const __m128d CCP1      = _mm_set1_pd(0.0175389834052493308818);
 431     const __m128d CCP0      = _mm_set1_pd(0.00628057170626964891937);
 432
 433     const __m128d CCQ6      = _mm_set1_pd(5.48409182238641741584);
 434     const __m128d CCQ5      = _mm_set1_pd(13.5064170191802889145);
 435     const __m128d CCQ4      = _mm_set1_pd(22.9367376522880577224);
 436     const __m128d CCQ3      = _mm_set1_pd(15.930646027911794143);
 437     const __m128d CCQ2      = _mm_set1_pd(11.0567237927800161565);
 438     const __m128d CCQ1      = _mm_set1_pd(2.79257750980575282228);
 439     /* CCQ0 == 1.0 */
 440     const __m128d CCoffset  = _mm_set1_pd(0.5579090118408203125);
 441
 442     const __m128d one       = _mm_set1_pd(1.0);
 443     const __m128d two       = _mm_set1_pd(2.0);
 444
 445     const __m128d signbit   = gmx_mm_castsi128_pd( _mm_set_epi32(0x80000000,0x00000000,0x80000000,0x00000000) );
 446
 447     __m128d xabs,x2,x4,t,t2,w,w2;
 448     __m128d PolyAP0,PolyAP1,PolyAQ0,PolyAQ1;
 449     __m128d PolyBP0,PolyBP1,PolyBQ0,PolyBQ1;
 450     __m128d PolyCP0,PolyCP1,PolyCQ0,PolyCQ1;
 451     __m128d res_erf,res_erfcB,res_erfcC,res_erfc,res;
 452     __m128d mask,expmx2;
 453
 454     /* Calculate erf() */
 455     xabs     = gmx_mm_abs_pd(x);
 456     x2       = _mm_mul_pd(x,x);
 457     x4       = _mm_mul_pd(x2,x2);
 458
 459     PolyAP0  = _mm_macc_pd(CAP4,x4,CAP2);
 460     PolyAP1  = _mm_macc_pd(CAP3,x4,CAP1);
 461     PolyAP0  = _mm_macc_pd(PolyAP0,x4,CAP0);
 462     PolyAP0  = _mm_macc_pd(PolyAP1,x2,PolyAP0);
 463
 464     PolyAQ1  = _mm_macc_pd(CAQ5,x4,CAQ3);
 465     PolyAQ0  = _mm_macc_pd(CAQ4,x4,CAQ2);
 466     PolyAQ1  = _mm_macc_pd(PolyAQ1,x4,CAQ1);
 467     PolyAQ0  = _mm_macc_pd(PolyAQ0,x4,one);
 468     PolyAQ0  = _mm_macc_pd(PolyAQ1,x2,PolyAQ0);
 469
 470     res_erf  = _mm_macc_pd(PolyAP0,gmx_mm_inv_pd(PolyAQ0),CAoffset);
 471     res_erf  = _mm_mul_pd(x,res_erf);
 472
 473     /* Calculate erfc() in range [1,4.5] */
 474     t       = _mm_sub_pd(xabs,one);
 475     t2      = _mm_mul_pd(t,t);
 476
 477     PolyBP0  = _mm_macc_pd(CBP6,t2,CBP4);
 478     PolyBP1  = _mm_macc_pd(CBP5,t2,CBP3);
 479     PolyBP0  = _mm_macc_pd(PolyBP0,t2,CBP2);
 480     PolyBP1  = _mm_macc_pd(PolyBP1,t2,CBP1);
 481     PolyBP0  = _mm_macc_pd(PolyBP0,t2,CBP0);
 482     PolyBP0  = _mm_macc_pd(PolyBP1,t,PolyBP0);
 483
 484     PolyBQ1 = _mm_macc_pd(CBQ7,t2,CBQ5);
 485     PolyBQ0 = _mm_macc_pd(CBQ6,t2,CBQ4);
 486     PolyBQ1 = _mm_macc_pd(PolyBQ1,t2,CBQ3);
 487     PolyBQ0 = _mm_macc_pd(PolyBQ0,t2,CBQ2);
 488     PolyBQ1 = _mm_macc_pd(PolyBQ1,t2,CBQ1);
 489     PolyBQ0 = _mm_macc_pd(PolyBQ0,t2,one);
 490     PolyBQ0 = _mm_macc_pd(PolyBQ1,t,PolyBQ0);
 491
 492     res_erfcB = _mm_mul_pd(PolyBP0,gmx_mm_inv_pd(PolyBQ0));
 493
 494     res_erfcB = _mm_mul_pd(res_erfcB,xabs);
 495
 496     /* Calculate erfc() in range [4.5,inf] */
 497     w       = gmx_mm_inv_pd(xabs);
 498     w2      = _mm_mul_pd(w,w);
 499
 500     PolyCP0  = _mm_macc_pd(CCP6,w2,CCP4);
 501     PolyCP1  = _mm_macc_pd(CCP5,w2,CCP3);
 502     PolyCP0  = _mm_macc_pd(PolyCP0,w2,CCP2);
 503     PolyCP1  = _mm_macc_pd(PolyCP1,w2,CCP1);
 504     PolyCP0  = _mm_macc_pd(PolyCP0,w2,CCP0);
 505     PolyCP0  = _mm_macc_pd(PolyCP1,w,PolyCP0);
 506
 507     PolyCQ0  = _mm_macc_pd(CCQ6,w2,CCQ4);
 508     PolyCQ1  = _mm_macc_pd(CCQ5,w2,CCQ3);
 509     PolyCQ0  = _mm_macc_pd(PolyCQ0,w2,CCQ2);
 510     PolyCQ1  = _mm_macc_pd(PolyCQ1,w2,CCQ1);
 511     PolyCQ0  = _mm_macc_pd(PolyCQ0,w2,one);
 512     PolyCQ0  = _mm_macc_pd(PolyCQ1,w,PolyCQ0);
 513
 514     expmx2   = gmx_mm_exp_pd( _mm_or_pd(signbit, x2) );
 515
 516     res_erfcC = _mm_macc_pd(PolyCP0,gmx_mm_inv_pd(PolyCQ0),CCoffset);
 517     res_erfcC = _mm_mul_pd(res_erfcC,w);
 518
 519     mask = _mm_cmpgt_pd(xabs,_mm_set1_pd(4.5));
 520     res_erfc = _mm_blendv_pd(res_erfcB,res_erfcC,mask);
 521
 522     res_erfc = _mm_mul_pd(res_erfc,expmx2);
 523
 524     /* erfc(x<0) = 2-erfc(|x|) */
 525     mask = _mm_cmplt_pd(x,_mm_setzero_pd());
 526     res_erfc = _mm_blendv_pd(res_erfc,_mm_sub_pd(two,res_erfc),mask);
 527
 528     /* Select erf() or erfc() */
 529     mask = _mm_cmplt_pd(xabs,one);
 530     res  = _mm_blendv_pd(_mm_sub_pd(one,res_erfc),res_erf,mask);
 531
 532     return res;
 533 }
 534
 535
 536 static __m128d
 537 gmx_mm_erfc_pd(__m128d x)
 538 {
 539     /* Coefficients for minimax approximation of erf(x)=x*(CAoffset + P(x^2)/Q(x^2)) in range [-0.75,0.75] */
 540     const __m128d CAP4      = _mm_set1_pd(-0.431780540597889301512e-4);
 541     const __m128d CAP3      = _mm_set1_pd(-0.00578562306260059236059);
 542     const __m128d CAP2      = _mm_set1_pd(-0.028593586920219752446);
