1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 /*
  26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29 
  30 #ifdef __RESTRICT
  31 #define restrict _Restrict
  32 #else
  33 #define restrict
  34 #endif
  35 
  36 /* float powf(float x, float y)
  37  *
  38  * Method :
  39  *      1. Special cases:
  40  *      for (anything) ** 0                                     => 1
  41  *              for (anything) ** NaN                           => QNaN + invalid
  42  *              for NaN ** (anything)                           => QNaN + invalid
  43  *              for +-1 ** +-Inf                                => QNaN + invalid
  44  *              for +-(|x| < 1) ** +Inf                              => +0
  45  *              for +-(|x| < 1) ** -Inf                              => +Inf
  46  *              for +-(|x| > 1) ** +Inf                              => +Inf
  47  *              for +-(|x| > 1) ** -Inf                              => +0
  48  *              for +Inf ** (negative)                          => +0
  49  *              for +Inf ** (positive)                          => +Inf
  50  *              for -Inf ** (negative except odd integer)       => +0
  51  *              for -Inf ** (negative odd integer)              => -0
  52  *              for -Inf ** (positive except odd integer)       => +Inf
  53  *              for -Inf ** (positive odd integer)              => -Inf
  54  *              for (negative) ** (non-integer)                 => QNaN + invalid
  55  *              for +0 ** (negative)                            => +Inf + overflow
  56  *              for +0 ** (positive)                            => +0
  57  *              for -0 ** (negative except odd integer)         => +Inf + overflow
  58  *              for -0 ** (negative odd integer)                => -Inf + overflow
  59  *              for -0 ** (positive except odd integer)         => +0
  60  *              for -0 ** (positive odd integer)                => -0
  61  *      2. Computes x**y from:
  62  *              x**y = 2**(y*log2(x)) = 2**(w/256), where w = 256*log2(|x|)*y.
  63  *      3. Computes w = 256 * log2(|x|) * y from
  64  *              |x| = m * 2**n => log2(|x|) = n + log2(m).
  65  *      Let m = m0 + dm, where m0 = 1 + k / 128,
  66  *              k = [0, 128],
  67  *              dm = [-1/256, 1/256].
  68  *      Then 256*log2(m) = 256*log2(m0 + dm) = 256*log2(m0) + 256*log2(1+z),
  69  *              where z = dm*(1/m0), z = [-1/258, 1/256].
  70  *      Then
  71  *              1/m0 is looked up in a table of 1, 1/(1+1/128), ..., 1/(1+128/128).
  72  *              256*log2(m0) is looked up in a table of 256*log2(1), 256*log2(1+1/128),
  73  *                      ..., 256*log2(1+128/128).
  74  *              256*log2(1+z) is computed using approximation:
  75  *                      256*log2(1+z) = (((a3*z + a2)*z + a1)*z + a0)*z.
  76  *      3. For w >= 32768
  77  *              then for (negative) ** (odd integer)            => -Inf + overflow
  78  *              else                                            => +Inf + overflow
  79  *      For w <= -38400
  80  *              then for (negative) ** (odd integer)            => -0 + underflow
  81  *              else                                            => +0 + underflow
  82  *      4. Computes 2 ** (w/256) from:
  83  *              2 ** (w/256) = 2**a  *  2**(k/256)  *  2**(r/256)
  84  *      Where:
  85  *              a    =    int  ( w ) >> 8;
  86  *              k    =    int  ( w ) & 0xFF;
  87  *              r    =    frac ( w ).
  88  *      Note that:
  89  *              k = 0, 1, ..., 255;
  90  *              r = (-1, 1).
  91  *      Then:
  92  *              2**(k/256) is looked up in a table of 2**0, 2**1/256, ...
  93  *              2**(r/256) is computed using approximation:
  94  *                      2**(r/256) =  a0 + a1 * r + a2 * r**2
  95  *              Multiplication by 2**a is done by adding "a" to
  96  *              the biased exponent.
  97  *      5. For (negative) ** (odd integer)      => -(2**(w/256))
  98  *      otherwise                               =>   2**(w/256)
  99  *
 100  * Accuracy:
 101  *      Max. relative aproximation error < 2**(-37.35) for 256*log2(1+z).
 102  *      Max. relative aproximation error < 2**(-29.18) for 2**(r/256).
 103  *      All calculations are done in double precision.
 104  *      Maximum error observed: less than 0.528 ulp after 700.000.000
 105  *      results.
 106  */
 107 
 108 static void __vpowfx( int n, float * restrict px, float * restrict py,
 109         int stridey, float * restrict pz, int stridez );
 110 
 111 static void __vpowf_n( int n, float * restrict px, int stridex, float * restrict py,
 112         int stridey, float * restrict pz, int stridez );
 113 
 114 static void __vpowfx_n( int n, double yy, float * restrict py,
 115         int stridey, float * restrict pz, int stridez );
 116 
 117 #pragma no_inline(__vpowfx)
 118 #pragma no_inline(__vpowf_n)
 119 #pragma no_inline(__vpowfx_n)
 120 
 121 static const double __TBL_exp2f[] = {
 122         /* 2^(i/256), i = [0, 255] */
 123 1.000000000000000000e+00, 1.002711275050202522e+00, 1.005429901112802726e+00,
 124 1.008155898118417548e+00, 1.010889286051700475e+00, 1.013630084951489430e+00,
 125 1.016378314910953096e+00, 1.019133996077737914e+00, 1.021897148654116627e+00,
 126 1.024667792897135721e+00, 1.027445949118763746e+00, 1.030231637686040980e+00,
 127 1.033024879021228415e+00, 1.035825693601957198e+00, 1.038634101961378731e+00,
 128 1.041450124688316103e+00, 1.044273782427413755e+00, 1.047105095879289793e+00,
 129 1.049944085800687210e+00, 1.052790773004626423e+00, 1.055645178360557157e+00,
 130 1.058507322794512762e+00, 1.061377227289262093e+00, 1.064254912884464499e+00,
 131 1.067140400676823697e+00, 1.070033711820241873e+00, 1.072934867525975555e+00,
