| File: | jdk/src/hotspot/share/runtime/sharedRuntimeTrig.cpp |
| Warning: | line 475, column 17 The left operand of '==' is a garbage value due to array index out of bounds |
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| 1 | /* | |||
| 2 | * Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved. | |||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |||
| 4 | * | |||
| 5 | * This code is free software; you can redistribute it and/or modify it | |||
| 6 | * under the terms of the GNU General Public License version 2 only, as | |||
| 7 | * published by the Free Software Foundation. | |||
| 8 | * | |||
| 9 | * This code is distributed in the hope that it will be useful, but WITHOUT | |||
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |||
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |||
| 12 | * version 2 for more details (a copy is included in the LICENSE file that | |||
| 13 | * accompanied this code). | |||
| 14 | * | |||
| 15 | * You should have received a copy of the GNU General Public License version | |||
| 16 | * 2 along with this work; if not, write to the Free Software Foundation, | |||
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |||
| 18 | * | |||
| 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |||
| 20 | * or visit www.oracle.com if you need additional information or have any | |||
| 21 | * questions. | |||
| 22 | * | |||
| 23 | */ | |||
| 24 | ||||
| 25 | #include "precompiled.hpp" | |||
| 26 | #include "jni.h" | |||
| 27 | #include "runtime/interfaceSupport.inline.hpp" | |||
| 28 | #include "runtime/sharedRuntime.hpp" | |||
| 29 | #include "runtime/sharedRuntimeMath.hpp" | |||
| 30 | ||||
| 31 | // This file contains copies of the fdlibm routines used by | |||
| 32 | // StrictMath. It turns out that it is almost always required to use | |||
| 33 | // these runtime routines; the Intel CPU doesn't meet the Java | |||
| 34 | // specification for sin/cos outside a certain limited argument range, | |||
| 35 | // and the SPARC CPU doesn't appear to have sin/cos instructions. It | |||
| 36 | // also turns out that avoiding the indirect call through function | |||
| 37 | // pointer out to libjava.so in SharedRuntime speeds these routines up | |||
| 38 | // by roughly 15% on both Win32/x86 and Solaris/SPARC. | |||
| 39 | ||||
| 40 | /* | |||
| 41 | * __kernel_rem_pio2(x,y,e0,nx,prec,ipio2) | |||
| 42 | * double x[],y[]; int e0,nx,prec; int ipio2[]; | |||
| 43 | * | |||
| 44 | * __kernel_rem_pio2 return the last three digits of N with | |||
| 45 | * y = x - N*pi/2 | |||
| 46 | * so that |y| < pi/2. | |||
| 47 | * | |||
| 48 | * The method is to compute the integer (mod 8) and fraction parts of | |||
| 49 | * (2/pi)*x without doing the full multiplication. In general we | |||
| 50 | * skip the part of the product that are known to be a huge integer ( | |||
| 51 | * more accurately, = 0 mod 8 ). Thus the number of operations are | |||
| 52 | * independent of the exponent of the input. | |||
| 53 | * | |||
| 54 | * (2/pi) is represented by an array of 24-bit integers in ipio2[]. | |||
| 55 | * | |||
| 56 | * Input parameters: | |||
| 57 | * x[] The input value (must be positive) is broken into nx | |||
| 58 | * pieces of 24-bit integers in double precision format. | |||
| 59 | * x[i] will be the i-th 24 bit of x. The scaled exponent | |||
| 60 | * of x[0] is given in input parameter e0 (i.e., x[0]*2^e0 | |||
| 61 | * match x's up to 24 bits. | |||
| 62 | * | |||
| 63 | * Example of breaking a double positive z into x[0]+x[1]+x[2]: | |||
| 64 | * e0 = ilogb(z)-23 | |||
| 65 | * z = scalbn(z,-e0) | |||
| 66 | * for i = 0,1,2 | |||
| 67 | * x[i] = floor(z) | |||
| 68 | * z = (z-x[i])*2**24 | |||
| 69 | * | |||
| 70 | * | |||
| 71 | * y[] ouput result in an array of double precision numbers. | |||
| 72 | * The dimension of y[] is: | |||
| 73 | * 24-bit precision 1 | |||
| 74 | * 53-bit precision 2 | |||
| 75 | * 64-bit precision 2 | |||
| 76 | * 113-bit precision 3 | |||
| 77 | * The actual value is the sum of them. Thus for 113-bit | |||
| 78 | * precsion, one may have to do something like: | |||
| 79 | * | |||
| 80 | * long double t,w,r_head, r_tail; | |||
| 81 | * t = (long double)y[2] + (long double)y[1]; | |||
| 82 | * w = (long double)y[0]; | |||
| 83 | * r_head = t+w; | |||
| 84 | * r_tail = w - (r_head - t); | |||
| 85 | * | |||
| 86 | * e0 The exponent of x[0] | |||
| 87 | * | |||
| 88 | * nx dimension of x[] | |||
| 89 | * | |||
| 90 | * prec an interger indicating the precision: | |||
| 91 | * 0 24 bits (single) | |||
| 92 | * 1 53 bits (double) | |||
| 93 | * 2 64 bits (extended) | |||