 543     const __m128d CAP1      = _mm_set1_pd(-0.315924962948621698209);
 544     const __m128d CAP0      = _mm_set1_pd(0.14952975608477029151);
 545
 546     const __m128d CAQ5      = _mm_set1_pd(-0.374089300177174709737e-5);
 547     const __m128d CAQ4      = _mm_set1_pd(0.00015126584532155383535);
 548     const __m128d CAQ3      = _mm_set1_pd(0.00536692680669480725423);
 549     const __m128d CAQ2      = _mm_set1_pd(0.0668686825594046122636);
 550     const __m128d CAQ1      = _mm_set1_pd(0.402604990869284362773);
 551     /* CAQ0 == 1.0 */
 552     const __m128d CAoffset  = _mm_set1_pd(0.9788494110107421875);
 553
 554     /* Coefficients for minimax approximation of erfc(x)=exp(-x^2)*x*(P(x-1)/Q(x-1)) in range [1.0,4.5] */
 555     const __m128d CBP6      = _mm_set1_pd(2.49650423685462752497647637088e-10);
 556     const __m128d CBP5      = _mm_set1_pd(0.00119770193298159629350136085658);
 557     const __m128d CBP4      = _mm_set1_pd(0.0164944422378370965881008942733);
 558     const __m128d CBP3      = _mm_set1_pd(0.0984581468691775932063932439252);
 559     const __m128d CBP2      = _mm_set1_pd(0.317364595806937763843589437418);
 560     const __m128d CBP1      = _mm_set1_pd(0.554167062641455850932670067075);
 561     const __m128d CBP0      = _mm_set1_pd(0.427583576155807163756925301060);
 562     const __m128d CBQ7      = _mm_set1_pd(0.00212288829699830145976198384930);
 563     const __m128d CBQ6      = _mm_set1_pd(0.0334810979522685300554606393425);
 564     const __m128d CBQ5      = _mm_set1_pd(0.2361713785181450957579508850717);
 565     const __m128d CBQ4      = _mm_set1_pd(0.955364736493055670530981883072);
 566     const __m128d CBQ3      = _mm_set1_pd(2.36815675631420037315349279199);
 567     const __m128d CBQ2      = _mm_set1_pd(3.55261649184083035537184223542);
 568     const __m128d CBQ1      = _mm_set1_pd(2.93501136050160872574376997993);
 569     /* CBQ0 == 1.0 */
 570
 571     /* Coefficients for minimax approximation of erfc(x)=exp(-x^2)/x*(P(1/x)/Q(1/x)) in range [4.5,inf] */
 572     const __m128d CCP6      = _mm_set1_pd(-2.8175401114513378771);
 573     const __m128d CCP5      = _mm_set1_pd(-3.22729451764143718517);
 574     const __m128d CCP4      = _mm_set1_pd(-2.5518551727311523996);
 575     const __m128d CCP3      = _mm_set1_pd(-0.687717681153649930619);
 576     const __m128d CCP2      = _mm_set1_pd(-0.212652252872804219852);
 577     const __m128d CCP1      = _mm_set1_pd(0.0175389834052493308818);
 578     const __m128d CCP0      = _mm_set1_pd(0.00628057170626964891937);
 579
 580     const __m128d CCQ6      = _mm_set1_pd(5.48409182238641741584);
 581     const __m128d CCQ5      = _mm_set1_pd(13.5064170191802889145);
 582     const __m128d CCQ4      = _mm_set1_pd(22.9367376522880577224);
 583     const __m128d CCQ3      = _mm_set1_pd(15.930646027911794143);
 584     const __m128d CCQ2      = _mm_set1_pd(11.0567237927800161565);
 585     const __m128d CCQ1      = _mm_set1_pd(2.79257750980575282228);
 586     /* CCQ0 == 1.0 */
 587     const __m128d CCoffset  = _mm_set1_pd(0.5579090118408203125);
 588
 589     const __m128d one       = _mm_set1_pd(1.0);
 590     const __m128d two       = _mm_set1_pd(2.0);
 591
 592     const __m128d signbit   = gmx_mm_castsi128_pd( _mm_set_epi32(0x80000000,0x00000000,0x80000000,0x00000000) );
 593
 594     __m128d xabs,x2,x4,t,t2,w,w2;
 595     __m128d PolyAP0,PolyAP1,PolyAQ0,PolyAQ1;
 596     __m128d PolyBP0,PolyBP1,PolyBQ0,PolyBQ1;
 597     __m128d PolyCP0,PolyCP1,PolyCQ0,PolyCQ1;
 598     __m128d res_erf,res_erfcB,res_erfcC,res_erfc,res;
 599     __m128d mask,expmx2;
 600
 601     /* Calculate erf() */
 602     xabs     = gmx_mm_abs_pd(x);
 603     x2       = _mm_mul_pd(x,x);
 604     x4       = _mm_mul_pd(x2,x2);
 605
 606     PolyAP0  = _mm_macc_pd(CAP4,x4,CAP2);
 607     PolyAP1  = _mm_macc_pd(CAP3,x4,CAP1);
 608     PolyAP0  = _mm_macc_pd(PolyAP0,x4,CAP0);
 609     PolyAP0  = _mm_macc_pd(PolyAP1,x2,PolyAP0);
 610
 611     PolyAQ1  = _mm_macc_pd(CAQ5,x4,CAQ3);
 612     PolyAQ0  = _mm_macc_pd(CAQ4,x4,CAQ2);
 613     PolyAQ1  = _mm_macc_pd(PolyAQ1,x4,CAQ1);
 614     PolyAQ0  = _mm_macc_pd(PolyAQ0,x4,one);
 615     PolyAQ0  = _mm_macc_pd(PolyAQ1,x2,PolyAQ0);
 616
 617     res_erf  = _mm_macc_pd(PolyAP0,gmx_mm_inv_pd(PolyAQ0),CAoffset);
 618     res_erf  = _mm_mul_pd(x,res_erf);
 619
 620     /* Calculate erfc() in range [1,4.5] */
 621     t       = _mm_sub_pd(xabs,one);
 622     t2      = _mm_mul_pd(t,t);
 623
 624     PolyBP0  = _mm_macc_pd(CBP6,t2,CBP4);
 625     PolyBP1  = _mm_macc_pd(CBP5,t2,CBP3);
 626     PolyBP0  = _mm_macc_pd(PolyBP0,t2,CBP2);
 627     PolyBP1  = _mm_macc_pd(PolyBP1,t2,CBP1);