 132 1.075843889062791048e+00, 1.078760797757119860e+00, 1.081685614993215250e+00,
 133 1.084618362213309206e+00, 1.087559060917769660e+00, 1.090507732665257690e+00,
 134 1.093464399072885840e+00, 1.096429081816376883e+00, 1.099401802630221914e+00,
 135 1.102382583307840891e+00, 1.105371445701741173e+00, 1.108368411723678726e+00,
 136 1.111373503344817548e+00, 1.114386742595892432e+00, 1.117408151567369279e+00,
 137 1.120437752409606746e+00, 1.123475567333019898e+00, 1.126521618608241848e+00,
 138 1.129575928566288079e+00, 1.132638519598719196e+00, 1.135709414157805464e+00,
 139 1.138788634756691565e+00, 1.141876203969561576e+00, 1.144972144431804173e+00,
 140 1.148076478840178938e+00, 1.151189229952982673e+00, 1.154310420590215935e+00,
 141 1.157440073633751121e+00, 1.160578212027498779e+00, 1.163724858777577476e+00,
 142 1.166880036952481658e+00, 1.170043769683250190e+00, 1.173216080163637320e+00,
 143 1.176396991650281221e+00, 1.179586527462875845e+00, 1.182784710984341014e+00,
 144 1.185991565660993841e+00, 1.189207115002721027e+00, 1.192431382583151178e+00,
 145 1.195664392039827328e+00, 1.198906167074380580e+00, 1.202156731452703076e+00,
 146 1.205416109005123859e+00, 1.208684323626581625e+00, 1.211961399276801243e+00,
 147 1.215247359980468955e+00, 1.218542229827408452e+00, 1.221846032972757623e+00,
 148 1.225158793637145527e+00, 1.228480536106870025e+00, 1.231811284734075862e+00,
 149 1.235151063936933413e+00, 1.238499898199816540e+00, 1.241857812073484002e+00,
 150 1.245224830175257980e+00, 1.248600977189204819e+00, 1.251986277866316222e+00,
 151 1.255380757024691096e+00, 1.258784439549716527e+00, 1.262197350394250739e+00,
 152 1.265619514578806282e+00, 1.269050957191733220e+00, 1.272491703389402762e+00,
 153 1.275941778396392001e+00, 1.279401207505669325e+00, 1.282870016078778264e+00,
 154 1.286348229546025568e+00, 1.289835873406665723e+00, 1.293332973229089466e+00,
 155 1.296839554651009641e+00, 1.300355643379650594e+00, 1.303881265191935812e+00,
 156 1.307416445934677318e+00, 1.310961211524764414e+00, 1.314515587949354636e+00,
 157 1.318079601266064049e+00, 1.321653277603157539e+00, 1.325236643159741323e+00,
 158 1.328829724205954355e+00, 1.332432547083161500e+00, 1.336045138204145832e+00,
 159 1.339667524053302916e+00, 1.343299731186835322e+00, 1.346941786232945804e+00,
 160 1.350593715892034474e+00, 1.354255546936892651e+00, 1.357927306212901142e+00,
 161 1.361609020638224754e+00, 1.365300717204011915e+00, 1.369002422974590516e+00,
 162 1.372714165087668414e+00, 1.376435970754530169e+00, 1.380167867260237990e+00,
 163 1.383909881963832023e+00, 1.387662042298529075e+00, 1.391424375771926236e+00,
 164 1.395196909966200272e+00, 1.398979672538311236e+00, 1.402772691220204759e+00,
 165 1.406575993819015435e+00, 1.410389608217270663e+00, 1.414213562373095145e+00,
 166 1.418047884320415175e+00, 1.421892602169165576e+00, 1.425747744105494208e+00,
 167 1.429613338391970023e+00, 1.433489413367788901e+00, 1.437375997448982368e+00,
 168 1.441273119128625657e+00, 1.445180806977046650e+00, 1.449099089642035043e+00,
 169 1.453027995849052623e+00, 1.456967554401443765e+00, 1.460917794180647045e+00,
 170 1.464878744146405731e+00, 1.468850433336981842e+00, 1.472832890869367528e+00,
 171 1.476826145939499346e+00, 1.480830227822471867e+00, 1.484845165872752393e+00,
 172 1.488870989524397004e+00, 1.492907728291264835e+00, 1.496955411767235455e+00,
 173 1.501014069626425584e+00, 1.505083731623406473e+00, 1.509164427593422841e+00,
 174 1.513256187452609813e+00, 1.517359041198214742e+00, 1.521473018908814590e+00,
 175 1.525598150744538417e+00, 1.529734466947286986e+00, 1.533881997840955913e+00,
 176 1.538040773831656827e+00, 1.542210825407940744e+00, 1.546392183141021448e+00,
 177 1.550584877684999974e+00, 1.554788939777088652e+00, 1.559004400237836929e+00,
 178 1.563231289971357629e+00, 1.567469639965552997e+00, 1.571719481292341403e+00,
 179 1.575980845107886497e+00, 1.580253762652824578e+00, 1.584538265252493749e+00,
 180 1.588834384317163950e+00, 1.593142151342266999e+00, 1.597461597908627073e+00,
 181 1.601792755682693414e+00, 1.606135656416771029e+00, 1.610490331949254283e+00,
 182 1.614856814204860713e+00, 1.619235135194863728e+00, 1.623625327017328868e+00,
 183 1.628027421857347834e+00, 1.632441451987274972e+00, 1.636867449766964411e+00,
 184 1.641305447644006321e+00, 1.645755478153964946e+00, 1.650217573920617742e+00,
 185 1.654691767656194301e+00, 1.659178092161616158e+00, 1.663676580326736376e+00,
 186 1.668187265130582464e+00, 1.672710179641596628e+00, 1.677245357017878469e+00,
 187 1.681792830507429004e+00, 1.686352633448393368e+00, 1.690924799269305279e+00,
 188 1.695509361489332623e+00, 1.700106353718523478e+00, 1.704715809658051251e+00,
 189 1.709337763100462926e+00, 1.713972247929925974e+00, 1.718619298122477934e+00,
 190 1.723278947746273992e+00, 1.727951230961837670e+00, 1.732636182022311067e+00,
 191 1.737333835273706217e+00, 1.742044225155156445e+00, 1.746767386199169048e+00,
 192 1.751503353031878207e+00, 1.756252160373299454e+00, 1.761013843037583904e+00,
 193 1.765788435933272726e+00, 1.770575974063554714e+00, 1.775376492526521188e+00,
 194 1.780190026515424462e+00, 1.785016611318934965e+00, 1.789856282321401038e+00,
 195 1.794709075003107168e+00, 1.799575024940535117e+00, 1.804454167806623932e+00,
 196 1.809346539371031959e+00, 1.814252175500398856e+00, 1.819171112158608494e+00,
 197 1.824103385407053413e+00, 1.829049031404897274e+00, 1.834008086409342431e+00,
 198 1.838980586775893711e+00, 1.843966568958625984e+00, 1.848966069510450838e+00,
 199 1.853979125083385471e+00, 1.859005772428820480e+00, 1.864046048397788979e+00,
 200 1.869099989941238604e+00, 1.874167634110299963e+00, 1.879249018056560194e+00,
 201 1.884344179032334532e+00, 1.889453154390939194e+00, 1.894575981586965607e+00,
 202 1.899712698176555303e+00, 1.904863341817674138e+00, 1.910027950270389852e+00,
