src/share/vm/runtime/sharedRuntimeTrig.cpp

Tue, 23 Nov 2010 13:22:55 -0800

author
stefank
date
Tue, 23 Nov 2010 13:22:55 -0800
changeset 2314
f95d63e2154a
parent 1907
c18cbe5936b8
child 6461
bdd155477289
permissions
-rw-r--r--

6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg

duke@435 1 /*
stefank@2314 2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435 4 *
duke@435 5 * This code is free software; you can redistribute it and/or modify it
duke@435 6 * under the terms of the GNU General Public License version 2 only, as
duke@435 7 * published by the Free Software Foundation.
duke@435 8 *
duke@435 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@435 13 * accompanied this code).
duke@435 14 *
duke@435 15 * You should have received a copy of the GNU General Public License version
duke@435 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@435 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435 18 *
trims@1907 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907 20 * or visit www.oracle.com if you need additional information or have any
trims@1907 21 * questions.
duke@435 22 *
duke@435 23 */
duke@435 24
stefank@2314 25 #include "precompiled.hpp"
stefank@2314 26 #include "prims/jni.h"
stefank@2314 27 #include "runtime/interfaceSupport.hpp"
stefank@2314 28 #include "runtime/sharedRuntime.hpp"
duke@435 29
duke@435 30 // This file contains copies of the fdlibm routines used by
duke@435 31 // StrictMath. It turns out that it is almost always required to use
duke@435 32 // these runtime routines; the Intel CPU doesn't meet the Java
duke@435 33 // specification for sin/cos outside a certain limited argument range,
duke@435 34 // and the SPARC CPU doesn't appear to have sin/cos instructions. It
duke@435 35 // also turns out that avoiding the indirect call through function
duke@435 36 // pointer out to libjava.so in SharedRuntime speeds these routines up
duke@435 37 // by roughly 15% on both Win32/x86 and Solaris/SPARC.
duke@435 38
duke@435 39 // Enabling optimizations in this file causes incorrect code to be
duke@435 40 // generated; can not figure out how to turn down optimization for one
duke@435 41 // file in the IDE on Windows
duke@435 42 #ifdef WIN32
duke@435 43 # pragma optimize ( "", off )
duke@435 44 #endif
duke@435 45
prr@1840 46 /* The above workaround now causes more problems with the latest MS compiler.
prr@1840 47 * Visual Studio 2010's /GS option tries to guard against buffer overruns.
prr@1840 48 * /GS is on by default if you specify optimizations, which we do globally
prr@1840 49 * via /W3 /O2. However the above selective turning off of optimizations means
prr@1840 50 * that /GS issues a warning "4748". And since we treat warnings as errors (/WX)
prr@1840 51 * then the compilation fails. There are several possible solutions
prr@1840 52 * (1) Remove that pragma above as obsolete with VS2010 - requires testing.
prr@1840 53 * (2) Stop treating warnings as errors - would be a backward step
prr@1840 54 * (3) Disable /GS - may help performance but you lose the security checks
prr@1840 55 * (4) Disable the warning with "#pragma warning( disable : 4748 )"
prr@1840 56 * (5) Disable planting the code with __declspec(safebuffers)
prr@1840 57 * I've opted for (5) although we should investigate the local performance
prr@1840 58 * benefits of (1) and global performance benefit of (3).
prr@1840 59 */
prr@1840 60 #if defined(WIN32) && (defined(_MSC_VER) && (_MSC_VER >= 1600))
prr@1840 61 #define SAFEBUF __declspec(safebuffers)
prr@1840 62 #else
prr@1840 63 #define SAFEBUF
prr@1840 64 #endif
prr@1840 65
duke@435 66 #include <math.h>
duke@435 67
duke@435 68 // VM_LITTLE_ENDIAN is #defined appropriately in the Makefiles
duke@435 69 // [jk] this is not 100% correct because the float word order may different
duke@435 70 // from the byte order (e.g. on ARM)
duke@435 71 #ifdef VM_LITTLE_ENDIAN
duke@435 72 # define __HI(x) *(1+(int*)&x)
duke@435 73 # define __LO(x) *(int*)&x
duke@435 74 #else
duke@435 75 # define __HI(x) *(int*)&x
duke@435 76 # define __LO(x) *(1+(int*)&x)
duke@435 77 #endif
duke@435 78
duke@435 79 static double copysignA(double x, double y) {
duke@435 80 __HI(x) = (__HI(x)&0x7fffffff)|(__HI(y)&0x80000000);
duke@435 81 return x;
duke@435 82 }
duke@435 83
duke@435 84 /*
duke@435 85 * scalbn (double x, int n)
duke@435 86 * scalbn(x,n) returns x* 2**n computed by exponent
duke@435 87 * manipulation rather than by actually performing an
duke@435 88 * exponentiation or a multiplication.