 628     PolyBP0  = _mm_macc_pd(PolyBP0,t2,CBP0);
 629     PolyBP0  = _mm_macc_pd(PolyBP1,t,PolyBP0);
 630
 631     PolyBQ1 = _mm_macc_pd(CBQ7,t2,CBQ5);
 632     PolyBQ0 = _mm_macc_pd(CBQ6,t2,CBQ4);
 633     PolyBQ1 = _mm_macc_pd(PolyBQ1,t2,CBQ3);
 634     PolyBQ0 = _mm_macc_pd(PolyBQ0,t2,CBQ2);
 635     PolyBQ1 = _mm_macc_pd(PolyBQ1,t2,CBQ1);
 636     PolyBQ0 = _mm_macc_pd(PolyBQ0,t2,one);
 637     PolyBQ0 = _mm_macc_pd(PolyBQ1,t,PolyBQ0);
 638
 639     res_erfcB = _mm_mul_pd(PolyBP0,gmx_mm_inv_pd(PolyBQ0));
 640
 641     res_erfcB = _mm_mul_pd(res_erfcB,xabs);
 642
 643     /* Calculate erfc() in range [4.5,inf] */
 644     w       = gmx_mm_inv_pd(xabs);
 645     w2      = _mm_mul_pd(w,w);
 646
 647     PolyCP0  = _mm_macc_pd(CCP6,w2,CCP4);
 648     PolyCP1  = _mm_macc_pd(CCP5,w2,CCP3);
 649     PolyCP0  = _mm_macc_pd(PolyCP0,w2,CCP2);
 650     PolyCP1  = _mm_macc_pd(PolyCP1,w2,CCP1);
 651     PolyCP0  = _mm_macc_pd(PolyCP0,w2,CCP0);
 652     PolyCP0  = _mm_macc_pd(PolyCP1,w,PolyCP0);
 653
 654     PolyCQ0  = _mm_macc_pd(CCQ6,w2,CCQ4);
 655     PolyCQ1  = _mm_macc_pd(CCQ5,w2,CCQ3);
 656     PolyCQ0  = _mm_macc_pd(PolyCQ0,w2,CCQ2);
 657     PolyCQ1  = _mm_macc_pd(PolyCQ1,w2,CCQ1);
 658     PolyCQ0  = _mm_macc_pd(PolyCQ0,w2,one);
 659     PolyCQ0  = _mm_macc_pd(PolyCQ1,w,PolyCQ0);
 660
 661     expmx2   = gmx_mm_exp_pd( _mm_or_pd(signbit, x2) );
 662
 663     res_erfcC = _mm_macc_pd(PolyCP0,gmx_mm_inv_pd(PolyCQ0),CCoffset);
 664     res_erfcC = _mm_mul_pd(res_erfcC,w);
 665
 666     mask = _mm_cmpgt_pd(xabs,_mm_set1_pd(4.5));
 667     res_erfc = _mm_blendv_pd(res_erfcB,res_erfcC,mask);
 668
 669     res_erfc = _mm_mul_pd(res_erfc,expmx2);
 670
 671     /* erfc(x<0) = 2-erfc(|x|) */
 672     mask = _mm_cmplt_pd(x,_mm_setzero_pd());
 673     res_erfc = _mm_blendv_pd(res_erfc,_mm_sub_pd(two,res_erfc),mask);
 674
 675     /* Select erf() or erfc() */
 676     mask = _mm_cmplt_pd(xabs,one);
 677     res  = _mm_blendv_pd(res_erfc,_mm_sub_pd(one,res_erf),mask);
 678
 679     return res;
 680 }
 681
 682
 683
 684 /* Calculate the force correction due to PME analytically.
 685  *
 686  * This routine is meant to enable analytical evaluation of the
 687  * direct-space PME electrostatic force to avoid tables.
 688  *
 689  * The direct-space potential should be Erfc(beta*r)/r, but there
 690  * are some problems evaluating that:
 691  *
 692  * First, the error function is difficult (read: expensive) to
 693  * approxmiate accurately for intermediate to large arguments, and
 694  * this happens already in ranges of beta*r that occur in simulations.
 695  * Second, we now try to avoid calculating potentials in Gromacs but
 696  * use forces directly.
 697  *
 698  * We can simply things slight by noting that the PME part is really
 699  * a correction to the normal Coulomb force since Erfc(z)=1-Erf(z), i.e.
 700  *
 701  * V= 1/r - Erf(beta*r)/r
 702  *
 703  * The first term we already have from the inverse square root, so
 704  * that we can leave out of this routine.
 705  *
 706  * For pme tolerances of 1e-3 to 1e-8 and cutoffs of 0.5nm to 1.8nm,
 707  * the argument beta*r will be in the range 0.15 to ~4. Use your
 708  * favorite plotting program to realize how well-behaved Erf(z)/z is
 709  * in this range!
 710  *
 711  * We approximate f(z)=erf(z)/z with a rational minimax polynomial.
 712  * However, it turns out it is more efficient to approximate f(z)/z and
 713  * then only use even powers. This is another minor optimization, since
 714  * we actually WANT f(z)/z, because it is going to be multiplied by
 715  * the vector between the two atoms to get the vectorial force. The
 716  * fastest flops are the ones we can avoid calculating!
 717  *
 718  * So, here's how it should be used:
 719  *
 720  * 1. Calculate r^2.
 721  * 2. Multiply by beta^2, so you get z^2=beta^2*r^2.
 722  * 3. Evaluate this routine with z^2 as the argument.
 723  * 4. The return value is the expression:
 724  *
 725  *
 726  *       2*exp(-z^2)     erf(z)
 727  *       ------------ - --------
 728  *       sqrt(Pi)*z^2      z^3
 729  *
 730  * 5. Multiply the entire expression by beta^3. This will get you
 731  *
 732  *       beta^3*2*exp(-z^2)     beta^3*erf(z)
 733  *       ------------------  - ---------------
 734  *          sqrt(Pi)*z^2            z^3
 735  *
 736  *    or, switching back to r (z=r*beta):
 737  *
 738  *       2*beta*exp(-r^2*beta^2)   erf(r*beta)
 739  *       ----------------------- - -----------
 740  *            sqrt(Pi)*r^2            r^3
 741  *
 742  *
 743  *    With a bit of math exercise you should be able to confirm that
 744  *    this is exactly D[Erf[beta*r]/r,r] divided by r another time.