 203 1.915206561397147400e+00, 1.920399213163047403e+00, 1.925605943636125028e+00,
 204 1.930826790987627106e+00, 1.936061793492294347e+00, 1.941310989528640452e+00,
 205 1.946574417579233218e+00, 1.951852116230978318e+00, 1.957144124175400179e+00,
 206 1.962450480208927317e+00, 1.967771223233175881e+00, 1.973106392255234320e+00,
 207 1.978456026387950928e+00, 1.983820164850219392e+00, 1.989198846967266343e+00,
 208 1.994592112170940235e+00
 209 };
 210 
 211 static const double __TBL_log2f[] = {
 212         /* __TBL_log2f[2*i] = 256*log2(1+i/128), i = [0, 128] */
 213         /* __TBL_log2f[2*i+1] = 2**(-23)/(1+i/128), i = [0, 128] */
 214 0.000000000000000000e+00, 1.192092895507812500e-07, 2.874177388353054585e+00,
 215 1.182851865310077503e-07, 5.726160135284354524e+00, 1.173753004807692373e-07,
 216 8.556288393587271557e+00, 1.164793058206106825e-07, 1.136489455576407970e+01,
 217 1.155968868371212153e-07, 1.415230348830453799e+01, 1.147277373120300688e-07,
 218 1.691883275718974389e+01, 1.138715601679104456e-07, 1.966479284501270897e+01,
 219 1.130280671296296339e-07, 2.239048736008688678e+01, 1.121969784007352926e-07,
 220 2.509621323789484038e+01, 1.113780223540145949e-07, 2.778226093521127638e+01,
 221 1.105709352355072477e-07, 3.044891461721790193e+01, 1.097754608812949697e-07,
 222 3.309645233791141550e+01, 1.089913504464285680e-07, 3.572514621409114710e+01,
 223 1.082183621453900683e-07, 3.833526259319860685e+01, 1.074562610035211292e-07,
 224 4.092706221526768928e+01, 1.067048186188811188e-07, 4.350080036923196758e+01,
 225 1.059638129340277719e-07, 4.605672704382322280e+01, 1.052330280172413778e-07,
 226 4.859508707328441091e+01, 1.045122538527397202e-07, 5.111612027810928538e+01,
 227 1.038012861394557784e-07, 5.362006160101114460e+01, 1.030999260979729787e-07,
 228 5.610714123831336053e+01, 1.024079802852348971e-07, 5.857758476694550609e+01,
 229 1.017252604166666732e-07, 6.103161326722020164e+01, 1.010515831953642383e-07,
 230 6.346944344155788542e+01, 1.003867701480263102e-07, 6.589128772931884725e+01,
 231 9.973064746732026447e-08, 6.829735441789475203e+01, 9.908304586038961692e-08,
 232 7.068784775020480993e+01, 9.844380040322580637e-08, 7.306296802873558249e+01,
 233 9.781275040064102225e-08, 7.542291171625650748e+01, 9.718973925159236158e-08,
 234 7.776787153333835079e+01, 9.657461431962025166e-08, 8.009803655279496581e+01,
 235 9.596722680817610579e-08, 8.241359229116476115e+01, 9.536743164062500529e-08,
 236 8.471472079734193983e+01, 9.477508734472049048e-08, 8.700160073846393516e+01,
 237 9.419005594135801946e-08, 8.927440748315585495e+01, 9.361220283742331508e-08,
 238 9.153331318222942059e+01, 9.304139672256097884e-08, 9.377848684692884262e+01,
 239 9.247750946969696962e-08, 9.601009442481273481e+01, 9.192041603915663129e-08,
 240 9.822829887335737453e+01, 9.136999438622755046e-08, 1.004332602313626381e+02,
 241 9.082612537202380448e-08, 1.026251356882391832e+02, 9.028869267751479078e-08,
 242 1.048040796512516550e+02, 8.975758272058823405e-08, 1.069702438107898530e+02,
 243 8.923268457602338686e-08, 1.091237772037370775e+02, 8.871388989825581272e-08,
 244 1.112648262750015107e+02, 8.820109284682080489e-08, 1.133935349372744383e+02,
 245 8.769419001436781487e-08, 1.155100446290761766e+02, 8.719308035714285707e-08,
 246 1.176144943711480977e+02, 8.669766512784091150e-08, 1.197070208212473403e+02,
 247 8.620784781073446298e-08, 1.217877583273978246e+02, 8.572353405898876167e-08,
 248 1.238568389796496376e+02, 8.524463163407821503e-08, 1.259143926603967287e+02,
 249 8.477105034722222546e-08, 1.279605470933005762e+02, 8.430270200276242743e-08,
 250 1.299954278908662388e+02, 8.383950034340659995e-08, 1.320191586007148601e+02,
 251 8.338136099726775949e-08, 1.340318607505952855e+02, 8.292820142663043248e-08,
 252 1.360336538921758915e+02, 8.247994087837838296e-08, 1.380246556436560468e+02,
 253 8.203650033602151192e-08, 1.400049817312349774e+02, 8.159780247326202734e-08,
 254 1.419747460294751704e+02, 8.116377160904255122e-08, 1.439340606005945915e+02,
 255 8.073433366402115954e-08, 1.458830357327226466e+02, 8.030941611842105082e-08,
 256 1.478217799771516638e+02, 7.988894797120419333e-08, 1.497504001846159838e+02,
 257 7.947285970052082892e-08, 1.516690015406285852e+02, 7.906108322538860398e-08,
 258 1.535776875999046922e+02, 7.865355186855669953e-08, 1.554765603199003294e+02,
 259 7.825020032051282044e-08, 1.573657200934933087e+02, 7.785096460459183052e-08,
 260 1.592452657808323124e+02, 7.745578204314720208e-08, 1.611152947403800511e+02,
 261 7.706459122474748130e-08, 1.629759028591741128e+02, 7.667733197236181018e-08,
 262 1.648271845823295223e+02, 7.629394531250000159e-08, 1.666692329418057170e+02,
 263 7.591437344527363039e-08, 1.685021395844594565e+02, 7.553855971534653557e-08,
 264 1.703259947994051231e+02, 7.516644858374384321e-08, 1.721408875447028777e+02,
 265 7.479798560049019504e-08, 1.739469054733941960e+02, 7.443311737804878042e-08,
 266 1.757441349589039135e+02, 7.407179156553397416e-08, 1.775326611198272531e+02,
 267 7.371395682367149407e-08, 1.793125678441195987e+02, 7.335956280048077330e-08,
 268 1.810839378127059831e+02, 7.300856010765549954e-08, 1.828468525225273993e+02,
 269 7.266090029761905417e-08, 1.846013923090393973e+02, 7.231653584123223301e-08,
 270 1.863476363681789962e+02, 7.197542010613207272e-08, 1.880856627778145764e+02,
 271 7.163750733568075279e-08, 1.898155485186936176e+02, 7.130275262850466758e-08,
 272 1.915373694949018386e+02, 7.097111191860465018e-08, 1.932512005538479514e+02,
 273 7.064254195601851460e-08, 1.949571155057867031e+02, 7.031700028801843312e-08,
 274 1.966551871428931406e+02, 6.999444524082569196e-08, 1.983454872579004018e+02,
 275 6.967483590182648015e-08, 2.000280866623128588e+02, 6.935813210227272390e-08,
 276 2.017030552042064926e+02, 6.904429440045249486e-08, 2.033704617856271284e+02,
 277 6.873328406531531472e-08, 2.050303743795980154e+02, 6.842506306053811558e-08,