| 94 | * 3 113 bits (quad) | |||
| 95 | * | |||
| 96 | * ipio2[] | |||
| 97 | * integer array, contains the (24*i)-th to (24*i+23)-th | |||
| 98 | * bit of 2/pi after binary point. The corresponding | |||
| 99 | * floating value is | |||
| 100 | * | |||
| 101 | * ipio2[i] * 2^(-24(i+1)). | |||
| 102 | * | |||
| 103 | * External function: | |||
| 104 | * double scalbn(), floor(); | |||
| 105 | * | |||
| 106 | * | |||
| 107 | * Here is the description of some local variables: | |||
| 108 | * | |||
| 109 | * jk jk+1 is the initial number of terms of ipio2[] needed | |||
| 110 | * in the computation. The recommended value is 2,3,4, | |||
| 111 | * 6 for single, double, extended,and quad. | |||
| 112 | * | |||
| 113 | * jz local integer variable indicating the number of | |||
| 114 | * terms of ipio2[] used. | |||
| 115 | * | |||
| 116 | * jx nx - 1 | |||
| 117 | * | |||
| 118 | * jv index for pointing to the suitable ipio2[] for the | |||
| 119 | * computation. In general, we want | |||
| 120 | * ( 2^e0*x[0] * ipio2[jv-1]*2^(-24jv) )/8 | |||
| 121 | * is an integer. Thus | |||
| 122 | * e0-3-24*jv >= 0 or (e0-3)/24 >= jv | |||
| 123 | * Hence jv = max(0,(e0-3)/24). | |||
| 124 | * | |||
| 125 | * jp jp+1 is the number of terms in PIo2[] needed, jp = jk. | |||
| 126 | * | |||
| 127 | * q[] double array with integral value, representing the | |||
| 128 | * 24-bits chunk of the product of x and 2/pi. | |||
| 129 | * | |||
| 130 | * q0 the corresponding exponent of q[0]. Note that the | |||
| 131 | * exponent for q[i] would be q0-24*i. | |||
| 132 | * | |||
| 133 | * PIo2[] double precision array, obtained by cutting pi/2 | |||
| 134 | * into 24 bits chunks. | |||
| 135 | * | |||
| 136 | * f[] ipio2[] in floating point | |||
| 137 | * | |||
| 138 | * iq[] integer array by breaking up q[] in 24-bits chunk. | |||
| 139 | * | |||
| 140 | * fq[] final product of x*(2/pi) in fq[0],..,fq[jk] | |||
| 141 | * | |||
| 142 | * ih integer. If >0 it indicates q[] is >= 0.5, hence | |||
| 143 | * it also indicates the *sign* of the result. | |||
| 144 | * | |||
| 145 | */ | |||
| 146 | ||||
| 147 | ||||
| 148 | /* | |||
| 149 | * Constants: | |||
| 150 | * The hexadecimal values are the intended ones for the following | |||
| 151 | * constants. The decimal values may be used, provided that the | |||
| 152 | * compiler will convert from decimal to binary accurately enough | |||
| 153 | * to produce the hexadecimal values shown. | |||
| 154 | */ | |||
| 155 | ||||
| 156 | ||||
| 157 | static const int init_jk[] = {2,3,4,6}; /* initial value for jk */ | |||
| 158 | ||||
| 159 | static const double PIo2[] = { | |||
| 160 | 1.57079625129699707031e+00, /* 0x3FF921FB, 0x40000000 */ | |||
| 161 | 7.54978941586159635335e-08, /* 0x3E74442D, 0x00000000 */ | |||
| 162 | 5.39030252995776476554e-15, /* 0x3CF84698, 0x80000000 */ | |||
| 163 | 3.28200341580791294123e-22, /* 0x3B78CC51, 0x60000000 */ | |||
| 164 | 1.27065575308067607349e-29, /* 0x39F01B83, 0x80000000 */ | |||
| 165 | 1.22933308981111328932e-36, /* 0x387A2520, 0x40000000 */ | |||
| 166 | 2.73370053816464559624e-44, /* 0x36E38222, 0x80000000 */ | |||
| 167 | 2.16741683877804819444e-51, /* 0x3569F31D, 0x00000000 */ | |||
| 168 | }; | |||
| 169 | ||||
| 170 | static const double | |||
| 171 | zeroB = 0.0, | |||
| 172 | one = 1.0, | |||
| 173 | two24B = 1.67772160000000000000e+07, /* 0x41700000, 0x00000000 */ | |||
| 174 | twon24 = 5.96046447753906250000e-08; /* 0x3E700000, 0x00000000 */ | |||
| 175 | ||||
| 176 | static int __kernel_rem_pio2(double *x, double *y, int e0, int nx, int prec, const int *ipio2) { | |||
| 177 | int jz,jx,jv,jp,jk,carry,n,iq[20],i,j,k,m,q0,ih; | |||
| 178 | double z,fw,f[20],fq[20],q[20]; | |||
| 179 | ||||
| 180 | /* initialize jk*/ | |||
| 181 | jk = init_jk[prec]; | |||
| 182 | jp = jk; | |||
| 183 | ||||
| 184 | /* determine jx,jv,q0, note that 3>q0 */ | |||
| 185 | jx = nx-1; | |||
| 186 | jv = (e0-3)/24; if(jv<0) jv=0; | |||
| 187 | q0 = e0-24*(jv+1); | |||
| 188 | ||||
| 189 | /* set up f[0] to f[jx+jk] where f[jx+jk] = ipio2[jv+jk] */ | |||
| 190 | j = jv-jx; m = jx+jk; | |||
| 191 | for(i=0;i<=m;i++,j++) f[i] = (j<0)? zeroB : (double) ipio2[j]; | |||
| 192 | ||||
| 193 | /* compute q[0],q[1],...q[jk] */ | |||
| 194 | for (i=0;i<=jk;i++) { | |||
| 195 | for(j=0,fw=0.0;j<=jx;j++) fw += x[j]*f[jx+i-j]; q[i] = fw; | |||
| 196 | } | |||
| 197 | ||||
| 198 | jz = jk; | |||
| 199 | recompute: | |||
| 200 | /* distill q[] into iq[] reversingly */ | |||
| 201 | for(i=0,j=jz,z=q[jz];j>0;i++,j--) { | |||
| 202 | fw = (double)((int)(twon24* z)); | |||
| 203 | iq[i] = (int)(z-two24B*fw); | |||
| 204 | z = q[j-1]+fw; | |||