 745  *
 746  * 6. Add the result to 1/r^3, multiply by the product of the charges,
 747  *    and you have your force (divided by r). A final multiplication
 748  *    with the vector connecting the two particles and you have your
 749  *    vectorial force to add to the particles.
 750  *
 751  */
 752 static __m128d
 753 gmx_mm_pmecorrF_pd(__m128d z2)
 754 {
 755     const __m128d  FN10     = _mm_set1_pd(-8.0072854618360083154e-14);
 756     const __m128d  FN9      = _mm_set1_pd(1.1859116242260148027e-11);
 757     const __m128d  FN8      = _mm_set1_pd(-8.1490406329798423616e-10);
 758     const __m128d  FN7      = _mm_set1_pd(3.4404793543907847655e-8);
 759     const __m128d  FN6      = _mm_set1_pd(-9.9471420832602741006e-7);
 760     const __m128d  FN5      = _mm_set1_pd(0.000020740315999115847456);
 761     const __m128d  FN4      = _mm_set1_pd(-0.00031991745139313364005);
 762     const __m128d  FN3      = _mm_set1_pd(0.0035074449373659008203);
 763     const __m128d  FN2      = _mm_set1_pd(-0.031750380176100813405);
 764     const __m128d  FN1      = _mm_set1_pd(0.13884101728898463426);
 765     const __m128d  FN0      = _mm_set1_pd(-0.75225277815249618847);
 766
 767     const __m128d  FD5      = _mm_set1_pd(0.000016009278224355026701);
 768     const __m128d  FD4      = _mm_set1_pd(0.00051055686934806966046);
 769     const __m128d  FD3      = _mm_set1_pd(0.0081803507497974289008);
 770     const __m128d  FD2      = _mm_set1_pd(0.077181146026670287235);
 771     const __m128d  FD1      = _mm_set1_pd(0.41543303143712535988);
 772     const __m128d  FD0      = _mm_set1_pd(1.0);
 773
 774     __m128d z4;
 775     __m128d polyFN0,polyFN1,polyFD0,polyFD1;
 776
 777     z4             = _mm_mul_pd(z2,z2);
 778
 779     polyFD1        = _mm_macc_pd(FD5,z4,FD3);
 780     polyFD1        = _mm_macc_pd(polyFD1,z4,FD1);
 781     polyFD1        = _mm_mul_pd(polyFD1,z2);
 782     polyFD0        = _mm_macc_pd(FD4,z4,FD2);
 783     polyFD0        = _mm_macc_pd(polyFD0,z4,FD0);
 784     polyFD0        = _mm_add_pd(polyFD0,polyFD1);
 785
 786     polyFD0        = gmx_mm_inv_pd(polyFD0);
 787
 788     polyFN0        = _mm_macc_pd(FN10,z4,FN8);
 789     polyFN0        = _mm_macc_pd(polyFN0,z4,FN6);
 790     polyFN0        = _mm_macc_pd(polyFN0,z4,FN4);
 791     polyFN0        = _mm_macc_pd(polyFN0,z4,FN2);
 792     polyFN0        = _mm_macc_pd(polyFN0,z4,FN0);
 793     polyFN1        = _mm_macc_pd(FN9,z4,FN7);
 794     polyFN1        = _mm_macc_pd(polyFN1,z4,FN5);
 795     polyFN1        = _mm_macc_pd(polyFN1,z4,FN3);
 796     polyFN1        = _mm_macc_pd(polyFN1,z4,FN1);
 797     polyFN0        = _mm_macc_pd(polyFN1,z2,polyFN0);
 798
 799     return   _mm_mul_pd(polyFN0,polyFD0);
 800 }
 801
 802
 803 /* Calculate the potential correction due to PME analytically.
 804  *
 805  * This routine calculates Erf(z)/z, although you should provide z^2
 806  * as the input argument.
 807  *
 808  * Here's how it should be used:
 809  *
 810  * 1. Calculate r^2.
 811  * 2. Multiply by beta^2, so you get z^2=beta^2*r^2.
 812  * 3. Evaluate this routine with z^2 as the argument.
 813  * 4. The return value is the expression:
 814  *
 815  *
 816  *        erf(z)
 817  *       --------
 818  *          z
 819  *
 820  * 5. Multiply the entire expression by beta and switching back to r (z=r*beta):
 821  *
 822  *       erf(r*beta)
 823  *       -----------
 824  *           r
 825  *
 826  * 6. Subtract the result from 1/r, multiply by the product of the charges,
 827  *    and you have your potential.