 278 2.066828600467466401e+02, 6.811959402901785336e-08, 2.083279849515614899e+02,
 279 6.781684027777777772e-08, 2.099658143782880586e+02, 6.751676576327433535e-08,
 280 2.115964127464742432e+02, 6.721933507709251725e-08, 2.132198436261738550e+02,
 281 6.692451343201754014e-08, 2.148361697528176535e+02, 6.663226664847161225e-08,
 282 2.164454530417600608e+02, 6.634256114130434863e-08, 2.180477546025107358e+02,
 283 6.605536390692640687e-08, 2.196431347526584545e+02, 6.577064251077586116e-08,
 284 2.212316530314957390e+02, 6.548836507510729591e-08, 2.228133682133515663e+02,
 285 6.520850026709402365e-08, 2.243883383206399174e+02, 6.493101728723404362e-08,
 286 2.259566206366313565e+02, 6.465588585805084723e-08, 2.275182717179543204e+02,
 287 6.438307621308016336e-08, 2.290733474068335340e+02, 6.411255908613445100e-08,
 288 2.306219028430716378e+02, 6.384430570083681460e-08, 2.321639924757807307e+02,
 289 6.357828776041666578e-08, 2.336996700748701699e+02, 6.331447743775933615e-08,
 290 2.352289887422961954e+02, 6.305284736570248109e-08, 2.367520009230799189e+02,
 291 6.279337062757202180e-08, 2.382687584160988763e+02, 6.253602074795082293e-08,
 292 2.397793123846580556e+02, 6.228077168367347501e-08, 2.412837133668454044e+02,
 293 6.202759781504065697e-08, 2.427820112856774699e+02, 6.177647393724696421e-08,
 294 2.442742554590400630e+02, 6.152737525201612732e-08, 2.457604946094287186e+02,
 295 6.128027735943774537e-08, 2.472407768734942692e+02, 6.103515625000000127e-08,
 296 2.487151498113976231e+02, 6.079198829681274795e-08, 2.501836604159786077e+02,
 297 6.055075024801586965e-08, 2.516463551217433974e+02, 6.031141921936758485e-08,
 298 2.531032798136744475e+02, 6.007397268700787318e-08, 2.545544798358676246e+02,
 299 5.983838848039215603e-08, 2.560000000000000000e+02, 5.960464477539062500e-08
 300 };
 301 
 302 static const double __TBL_expfb[] = {
 303 7.006492321624085355e-46, 1.401298464324817071e-45, 2.802596928649634142e-45,
 304 5.605193857299268284e-45, 1.121038771459853657e-44, 2.242077542919707313e-44,
 305 4.484155085839414627e-44, 8.968310171678829254e-44, 1.793662034335765851e-43,
 306 3.587324068671531702e-43, 7.174648137343063403e-43, 1.434929627468612681e-42,
 307 2.869859254937225361e-42, 5.739718509874450723e-42, 1.147943701974890145e-41,
 308 2.295887403949780289e-41, 4.591774807899560578e-41, 9.183549615799121156e-41,
 309 1.836709923159824231e-40, 3.673419846319648462e-40, 7.346839692639296925e-40,
 310 1.469367938527859385e-39, 2.938735877055718770e-39, 5.877471754111437540e-39,
 311 1.175494350822287508e-38, 2.350988701644575016e-38, 4.701977403289150032e-38,
 312 9.403954806578300064e-38, 1.880790961315660013e-37, 3.761581922631320025e-37,
 313 7.523163845262640051e-37, 1.504632769052528010e-36, 3.009265538105056020e-36,
 314 6.018531076210112041e-36, 1.203706215242022408e-35, 2.407412430484044816e-35,
 315 4.814824860968089633e-35, 9.629649721936179265e-35, 1.925929944387235853e-34,
 316 3.851859888774471706e-34, 7.703719777548943412e-34, 1.540743955509788682e-33,
 317 3.081487911019577365e-33, 6.162975822039154730e-33, 1.232595164407830946e-32,
 318 2.465190328815661892e-32, 4.930380657631323784e-32, 9.860761315262647568e-32,
 319 1.972152263052529514e-31, 3.944304526105059027e-31, 7.888609052210118054e-31,
 320 1.577721810442023611e-30, 3.155443620884047222e-30, 6.310887241768094443e-30,
 321 1.262177448353618889e-29, 2.524354896707237777e-29, 5.048709793414475555e-29,
 322 1.009741958682895111e-28, 2.019483917365790222e-28, 4.038967834731580444e-28,
 323 8.077935669463160887e-28, 1.615587133892632177e-27, 3.231174267785264355e-27,
 324 6.462348535570528710e-27, 1.292469707114105742e-26, 2.584939414228211484e-26,
 325 5.169878828456422968e-26, 1.033975765691284594e-25, 2.067951531382569187e-25,
 326 4.135903062765138374e-25, 8.271806125530276749e-25, 1.654361225106055350e-24,
 327 3.308722450212110699e-24, 6.617444900424221399e-24, 1.323488980084844280e-23,
 328 2.646977960169688560e-23, 5.293955920339377119e-23, 1.058791184067875424e-22,
 329 2.117582368135750848e-22, 4.235164736271501695e-22, 8.470329472543003391e-22,
 330 1.694065894508600678e-21, 3.388131789017201356e-21, 6.776263578034402713e-21,
 331 1.355252715606880543e-20, 2.710505431213761085e-20, 5.421010862427522170e-20,
 332 1.084202172485504434e-19, 2.168404344971008868e-19, 4.336808689942017736e-19,
 333 8.673617379884035472e-19, 1.734723475976807094e-18, 3.469446951953614189e-18,
 334 6.938893903907228378e-18, 1.387778780781445676e-17, 2.775557561562891351e-17,
 335 5.551115123125782702e-17, 1.110223024625156540e-16, 2.220446049250313081e-16,
 336 4.440892098500626162e-16, 8.881784197001252323e-16, 1.776356839400250465e-15,
 337 3.552713678800500929e-15, 7.105427357601001859e-15, 1.421085471520200372e-14,
 338 2.842170943040400743e-14, 5.684341886080801487e-14, 1.136868377216160297e-13,
 339 2.273736754432320595e-13, 4.547473508864641190e-13, 9.094947017729282379e-13,
 340 1.818989403545856476e-12, 3.637978807091712952e-12, 7.275957614183425903e-12,
 341 1.455191522836685181e-11, 2.910383045673370361e-11, 5.820766091346740723e-11,
 342 1.164153218269348145e-10, 2.328306436538696289e-10, 4.656612873077392578e-10,
 343 9.313225746154785156e-10, 1.862645149230957031e-09, 3.725290298461914062e-09,
 344 7.450580596923828125e-09, 1.490116119384765625e-08, 2.980232238769531250e-08,
 345 5.960464477539062500e-08, 1.192092895507812500e-07, 2.384185791015625000e-07,
 346 4.768371582031250000e-07, 9.536743164062500000e-07, 1.907348632812500000e-06,
 347 3.814697265625000000e-06, 7.629394531250000000e-06, 1.525878906250000000e-05,
 348 3.051757812500000000e-05, 6.103515625000000000e-05, 1.220703125000000000e-04,
 349 2.441406250000000000e-04, 4.882812500000000000e-04, 9.765625000000000000e-04,
 350 1.953125000000000000e-03, 3.906250000000000000e-03, 7.812500000000000000e-03,
 351 1.562500000000000000e-02, 3.125000000000000000e-02, 6.250000000000000000e-02,