| 205 | } | |||
| 206 | ||||
| 207 | /* compute n */ | |||
| 208 | z = scalbnA(z,q0); /* actual value of z */ | |||
| 209 | z -= 8.0*floor(z*0.125); /* trim off integer >= 8 */ | |||
| 210 | n = (int) z; | |||
| 211 | z -= (double)n; | |||
| 212 | ih = 0; | |||
| 213 | if(q0>0) { /* need iq[jz-1] to determine n */ | |||
| 214 | i = (iq[jz-1]>>(24-q0)); n += i; | |||
| 215 | iq[jz-1] -= i<<(24-q0); | |||
| 216 | ih = iq[jz-1]>>(23-q0); | |||
| 217 | } | |||
| 218 | else if(q0==0) ih = iq[jz-1]>>23; | |||
| 219 | else if(z>=0.5) ih=2; | |||
| 220 | ||||
| 221 | if(ih>0) { /* q > 0.5 */ | |||
| 222 | n += 1; carry = 0; | |||
| 223 | for(i=0;i<jz ;i++) { /* compute 1-q */ | |||
| 224 | j = iq[i]; | |||
| 225 | if(carry==0) { | |||
| 226 | if(j!=0) { | |||
| 227 | carry = 1; iq[i] = 0x1000000- j; | |||
| 228 | } | |||
| 229 | } else iq[i] = 0xffffff - j; | |||
| 230 | } | |||
| 231 | if(q0>0) { /* rare case: chance is 1 in 12 */ | |||
| 232 | switch(q0) { | |||
| 233 | case 1: | |||
| 234 | iq[jz-1] &= 0x7fffff; break; | |||
| 235 | case 2: | |||
| 236 | iq[jz-1] &= 0x3fffff; break; | |||
| 237 | } | |||
| 238 | } | |||
| 239 | if(ih==2) { | |||
| 240 | z = one - z; | |||
| 241 | if(carry!=0) z -= scalbnA(one,q0); | |||
| 242 | } | |||
| 243 | } | |||
| 244 | ||||
| 245 | /* check if recomputation is needed */ | |||
| 246 | if(z==zeroB) { | |||
| 247 | j = 0; | |||
| 248 | for (i=jz-1;i>=jk;i--) j |= iq[i]; | |||
| 249 | if(j==0) { /* need recomputation */ | |||
| 250 | for(k=1;iq[jk-k]==0;k++); /* k = no. of terms needed */ | |||
| 251 | ||||
| 252 | for(i=jz+1;i<=jz+k;i++) { /* add q[jz+1] to q[jz+k] */ | |||
| 253 | f[jx+i] = (double) ipio2[jv+i]; | |||
| 254 | for(j=0,fw=0.0;j<=jx;j++) fw += x[j]*f[jx+i-j]; | |||
| 255 | q[i] = fw; | |||
| 256 | } | |||
| 257 | jz += k; | |||
| 258 | goto recompute; | |||
| 259 | } | |||
| 260 | } | |||
| 261 | ||||
| 262 | /* chop off zero terms */ | |||
| 263 | if(z==0.0) { | |||
| 264 | jz -= 1; q0 -= 24; | |||
| 265 | while(iq[jz]==0) { jz--; q0-=24;} | |||
| 266 | } else { /* break z into 24-bit if necessary */ | |||
| 267 | z = scalbnA(z,-q0); | |||
| 268 | if(z>=two24B) { | |||
| 269 | fw = (double)((int)(twon24*z)); | |||
| 270 | iq[jz] = (int)(z-two24B*fw); | |||
| 271 | jz += 1; q0 += 24; | |||
| 272 | iq[jz] = (int) fw; | |||
| 273 | } else iq[jz] = (int) z ; | |||
| 274 | } | |||
| 275 | ||||
| 276 | /* convert integer "bit" chunk to floating-point value */ | |||
| 277 | fw = scalbnA(one,q0); | |||
| 278 | for(i=jz;i>=0;i--) { | |||
| 279 | q[i] = fw*(double)iq[i]; fw*=twon24; | |||
| 280 | } | |||
| 281 | ||||
| 282 | /* compute PIo2[0,...,jp]*q[jz,...,0] */ | |||
| 283 | for(i=jz;i>=0;i--) { | |||
| 284 | for(fw=0.0,k=0;k<=jp&&k<=jz-i;k++) fw += PIo2[k]*q[i+k]; | |||
| 285 | fq[jz-i] = fw; | |||
| 286 | } | |||
| 287 | ||||
| 288 | /* compress fq[] into y[] */ | |||
| 289 | switch(prec) { | |||
| 290 | case 0: | |||
| 291 | fw = 0.0; | |||
| 292 | for (i=jz;i>=0;i--) fw += fq[i]; | |||
| 293 | y[0] = (ih==0)? fw: -fw; | |||
| 294 | break; | |||
| 295 | case 1: | |||
| 296 | case 2: | |||
| 297 | fw = 0.0; | |||
| 298 | for (i=jz;i>=0;i--) fw += fq[i]; | |||
| 299 | y[0] = (ih==0)? fw: -fw; | |||
| 300 | fw = fq[0]-fw; | |||
| 301 | for (i=1;i<=jz;i++) fw += fq[i]; | |||
| 302 | y[1] = (ih==0)? fw: -fw; | |||
| 303 | break; | |||
| 304 | case 3: /* painful */ | |||
| 305 | for (i=jz;i>0;i--) { | |||
| 306 | fw = fq[i-1]+fq[i]; | |||
| 307 | fq[i] += fq[i-1]-fw; | |||
| 308 | fq[i-1] = fw; | |||
| 309 | } | |||
| 310 | for (i=jz;i>1;i--) { | |||
| 311 | fw = fq[i-1]+fq[i]; | |||
| 312 | fq[i] += fq[i-1]-fw; | |||
| 313 | fq[i-1] = fw; | |||
| 314 | } | |||
| 315 | for (fw=0.0,i=jz;i>=2;i--) fw += fq[i]; | |||
| 316 | if(ih==0) { | |||
| 317 | y[0] = fq[0]; y[1] = fq[1]; y[2] = fw; | |||
| 318 | } else { | |||
| 319 | y[0] = -fq[0]; y[1] = -fq[1]; y[2] = -fw; | |||
| 320 | } | |||
| 321 | } | |||
| 322 | return n&7; | |||
| 323 | } | |||
| 324 | ||||
| 325 | ||||
| 326 | /* | |||
| 327 | * ==================================================== | |||
| 328 | * Copyright (c) 1993 Oracle and/or its affiliates. All rights reserved. | |||
| 329 | * | |||
| 330 | * Developed at SunPro, a Sun Microsystems, Inc. business. | |||
| 331 | * Permission to use, copy, modify, and distribute this | |||
| 332 | * software is freely granted, provided that this notice | |||
| 333 | * is preserved. | |||
| 334 | * ==================================================== | |||
| 335 | * | |||
| 336 | */ | |||
| 337 | ||||
| 338 | /* __ieee754_rem_pio2(x,y) | |||
| 339 | * | |||
| 340 | * return the remainder of x rem pi/2 in y[0]+y[1] | |||