 828  *
 829  */
 830 static __m128d
 831 gmx_mm_pmecorrV_pd(__m128d z2)
 832 {
 833     const __m128d  VN9      = _mm_set1_pd(-9.3723776169321855475e-13);
 834     const __m128d  VN8      = _mm_set1_pd(1.2280156762674215741e-10);
 835     const __m128d  VN7      = _mm_set1_pd(-7.3562157912251309487e-9);
 836     const __m128d  VN6      = _mm_set1_pd(2.6215886208032517509e-7);
 837     const __m128d  VN5      = _mm_set1_pd(-4.9532491651265819499e-6);
 838     const __m128d  VN4      = _mm_set1_pd(0.00025907400778966060389);
 839     const __m128d  VN3      = _mm_set1_pd(0.0010585044856156469792);
 840     const __m128d  VN2      = _mm_set1_pd(0.045247661136833092885);
 841     const __m128d  VN1      = _mm_set1_pd(0.11643931522926034421);
 842     const __m128d  VN0      = _mm_set1_pd(1.1283791671726767970);
 843
 844     const __m128d  VD5      = _mm_set1_pd(0.000021784709867336150342);
 845     const __m128d  VD4      = _mm_set1_pd(0.00064293662010911388448);
 846     const __m128d  VD3      = _mm_set1_pd(0.0096311444822588683504);
 847     const __m128d  VD2      = _mm_set1_pd(0.085608012351550627051);
 848     const __m128d  VD1      = _mm_set1_pd(0.43652499166614811084);
 849     const __m128d  VD0      = _mm_set1_pd(1.0);
 850
 851     __m128d z4;
 852     __m128d polyVN0,polyVN1,polyVD0,polyVD1;
 853
 854     z4             = _mm_mul_pd(z2,z2);
 855
 856     polyVD1        = _mm_macc_pd(VD5,z4,VD3);
 857     polyVD0        = _mm_macc_pd(VD4,z4,VD2);
 858     polyVD1        = _mm_macc_pd(polyVD1,z4,VD1);
 859     polyVD0        = _mm_macc_pd(polyVD0,z4,VD0);
 860     polyVD0        = _mm_macc_pd(polyVD1,z2,polyVD0);
 861
 862     polyVD0        = gmx_mm_inv_pd(polyVD0);
 863
 864     polyVN1        = _mm_macc_pd(VN9,z4,VN7);
 865     polyVN0        = _mm_macc_pd(VN8,z4,VN6);
 866     polyVN1        = _mm_macc_pd(polyVN1,z4,VN5);
 867     polyVN0        = _mm_macc_pd(polyVN0,z4,VN4);
 868     polyVN1        = _mm_macc_pd(polyVN1,z4,VN3);
 869     polyVN0        = _mm_macc_pd(polyVN0,z4,VN2);
 870     polyVN1        = _mm_macc_pd(polyVN1,z4,VN1);
 871     polyVN0        = _mm_macc_pd(polyVN0,z4,VN0);
 872     polyVN0        = _mm_macc_pd(polyVN1,z2,polyVN0);
 873
 874     return   _mm_mul_pd(polyVN0,polyVD0);
 875 }
 876
 877
 878 static int
 879 gmx_mm_sincos_pd(__m128d x,
 880                  __m128d *sinval,
 881                  __m128d *cosval)
 882 {
 883 #ifdef _MSC_VER
 884     __declspec(align(16))
 885     const double sintable[34] =
 886     {
 887         1.00000000000000000e+00 , 0.00000000000000000e+00 ,
 888         9.95184726672196929e-01 , 9.80171403295606036e-02 ,
 889         9.80785280403230431e-01 , 1.95090322016128248e-01 ,
 890         9.56940335732208824e-01 , 2.90284677254462331e-01 ,
 891         9.23879532511286738e-01 , 3.82683432365089782e-01 ,
 892         8.81921264348355050e-01 , 4.71396736825997642e-01 ,
 893         8.31469612302545236e-01 , 5.55570233019602178e-01 ,
 894         7.73010453362736993e-01 , 6.34393284163645488e-01 ,
 895         7.07106781186547573e-01 , 7.07106781186547462e-01 ,
 896         6.34393284163645599e-01 , 7.73010453362736882e-01 ,
 897         5.55570233019602289e-01 , 8.31469612302545125e-01 ,
 898         4.71396736825997809e-01 , 8.81921264348354939e-01 ,
 899         3.82683432365089837e-01 , 9.23879532511286738e-01 ,
 900         2.90284677254462276e-01 , 9.56940335732208935e-01 ,
 901         1.95090322016128304e-01 , 9.80785280403230431e-01 ,
 902         9.80171403295607702e-02 , 9.95184726672196818e-01 ,
 903         0.0 , 1.00000000000000000e+00
 904     };
 905 #else
 906     const __m128d sintable[17] =
 907     {
 908         _mm_set_pd( 0.0 , 1.0 ),
 909         _mm_set_pd( sin(  1.0 * (M_PI/2.0) / 16.0) , cos(  1.0 * (M_PI/2.0) / 16.0) ),
 910         _mm_set_pd( sin(  2.0 * (M_PI/2.0) / 16.0) , cos(  2.0 * (M_PI/2.0) / 16.0) ),
 911         _mm_set_pd( sin(  3.0 * (M_PI/2.0) / 16.0) , cos(  3.0 * (M_PI/2.0) / 16.0) ),
 912         _mm_set_pd( sin(  4.0 * (M_PI/2.0) / 16.0) , cos(  4.0 * (M_PI/2.0) / 16.0) ),
 913         _mm_set_pd( sin(  5.0 * (M_PI/2.0) / 16.0) , cos(  5.0 * (M_PI/2.0) / 16.0) ),
 914         _mm_set_pd( sin(  6.0 * (M_PI/2.0) / 16.0) , cos(  6.0 * (M_PI/2.0) / 16.0) ),
 915         _mm_set_pd( sin(  7.0 * (M_PI/2.0) / 16.0) , cos(  7.0 * (M_PI/2.0) / 16.0) ),
 916         _mm_set_pd( sin(  8.0 * (M_PI/2.0) / 16.0) , cos(  8.0 * (M_PI/2.0) / 16.0) ),
 917         _mm_set_pd( sin(  9.0 * (M_PI/2.0) / 16.0) , cos(  9.0 * (M_PI/2.0) / 16.0) ),
 918         _mm_set_pd( sin( 10.0 * (M_PI/2.0) / 16.0) , cos( 10.0 * (M_PI/2.0) / 16.0) ),
 919         _mm_set_pd( sin( 11.0 * (M_PI/2.0) / 16.0) , cos( 11.0 * (M_PI/2.0) / 16.0) ),
 920         _mm_set_pd( sin( 12.0 * (M_PI/2.0) / 16.0) , cos( 12.0 * (M_PI/2.0) / 16.0) ),