 352 1.250000000000000000e-01, 2.500000000000000000e-01, 5.000000000000000000e-01,
 353 1.000000000000000000e+00, 2.000000000000000000e+00, 4.000000000000000000e+00,
 354 8.000000000000000000e+00, 1.600000000000000000e+01, 3.200000000000000000e+01,
 355 6.400000000000000000e+01, 1.280000000000000000e+02, 2.560000000000000000e+02,
 356 5.120000000000000000e+02, 1.024000000000000000e+03, 2.048000000000000000e+03,
 357 4.096000000000000000e+03, 8.192000000000000000e+03, 1.638400000000000000e+04,
 358 3.276800000000000000e+04, 6.553600000000000000e+04, 1.310720000000000000e+05,
 359 2.621440000000000000e+05, 5.242880000000000000e+05, 1.048576000000000000e+06,
 360 2.097152000000000000e+06, 4.194304000000000000e+06, 8.388608000000000000e+06,
 361 1.677721600000000000e+07, 3.355443200000000000e+07, 6.710886400000000000e+07,
 362 1.342177280000000000e+08, 2.684354560000000000e+08, 5.368709120000000000e+08,
 363 1.073741824000000000e+09, 2.147483648000000000e+09, 4.294967296000000000e+09,
 364 8.589934592000000000e+09, 1.717986918400000000e+10, 3.435973836800000000e+10,
 365 6.871947673600000000e+10, 1.374389534720000000e+11, 2.748779069440000000e+11,
 366 5.497558138880000000e+11, 1.099511627776000000e+12, 2.199023255552000000e+12,
 367 4.398046511104000000e+12, 8.796093022208000000e+12, 1.759218604441600000e+13,
 368 3.518437208883200000e+13, 7.036874417766400000e+13, 1.407374883553280000e+14,
 369 2.814749767106560000e+14, 5.629499534213120000e+14, 1.125899906842624000e+15,
 370 2.251799813685248000e+15, 4.503599627370496000e+15, 9.007199254740992000e+15,
 371 1.801439850948198400e+16, 3.602879701896396800e+16, 7.205759403792793600e+16,
 372 1.441151880758558720e+17, 2.882303761517117440e+17, 5.764607523034234880e+17,
 373 1.152921504606846976e+18, 2.305843009213693952e+18, 4.611686018427387904e+18,
 374 9.223372036854775808e+18, 1.844674407370955162e+19, 3.689348814741910323e+19,
 375 7.378697629483820646e+19, 1.475739525896764129e+20, 2.951479051793528259e+20,
 376 5.902958103587056517e+20, 1.180591620717411303e+21, 2.361183241434822607e+21,
 377 4.722366482869645214e+21, 9.444732965739290427e+21, 1.888946593147858085e+22,
 378 3.777893186295716171e+22, 7.555786372591432342e+22, 1.511157274518286468e+23,
 379 3.022314549036572937e+23, 6.044629098073145874e+23, 1.208925819614629175e+24,
 380 2.417851639229258349e+24, 4.835703278458516699e+24, 9.671406556917033398e+24,
 381 1.934281311383406680e+25, 3.868562622766813359e+25, 7.737125245533626718e+25,
 382 1.547425049106725344e+26, 3.094850098213450687e+26, 6.189700196426901374e+26,
 383 1.237940039285380275e+27, 2.475880078570760550e+27, 4.951760157141521100e+27,
 384 9.903520314283042199e+27, 1.980704062856608440e+28, 3.961408125713216880e+28,
 385 7.922816251426433759e+28, 1.584563250285286752e+29, 3.169126500570573504e+29,
 386 6.338253001141147007e+29, 1.267650600228229401e+30, 2.535301200456458803e+30,
 387 5.070602400912917606e+30, 1.014120480182583521e+31, 2.028240960365167042e+31,
 388 4.056481920730334085e+31, 8.112963841460668170e+31, 1.622592768292133634e+32,
 389 3.245185536584267268e+32, 6.490371073168534536e+32, 1.298074214633706907e+33,
 390 2.596148429267413814e+33, 5.192296858534827629e+33, 1.038459371706965526e+34,
 391 2.076918743413931051e+34, 4.153837486827862103e+34, 8.307674973655724206e+34,
 392 1.661534994731144841e+35, 3.323069989462289682e+35, 6.646139978924579365e+35,
 393 1.329227995784915873e+36, 2.658455991569831746e+36, 5.316911983139663492e+36,
 394 1.063382396627932698e+37, 2.126764793255865397e+37, 4.253529586511730793e+37,
 395 8.507059173023461587e+37, 1.701411834604692317e+38, 3.402823669209384635e+38
 396 };
 397 
 398 static const double
 399         KA3 = -3.60659926599003171364e-01*256.0,
 400         KA2 =  4.80902715189356683026e-01*256.0,
 401         KA1 = -7.21347520569871841065e-01*256.0,
 402         KA0 =  1.44269504088069658645e+00*256.0,
 403         KB2 =  3.66556671660783833261e-06,
 404         KB1 =  2.70760782821392980564e-03,
 405         DONE = 1.0,
 406         HTHRESH = 32768.0,
 407         LTHRESH = -38400.0;
 408 
 409 #define RETURN(ret)                                             \
 410 {                                                               \
 411         *pz = (ret);                                            \
 412         px += stridex;                                          \
 413         py += stridey;                                          \
 414         pz += stridez;                                          \
 415         if ( n_n == 0 )                                         \
 416         {                                                       \
 417                 spx = px; spy = py; spz = pz;                   \
 418                 continue;                                       \
 419         }                                                       \
 420         n--;                                                    \
 421         break;                                                  \
 422 }
 423 
 424 void
 425 __vpowf( int n, float * restrict px, int stridex, float * restrict py,
 426         int stridey, float * restrict pz, int stridez )
 427 {
 428         float           *spx, *spy, *spz;
 429         double          y0, yy0;
 430         long long       di0;
 431         unsigned        ux, sx, uy, ay, ax0;
 432         int             exp, i0, ind0, exp0, yisint0, n_n;
 433 
 434 #ifndef NOPOWFIX
 435         if ( stridex == 0 )
 436         {
 437                 unsigned        hx = *(unsigned*)px;
 438 
 439                 if ( (hx >= 0x00800000) &&   /* x not zero or subnormal              */
 440                 (hx < 0x7f800000) &&         /* x not inf, nan or negative sign bit  */
 441                 (hx != 0x3f800000) )            /* x not 1                              */
 442                 {