| 341 | * use __kernel_rem_pio2() | |||
| 342 | */ | |||
| 343 | ||||
| 344 | /* | |||
| 345 | * Table of constants for 2/pi, 396 Hex digits (476 decimal) of 2/pi | |||
| 346 | */ | |||
| 347 | static const int two_over_pi[] = { | |||
| 348 | 0xA2F983, 0x6E4E44, 0x1529FC, 0x2757D1, 0xF534DD, 0xC0DB62, | |||
| 349 | 0x95993C, 0x439041, 0xFE5163, 0xABDEBB, 0xC561B7, 0x246E3A, | |||
| 350 | 0x424DD2, 0xE00649, 0x2EEA09, 0xD1921C, 0xFE1DEB, 0x1CB129, | |||
| 351 | 0xA73EE8, 0x8235F5, 0x2EBB44, 0x84E99C, 0x7026B4, 0x5F7E41, | |||
| 352 | 0x3991D6, 0x398353, 0x39F49C, 0x845F8B, 0xBDF928, 0x3B1FF8, | |||
| 353 | 0x97FFDE, 0x05980F, 0xEF2F11, 0x8B5A0A, 0x6D1F6D, 0x367ECF, | |||
| 354 | 0x27CB09, 0xB74F46, 0x3F669E, 0x5FEA2D, 0x7527BA, 0xC7EBE5, | |||
| 355 | 0xF17B3D, 0x0739F7, 0x8A5292, 0xEA6BFB, 0x5FB11F, 0x8D5D08, | |||
| 356 | 0x560330, 0x46FC7B, 0x6BABF0, 0xCFBC20, 0x9AF436, 0x1DA9E3, | |||
| 357 | 0x91615E, 0xE61B08, 0x659985, 0x5F14A0, 0x68408D, 0xFFD880, | |||
| 358 | 0x4D7327, 0x310606, 0x1556CA, 0x73A8C9, 0x60E27B, 0xC08C6B, | |||
| 359 | }; | |||
| 360 | ||||
| 361 | static const int npio2_hw[] = { | |||
| 362 | 0x3FF921FB, 0x400921FB, 0x4012D97C, 0x401921FB, 0x401F6A7A, 0x4022D97C, | |||
| 363 | 0x4025FDBB, 0x402921FB, 0x402C463A, 0x402F6A7A, 0x4031475C, 0x4032D97C, | |||
| 364 | 0x40346B9C, 0x4035FDBB, 0x40378FDB, 0x403921FB, 0x403AB41B, 0x403C463A, | |||
| 365 | 0x403DD85A, 0x403F6A7A, 0x40407E4C, 0x4041475C, 0x4042106C, 0x4042D97C, | |||
| 366 | 0x4043A28C, 0x40446B9C, 0x404534AC, 0x4045FDBB, 0x4046C6CB, 0x40478FDB, | |||
| 367 | 0x404858EB, 0x404921FB, | |||
| 368 | }; | |||
| 369 | ||||
| 370 | /* | |||
| 371 | * invpio2: 53 bits of 2/pi | |||
| 372 | * pio2_1: first 33 bit of pi/2 | |||
| 373 | * pio2_1t: pi/2 - pio2_1 | |||
| 374 | * pio2_2: second 33 bit of pi/2 | |||
| 375 | * pio2_2t: pi/2 - (pio2_1+pio2_2) | |||
| 376 | * pio2_3: third 33 bit of pi/2 | |||
| 377 | * pio2_3t: pi/2 - (pio2_1+pio2_2+pio2_3) | |||
| 378 | */ | |||
| 379 | ||||
| 380 | static const double | |||
| 381 | zeroA = 0.00000000000000000000e+00, /* 0x00000000, 0x00000000 */ | |||
| 382 | half = 5.00000000000000000000e-01, /* 0x3FE00000, 0x00000000 */ | |||
| 383 | two24A = 1.67772160000000000000e+07, /* 0x41700000, 0x00000000 */ | |||
| 384 | invpio2 = 6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */ | |||
| 385 | pio2_1 = 1.57079632673412561417e+00, /* 0x3FF921FB, 0x54400000 */ | |||
| 386 | pio2_1t = 6.07710050650619224932e-11, /* 0x3DD0B461, 0x1A626331 */ | |||
| 387 | pio2_2 = 6.07710050630396597660e-11, /* 0x3DD0B461, 0x1A600000 */ | |||
| 388 | pio2_2t = 2.02226624879595063154e-21, /* 0x3BA3198A, 0x2E037073 */ | |||
| 389 | pio2_3 = 2.02226624871116645580e-21, /* 0x3BA3198A, 0x2E000000 */ | |||
| 390 | pio2_3t = 8.47842766036889956997e-32; /* 0x397B839A, 0x252049C1 */ | |||
| 391 | ||||
| 392 | static int __ieee754_rem_pio2(double x, double *y) { | |||
| 393 | double z,w,t,r,fn; | |||
| 394 | double tx[3]; | |||
| 395 | int e0,i,j,nx,n,ix,hx,i0; | |||
| 396 | ||||
| 397 | i0 = ((*(int*)&two24A)>>30)^1; /* high word index */ | |||
| 398 | hx = *(i0+(int*)&x); /* high word of x */ | |||
| 399 | ix = hx&0x7fffffff; | |||
| 400 | if(ix<=0x3fe921fb) /* |x| ~<= pi/4 , no need for reduction */ | |||
| 401 | {y[0] = x; y[1] = 0; return 0;} | |||
| 402 | if(ix<0x4002d97c) { /* |x| < 3pi/4, special case with n=+-1 */ | |||
| 403 | if(hx>0) { | |||
| 404 | z = x - pio2_1; | |||
| 405 | if(ix!=0x3ff921fb) { /* 33+53 bit pi is good enough */ | |||
| 406 | y[0] = z - pio2_1t; | |||
| 407 | y[1] = (z-y[0])-pio2_1t; | |||
| 408 | } else { /* near pi/2, use 33+33+53 bit pi */ | |||
| 409 | z -= pio2_2; | |||
| 410 | y[0] = z - pio2_2t; | |||
| 411 | y[1] = (z-y[0])-pio2_2t; | |||
| 412 | } | |||
| 413 | return 1; | |||
| 414 | } else { /* negative x */ | |||
| 415 | z = x + pio2_1; | |||
| 416 | if(ix!=0x3ff921fb) { /* 33+53 bit pi is good enough */ | |||
| 417 | y[0] = z + pio2_1t; | |||
| 418 | y[1] = (z-y[0])+pio2_1t; | |||
| 419 | } else { /* near pi/2, use 33+33+53 bit pi */ | |||
| 420 | z += pio2_2; | |||
| 421 | y[0] = z + pio2_2t; | |||
| 422 | y[1] = (z-y[0])+pio2_2t; | |||
| 423 | } | |||
| 424 | return -1; | |||
| 425 | } | |||
| 426 | } | |||
| 427 | if(ix<=0x413921fb) { /* |x| ~<= 2^19*(pi/2), medium size */ | |||
| 428 | t = fabsd(x); | |||
| 429 | n = (int) (t*invpio2+half); | |||
| 430 | fn = (double)n; | |||
| 431 | r = t-fn*pio2_1; | |||
| 432 | w = fn*pio2_1t; /* 1st round good to 85 bit */ | |||
| 433 | if(n<32&&ix!=npio2_hw[n-1]) { | |||
| 434 | y[0] = r-w; /* quick check no cancellation */ | |||
| 435 | } else { | |||
