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 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 23 */ 24 /* 25 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 26 * Use is subject to license terms. 27 */ 28 29 #pragma weak __atan2f = atan2f 30 31 #include "libm.h" 32 33 #if defined(__i386) && !defined(__amd64) 34 extern int __swapRP(int); 35 #endif 36 37 /* 38 * For i = 0, ..., 192, let x[i] be the double precision number whose 39 * high order 32 bits are 0x3f900000 + (i << 16) and whose low order 40 * 32 bits are zero. Then TBL[i] := atan(x[i]) to double precision. 41 */ 42 43 static const double TBL[] = { 44 1.56237286204768313e-02, 45 1.66000375562312640e-02, 46 1.75763148444955872e-02, 47 1.85525586258889763e-02, 48 1.95287670414137082e-02, 49 2.05049382324763683e-02, 50 2.14810703409090559e-02, 51 2.24571615089905717e-02, 52 2.34332098794675855e-02, 53 2.44092135955758099e-02, 54 2.53851708010611396e-02, 55 2.63610796402007873e-02, 56 2.73369382578244127e-02, 57 2.83127447993351995e-02, 58 2.92884974107309737e-02, 59 3.02641942386252458e-02, 60 3.12398334302682774e-02, 61 3.31909314971115949e-02, 62 3.51417768027967800e-02, 63 3.70923545503918164e-02, 64 3.90426499551669928e-02, 65 4.09926482452637811e-02, 66 4.29423346623621707e-02, 67 4.48916944623464972e-02, 68 4.68407129159696539e-02, 69 4.87893753095156174e-02, 70 5.07376669454602178e-02, 71 5.26855731431300420e-02, 72 5.46330792393594777e-02, 73 5.65801705891457105e-02, 74 5.85268325663017702e-02, 75 6.04730505641073168e-02, 76 6.24188099959573500e-02, 77 6.63088949198234884e-02, 78 7.01969710718705203e-02, 79 7.40829225490337306e-02, 80 7.79666338315423008e-02, 81 8.18479898030765457e-02, 82 8.57268757707448092e-02, 83 8.96031774848717461e-02, 84 9.34767811585894698e-02, 85 9.73475734872236709e-02, 86 1.01215441667466668e-01, 87 1.05080273416329528e-01, 88 1.08941956989865793e-01, 89 1.12800381201659389e-01, 90 1.16655435441069349e-01, 91 1.20507009691224562e-01, 92 1.24354994546761438e-01, 93 1.32039761614638762e-01, 94 1.39708874289163648e-01, 95 1.47361481088651630e-01, 96 1.54996741923940973e-01, 97 1.62613828597948568e-01, 98 1.70211925285474408e-01, 99 1.77790228992676075e-01, 100 1.85347949995694761e-01, 101 1.92884312257974672e-01, 102 2.00398553825878512e-01, 103 2.07889927202262986e-01, 104 2.15357699697738048e-01, 105 2.22801153759394521e-01, 106 2.30219587276843718e-01, 107 2.37612313865471242e-01, 108 2.44978663126864143e-01, 109 2.59629629408257512e-01, 110 2.74167451119658789e-01, 111 2.88587361894077410e-01, 112 3.02884868374971417e-01, 113 3.17055753209147029e-01, 114 3.31096076704132103e-01, 115 3.45002177207105132e-01, 116 3.58770670270572245e-01, 117 3.72398446676754202e-01, 118 3.85882669398073752e-01, 119 3.99220769575252543e-01, 120 4.12410441597387323e-01, 121 4.25449637370042266e-01, 122 4.38336559857957830e-01, 123 4.51069655988523499e-01, 124 4.63647609000806094e-01, 125 4.88333951056405535e-01, 126 5.12389460310737732e-01, 127 5.35811237960463704e-01, 128 5.58599315343562441e-01, 129 5.80756353567670414e-01, 130 6.02287346134964152e-01, 131 6.23199329934065904e-01, 132 6.43501108793284371e-01, 133 6.63202992706093286e-01, 134 6.82316554874748071e-01, 135 7.00854407884450192e-01, 136 7.18829999621624527e-01, 137 7.36257428981428097e-01, 138 7.53151280962194414e-01, 139 7.69526480405658297e-01, 140 7.85398163397448279e-01, 141 8.15691923316223422e-01, 142 8.44153986113171051e-01, 143 8.70903457075652976e-01, 144 8.96055384571343927e-01, 145 9.19719605350416858e-01, 146 9.42000040379463610e-01, 147 9.62994330680936206e-01, 148 9.82793723247329054e-01, 149 1.00148313569423464e+00, 150 1.01914134426634972e+00, 151 1.03584125300880014e+00, 152 1.05165021254837376e+00, 153 1.06663036531574362e+00, 154 1.08083900054116833e+00, 155 1.09432890732118993e+00, 156 1.10714871779409041e+00, 157 1.13095374397916038e+00, 158 1.15257199721566761e+00, 159 1.17227388112847630e+00, 160 1.19028994968253166e+00, 161 1.20681737028525249e+00, 162 1.22202532321098967e+00, 163 1.23605948947808186e+00, 164 1.24904577239825443e+00, 165 1.26109338225244039e+00, 166 1.27229739520871732e+00, 167 1.28274087974427076e+00, 168 