 443                         __vpowfx( n, px, py, stridey, pz, stridez );
 444                         return;
 445                 }
 446         }
 447 #endif
 448 
 449         while ( n > 0 )
 450         {
 451                 n_n = 0;
 452                 spx = px;
 453                 spy = py;
 454                 spz = pz;
 455                 for ( ; n > 0 ; n-- )
 456                 {
 457                         uy = *(unsigned int*)py;
 458                         ux = *(unsigned int*)px;
 459                         ay = uy & 0x7fffffff;
 460                         ax0 = ux & 0x7fffffff;
 461                         sx = ux >> 31;
 462                         yisint0 = 0;    /* Y - non-integer */
 463 
 464                         /* |X| or |Y| = Inf,Nan */
 465                         if ( ax0 >= 0x7f800000 || ay >= 0x7f800000 )
 466                         {
 467                                 if ( ay == 0 )
 468                                         RETURN( 1.0f )  /* pow(X,0) */
 469                                 /* |X| or |Y| = Nan */
 470                                 if ( ax0 > 0x7f800000 || ay > 0x7f800000 )
 471                                         RETURN ( *px + *py )
 472                                 if ( ay == 0x7f800000 )         /* |Y| = Inf */
 473                                 {
 474                                         float fy;
 475                                         if ( ax0 == 0x3f800000 )
 476                                                 fy = *py - *py;         /* +-1 ** +-Inf = NaN */
 477                                         else
 478                                                 fy = ( (ax0 < 0x3f800000) != (uy >> 31) ) ? 0.0f : *(float*) &ay;
 479                                         RETURN( fy )
 480                                 }
 481                                 if ( sx )       /* X = -Inf */
 482                                 {
 483                                         exp = ay >> 23;
 484                                         if ( exp >= 0x97 )   /* |Y| >= 2^24 */
 485                                                 yisint0 = 2;    /* Y - even */
 486                                         else if ( exp >= 0x7f )      /* |Y| >= 1 */
 487                                         {
 488                                                 i0 = ay >> ((0x7f + 23) - exp);
 489                                                 if ( (i0 << ((0x7f + 23) - exp)) == ay )
 490                                                         yisint0 = 2 - (i0 & 1);
 491                                         }
 492                                 }
 493                                 if ( uy >> 31 )
 494                                         ax0 = 0;
 495                                 ax0 += yisint0 << 31;
 496                                 RETURN( *(float*)&ax0 )
 497                         }
 498 
 499                         if ( (int)ux < 0x00800000 )  /* X = denormal or negative */
 500                         {
 501                                 if ( ay == 0 )
 502                                         RETURN( 1.0f )  /* pow(X,0) */
 503                                 exp0 = (ax0 >> 23) - 127;
 504 
 505                                 if ( (int)ax0 < 0x00800000 ) /* X = denormal */
 506                                 {
 507                                         *((float*) &ax0) = (float) (int)ax0;
 508                                         exp0 = (ax0 >> 23) - (127 + 149);
 509                                 }
 510 
 511                                 if ( (int)ux <= 0 )  /* X <= 0 */
 512                                 {
 513                                         exp = ay >> 23;
 514                                         if ( exp >= 0x97 )   /* |Y| >= 2^24 */
 515                                                 yisint0 = 2;    /* Y - even */
 516                                         else if ( exp >= 0x7f )      /* |Y| >= 1 */
 517                                         {
 518                                                 i0 = ay >> ((0x7f + 23) - exp);
 519                                                 if ( (i0 << ((0x7f + 23) - exp)) == ay )
 520                                                         yisint0 = 2 - (i0 & 1);
 521                                         }
 522 
 523                                         if ( ax0 == 0 )         /* pow(0,Y) */
 524                                         {
 525                                                 float fy;
 526                                                 fy = (uy >> 31) ? 1.0f / 0.0f : 0.0f;
 527                                                 if ( sx & yisint0 )
 528                                                         fy = -fy;
 529                                                 RETURN( fy )
 530                                         }
 531 
 532                                         if ( yisint0 == 0 )     /* pow(neg,non-integer) */
 533                                                 RETURN( 0.0f / 0.0f )   /* NaN */
 534                                 }
 535 
 536                                 /* perform yy0 = 256*log2(xi)*yi */
 537                                 ax0 &= 0x007fffff;
 538                                 i0 = (ax0 + 0x8000) & 0xffff0000;
 539                                 ind0 = i0 >> 15;
 540                                 i0 = ax0 - i0;
 541                                 y0 = (double) i0 * __TBL_log2f[ind0 + 1];
 542                                 yy0 = __TBL_log2f[ind0] + (double) (exp0 << 8);
 543                                 yy0 += (((KA3 * y0 + KA2) * y0 + KA1) * y0 + KA0) * y0;
 544                                 yy0 = (double)py[0] * yy0;
 545 
 546                                 /* perform 2 ** (yy0/256) */
 547                                 if ( yy0 >= HTHRESH )
 548                                         yy0 = HTHRESH;