| 436 | j = ix>>20; | |||
| 437 | y[0] = r-w; | |||
| 438 | i = j-(((*(i0+(int*)&y[0]))>>20)&0x7ff); | |||
| 439 | if(i>16) { /* 2nd iteration needed, good to 118 */ | |||
| 440 | t = r; | |||
| 441 | w = fn*pio2_2; | |||
| 442 | r = t-w; | |||
| 443 | w = fn*pio2_2t-((t-r)-w); | |||
| 444 | y[0] = r-w; | |||
| 445 | i = j-(((*(i0+(int*)&y[0]))>>20)&0x7ff); | |||
| 446 | if(i>49) { /* 3rd iteration need, 151 bits acc */ | |||
| 447 | t = r; /* will cover all possible cases */ | |||
| 448 | w = fn*pio2_3; | |||
| 449 | r = t-w; | |||
| 450 | w = fn*pio2_3t-((t-r)-w); | |||
| 451 | y[0] = r-w; | |||
| 452 | } | |||
| 453 | } | |||
| 454 | } | |||
| 455 | y[1] = (r-y[0])-w; | |||
| 456 | if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;} | |||
| 457 | else return n; | |||
| 458 | } | |||
| 459 | /* | |||
| 460 | * all other (large) arguments | |||
| 461 | */ | |||
| 462 | if(ix>=0x7ff00000) { /* x is inf or NaN */ | |||
| 463 | y[0]=y[1]=x-x; return 0; | |||
| 464 | } | |||
| 465 | /* set z = scalbn(|x|,ilogb(x)-23) */ | |||
| 466 | *(1-i0+(int*)&z) = *(1-i0+(int*)&x); | |||
| 467 | e0 = (ix>>20)-1046; /* e0 = ilogb(z)-23; */ | |||
| 468 | *(i0+(int*)&z) = ix - (e0<<20); | |||
| 469 | for(i=0;i<2;i++) { | |||
| 470 | tx[i] = (double)((int)(z)); | |||
| 471 | z = (z-tx[i])*two24A; | |||
| 472 | } | |||
| 473 | tx[2] = z; | |||
| 474 | nx = 3; | |||
| 475 | while(tx[nx-1]==zeroA) nx--; /* skip zero term */ | |||
| ||||
| 476 | n = __kernel_rem_pio2(tx,y,e0,nx,2,two_over_pi); | |||
| 477 | if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;} | |||
| 478 | return n; | |||
| 479 | } | |||
| 480 | ||||
| 481 | ||||
| 482 | /* __kernel_sin( x, y, iy) | |||
| 483 | * kernel sin function on [-pi/4, pi/4], pi/4 ~ 0.7854 | |||
| 484 | * Input x is assumed to be bounded by ~pi/4 in magnitude. | |||
| 485 | * Input y is the tail of x. | |||
| 486 | * Input iy indicates whether y is 0. (if iy=0, y assume to be 0). | |||
| 487 | * | |||
| 488 | * Algorithm | |||
| 489 | * 1. Since sin(-x) = -sin(x), we need only to consider positive x. | |||
| 490 | * 2. if x < 2^-27 (hx<0x3e400000 0), return x with inexact if x!=0. | |||
| 491 | * 3. sin(x) is approximated by a polynomial of degree 13 on | |||
| 492 | * [0,pi/4] | |||
| 493 | * 3 13 | |||
| 494 | * sin(x) ~ x + S1*x + ... + S6*x | |||
| 495 | * where | |||
| 496 | * | |||
| 497 | * |sin(x) 2 4 6 8 10 12 | -58 | |||
| 498 | * |----- - (1+S1*x +S2*x +S3*x +S4*x +S5*x +S6*x )| <= 2 | |||
| 499 | * | x | | |||
| 500 | * | |||
| 501 | * 4. sin(x+y) = sin(x) + sin'(x')*y | |||
| 502 | * ~ sin(x) + (1-x*x/2)*y | |||
| 503 | * For better accuracy, let | |||
| 504 | * 3 2 2 2 2 | |||
| 505 | * r = x *(S2+x *(S3+x *(S4+x *(S5+x *S6)))) | |||
| 506 | * then 3 2 | |||
| 507 | * sin(x) = x + (S1*x + (x *(r-y/2)+y)) | |||
| 508 | */ | |||
| 509 | ||||
| 510 | static const double | |||
| 511 | S1 = -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */ | |||
| 512 | S2 = 8.33333333332248946124e-03, /* 0x3F811111, 0x1110F8A6 */ | |||
| 513 | S3 = -1.98412698298579493134e-04, /* 0xBF2A01A0, 0x19C161D5 */ | |||
| 514 | S4 = 2.75573137070700676789e-06, /* 0x3EC71DE3, 0x57B1FE7D */ | |||
| 515 | S5 = -2.50507602534068634195e-08, /* 0xBE5AE5E6, 0x8A2B9CEB */ | |||
| 516 | S6 = 1.58969099521155010221e-10; /* 0x3DE5D93A, 0x5ACFD57C */ | |||
| 517 | ||||
| 518 | static double __kernel_sin(double x, double y, int iy) | |||
| 519 | { | |||
| 520 | double z,r,v; | |||
| 521 | int ix; | |||
| 522 | ix = high(x)&0x7fffffff; /* high word of x */ | |||
| 523 | if(ix<0x3e400000) /* |x| < 2**-27 */ | |||
| 524 | {if((int)x==0) return x;} /* generate inexact */ | |||
| 525 | z = x*x; | |||
| 526 | v = z*x; | |||
| 527 | r = S2+z*(S3+z*(S4+z*(S5+z*S6))); | |||
| 528 | if(iy==0) return x+v*(S1+z*r); | |||
| 529 | else return x-((z*(half*y-v*r)-y)-v*S1); | |||
| 530 | } | |||
| 531 | ||||
| 532 | /* | |||
| 533 | * __kernel_cos( x, y ) | |||
| 534 | * kernel cos function on [-pi/4, pi/4], pi/4 ~ 0.785398164 | |||
| 535 | * Input x is assumed to be bounded by ~pi/4 in magnitude. | |||
| 536 | * Input y is the tail of x. | |||
| 537 | * | |||
| 538 | * Algorithm | |||
| 539 | * 1. Since cos(-x) = cos(x), we need only to consider positive x. | |||
| 540 | * 2. if x < 2^-27 (hx<0x3e400000 0), return 1 with inexact if x!=0. | |||
| 541 | * 3. cos(x) is approximated by a polynomial of degree 14 on | |||
| 542 | * [0,pi/4] | |||
| 543 | * 4 14 | |||
| 544 | * cos(x) ~ 1 - x*x/2 + C1*x + ... + C6*x | |||
| 545 | * where the remez error is | |||
| 546 | * | |||
| 547 | * | 2 4 6 8 10 12 14 | -58 | |||
| 548 | * |cos(x)-(1-.5*x +C1*x +C2*x +C3*x +C4*x +C5*x +C6*x )| <= 2 | |||