duke@435 89 */
duke@435 90
duke@435 91 static const double
duke@435 92 two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
duke@435 93 twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
duke@435 94 hugeX = 1.0e+300,
duke@435 95 tiny = 1.0e-300;
duke@435 96
duke@435 97 static double scalbnA (double x, int n) {
duke@435 98 int k,hx,lx;
duke@435 99 hx = __HI(x);
duke@435 100 lx = __LO(x);
duke@435 101 k = (hx&0x7ff00000)>>20; /* extract exponent */
duke@435 102 if (k==0) { /* 0 or subnormal x */
duke@435 103 if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
duke@435 104 x *= two54;
duke@435 105 hx = __HI(x);
duke@435 106 k = ((hx&0x7ff00000)>>20) - 54;
duke@435 107 if (n< -50000) return tiny*x; /*underflow*/
duke@435 108 }
duke@435 109 if (k==0x7ff) return x+x; /* NaN or Inf */
duke@435 110 k = k+n;
duke@435 111 if (k > 0x7fe) return hugeX*copysignA(hugeX,x); /* overflow */
duke@435 112 if (k > 0) /* normal result */
duke@435 113 {__HI(x) = (hx&0x800fffff)|(k<<20); return x;}
duke@435 114 if (k <= -54) {
duke@435 115 if (n > 50000) /* in case integer overflow in n+k */
duke@435 116 return hugeX*copysignA(hugeX,x); /*overflow*/
duke@435 117 else return tiny*copysignA(tiny,x); /*underflow*/
duke@435 118 }
duke@435 119 k += 54; /* subnormal result */
duke@435 120 __HI(x) = (hx&0x800fffff)|(k<<20);
duke@435 121 return x*twom54;
duke@435 122 }
duke@435 123
duke@435 124 /*
duke@435 125 * __kernel_rem_pio2(x,y,e0,nx,prec,ipio2)
duke@435 126 * double x[],y[]; int e0,nx,prec; int ipio2[];
duke@435 127 *
duke@435 128 * __kernel_rem_pio2 return the last three digits of N with
duke@435 129 * y = x - N*pi/2
duke@435 130 * so that |y| < pi/2.
duke@435 131 *
duke@435 132 * The method is to compute the integer (mod 8) and fraction parts of
duke@435 133 * (2/pi)*x without doing the full multiplication. In general we
duke@435 134 * skip the part of the product that are known to be a huge integer (
duke@435 135 * more accurately, = 0 mod 8 ). Thus the number of operations are
duke@435 136 * independent of the exponent of the input.
duke@435 137 *
duke@435 138 * (2/pi) is represented by an array of 24-bit integers in ipio2[].
duke@435 139 *
duke@435 140 * Input parameters:
duke@435 141 * x[] The input value (must be positive) is broken into nx
duke@435 142 * pieces of 24-bit integers in double precision format.
duke@435 143 * x[i] will be the i-th 24 bit of x. The scaled exponent
duke@435 144 * of x[0] is given in input parameter e0 (i.e., x[0]*2^e0
duke@435 145 * match x's up to 24 bits.
duke@435 146 *
duke@435 147 * Example of breaking a double positive z into x[0]+x[1]+x[2]:
duke@435 148 * e0 = ilogb(z)-23
duke@435 149 * z = scalbn(z,-e0)
duke@435 150 * for i = 0,1,2
duke@435 151 * x[i] = floor(z)
duke@435 152 * z = (z-x[i])*2**24
duke@435 153 *
duke@435 154 *
duke@435 155 * y[] ouput result in an array of double precision numbers.
duke@435 156 * The dimension of y[] is:
duke@435 157 * 24-bit precision 1
duke@435 158 * 53-bit precision 2
duke@435 159 * 64-bit precision 2
duke@435 160 * 113-bit precision 3
duke@435 161 * The actual value is the sum of them. Thus for 113-bit
duke@435 162 * precsion, one may have to do something like:
duke@435 163 *
duke@435 164 * long double t,w,r_head, r_tail;
duke@435 165 * t = (long double)y[2] + (long double)y[1];
duke@435 166 * w = (long double)y[0];
duke@435 167 * r_head = t+w;
duke@435 168 * r_tail = w - (r_head - t);
duke@435 169 *
duke@435 170 * e0 The exponent of x[0]
duke@435 171 *
duke@435 172 * nx dimension of x[]
duke@435 173 *
duke@435 174 * prec an interger indicating the precision:
duke@435 175 * 0 24 bits (single)
duke@435 176 * 1 53 bits (double)
duke@435 177 * 2 64 bits (extended)
duke@435 178 * 3 113 bits (quad)
duke@435 179 *
duke@435 180 * ipio2[]
duke@435 181 * integer array, contains the (24*i)-th to (24*i+23)-th
duke@435 182 * bit of 2/pi after binary point. The corresponding
duke@435 183 * floating value is
duke@435 184 *
duke@435 185 * ipio2[i] * 2^(-24(i+1)).
duke@435 186 *
duke@435 187 * External function:
duke@435 188 * double scalbn(), floor();
duke@435 189 *
duke@435 190 *
duke@435 191 * Here is the description of some local variables:
duke@435 192 *
duke@435 193 * jk jk+1 is the initial number of terms of ipio2[] needed
duke@435 194 * in the computation. The recommended value is 2,3,4,
duke@435 195 * 6 for single, double, extended,and quad.
duke@435 196 *
duke@435 197 * jz local integer variable indicating the number of
duke@435 198 * terms of ipio2[] used.