 921         _mm_set_pd( sin( 13.0 * (M_PI/2.0) / 16.0) , cos( 13.0 * (M_PI/2.0) / 16.0) ),
 922         _mm_set_pd( sin( 14.0 * (M_PI/2.0) / 16.0) , cos( 14.0 * (M_PI/2.0) / 16.0) ),
 923         _mm_set_pd( sin( 15.0 * (M_PI/2.0) / 16.0) , cos( 15.0 * (M_PI/2.0) / 16.0) ),
 924         _mm_set_pd(  1.0 , 0.0 )
 925     };
 926 #endif
 927
 928     const __m128d signmask    = gmx_mm_castsi128_pd( _mm_set_epi32(0x7FFFFFFF,0xFFFFFFFF,0x7FFFFFFF,0xFFFFFFFF) );
 929     const __m128i signbit_epi32  = _mm_set1_epi32(0x80000000);
 930
 931     const __m128d tabscale      = _mm_set1_pd(32.0/M_PI);
 932     const __m128d invtabscale0  = _mm_set1_pd(9.81747508049011230469e-02);
 933     const __m128d invtabscale1  = _mm_set1_pd(1.96197799156550576057e-08);
 934     const __m128i ione          = _mm_set1_epi32(1);
 935     const __m128i i32           = _mm_set1_epi32(32);
 936     const __m128i i16           = _mm_set1_epi32(16);
 937     const __m128i tabmask       = _mm_set1_epi32(0x3F);
 938     const __m128d sinP7         = _mm_set1_pd(-1.0/5040.0);
 939     const __m128d sinP5         = _mm_set1_pd(1.0/120.0);
 940     const __m128d sinP3         = _mm_set1_pd(-1.0/6.0);
 941     const __m128d sinP1         = _mm_set1_pd(1.0);
 942
 943     const __m128d cosP6         = _mm_set1_pd(-1.0/720.0);
 944     const __m128d cosP4         = _mm_set1_pd(1.0/24.0);
 945     const __m128d cosP2         = _mm_set1_pd(-1.0/2.0);
 946     const __m128d cosP0         = _mm_set1_pd(1.0);
 947
 948     __m128d scalex;
 949     __m128i tabidx,corridx;
 950     __m128d xabs,z,z2,polySin,polyCos;
 951     __m128d xpoint;
 952     __m128d ypoint0,ypoint1;
 953
 954     __m128d sinpoint,cospoint;
 955     __m128d xsign,ssign,csign;
 956     __m128i imask,sswapsign,cswapsign;
 957     __m128d minusone;
 958
 959     xsign    = _mm_andnot_pd(signmask,x);
 960     xabs     = _mm_and_pd(x,signmask);
 961
 962     scalex   = _mm_mul_pd(tabscale,xabs);
 963     tabidx   = _mm_cvtpd_epi32(scalex);
 964
 965     xpoint   = _mm_round_pd(scalex,_MM_FROUND_TO_NEAREST_INT);
 966
 967     /* Extended precision arithmetics */
 968     z        = _mm_nmacc_pd(invtabscale0,xpoint,xabs);
 969     z        = _mm_nmacc_pd(invtabscale1,xpoint,z);
 970
 971     /* Range reduction to 0..2*Pi */
 972     tabidx   = _mm_and_si128(tabidx,tabmask);
 973
 974     /* tabidx is now in range [0,..,64] */
 975     imask     = _mm_cmpgt_epi32(tabidx,i32);
 976     sswapsign = imask;
 977     cswapsign = imask;
 978     corridx   = _mm_and_si128(imask,i32);
 979     tabidx    = _mm_sub_epi32(tabidx,corridx);
 980
 981     /* tabidx is now in range [0..32] */
 982     imask     = _mm_cmpgt_epi32(tabidx,i16);
 983     cswapsign = _mm_xor_si128(cswapsign,imask);
 984     corridx   = _mm_sub_epi32(i32,tabidx);
 985     tabidx    = _mm_blendv_epi8(tabidx,corridx,imask);
 986     /* tabidx is now in range [0..16] */
 987     ssign     = _mm_cvtepi32_pd( _mm_or_si128( sswapsign , ione ) );
 988     csign     = _mm_cvtepi32_pd( _mm_or_si128( cswapsign , ione ) );
 989
 990 #ifdef _MSC_VER
 991     ypoint0  = _mm_load_pd(sintable + 2*_mm_extract_epi32(tabidx,0));
 992     ypoint1  = _mm_load_pd(sintable + 2*_mm_extract_epi32(tabidx,1));
 993 #else
 994     ypoint0  = sintable[_mm_extract_epi32(tabidx,0)];
 995     ypoint1  = sintable[_mm_extract_epi32(tabidx,1)];
 996 #endif
 997     sinpoint = _mm_unpackhi_pd(ypoint0,ypoint1);
 998     cospoint = _mm_unpacklo_pd(ypoint0,ypoint1);
 999
1000     sinpoint = _mm_mul_pd(sinpoint,ssign);
1001     cospoint = _mm_mul_pd(cospoint,csign);
1002
1003     z2       = _mm_mul_pd(z,z);
1004
1005     polySin  = _mm_macc_pd(sinP7,z2,sinP5);
1006     polySin  = _mm_macc_pd(polySin,z2,sinP3);
1007     polySin  = _mm_macc_pd(polySin,z2,sinP1);
1008     polySin  = _mm_mul_pd(polySin,z);
1009
1010     polyCos  = _mm_macc_pd(cosP6,z2,cosP4);
1011     polyCos  = _mm_macc_pd(polyCos,z2,cosP2);
1012     polyCos  = _mm_macc_pd(polyCos,z2,cosP0);
1013
1014     *sinval  = _mm_xor_pd(_mm_add_pd( _mm_mul_pd(sinpoint,polyCos) , _mm_mul_pd(cospoint,polySin) ),xsign);
1015     *cosval  = _mm_sub_pd( _mm_mul_pd(cospoint,polyCos) , _mm_mul_pd(sinpoint,polySin) );
1016
1017     return 0;
1018 }
1019
1020 /*
1021  * IMPORTANT: Do NOT call both sin & cos if you need both results, since each of them
1022  * will then call the sincos() routine and waste a factor 2 in performance!
1023  */
1024 static __m128d
1025 gmx_mm_sin_pd(__m128d x)
1026 {
1027     __m128d s,c;
1028     gmx_mm_sincos_pd(x,&s,&c);
1029     return s;
1030 }
1031
1032 /*
1033  * IMPORTANT: Do NOT call both sin & cos if you need both results, since each of them
1034  * will then call the sincos() routine and waste a factor 2 in performance!