| 549 | * | | | |||
| 550 | * | |||
| 551 | * 4 6 8 10 12 14 | |||
| 552 | * 4. let r = C1*x +C2*x +C3*x +C4*x +C5*x +C6*x , then | |||
| 553 | * cos(x) = 1 - x*x/2 + r | |||
| 554 | * since cos(x+y) ~ cos(x) - sin(x)*y | |||
| 555 | * ~ cos(x) - x*y, | |||
| 556 | * a correction term is necessary in cos(x) and hence | |||
| 557 | * cos(x+y) = 1 - (x*x/2 - (r - x*y)) | |||
| 558 | * For better accuracy when x > 0.3, let qx = |x|/4 with | |||
| 559 | * the last 32 bits mask off, and if x > 0.78125, let qx = 0.28125. | |||
| 560 | * Then | |||
| 561 | * cos(x+y) = (1-qx) - ((x*x/2-qx) - (r-x*y)). | |||
| 562 | * Note that 1-qx and (x*x/2-qx) is EXACT here, and the | |||
| 563 | * magnitude of the latter is at least a quarter of x*x/2, | |||
| 564 | * thus, reducing the rounding error in the subtraction. | |||
| 565 | */ | |||
| 566 | ||||
| 567 | static const double | |||
| 568 | C1 = 4.16666666666666019037e-02, /* 0x3FA55555, 0x5555554C */ | |||
| 569 | C2 = -1.38888888888741095749e-03, /* 0xBF56C16C, 0x16C15177 */ | |||
| 570 | C3 = 2.48015872894767294178e-05, /* 0x3EFA01A0, 0x19CB1590 */ | |||
| 571 | C4 = -2.75573143513906633035e-07, /* 0xBE927E4F, 0x809C52AD */ | |||
| 572 | C5 = 2.08757232129817482790e-09, /* 0x3E21EE9E, 0xBDB4B1C4 */ | |||
| 573 | C6 = -1.13596475577881948265e-11; /* 0xBDA8FAE9, 0xBE8838D4 */ | |||
| 574 | ||||
| 575 | static double __kernel_cos(double x, double y) | |||
| 576 | { | |||
| 577 | double a,h,z,r,qx=0; | |||
| 578 | int ix; | |||
| 579 | ix = high(x)&0x7fffffff; /* ix = |x|'s high word*/ | |||
| 580 | if(ix<0x3e400000) { /* if x < 2**27 */ | |||
| 581 | if(((int)x)==0) return one; /* generate inexact */ | |||
| 582 | } | |||
| 583 | z = x*x; | |||
| 584 | r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6))))); | |||
| 585 | if(ix < 0x3FD33333) /* if |x| < 0.3 */ | |||
| 586 | return one - (0.5*z - (z*r - x*y)); | |||
| 587 | else { | |||
| 588 | if(ix > 0x3fe90000) { /* x > 0.78125 */ | |||
| 589 | qx = 0.28125; | |||
| 590 | } else { | |||
| 591 | set_high(&qx, ix-0x00200000); /* x/4 */ | |||
| 592 | set_low(&qx, 0); | |||
| 593 | } | |||
| 594 | h = 0.5*z-qx; | |||
| 595 | a = one-qx; | |||
| 596 | return a - (h - (z*r-x*y)); | |||
| 597 | } | |||
| 598 | } | |||
| 599 | ||||
| 600 | /* __kernel_tan( x, y, k ) | |||
| 601 | * kernel tan function on [-pi/4, pi/4], pi/4 ~ 0.7854 | |||
| 602 | * Input x is assumed to be bounded by ~pi/4 in magnitude. | |||
| 603 | * Input y is the tail of x. | |||
| 604 | * Input k indicates whether tan (if k=1) or | |||
| 605 | * -1/tan (if k= -1) is returned. | |||
| 606 | * | |||
| 607 | * Algorithm | |||
| 608 | * 1. Since tan(-x) = -tan(x), we need only to consider positive x. | |||
| 609 | * 2. if x < 2^-28 (hx<0x3e300000 0), return x with inexact if x!=0. | |||
| 610 | * 3. tan(x) is approximated by a odd polynomial of degree 27 on | |||
| 611 | * [0,0.67434] | |||
| 612 | * 3 27 | |||
| 613 | * tan(x) ~ x + T1*x + ... + T13*x | |||
| 614 | * where | |||
| 615 | * | |||
| 616 | * |tan(x) 2 4 26 | -59.2 | |||
| 617 | * |----- - (1+T1*x +T2*x +.... +T13*x )| <= 2 | |||
| 618 | * | x | | |||
| 619 | * | |||
| 620 | * Note: tan(x+y) = tan(x) + tan'(x)*y | |||
| 621 | * ~ tan(x) + (1+x*x)*y | |||
| 622 | * Therefore, for better accuracy in computing tan(x+y), let | |||
| 623 | * 3 2 2 2 2 | |||
| 624 | * r = x *(T2+x *(T3+x *(...+x *(T12+x *T13)))) | |||
| 625 | * then | |||
| 626 | * 3 2 | |||
| 627 | * tan(x+y) = x + (T1*x + (x *(r+y)+y)) | |||
| 628 | * | |||
| 629 | * 4. For x in [0.67434,pi/4], let y = pi/4 - x, then | |||
| 630 | * tan(x) = tan(pi/4-y) = (1-tan(y))/(1+tan(y)) | |||
| 631 | * = 1 - 2*(tan(y) - (tan(y)^2)/(1+tan(y))) | |||
| 632 | */ | |||
| 633 | ||||
| 634 | static const double | |||
| 635 | pio4 = 7.85398163397448278999e-01, /* 0x3FE921FB, 0x54442D18 */ | |||
| 636 | pio4lo= 3.06161699786838301793e-17, /* 0x3C81A626, 0x33145C07 */ | |||
| 637 | T[] = { | |||
| 638 | 3.33333333333334091986e-01, /* 0x3FD55555, 0x55555563 */ | |||
| 639 | 1.33333333333201242699e-01, /* 0x3FC11111, 0x1110FE7A */ | |||
| 640 | 5.39682539762260521377e-02, /* 0x3FABA1BA, 0x1BB341FE */ | |||
| 641 | 2.18694882948595424599e-02, /* 0x3F9664F4, 0x8406D637 */ | |||
| 642 | 8.86323982359930005737e-03, /* 0x3F8226E3, 0xE96E8493 */ | |||
| 643 | 3.59207910759131235356e-03, /* 0x3F6D6D22, 0xC9560328 */ | |||
| 644 | 1.45620945432529025516e-03, /* 0x3F57DBC8, 0xFEE08315 */ | |||
| 645 | 5.88041240820264096874e-04, /* 0x3F4344D8, 0xF2F26501 */ | |||
| 646 | 2.46463134818469906812e-04, /* 0x3F3026F7, 0x1A8D1068 */ | |||
| 647 | 7.81794442939557092300e-05, /* 0x3F147E88, 0xA03792A6 */ | |||