duke@435 199 *
duke@435 200 * jx nx - 1
duke@435 201 *
duke@435 202 * jv index for pointing to the suitable ipio2[] for the
duke@435 203 * computation. In general, we want
duke@435 204 * ( 2^e0*x[0] * ipio2[jv-1]*2^(-24jv) )/8
duke@435 205 * is an integer. Thus
duke@435 206 * e0-3-24*jv >= 0 or (e0-3)/24 >= jv
duke@435 207 * Hence jv = max(0,(e0-3)/24).
duke@435 208 *
duke@435 209 * jp jp+1 is the number of terms in PIo2[] needed, jp = jk.
duke@435 210 *
duke@435 211 * q[] double array with integral value, representing the
duke@435 212 * 24-bits chunk of the product of x and 2/pi.
duke@435 213 *
duke@435 214 * q0 the corresponding exponent of q[0]. Note that the
duke@435 215 * exponent for q[i] would be q0-24*i.
duke@435 216 *
duke@435 217 * PIo2[] double precision array, obtained by cutting pi/2
duke@435 218 * into 24 bits chunks.
duke@435 219 *
duke@435 220 * f[] ipio2[] in floating point
duke@435 221 *
duke@435 222 * iq[] integer array by breaking up q[] in 24-bits chunk.
duke@435 223 *
duke@435 224 * fq[] final product of x*(2/pi) in fq[0],..,fq[jk]
duke@435 225 *
duke@435 226 * ih integer. If >0 it indicats q[] is >= 0.5, hence
duke@435 227 * it also indicates the *sign* of the result.
duke@435 228 *
duke@435 229 */
duke@435 230
duke@435 231
duke@435 232 /*
duke@435 233 * Constants:
duke@435 234 * The hexadecimal values are the intended ones for the following
duke@435 235 * constants. The decimal values may be used, provided that the
duke@435 236 * compiler will convert from decimal to binary accurately enough
duke@435 237 * to produce the hexadecimal values shown.
duke@435 238 */
duke@435 239
duke@435 240
duke@435 241 static const int init_jk[] = {2,3,4,6}; /* initial value for jk */
duke@435 242
duke@435 243 static const double PIo2[] = {
duke@435 244 1.57079625129699707031e+00, /* 0x3FF921FB, 0x40000000 */
duke@435 245 7.54978941586159635335e-08, /* 0x3E74442D, 0x00000000 */
duke@435 246 5.39030252995776476554e-15, /* 0x3CF84698, 0x80000000 */
duke@435 247 3.28200341580791294123e-22, /* 0x3B78CC51, 0x60000000 */
duke@435 248 1.27065575308067607349e-29, /* 0x39F01B83, 0x80000000 */
duke@435 249 1.22933308981111328932e-36, /* 0x387A2520, 0x40000000 */
duke@435 250 2.73370053816464559624e-44, /* 0x36E38222, 0x80000000 */
duke@435 251 2.16741683877804819444e-51, /* 0x3569F31D, 0x00000000 */
duke@435 252 };
duke@435 253
duke@435 254 static const double
duke@435 255 zeroB = 0.0,
duke@435 256 one = 1.0,
duke@435 257 two24B = 1.67772160000000000000e+07, /* 0x41700000, 0x00000000 */
duke@435 258 twon24 = 5.96046447753906250000e-08; /* 0x3E700000, 0x00000000 */
duke@435 259
prr@1840 260 static SAFEBUF int __kernel_rem_pio2(double *x, double *y, int e0, int nx, int prec, const int *ipio2) {
duke@435 261 int jz,jx,jv,jp,jk,carry,n,iq[20],i,j,k,m,q0,ih;
duke@435 262 double z,fw,f[20],fq[20],q[20];
duke@435 263
duke@435 264 /* initialize jk*/
duke@435 265 jk = init_jk[prec];
duke@435 266 jp = jk;
duke@435 267
duke@435 268 /* determine jx,jv,q0, note that 3>q0 */
duke@435 269 jx = nx-1;
duke@435 270 jv = (e0-3)/24; if(jv<0) jv=0;
duke@435 271 q0 = e0-24*(jv+1);
duke@435 272
duke@435 273 /* set up f[0] to f[jx+jk] where f[jx+jk] = ipio2[jv+jk] */
duke@435 274 j = jv-jx; m = jx+jk;
duke@435 275 for(i=0;i<=m;i++,j++) f[i] = (j<0)? zeroB : (double) ipio2[j];
duke@435 276
duke@435 277 /* compute q[0],q[1],...q[jk] */
duke@435 278 for (i=0;i<=jk;i++) {
duke@435 279 for(j=0,fw=0.0;j<=jx;j++) fw += x[j]*f[jx+i-j]; q[i] = fw;
duke@435 280 }
duke@435 281
duke@435 282 jz = jk;
duke@435 283 recompute:
duke@435 284 /* distill q[] into iq[] reversingly */
duke@435 285 for(i=0,j=jz,z=q[jz];j>0;i++,j--) {
duke@435 286 fw = (double)((int)(twon24* z));
duke@435 287 iq[i] = (int)(z-two24B*fw);
duke@435 288 z = q[j-1]+fw;
duke@435 289 }
duke@435 290
duke@435 291 /* compute n */
duke@435 292 z = scalbnA(z,q0); /* actual value of z */