 549                                 if ( yy0 <= LTHRESH )
 550                                         yy0 = LTHRESH;
 551                                 ind0 = (int) yy0;
 552                                 y0 = yy0 - (double)ind0;
 553                                 yy0 = (KB2 * y0 + KB1) * y0 + DONE;
 554                                 di0 = ((long long)((ind0 >> 8) + (yisint0 << 11))) << 52;
 555                                 di0 += ((long long*)__TBL_exp2f)[ind0 & 255];
 556                                 RETURN( (float) (yy0 * *(double*)&di0) )
 557                         }
 558                         px += stridex;
 559                         py += stridey;
 560                         pz += stridez;
 561                         n_n++;
 562                 }
 563                 if ( n_n > 0 )
 564                         __vpowf_n( n_n, spx, stridex, spy, stridey, spz, stridez );
 565         }
 566 }
 567 
 568 
 569 static void
 570 __vpowf_n( int n, float * restrict px, int stridex, float * restrict py,
 571         int stridey, float * restrict pz, int stridez )
 572 {
 573         double          y0, yy0;
 574         double          di0;
 575         int             ind0, i0, exp0;
 576         unsigned        ax0;
 577         double          y1, yy1;
 578         double          di1;
 579         int             ind1, i1, exp1;
 580         unsigned        ax1;
 581         double          y2, yy2;
 582         double          di2;
 583         int             ind2, i2, exp2;
 584         unsigned        ax2;
 585 
 586         for ( ; n > 2 ; n -= 3 )
 587         {
 588                 /* perform yy0 = 256*log2(xi)*yi */
 589                 ax0 = ((int*)px)[0];
 590                 px += stridex;
 591                 ax1 = ((int*)px)[0];
 592                 px += stridex;
 593                 ax2 = ((int*)px)[0];
 594                 px += stridex;
 595                 exp0 = ((ax0 & 0x7fffffff) >> 23) - 127;
 596                 exp1 = ((ax1 & 0x7fffffff) >> 23) - 127;
 597                 exp2 = ((ax2 & 0x7fffffff) >> 23) - 127;
 598                 ax0 &= 0x007fffff;
 599                 ax1 &= 0x007fffff;
 600                 ax2 &= 0x007fffff;
 601                 i0 = (ax0 + 0x8000) & 0xffff0000;
 602                 i1 = (ax1 + 0x8000) & 0xffff0000;
 603                 i2 = (ax2 + 0x8000) & 0xffff0000;
 604                 ind0 = i0 >> 15;
 605                 ind1 = i1 >> 15;
 606                 ind2 = i2 >> 15;
 607                 i0 = ax0 - i0;
 608                 i1 = ax1 - i1;
 609                 i2 = ax2 - i2;
 610                 y0 = (double) i0 * __TBL_log2f[ind0 + 1];
 611                 y1 = (double) i1 * __TBL_log2f[ind1 + 1];
 612                 y2 = (double) i2 * __TBL_log2f[ind2 + 1];
 613                 yy0 = __TBL_log2f[ind0] + (double) (exp0 << 8);
 614                 yy1 = __TBL_log2f[ind1] + (double) (exp1 << 8);
 615                 yy2 = __TBL_log2f[ind2] + (double) (exp2 << 8);
 616                 yy0 += (((KA3 * y0 + KA2) * y0 + KA1) * y0 + KA0) * y0;
 617                 yy1 += (((KA3 * y1 + KA2) * y1 + KA1) * y1 + KA0) * y1;
 618                 yy2 += (((KA3 * y2 + KA2) * y2 + KA1) * y2 + KA0) * y2;
 619                 yy0 = (double)py[0] * yy0;
 620                 py += stridey;
 621                 yy1 = (double)py[0] * yy1;
 622                 py += stridey;
 623                 yy2 = (double)py[0] * yy2;
 624                 py += stridey;
 625 
 626                 /* perform 2 ** (yy0/256) */
 627                 if ( yy0 >= HTHRESH )
 628                         yy0 = HTHRESH;
 629                 if ( yy0 <= LTHRESH )
 630                         yy0 = LTHRESH;
 631                 if ( yy1 >= HTHRESH )
 632                         yy1 = HTHRESH;
 633                 if ( yy1 <= LTHRESH )
 634                         yy1 = LTHRESH;
 635                 if ( yy2 >= HTHRESH )
 636                         yy2 = HTHRESH;
 637                 if ( yy2 <= LTHRESH )
 638                         yy2 = LTHRESH;
 639 
 640                 ind0 = (int) yy0;
 641                 ind1 = (int) yy1;
 642                 ind2 = (int) yy2;
 643                 y0 = yy0 - (double)ind0;
 644                 y1 = yy1 - (double)ind1;
 645                 y2 = yy2 - (double)ind2;
 646                 yy0 = (KB2 * y0 + KB1) * y0 + DONE;
 647                 yy1 = (KB2 * y1 + KB1) * y1 + DONE;
 648                 yy2 = (KB2 * y2 + KB1) * y2 + DONE;
 649                 di0 = (__TBL_expfb + 150)[ind0 >> 8];
 650                 di1 = (__TBL_expfb + 150)[ind1 >> 8];
 651                 di2 = (__TBL_expfb + 150)[ind2 >> 8];
 652                 di0 *= __TBL_exp2f[ind0 & 255];
 653                 di1 *= __TBL_exp2f[ind1 & 255];
 654                 di2 *= __TBL_exp2f[ind2 & 255];
 655                 pz[0] = (float) (yy0 * di0);
 656                 pz += stridez;
 657                 pz[0] = (float) (yy1 * di1);
 658                 pz += stridez;
 659                 pz[0] = (float) (yy2 * di2);
 660                 pz += stridez;
 661         }
 662 
 663         for ( ; n > 0 ; n-- )
 664         {
 665                 /* perform yy0 = 256*log2(xi)*yi */
 666                 ax0 = ((int*)px)[0];
 667                 exp0 = ((ax0 & 0x7fffffff) >> 23) - 127;
 668                 ax0 &= 0x007fffff;
 669                 i0 = (ax0 + 0x8000) & 0xffff0000;
 670                 ind0 = i0 >> 15;
 671                 i0 = ax0 - i0;
 672                 y0 = (double) i0 * __TBL_log2f[ind0 + 1];
 673                 yy0 = __TBL_log2f[ind0] + (double) (exp0 << 8);
 674                 yy0 += (((KA3 * y0 + KA2) * y0 + KA1) * y0 + KA0) * y0;
 675                 yy0 = (double)py[0] * yy0;
 676 
 677                 /* perform 2 ** (yy0/256) */
 678                 if ( yy0 >= HTHRESH )
 679                         yy0 = HTHRESH;