| 648 | 7.14072491382608190305e-05, /* 0x3F12B80F, 0x32F0A7E9 */ | |||
| 649 | -1.85586374855275456654e-05, /* 0xBEF375CB, 0xDB605373 */ | |||
| 650 | 2.59073051863633712884e-05, /* 0x3EFB2A70, 0x74BF7AD4 */ | |||
| 651 | }; | |||
| 652 | ||||
| 653 | static double __kernel_tan(double x, double y, int iy) | |||
| 654 | { | |||
| 655 | double z,r,v,w,s; | |||
| 656 | int ix,hx; | |||
| 657 | hx = high(x); /* high word of x */ | |||
| 658 | ix = hx&0x7fffffff; /* high word of |x| */ | |||
| 659 | if(ix<0x3e300000) { /* x < 2**-28 */ | |||
| 660 | if((int)x==0) { /* generate inexact */ | |||
| 661 | if (((ix | low(x)) | (iy + 1)) == 0) | |||
| 662 | return one / fabsd(x); | |||
| 663 | else { | |||
| 664 | if (iy == 1) | |||
| 665 | return x; | |||
| 666 | else { /* compute -1 / (x+y) carefully */ | |||
| 667 | double a, t; | |||
| 668 | ||||
| 669 | z = w = x + y; | |||
| 670 | set_low(&z, 0); | |||
| 671 | v = y - (z - x); | |||
| 672 | t = a = -one / w; | |||
| 673 | set_low(&t, 0); | |||
| 674 | s = one + t * z; | |||
| 675 | return t + a * (s + t * v); | |||
| 676 | } | |||
| 677 | } | |||
| 678 | } | |||
| 679 | } | |||
| 680 | if(ix>=0x3FE59428) { /* |x|>=0.6744 */ | |||
| 681 | if(hx<0) {x = -x; y = -y;} | |||
| 682 | z = pio4-x; | |||
| 683 | w = pio4lo-y; | |||
| 684 | x = z+w; y = 0.0; | |||
| 685 | } | |||
| 686 | z = x*x; | |||
| 687 | w = z*z; | |||
| 688 | /* Break x^5*(T[1]+x^2*T[2]+...) into | |||
| 689 | * x^5(T[1]+x^4*T[3]+...+x^20*T[11]) + | |||
| 690 | * x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12])) | |||
| 691 | */ | |||
| 692 | r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11])))); | |||
| 693 | v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12]))))); | |||
| 694 | s = z*x; | |||
| 695 | r = y + z*(s*(r+v)+y); | |||
| 696 | r += T[0]*s; | |||
| 697 | w = x+r; | |||
| 698 | if(ix>=0x3FE59428) { | |||
| 699 | v = (double)iy; | |||
| 700 | return (double)(1-((hx>>30)&2))*(v-2.0*(x-(w*w/(w+v)-r))); | |||
| 701 | } | |||
| 702 | if(iy==1) return w; | |||
| 703 | else { /* if allow error up to 2 ulp, | |||
| 704 | simply return -1.0/(x+r) here */ | |||
| 705 | /* compute -1.0/(x+r) accurately */ | |||
| 706 | double a,t; | |||
| 707 | z = w; | |||
| 708 | set_low(&z, 0); | |||
| 709 | v = r-(z - x); /* z+v = r+x */ | |||
| 710 | t = a = -1.0/w; /* a = -1.0/w */ | |||
| 711 | set_low(&t, 0); | |||
| 712 | s = 1.0+t*z; | |||
| 713 | return t+a*(s+t*v); | |||
| 714 | } | |||
| 715 | } | |||
| 716 | ||||
| 717 | ||||
| 718 | //---------------------------------------------------------------------- | |||
| 719 | // | |||
| 720 | // Routines for new sin/cos implementation | |||
| 721 | // | |||
| 722 | //---------------------------------------------------------------------- | |||
| 723 | ||||
| 724 | /* sin(x) | |||
| 725 | * Return sine function of x. | |||
| 726 | * | |||
| 727 | * kernel function: | |||
| 728 | * __kernel_sin ... sine function on [-pi/4,pi/4] | |||
| 729 | * __kernel_cos ... cose function on [-pi/4,pi/4] | |||
| 730 | * __ieee754_rem_pio2 ... argument reduction routine | |||
| 731 | * | |||
| 732 | * Method. | |||
| 733 | * Let S,C and T denote the sin, cos and tan respectively on | |||
| 734 | * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2 | |||
| 735 | * in [-pi/4 , +pi/4], and let n = k mod 4. | |||
| 736 | * We have | |||
| 737 | * | |||
| 738 | * n sin(x) cos(x) tan(x) | |||
| 739 | * ---------------------------------------------------------- | |||
| 740 | * 0 S C T | |||
| 741 | * 1 C -S -1/T | |||
| 742 | * 2 -S -C T | |||
| 743 | * 3 -C S -1/T | |||
| 744 | * ---------------------------------------------------------- | |||
| 745 | * | |||
| 746 | * Special cases: | |||
| 747 | * Let trig be any of sin, cos, or tan. | |||
| 748 | * trig(+-INF) is NaN, with signals; | |||
| 749 | * trig(NaN) is that NaN; | |||
| 750 | * | |||
| 751 | * Accuracy: | |||
| 752 | * TRIG(x) returns trig(x) nearly rounded | |||
| 753 | */ | |||
| 754 | ||||
| 755 | JRT_LEAF(jdouble, SharedRuntime::dsin(jdouble x))jdouble SharedRuntime::dsin(jdouble x) { NoHandleMark __hm; ; os::verify_stack_alignment(); NoSafepointVerifier __nsv; | |||
| 756 | double y[2],z=0.0; | |||
| 757 | int n, ix; | |||
| 758 | ||||
| 759 | /* High word of x. */ | |||
| 760 | ix = high(x); | |||
| 761 | ||||
| 762 | /* |x| ~< pi/4 */ | |||
| 763 | ix &= 0x7fffffff; | |||
| 764 | if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0); | |||
| 765 | ||||
| 766 | /* sin(Inf or NaN) is NaN */ | |||
| 767 | else if (ix>=0x7ff00000) return x-x; | |||
| 768 | ||||
| 769 | /* argument reduction needed */ | |||