duke@435 293 z -= 8.0*floor(z*0.125); /* trim off integer >= 8 */
duke@435 294 n = (int) z;
duke@435 295 z -= (double)n;
duke@435 296 ih = 0;
duke@435 297 if(q0>0) { /* need iq[jz-1] to determine n */
duke@435 298 i = (iq[jz-1]>>(24-q0)); n += i;
duke@435 299 iq[jz-1] -= i<<(24-q0);
duke@435 300 ih = iq[jz-1]>>(23-q0);
duke@435 301 }
duke@435 302 else if(q0==0) ih = iq[jz-1]>>23;
duke@435 303 else if(z>=0.5) ih=2;
duke@435 304
duke@435 305 if(ih>0) { /* q > 0.5 */
duke@435 306 n += 1; carry = 0;
duke@435 307 for(i=0;i<jz ;i++) { /* compute 1-q */
duke@435 308 j = iq[i];
duke@435 309 if(carry==0) {
duke@435 310 if(j!=0) {
duke@435 311 carry = 1; iq[i] = 0x1000000- j;
duke@435 312 }
duke@435 313 } else iq[i] = 0xffffff - j;
duke@435 314 }
duke@435 315 if(q0>0) { /* rare case: chance is 1 in 12 */
duke@435 316 switch(q0) {
duke@435 317 case 1:
duke@435 318 iq[jz-1] &= 0x7fffff; break;
duke@435 319 case 2:
duke@435 320 iq[jz-1] &= 0x3fffff; break;
duke@435 321 }
duke@435 322 }
duke@435 323 if(ih==2) {
duke@435 324 z = one - z;
duke@435 325 if(carry!=0) z -= scalbnA(one,q0);
duke@435 326 }
duke@435 327 }
duke@435 328
duke@435 329 /* check if recomputation is needed */
duke@435 330 if(z==zeroB) {
duke@435 331 j = 0;
duke@435 332 for (i=jz-1;i>=jk;i--) j |= iq[i];
duke@435 333 if(j==0) { /* need recomputation */
duke@435 334 for(k=1;iq[jk-k]==0;k++); /* k = no. of terms needed */
duke@435 335
duke@435 336 for(i=jz+1;i<=jz+k;i++) { /* add q[jz+1] to q[jz+k] */
duke@435 337 f[jx+i] = (double) ipio2[jv+i];
duke@435 338 for(j=0,fw=0.0;j<=jx;j++) fw += x[j]*f[jx+i-j];
duke@435 339 q[i] = fw;
duke@435 340 }
duke@435 341 jz += k;
duke@435 342 goto recompute;
duke@435 343 }
duke@435 344 }
duke@435 345
duke@435 346 /* chop off zero terms */
duke@435 347 if(z==0.0) {
duke@435 348 jz -= 1; q0 -= 24;
duke@435 349 while(iq[jz]==0) { jz--; q0-=24;}
duke@435 350 } else { /* break z into 24-bit if neccessary */
duke@435 351 z = scalbnA(z,-q0);
duke@435 352 if(z>=two24B) {
duke@435 353 fw = (double)((int)(twon24*z));
duke@435 354 iq[jz] = (int)(z-two24B*fw);
duke@435 355 jz += 1; q0 += 24;
duke@435 356 iq[jz] = (int) fw;
duke@435 357 } else iq[jz] = (int) z ;
duke@435 358 }
duke@435 359
duke@435 360 /* convert integer "bit" chunk to floating-point value */
duke@435 361 fw = scalbnA(one,q0);
duke@435 362 for(i=jz;i>=0;i--) {
duke@435 363 q[i] = fw*(double)iq[i]; fw*=twon24;
duke@435 364 }
duke@435 365
duke@435 366 /* compute PIo2[0,...,jp]*q[jz,...,0] */
duke@435 367 for(i=jz;i>=0;i--) {
duke@435 368 for(fw=0.0,k=0;k<=jp&&k<=jz-i;k++) fw += PIo2[k]*q[i+k];
duke@435 369 fq[jz-i] = fw;
duke@435 370 }
duke@435 371
duke@435 372 /* compress fq[] into y[] */
duke@435 373 switch(prec) {
duke@435 374 case 0:
duke@435 375 fw = 0.0;
duke@435 376 for (i=jz;i>=0;i--) fw += fq[i];
duke@435 377 y[0] = (ih==0)? fw: -fw;
duke@435 378 break;
duke@435 379 case 1:
duke@435 380 case 2:
duke@435 381 fw = 0.0;
duke@435 382 for (i=jz;i>=0;i--) fw += fq[i];
duke@435 383 y[0] = (ih==0)? fw: -fw;
duke@435 384 fw = fq[0]-fw;
duke@435 385 for (i=1;i<=jz;i++) fw += fq[i];
duke@435 386 y[1] = (ih==0)? fw: -fw;
duke@435 387 break;
duke@435 388 case 3: /* painful */
duke@435 389 for (i=jz;i>0;i--) {
duke@435 390 fw = fq[i-1]+fq[i];
duke@435 391 fq[i] += fq[i-1]-fw;
duke@435 392 fq[i-1] = fw;
duke@435 393 }
duke@435 394 for (i=jz;i>1;i--) {
duke@435 395 fw = fq[i-1]+fq[i];
duke@435 396 fq[i] += fq[i-1]-fw;
duke@435 397 fq[i-1] = fw;
duke@435 398 }
duke@435 399 for (fw=0.0,i=jz;i>=2;i--) fw += fq[i];
duke@435 400 if(ih==0) {
duke@435 401 y[0] = fq[0]; y[1] = fq[1]; y[2] = fw;
duke@435 402 } else {
duke@435 403 y[0] = -fq[0]; y[1] = -fq[1]; y[2] = -fw;
duke@435 404 }
duke@435 405 }
duke@435 406 return n&7;
duke@435 407 }
duke@435 408
duke@435 409
duke@435 410 /*
duke@435 411 * ====================================================
trims@1907 412 * Copyright (c) 1993 Oracle and/or its affilates. All rights reserved.