1035  */
1036 static __m128d
1037 gmx_mm_cos_pd(__m128d x)
1038 {
1039     __m128d s,c;
1040     gmx_mm_sincos_pd(x,&s,&c);
1041     return c;
1042 }
1043
1044
1045
1046 static __m128d
1047 gmx_mm_tan_pd(__m128d x)
1048 {
1049     __m128d sinval,cosval;
1050     __m128d tanval;
1051
1052     gmx_mm_sincos_pd(x,&sinval,&cosval);
1053
1054     tanval = _mm_mul_pd(sinval,gmx_mm_inv_pd(cosval));
1055
1056     return tanval;
1057 }
1058
1059
1060
1061 static __m128d
1062 gmx_mm_asin_pd(__m128d x)
1063 {
1064     /* Same algorithm as cephes library */
1065     const __m128d signmask  = gmx_mm_castsi128_pd( _mm_set_epi32(0x7FFFFFFF,0xFFFFFFFF,0x7FFFFFFF,0xFFFFFFFF) );
1066     const __m128d limit1    = _mm_set1_pd(0.625);
1067     const __m128d limit2    = _mm_set1_pd(1e-8);
1068     const __m128d one       = _mm_set1_pd(1.0);
1069     const __m128d halfpi    = _mm_set1_pd(M_PI/2.0);
1070     const __m128d quarterpi = _mm_set1_pd(M_PI/4.0);
1071     const __m128d morebits  = _mm_set1_pd(6.123233995736765886130e-17);
1072
1073     const __m128d P5        = _mm_set1_pd(4.253011369004428248960e-3);
1074     const __m128d P4        = _mm_set1_pd(-6.019598008014123785661e-1);
1075     const __m128d P3        = _mm_set1_pd(5.444622390564711410273e0);
1076     const __m128d P2        = _mm_set1_pd(-1.626247967210700244449e1);
1077     const __m128d P1        = _mm_set1_pd(1.956261983317594739197e1);
1078     const __m128d P0        = _mm_set1_pd(-8.198089802484824371615e0);
1079
1080     const __m128d Q4        = _mm_set1_pd(-1.474091372988853791896e1);
1081     const __m128d Q3        = _mm_set1_pd(7.049610280856842141659e1);
1082     const __m128d Q2        = _mm_set1_pd(-1.471791292232726029859e2);
1083     const __m128d Q1        = _mm_set1_pd(1.395105614657485689735e2);
1084     const __m128d Q0        = _mm_set1_pd(-4.918853881490881290097e1);
1085
1086     const __m128d R4        = _mm_set1_pd(2.967721961301243206100e-3);
1087     const __m128d R3        = _mm_set1_pd(-5.634242780008963776856e-1);
1088     const __m128d R2        = _mm_set1_pd(6.968710824104713396794e0);
1089     const __m128d R1        = _mm_set1_pd(-2.556901049652824852289e1);
1090     const __m128d R0        = _mm_set1_pd(2.853665548261061424989e1);
1091
1092     const __m128d S3        = _mm_set1_pd(-2.194779531642920639778e1);
1093     const __m128d S2        = _mm_set1_pd(1.470656354026814941758e2);
1094     const __m128d S1        = _mm_set1_pd(-3.838770957603691357202e2);
1095     const __m128d S0        = _mm_set1_pd(3.424398657913078477438e2);
1096
1097     __m128d sign;
1098     __m128d mask;
1099     __m128d xabs;
1100     __m128d zz,ww,z,q,w,y,zz2,ww2;
1101     __m128d PA,PB;
1102     __m128d QA,QB;
1103     __m128d RA,RB;
1104     __m128d SA,SB;
1105     __m128d nom,denom;
1106
1107     sign  = _mm_andnot_pd(signmask,x);
1108     xabs  = _mm_and_pd(x,signmask);
1109
1110     mask  = _mm_cmpgt_pd(xabs,limit1);
1111
1112     zz    = _mm_sub_pd(one,xabs);
1113     ww    = _mm_mul_pd(xabs,xabs);
1114     zz2   = _mm_mul_pd(zz,zz);
1115     ww2   = _mm_mul_pd(ww,ww);
1116
1117     /* R */
1118     RA    = _mm_macc_pd(R4,zz2,R2);
1119     RB    = _mm_macc_pd(R3,zz2,R1);
1120     RA    = _mm_macc_pd(RA,zz2,R0);
1121     RA    = _mm_macc_pd(RB,zz,RA);
1122
1123     /* S, SA = zz2 */
1124     SB    = _mm_macc_pd(S3,zz2,S1);
1125     SA    = _mm_add_pd(zz2,S2);
1126     SA    = _mm_macc_pd(SA,zz2,S0);
1127     SA    = _mm_macc_pd(SB,zz,SA);
1128
1129     /* P */
1130     PA    = _mm_macc_pd(P5,ww2,P3);
1131     PB    = _mm_macc_pd(P4,ww2,P2);
1132     PA    = _mm_macc_pd(PA,ww2,P1);
1133     PB    = _mm_macc_pd(PB,ww2,P0);
1134     PA    = _mm_macc_pd(PA,ww,PB);
1135
1136     /* Q, QA = ww2 */
1137     QB    = _mm_macc_pd(Q4,ww2,Q2);
1138     QA    = _mm_add_pd(ww2,Q3);
1139     QA    = _mm_macc_pd(QA,ww2,Q1);
1140     QB    = _mm_macc_pd(QB,ww2,Q0);
1141     QA    = _mm_macc_pd(QA,ww,QB);
1142
1143     RA    = _mm_mul_pd(RA,zz);
1144     PA    = _mm_mul_pd(PA,ww);
1145
1146     nom   = _mm_blendv_pd( PA,RA,mask );
1147     denom = _mm_blendv_pd( QA,SA,mask );
1148
1149     q     = _mm_mul_pd( nom, gmx_mm_inv_pd(denom) );
1150
1151     zz    = _mm_add_pd(zz,zz);
1152     zz    = gmx_mm_sqrt_pd(zz);
1153     z     = _mm_sub_pd(quarterpi,zz);
1154     zz    = _mm_mul_pd(zz,q);
1155     zz    = _mm_sub_pd(zz,morebits);
1156     z     = _mm_sub_pd(z,zz);
1157     z     = _mm_add_pd(z,quarterpi);
1158
1159     w     = _mm_macc_pd(xabs,q,xabs);
1160
1161     z     = _mm_blendv_pd( w,z,mask );
1162
1163     mask  = _mm_cmpgt_pd(xabs,limit2);
1164     z     = _mm_blendv_pd( xabs,z,mask );
1165
1166     z = _mm_xor_pd(z,sign);
1167
1168     return z;
1169 }
1170
1171
1172 static __m128d
1173 gmx_mm_acos_pd(__m128d x)
1174 {
1175     const __m128d signmask  = gmx_mm_castsi128_pd( _mm_set_epi32(0x7FFFFFFF,0xFFFFFFFF,0x7FFFFFFF,0xFFFFFFFF) );
1176     const __m128d one        = _mm_set1_pd(1.0);
1177     const __m128d half       = _mm_set1_pd(0.5);
1178     const __m128d pi         = _mm_set1_pd(M_PI);
1179     const __m128d quarterpi0 = _mm_set1_pd(7.85398163397448309616e-1);
1180     const __m128d quarterpi1 = _mm_set1_pd(6.123233995736765886130e-17);
1181
1182
1183     __m128d mask1;
1184
1185     __m128d z,z1,z2;
1186