| 770 | else { | |||
| 771 | n = __ieee754_rem_pio2(x,y); | |||
| 772 | switch(n&3) { | |||
| 773 | case 0: return __kernel_sin(y[0],y[1],1); | |||
| 774 | case 1: return __kernel_cos(y[0],y[1]); | |||
| 775 | case 2: return -__kernel_sin(y[0],y[1],1); | |||
| 776 | default: | |||
| 777 | return -__kernel_cos(y[0],y[1]); | |||
| 778 | } | |||
| 779 | } | |||
| 780 | JRT_END} | |||
| 781 | ||||
| 782 | /* cos(x) | |||
| 783 | * Return cosine function of x. | |||
| 784 | * | |||
| 785 | * kernel function: | |||
| 786 | * __kernel_sin ... sine function on [-pi/4,pi/4] | |||
| 787 | * __kernel_cos ... cosine function on [-pi/4,pi/4] | |||
| 788 | * __ieee754_rem_pio2 ... argument reduction routine | |||
| 789 | * | |||
| 790 | * Method. | |||
| 791 | * Let S,C and T denote the sin, cos and tan respectively on | |||
| 792 | * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2 | |||
| 793 | * in [-pi/4 , +pi/4], and let n = k mod 4. | |||
| 794 | * We have | |||
| 795 | * | |||
| 796 | * n sin(x) cos(x) tan(x) | |||
| 797 | * ---------------------------------------------------------- | |||
| 798 | * 0 S C T | |||
| 799 | * 1 C -S -1/T | |||
| 800 | * 2 -S -C T | |||
| 801 | * 3 -C S -1/T | |||
| 802 | * ---------------------------------------------------------- | |||
| 803 | * | |||
| 804 | * Special cases: | |||
| 805 | * Let trig be any of sin, cos, or tan. | |||
| 806 | * trig(+-INF) is NaN, with signals; | |||
| 807 | * trig(NaN) is that NaN; | |||
| 808 | * | |||
| 809 | * Accuracy: | |||
| 810 | * TRIG(x) returns trig(x) nearly rounded | |||
| 811 | */ | |||
| 812 | ||||
| 813 | JRT_LEAF(jdouble, SharedRuntime::dcos(jdouble x))jdouble SharedRuntime::dcos(jdouble x) { NoHandleMark __hm; ; os::verify_stack_alignment(); NoSafepointVerifier __nsv; | |||
| 814 | double y[2],z=0.0; | |||
| 815 | int n, ix; | |||
| 816 | ||||
| 817 | /* High word of x. */ | |||
| 818 | ix = high(x); | |||
| 819 | ||||
| 820 | /* |x| ~< pi/4 */ | |||
| 821 | ix &= 0x7fffffff; | |||
| 822 | if(ix <= 0x3fe921fb) return __kernel_cos(x,z); | |||
| 823 | ||||
| 824 | /* cos(Inf or NaN) is NaN */ | |||
| 825 | else if (ix>=0x7ff00000) return x-x; | |||
| 826 | ||||
| 827 | /* argument reduction needed */ | |||
| 828 | else { | |||
| 829 | n = __ieee754_rem_pio2(x,y); | |||
| 830 | switch(n&3) { | |||
| 831 | case 0: return __kernel_cos(y[0],y[1]); | |||
| 832 | case 1: return -__kernel_sin(y[0],y[1],1); | |||
| 833 | case 2: return -__kernel_cos(y[0],y[1]); | |||
| 834 | default: | |||
| 835 | return __kernel_sin(y[0],y[1],1); | |||
| 836 | } | |||
| 837 | } | |||
| 838 | JRT_END} | |||
| 839 | ||||
| 840 | /* tan(x) | |||
| 841 | * Return tangent function of x. | |||
| 842 | * | |||
| 843 | * kernel function: | |||
| 844 | * __kernel_tan ... tangent function on [-pi/4,pi/4] | |||
| 845 | * __ieee754_rem_pio2 ... argument reduction routine | |||
| 846 | * | |||
| 847 | * Method. | |||
| 848 | * Let S,C and T denote the sin, cos and tan respectively on | |||
| 849 | * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2 | |||
| 850 | * in [-pi/4 , +pi/4], and let n = k mod 4. | |||
| 851 | * We have | |||
| 852 | * | |||
| 853 | * n sin(x) cos(x) tan(x) | |||
| 854 | * ---------------------------------------------------------- | |||
| 855 | * 0 S C T | |||
| 856 | * 1 C -S -1/T | |||
| 857 | * 2 -S -C T | |||
| 858 | * 3 -C S -1/T | |||
| 859 | * ---------------------------------------------------------- | |||
| 860 | * | |||
| 861 | * Special cases: | |||
| 862 | * Let trig be any of sin, cos, or tan. | |||
| 863 | * trig(+-INF) is NaN, with signals; | |||
| 864 | * trig(NaN) is that NaN; | |||
| 865 | * | |||
| 866 | * Accuracy: | |||
| 867 | * TRIG(x) returns trig(x) nearly rounded | |||
| 868 | */ | |||
| 869 | ||||
| 870 | JRT_LEAF(jdouble, SharedRuntime::dtan(jdouble x))jdouble SharedRuntime::dtan(jdouble x) { NoHandleMark __hm; ; os::verify_stack_alignment(); NoSafepointVerifier __nsv; | |||
| 871 | double y[2],z=0.0; | |||
| 872 | int n, ix; | |||
| 873 | ||||
| 874 | /* High word of x. */ | |||
| 875 | ix = high(x); | |||
| 876 | ||||
| 877 | /* |x| ~< pi/4 */ | |||
| 878 | ix &= 0x7fffffff; | |||
| 879 | if(ix <= 0x3fe921fb) return __kernel_tan(x,z,1); | |||
| ||||
| 880 | ||||
| 881 | /* tan(Inf or NaN) is NaN */ | |||
| 882 | else if (ix>=0x7ff00000) return x-x; /* NaN */ | |||
| 883 | ||||
| 884 | /* argument reduction needed */ | |||
| 885 | else { | |||
| 886 | n = __ieee754_rem_pio2(x,y); | |||
| 887 | return __kernel_tan(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even | |||
| 888 | -1 -- n odd */ | |||
| 889 | } | |||
| 890 | JRT_END} |