duke@435 413 *
duke@435 414 * Developed at SunPro, a Sun Microsystems, Inc. business.
duke@435 415 * Permission to use, copy, modify, and distribute this
duke@435 416 * software is freely granted, provided that this notice
duke@435 417 * is preserved.
duke@435 418 * ====================================================
duke@435 419 *
duke@435 420 */
duke@435 421
duke@435 422 /* __ieee754_rem_pio2(x,y)
duke@435 423 *
duke@435 424 * return the remainder of x rem pi/2 in y[0]+y[1]
duke@435 425 * use __kernel_rem_pio2()
duke@435 426 */
duke@435 427
duke@435 428 /*
duke@435 429 * Table of constants for 2/pi, 396 Hex digits (476 decimal) of 2/pi
duke@435 430 */
duke@435 431 static const int two_over_pi[] = {
duke@435 432 0xA2F983, 0x6E4E44, 0x1529FC, 0x2757D1, 0xF534DD, 0xC0DB62,
duke@435 433 0x95993C, 0x439041, 0xFE5163, 0xABDEBB, 0xC561B7, 0x246E3A,
duke@435 434 0x424DD2, 0xE00649, 0x2EEA09, 0xD1921C, 0xFE1DEB, 0x1CB129,
duke@435 435 0xA73EE8, 0x8235F5, 0x2EBB44, 0x84E99C, 0x7026B4, 0x5F7E41,
duke@435 436 0x3991D6, 0x398353, 0x39F49C, 0x845F8B, 0xBDF928, 0x3B1FF8,
duke@435 437 0x97FFDE, 0x05980F, 0xEF2F11, 0x8B5A0A, 0x6D1F6D, 0x367ECF,
duke@435 438 0x27CB09, 0xB74F46, 0x3F669E, 0x5FEA2D, 0x7527BA, 0xC7EBE5,
duke@435 439 0xF17B3D, 0x0739F7, 0x8A5292, 0xEA6BFB, 0x5FB11F, 0x8D5D08,
duke@435 440 0x560330, 0x46FC7B, 0x6BABF0, 0xCFBC20, 0x9AF436, 0x1DA9E3,
duke@435 441 0x91615E, 0xE61B08, 0x659985, 0x5F14A0, 0x68408D, 0xFFD880,
duke@435 442 0x4D7327, 0x310606, 0x1556CA, 0x73A8C9, 0x60E27B, 0xC08C6B,
duke@435 443 };
duke@435 444
duke@435 445 static const int npio2_hw[] = {
duke@435 446 0x3FF921FB, 0x400921FB, 0x4012D97C, 0x401921FB, 0x401F6A7A, 0x4022D97C,
duke@435 447 0x4025FDBB, 0x402921FB, 0x402C463A, 0x402F6A7A, 0x4031475C, 0x4032D97C,
duke@435 448 0x40346B9C, 0x4035FDBB, 0x40378FDB, 0x403921FB, 0x403AB41B, 0x403C463A,
duke@435 449 0x403DD85A, 0x403F6A7A, 0x40407E4C, 0x4041475C, 0x4042106C, 0x4042D97C,
duke@435 450 0x4043A28C, 0x40446B9C, 0x404534AC, 0x4045FDBB, 0x4046C6CB, 0x40478FDB,
duke@435 451 0x404858EB, 0x404921FB,
duke@435 452 };
duke@435 453
duke@435 454 /*
duke@435 455 * invpio2: 53 bits of 2/pi
duke@435 456 * pio2_1: first 33 bit of pi/2
duke@435 457 * pio2_1t: pi/2 - pio2_1
duke@435 458 * pio2_2: second 33 bit of pi/2
duke@435 459 * pio2_2t: pi/2 - (pio2_1+pio2_2)
duke@435 460 * pio2_3: third 33 bit of pi/2
duke@435 461 * pio2_3t: pi/2 - (pio2_1+pio2_2+pio2_3)
duke@435 462 */
duke@435 463
duke@435 464 static const double
duke@435 465 zeroA = 0.00000000000000000000e+00, /* 0x00000000, 0x00000000 */
duke@435 466 half = 5.00000000000000000000e-01, /* 0x3FE00000, 0x00000000 */
duke@435 467 two24A = 1.67772160000000000000e+07, /* 0x41700000, 0x00000000 */
duke@435 468 invpio2 = 6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */
duke@435 469 pio2_1 = 1.57079632673412561417e+00, /* 0x3FF921FB, 0x54400000 */
duke@435 470 pio2_1t = 6.07710050650619224932e-11, /* 0x3DD0B461, 0x1A626331 */
duke@435 471 pio2_2 = 6.07710050630396597660e-11, /* 0x3DD0B461, 0x1A600000 */
duke@435 472 pio2_2t = 2.02226624879595063154e-21, /* 0x3BA3198A, 0x2E037073 */
duke@435 473 pio2_3 = 2.02226624871116645580e-21, /* 0x3BA3198A, 0x2E000000 */
duke@435 474 pio2_3t = 8.47842766036889956997e-32; /* 0x397B839A, 0x252049C1 */
duke@435 475
prr@1840 476 static SAFEBUF int __ieee754_rem_pio2(double x, double *y) {
duke@435 477 double z,w,t,r,fn;