1.29249666778978534e+00, 169 1.30162883400919616e+00, 170 1.31019393504755555e+00, 171 1.31824205101683711e+00, 172 1.32581766366803255e+00, 173 1.33970565959899957e+00, 174 1.35212738092095464e+00, 175 1.36330010035969384e+00, 176 1.37340076694501589e+00, 177 1.38257482149012589e+00, 178 1.39094282700241845e+00, 179 1.39860551227195762e+00, 180 1.40564764938026987e+00, 181 1.41214106460849531e+00, 182 1.41814699839963154e+00, 183 1.42371797140649403e+00, 184 1.42889927219073276e+00, 185 1.43373015248470903e+00, 186 1.43824479449822262e+00, 187 1.44247309910910193e+00, 188 1.44644133224813509e+00, 189 1.45368758222803240e+00, 190 1.46013910562100091e+00, 191 1.46591938806466282e+00, 192 1.47112767430373470e+00, 193 1.47584462045214027e+00, 194 1.48013643959415142e+00, 195 1.48405798811891154e+00, 196 1.48765509490645531e+00, 197 1.49096634108265924e+00, 198 1.49402443552511865e+00, 199 1.49685728913695626e+00, 200 1.49948886200960629e+00, 201 1.50193983749385196e+00, 202 1.50422816301907281e+00, 203 1.50636948736934317e+00, 204 1.50837751679893928e+00, 205 1.51204050407917401e+00, 206 1.51529782154917969e+00, 207 1.51821326518395483e+00, 208 1.52083793107295384e+00, 209 1.52321322351791322e+00, 210 1.52537304737331958e+00, 211 1.52734543140336587e+00, 212 1.52915374769630819e+00, 213 1.53081763967160667e+00, 214 1.53235373677370856e+00, 215 1.53377621092096650e+00, 216 1.53509721411557254e+00, 217 1.53632722579538861e+00, 218 1.53747533091664934e+00, 219 1.53854944435964280e+00, 220 1.53955649336462841e+00, 221 1.54139303859089161e+00, 222 1.54302569020147562e+00, 223 1.54448660954197448e+00, 224 1.54580153317597646e+00, 225 1.54699130060982659e+00, 226 1.54807296595325550e+00, 227 1.54906061995310385e+00, 228 1.54996600675867957e+00, 229 1.55079899282174605e+00, 230 1.55156792769518947e+00, 231 1.55227992472688747e+00, 232 1.55294108165534417e+00, 233 1.55355665560036682e+00, 234 1.55413120308095598e+00, 235 1.55466869295126031e+00, 236 1.55517259817441977e+00, 237 }; 238 239 static const double 240 pio4 = 7.8539816339744827900e-01, 241 pio2 = 1.5707963267948965580e+00, 242 negpi = -3.1415926535897931160e+00, 243 q1 = -3.3333333333296428046e-01, 244 q2 = 1.9999999186853752618e-01, 245 zero = 0.0; 246 247 static const float two24 = 16777216.0; 248 249 float 250 atan2f(float fy, float fx) 251 { 252 double a, t, s, dbase; 253 float x, y, base; 254 int i, k, hx, hy, ix, iy, sign; 255 #if defined(__i386) && !defined(__amd64) 256 int rp; 257 #endif 258 259 iy = *(int *)&fy; 260 ix = *(int *)&fx; 261 hy = iy & ~0x80000000; 262 hx = ix & ~0x80000000; 263 264 sign = 0; 265 if (hy > hx) { 266 x = fy; 267 y = fx; 268 i = hx; 269 hx = hy; 270 hy = i; 271 if (iy < 0) { 272 x = -x; 273 sign = 1; 274 } 275 if (ix < 0) { 276 y = -y; 277 a = pio2; 278 } else { 279 a = -pio2; 280 sign = 1 - sign; 281 } 282 } else { 283 y = fy; 284 x = fx; 285 if (iy < 0) { 286 y = -y; 287 sign = 1; 288 } 289 if (ix < 0) { 290 x = -x; 291 a = negpi; 292 sign = 1 - sign; 293 } else { 294 a = zero; 295 } 296 } 297 298 if (hx >= 0x7f800000 || hx - hy >= 0x0c800000) { 299 if (hx >= 0x7f800000) { 300 if (hx > 0x7f800000) /* nan */ 301 return (x * y); 302 else if (hy >= 0x7f800000) 303 a += pio4; 304 } else if ((int)a == 0) { 305 a = (double)y / x; 306 } 307 return ((float)((sign)? -a : a)); 308 } 309 310 if (hy < 0x00800000) { 311 if (hy == 0) 312 return ((float)((sign)? -a : a)); 313 /* scale subnormal y */ 314 y *= two24; 315 x *= two24; 316 hy = *(int *)&y; 317 hx = *(int *)&x; 318 } 319 320 #if defined(__i386) && !defined(__amd64) 321 rp = __swapRP(fp_extended); 322 #endif 323 k = (hy - hx + 0x3f800000) & 0xfff80000; 324 if (k >= 0x3c800000) { /* |y/x| >= 1/64 */ 325 *(int *)&base = k; 326 k = (k - 0x3c800000) >> 19; 327 a += TBL[k]; 328 } else { 329 /* 330 * For some reason this is faster on USIII than just 331 * doing t = y/x in this case. 332 */ 333 *(int *)&base = 0; 334 } 335 dbase = (double)base; 336 t = (y - x * dbase) / (x + y * dbase); 337 s = t * t; 338 a = (a + t) + t * s * (q1 + s * q2); 339 #if defined(__i386) && !defined(__amd64) 340 if (rp != fp_extended) 341 (void) __swapRP(rp); 342 #endif 343 return ((float)((sign)? -a : a)); 344 } 345