 680                 if ( yy0 <= LTHRESH )
 681                         yy0 = LTHRESH;
 682                 ind0 = (int) yy0;
 683                 y0 = yy0 - (double)ind0;
 684                 yy0 = (KB2 * y0 + KB1) * y0 + DONE;
 685                 di0 = (__TBL_expfb + 150)[ind0 >> 8];
 686                 di0 *= __TBL_exp2f[ind0 & 255];
 687                 pz[0] = (float) (yy0 * di0);
 688                 px += stridex;
 689                 py += stridey;
 690                 pz += stridez;
 691         }
 692 }
 693 
 694 
 695 static void
 696 __vpowfx( int n, float * restrict px, float * restrict py,
 697         int stridey, float * restrict pz, int stridez )
 698 {
 699         float           *spy, *spz;
 700         double          yy, y0;
 701         int             ind0, exp0, i0, n_n;
 702         unsigned        ux, ax, ax0, uy, ay;
 703 
 704         /* perform yy = 256*log2(xi)*yi */
 705         ux = *(unsigned int*)px;
 706         ax = ux & 0x7fffffff;
 707         exp0 = (ax >> 23) - 127;
 708         ax0 = ux & 0x007fffff;
 709         i0 = (ax0 + 0x8000) & 0xffff0000;
 710         ind0 = i0 >> 15;
 711         i0 = ax0 - i0;
 712         y0 = (double) i0 * __TBL_log2f[ind0 + 1];
 713         yy = __TBL_log2f[ind0] + (double) (exp0 << 8);
 714         yy += (((KA3 * y0 + KA2) * y0 + KA1) * y0 + KA0) * y0;
 715 
 716         while ( n > 0 )
 717         {
 718                 n_n = 0;
 719                 spy = py;
 720                 spz = pz;
 721                 for ( ; n > 0 ; n-- )
 722                 {
 723                         uy = *(unsigned int*)py;
 724                         ay = uy & 0x7fffffff;
 725 
 726                         if ( ay >= 0x7f800000 )              /* |Y| = Inf or Nan */
 727                         {
 728                                 float fy;
 729                                 if ( ay > 0x7f800000 )
 730                                         fy = *py + *py; /* |Y| = Nan */
 731                                 else
 732                                         fy = ( (ax < 0x3f800000) != (uy >> 31) ) ? 0.0f : *(float*)&ay;
 733                                 *pz = fy;
 734                                 py += stridey;
 735                                 pz += stridez;
 736                                 if ( n_n == 0 )
 737                                 {
 738                                         spy = py;
 739                                         spz = pz;
 740                                         continue;
 741                                 }
 742                                 n--;
 743                                 break;
 744                         }
 745                         py += stridey;
 746                         pz += stridez;
 747                         n_n++;
 748                 }
 749                 if ( n_n > 0 )
 750                         __vpowfx_n( n_n, yy, spy, stridey, spz, stridez );
 751         }
 752 }
 753 
 754 
 755 static void
 756 __vpowfx_n( int n, double yy, float * restrict py,
 757         int stridey, float * restrict pz, int stridez )
 758 {
 759         double          y0, yy0, di0;
 760         double          y1, yy1, di1;
 761         double          y2, yy2, di2;
 762         int             ind0, ind1, ind2;
 763 
 764         for ( ; n > 2 ; n-= 3 )
 765         {
 766                 /* perform 2 ** (yy/256) */
 767                 yy0 = (double)py[0] * yy;
 768                 py += stridey;
 769                 yy1 = (double)py[0] * yy;
 770                 py += stridey;
 771                 yy2 = (double)py[0] * yy;
 772                 py += stridey;
 773                 if ( yy0 >= HTHRESH )
 774                         yy0 = HTHRESH;
 775                 if ( yy0 <= LTHRESH )
 776                         yy0 = LTHRESH;
 777                 if ( yy1 >= HTHRESH )
 778                         yy1 = HTHRESH;
 779                 if ( yy1 <= LTHRESH )
 780                         yy1 = LTHRESH;
 781                 if ( yy2 >= HTHRESH )
 782                         yy2 = HTHRESH;
 783                 if ( yy2 <= LTHRESH )
 784                         yy2 = LTHRESH;
 785                 ind0 = (int) yy0;
 786                 ind1 = (int) yy1;
 787                 ind2 = (int) yy2;
 788                 y0 = yy0 - (double)ind0;
 789                 y1 = yy1 - (double)ind1;
 790                 y2 = yy2 - (double)ind2;
 791                 yy0 = (KB2 * y0 + KB1) * y0 + DONE;
 792                 yy1 = (KB2 * y1 + KB1) * y1 + DONE;
 793                 yy2 = (KB2 * y2 + KB1) * y2 + DONE;
 794                 di0 = (__TBL_expfb + 150)[ind0 >> 8];
 795                 di1 = (__TBL_expfb + 150)[ind1 >> 8];
 796                 di2 = (__TBL_expfb + 150)[ind2 >> 8];
 797                 di0 *= __TBL_exp2f[ind0 & 255];
 798                 di1 *= __TBL_exp2f[ind1 & 255];
 799                 di2 *= __TBL_exp2f[ind2 & 255];
 800                 pz[0] = (float) (yy0 * di0);
 801                 pz += stridez;
 802                 pz[0] = (float) (yy1 * di1);
 803                 pz += stridez;
 804                 pz[0] = (float) (yy2 * di2);
 805                 pz += stridez;
 806         }
 807         for ( ; n > 0 ; n-- )
 808         {
 809                 /* perform 2 ** (yy/256) */
 810                 yy0 = (double)py[0] * yy;
 811                 if ( yy0 >= HTHRESH )
 812                         yy0 = HTHRESH;
 813                 if ( yy0 <= LTHRESH )
 814                         yy0 = LTHRESH;
 815                 ind0 = (int) yy0;
 816                 y0 = yy0 - (double)ind0;
 817                 yy0 = (KB2 * y0 + KB1) * y0 + DONE;
 818                 di0 = (__TBL_expfb + 150)[ind0 >> 8];
 819                 di0 *= __TBL_exp2f[ind0 & 255];
 820                 pz[0] = (float) (yy0 * di0);
 821                 py += stridey;
 822                 pz += stridez;
 823         }
 824 }