duke@435 478 double tx[3];
duke@435 479 int e0,i,j,nx,n,ix,hx,i0;
duke@435 480
duke@435 481 i0 = ((*(int*)&two24A)>>30)^1; /* high word index */
duke@435 482 hx = *(i0+(int*)&x); /* high word of x */
duke@435 483 ix = hx&0x7fffffff;
duke@435 484 if(ix<=0x3fe921fb) /* |x| ~<= pi/4 , no need for reduction */
duke@435 485 {y[0] = x; y[1] = 0; return 0;}
duke@435 486 if(ix<0x4002d97c) { /* |x| < 3pi/4, special case with n=+-1 */
duke@435 487 if(hx>0) {
duke@435 488 z = x - pio2_1;
duke@435 489 if(ix!=0x3ff921fb) { /* 33+53 bit pi is good enough */
duke@435 490 y[0] = z - pio2_1t;
duke@435 491 y[1] = (z-y[0])-pio2_1t;
duke@435 492 } else { /* near pi/2, use 33+33+53 bit pi */
duke@435 493 z -= pio2_2;
duke@435 494 y[0] = z - pio2_2t;
duke@435 495 y[1] = (z-y[0])-pio2_2t;
duke@435 496 }
duke@435 497 return 1;
duke@435 498 } else { /* negative x */
duke@435 499 z = x + pio2_1;
duke@435 500 if(ix!=0x3ff921fb) { /* 33+53 bit pi is good enough */
duke@435 501 y[0] = z + pio2_1t;
duke@435 502 y[1] = (z-y[0])+pio2_1t;
duke@435 503 } else { /* near pi/2, use 33+33+53 bit pi */
duke@435 504 z += pio2_2;
duke@435 505 y[0] = z + pio2_2t;
duke@435 506 y[1] = (z-y[0])+pio2_2t;
duke@435 507 }
duke@435 508 return -1;
duke@435 509 }
duke@435 510 }
duke@435 511 if(ix<=0x413921fb) { /* |x| ~<= 2^19*(pi/2), medium size */
duke@435 512 t = fabsd(x);
duke@435 513 n = (int) (t*invpio2+half);
duke@435 514 fn = (double)n;
duke@435 515 r = t-fn*pio2_1;
duke@435 516 w = fn*pio2_1t; /* 1st round good to 85 bit */
duke@435 517 if(n<32&&ix!=npio2_hw[n-1]) {
duke@435 518 y[0] = r-w; /* quick check no cancellation */
duke@435 519 } else {
duke@435 520 j = ix>>20;
duke@435 521 y[0] = r-w;
duke@435 522 i = j-(((*(i0+(int*)&y[0]))>>20)&0x7ff);
duke@435 523 if(i>16) { /* 2nd iteration needed, good to 118 */
duke@435 524 t = r;
duke@435 525 w = fn*pio2_2;
duke@435 526 r = t-w;
duke@435 527 w = fn*pio2_2t-((t-r)-w);
duke@435 528 y[0] = r-w;
duke@435 529 i = j-(((*(i0+(int*)&y[0]))>>20)&0x7ff);
duke@435 530 if(i>49) { /* 3rd iteration need, 151 bits acc */
duke@435 531 t = r; /* will cover all possible cases */
duke@435 532 w = fn*pio2_3;
duke@435 533 r = t-w;
duke@435 534 w = fn*pio2_3t-((t-r)-w);
duke@435 535 y[0] = r-w;
duke@435 536 }
duke@435 537 }
duke@435 538 }
duke@435 539 y[1] = (r-y[0])-w;
duke@435 540 if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;}
duke@435 541 else return n;
duke@435 542 }
duke@435 543 /*
duke@435 544 * all other (large) arguments
duke@435 545 */
duke@435 546 if(ix>=0x7ff00000) { /* x is inf or NaN */
duke@435 547 y[0]=y[1]=x-x; return 0;
duke@435 548 }
duke@435 549 /* set z = scalbn(|x|,ilogb(x)-23) */
duke@435 550 *(1-i0+(int*)&z) = *(1-i0+(int*)&x);
duke@435 551 e0 = (ix>>20)-1046; /* e0 = ilogb(z)-23; */
duke@435 552 *(i0+(int*)&z) = ix - (e0<<20);
duke@435 553 for(i=0;i<2;i++) {
duke@435 554 tx[i] = (double)((int)(z));
duke@435 555 z = (z-tx[i])*two24A;
duke@435 556 }
duke@435 557 tx[2] = z;
duke@435 558 nx = 3;
duke@435 559 while(tx[nx-1]==zeroA) nx--; /* skip zero term */
duke@435 560 n = __kernel_rem_pio2(tx,y,e0,nx,2,two_over_pi);
duke@435 561 if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;}
duke@435 562 return n;
duke@435 563 }
duke@435 564
duke@435 565
duke@435 566 /* __kernel_sin( x, y, iy)
duke@435 567 * kernel sin function on [-pi/4, pi/4], pi/4 ~ 0.7854
duke@435 568 * Input x is assumed to be bounded by ~pi/4 in magnitude.