1187     mask1 = _mm_cmpgt_pd(x,half);
1188     z1    = _mm_mul_pd(half,_mm_sub_pd(one,x));
1189     z1    = gmx_mm_sqrt_pd(z1);
1190     z     = _mm_blendv_pd( x,z1,mask1 );
1191
1192     z     = gmx_mm_asin_pd(z);
1193
1194     z1    = _mm_add_pd(z,z);
1195
1196     z2    = _mm_sub_pd(quarterpi0,z);
1197     z2    = _mm_add_pd(z2,quarterpi1);
1198     z2    = _mm_add_pd(z2,quarterpi0);
1199
1200     z     = _mm_blendv_pd(z2,z1,mask1);
1201
1202     return z;
1203 }
1204
1205 static __m128d
1206 gmx_mm_atan_pd(__m128d x)
1207 {
1208     /* Same algorithm as cephes library */
1209     const __m128d signmask  = gmx_mm_castsi128_pd( _mm_set_epi32(0x7FFFFFFF,0xFFFFFFFF,0x7FFFFFFF,0xFFFFFFFF) );
1210     const __m128d limit1    = _mm_set1_pd(0.66);
1211     const __m128d limit2    = _mm_set1_pd(2.41421356237309504880);
1212     const __m128d quarterpi = _mm_set1_pd(M_PI/4.0);
1213     const __m128d halfpi    = _mm_set1_pd(M_PI/2.0);
1214     const __m128d mone      = _mm_set1_pd(-1.0);
1215     const __m128d morebits1 = _mm_set1_pd(0.5*6.123233995736765886130E-17);
1216     const __m128d morebits2 = _mm_set1_pd(6.123233995736765886130E-17);
1217
1218     const __m128d P4        = _mm_set1_pd(-8.750608600031904122785E-1);
1219     const __m128d P3        = _mm_set1_pd(-1.615753718733365076637E1);
1220     const __m128d P2        = _mm_set1_pd(-7.500855792314704667340E1);
1221     const __m128d P1        = _mm_set1_pd(-1.228866684490136173410E2);
1222     const __m128d P0        = _mm_set1_pd(-6.485021904942025371773E1);
1223
1224     const __m128d Q4        = _mm_set1_pd(2.485846490142306297962E1);
1225     const __m128d Q3        = _mm_set1_pd(1.650270098316988542046E2);
1226     const __m128d Q2        = _mm_set1_pd(4.328810604912902668951E2);
1227     const __m128d Q1        = _mm_set1_pd(4.853903996359136964868E2);
1228     const __m128d Q0        = _mm_set1_pd(1.945506571482613964425E2);
1229
1230     __m128d sign;
1231     __m128d mask1,mask2;
1232     __m128d y,t1,t2;
1233     __m128d z,z2;
1234     __m128d P_A,P_B,Q_A,Q_B;
1235
1236     sign   = _mm_andnot_pd(signmask,x);
1237     x      = _mm_and_pd(x,signmask);
1238
1239     mask1  = _mm_cmpgt_pd(x,limit1);
1240     mask2  = _mm_cmpgt_pd(x,limit2);
1241
1242     t1     = _mm_mul_pd(_mm_add_pd(x,mone),gmx_mm_inv_pd(_mm_sub_pd(x,mone)));
1243     t2     = _mm_mul_pd(mone,gmx_mm_inv_pd(x));
1244
1245     y      = _mm_and_pd(mask1,quarterpi);
1246     y      = _mm_or_pd( _mm_and_pd(mask2,halfpi) , _mm_andnot_pd(mask2,y) );
1247
1248     x      = _mm_or_pd( _mm_and_pd(mask1,t1) , _mm_andnot_pd(mask1,x) );
1249     x      = _mm_or_pd( _mm_and_pd(mask2,t2) , _mm_andnot_pd(mask2,x) );
1250
1251     z      = _mm_mul_pd(x,x);
1252     z2     = _mm_mul_pd(z,z);
1253
1254     P_A    = _mm_macc_pd(P4,z2,P2);
1255     P_B    = _mm_macc_pd(P3,z2,P1);
1256     P_A    = _mm_macc_pd(P_A,z2,P0);
1257     P_A    = _mm_macc_pd(P_B,z,P_A);
1258
1259     /* Q_A = z2 */
1260     Q_B    = _mm_macc_pd(Q4,z2,Q2);
1261     Q_A    = _mm_add_pd(z2,Q3);
1262     Q_A    = _mm_macc_pd(Q_A,z2,Q1);
1263     Q_B    = _mm_macc_pd(Q_B,z2,Q0);
1264     Q_A    = _mm_macc_pd(Q_A,z,Q_B);
1265
1266     z      = _mm_mul_pd(z,P_A);
1267     z      = _mm_mul_pd(z,gmx_mm_inv_pd(Q_A));
1268     z      = _mm_macc_pd(z,x,x);
1269
1270     t1     = _mm_and_pd(mask1,morebits1);
1271     t1     = _mm_or_pd( _mm_and_pd(mask2,morebits2) , _mm_andnot_pd(mask2,t1) );
1272
1273     z      = _mm_add_pd(z,t1);
1274     y      = _mm_add_pd(y,z);
1275
1276     y      = _mm_xor_pd(y,sign);
1277
1278     return y;
1279 }
1280
1281
1282 static __m128d
1283 gmx_mm_atan2_pd(__m128d y, __m128d x)
1284 {
1285     const __m128d pi          = _mm_set1_pd(M_PI);
1286     const __m128d minuspi     = _mm_set1_pd(-M_PI);
1287     const __m128d halfpi      = _mm_set1_pd(M_PI/2.0);
1288     const __m128d minushalfpi = _mm_set1_pd(-M_PI/2.0);
1289
1290     __m128d z,z1,z3,z4;
1291     __m128d w;
1292     __m128d maskx_lt,maskx_eq;
1293     __m128d masky_lt,masky_eq;
1294     __m128d mask1,mask2,mask3,mask4,maskall;
1295
1296     maskx_lt  = _mm_cmplt_pd(x,_mm_setzero_pd());
1297     masky_lt  = _mm_cmplt_pd(y,_mm_setzero_pd());
1298     maskx_eq  = _mm_cmpeq_pd(x,_mm_setzero_pd());
1299     masky_eq  = _mm_cmpeq_pd(y,_mm_setzero_pd());
1300
1301     z         = _mm_mul_pd(y,gmx_mm_inv_pd(x));
1302     z         = gmx_mm_atan_pd(z);
1303
1304     mask1     = _mm_and_pd(maskx_eq,masky_lt);
1305     mask2     = _mm_andnot_pd(maskx_lt,masky_eq);
1306     mask3     = _mm_andnot_pd( _mm_or_pd(masky_lt,masky_eq) , maskx_eq);
1307     mask4     = _mm_and_pd(masky_eq,maskx_lt);
1308
1309     maskall   = _mm_or_pd( _mm_or_pd(mask1,mask2), _mm_or_pd(mask3,mask4) );
1310
1311     z         = _mm_andnot_pd(maskall,z);
1312     z1        = _mm_and_pd(mask1,minushalfpi);
1313     z3        = _mm_and_pd(mask3,halfpi);
1314     z4        = _mm_and_pd(mask4,pi);
1315
1316     z         = _mm_or_pd( _mm_or_pd(z,z1), _mm_or_pd(z3,z4) );
1317
1318     w         = _mm_blendv_pd(pi,minuspi,masky_lt);
1319     w         = _mm_and_pd(w,maskx_lt);
1320
1321     w         = _mm_andnot_pd(maskall,w);
1322
1323     z         = _mm_add_pd(z,w);
1324
1325     return z;
1326 }
1327
1328 #endif /*_gmx_math_x86_avx_128_fma_double_h_ */