duke@435 569 * Input y is the tail of x.
duke@435 570 * Input iy indicates whether y is 0. (if iy=0, y assume to be 0).
duke@435 571 *
duke@435 572 * Algorithm
duke@435 573 * 1. Since sin(-x) = -sin(x), we need only to consider positive x.
duke@435 574 * 2. if x < 2^-27 (hx<0x3e400000 0), return x with inexact if x!=0.
duke@435 575 * 3. sin(x) is approximated by a polynomial of degree 13 on
duke@435 576 * [0,pi/4]
duke@435 577 * 3 13
duke@435 578 * sin(x) ~ x + S1*x + ... + S6*x
duke@435 579 * where
duke@435 580 *
duke@435 581 * |sin(x) 2 4 6 8 10 12 | -58
duke@435 582 * |----- - (1+S1*x +S2*x +S3*x +S4*x +S5*x +S6*x )| <= 2
duke@435 583 * | x |
duke@435 584 *
duke@435 585 * 4. sin(x+y) = sin(x) + sin'(x')*y
duke@435 586 * ~ sin(x) + (1-x*x/2)*y
duke@435 587 * For better accuracy, let
duke@435 588 * 3 2 2 2 2
duke@435 589 * r = x *(S2+x *(S3+x *(S4+x *(S5+x *S6))))
duke@435 590 * then 3 2
duke@435 591 * sin(x) = x + (S1*x + (x *(r-y/2)+y))
duke@435 592 */
duke@435 593
duke@435 594 static const double
duke@435 595 S1 = -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */
duke@435 596 S2 = 8.33333333332248946124e-03, /* 0x3F811111, 0x1110F8A6 */
duke@435 597 S3 = -1.98412698298579493134e-04, /* 0xBF2A01A0, 0x19C161D5 */
duke@435 598 S4 = 2.75573137070700676789e-06, /* 0x3EC71DE3, 0x57B1FE7D */
duke@435 599 S5 = -2.50507602534068634195e-08, /* 0xBE5AE5E6, 0x8A2B9CEB */
duke@435 600 S6 = 1.58969099521155010221e-10; /* 0x3DE5D93A, 0x5ACFD57C */
duke@435 601
duke@435 602 static double __kernel_sin(double x, double y, int iy)
duke@435 603 {
duke@435 604 double z,r,v;
duke@435 605 int ix;
duke@435 606 ix = __HI(x)&0x7fffffff; /* high word of x */
duke@435 607 if(ix<0x3e400000) /* |x| < 2**-27 */
duke@435 608 {if((int)x==0) return x;} /* generate inexact */
duke@435 609 z = x*x;
duke@435 610 v = z*x;
duke@435 611 r = S2+z*(S3+z*(S4+z*(S5+z*S6)));
duke@435 612 if(iy==0) return x+v*(S1+z*r);
duke@435 613 else return x-((z*(half*y-v*r)-y)-v*S1);
duke@435 614 }
duke@435 615
duke@435 616 /*
duke@435 617 * __kernel_cos( x, y )
duke@435 618 * kernel cos function on [-pi/4, pi/4], pi/4 ~ 0.785398164
duke@435 619 * Input x is assumed to be bounded by ~pi/4 in magnitude.
duke@435 620 * Input y is the tail of x.
duke@435 621 *
duke@435 622 * Algorithm
duke@435 623 * 1. Since cos(-x) = cos(x), we need only to consider positive x.
duke@435 624 * 2. if x < 2^-27 (hx<0x3e400000 0), return 1 with inexact if x!=0.
duke@435 625 * 3. cos(x) is approximated by a polynomial of degree 14 on
duke@435 626 * [0,pi/4]
duke@435 627 * 4 14
duke@435 628 * cos(x) ~ 1 - x*x/2 + C1*x + ... + C6*x
duke@435 629 * where the remez error is
duke@435 630 *
duke@435 631 * | 2 4 6 8 10 12 14 | -58
duke@435 632 * |cos(x)-(1-.5*x +C1*x +C2*x +C3*x +C4*x +C5*x +C6*x )| <= 2
duke@435 633 * | |
duke@435 634 *
duke@435 635 * 4 6 8 10 12 14
duke@435 636 * 4. let r = C1*x +C2*x +C3*x +C4*x +C5*x +C6*x , then
duke@435 637 * cos(x) = 1 - x*x/2 + r
duke@435 638 * since cos(x+y) ~ cos(x) - sin(x)*y
duke@435 639 * ~ cos(x) - x*y,
duke@435 640 * a correction term is necessary in cos(x) and hence
duke@435 641 * cos(x+y) = 1 - (x*x/2 - (r - x*y))
duke@435 642 * For better accuracy when x > 0.3, let qx = |x|/4 with
duke@435 643 * the last 32 bits mask off, and if x > 0.78125, let qx = 0.28125.
duke@435 644 * Then
duke@435 645 * cos(x+y) = (1-qx) - ((x*x/2-qx) - (r-x*y)).
duke@435 646 * Note that 1-qx and (x*x/2-qx) is EXACT here, and the
duke@435 647 * magnitude of the latter is at least a quarter of x*x/2,
duke@435 648 * thus, reducing the rounding error in the subtraction.
duke@435 649 */
duke@435 650
duke@435 651 static const double
duke@435 652 C1 = 4.16666666666666019037e-02, /* 0x3FA55555, 0x5555554C */
duke@435 653 C2 = -1.38888888888741095749e-03, /* 0xBF56C16C, 0x16C15177 */
duke@435 654 C3 = 2.48015872894767294178e-05, /* 0x3EFA01A0, 0x19CB1590 */
duke@435 655 C4 = -2.75573143513906633035e-07, /* 0xBE927E4F, 0x809C52AD */
duke@435 656 C5 = 2.08757232129817482790e-09, /* 0x3E21EE9E, 0xBDB4B1C4 */
duke@435 657 C6 = -1.13596475577881948265e-11; /* 0xBDA8FAE9, 0xBE8838D4 */
duke@435 658
duke@435 659 static double __kernel_cos(double x, double y)
duke@435 660 {
duke@435 661 double a,hz,z,r,qx;
duke@435 662 int ix;
duke@435 663 ix = __HI(x)&0x7fffffff; /* ix = |x|'s high word*/
duke@435 664 if(ix<0x3e400000) { /* if x < 2**27 */
duke@435 665 if(((int)x)==0) return one; /* generate inexact */
duke@435 666 }
duke@435 667 z = x*x;
duke@435 668 r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
duke@435 669 if(ix < 0x3FD33333) /* if |x| < 0.3 */
duke@435 670 return one - (0.5*z - (z*r - x*y));
duke@435 671 else {
duke@435 672 if(ix > 0x3fe90000) { /* x > 0.78125 */
duke@435 673 qx = 0.28125;
duke@435 674 } else {
duke@435 675 __HI(qx) = ix-0x00200000; /* x/4 */
duke@435 676 __LO(qx) = 0;
duke@435 677 }
duke@435 678 hz = 0.5*z-qx;
duke@435 679 a = one-qx;
duke@435 680 return a - (hz - (z*r-x*y));
duke@435 681 }
duke@435 682 }
duke@435 683
duke@435 684 /* __kernel_tan( x, y, k )
duke@435 685 * kernel tan function on [-pi/4, pi/4], pi/4 ~ 0.7854
duke@435 686 * Input x is assumed to be bounded by ~pi/4 in magnitude.
duke@435 687 * Input y is the tail of x.
duke@435 688 * Input k indicates whether tan (if k=1) or
duke@435 689 * -1/tan (if k= -1) is returned.
duke@435 690 *
duke@435 691 * Algorithm
duke@435 692 * 1. Since tan(-x) = -tan(x), we need only to consider positive x.
duke@435 693 * 2. if x < 2^-28 (hx<0x3e300000 0), return x with inexact if x!=0.
duke@435 694 * 3. tan(x) is approximated by a odd polynomial of degree 27 on
duke@435 695 * [0,0.67434]
duke@435 696 * 3 27
duke@435 697 * tan(x) ~ x + T1*x + ... + T13*x
duke@435 698 * where
duke@435 699 *
duke@435 700 * |tan(x) 2 4 26 | -59.2
duke@435 701 * |----- - (1+T1*x +T2*x +.... +T13*x )| <= 2
duke@435 702 * | x |
duke@435 703 *
duke@435 704 * Note: tan(x+y) = tan(x) + tan'(x)*y
duke@435 705 * ~ tan(x) + (1+x*x)*y
duke@435 706 * Therefore, for better accuracy in computing tan(x+y), let
duke@435 707 * 3 2 2 2 2
duke@435 708 * r = x *(T2+x *(T3+x *(...+x *(T12+x *T13))))
duke@435 709 * then
duke@435 710 * 3 2
duke@435 711 * tan(x+y) = x + (T1*x + (x *(r+y)+y))
duke@435 712 *
duke@435 713 * 4. For x in [0.67434,pi/4], let y = pi/4 - x, then
duke@435 714 * tan(x) = tan(pi/4-y) = (1-tan(y))/(1+tan(y))
duke@435 715 * = 1 - 2*(tan(y) - (tan(y)^2)/(1+tan(y)))
duke@435 716 */
duke@435 717
duke@435 718 static const double
duke@435 719 pio4 = 7.85398163397448278999e-01, /* 0x3FE921FB, 0x54442D18 */
duke@435 720 pio4lo= 3.06161699786838301793e-17, /* 0x3C81A626, 0x33145C07 */
duke@435 721 T[] = {
duke@435 722 3.33333333333334091986e-01, /* 0x3FD55555, 0x55555563 */
duke@435 723 1.33333333333201242699e-01, /* 0x3FC11111, 0x1110FE7A */
duke@435 724 5.39682539762260521377e-02, /* 0x3FABA1BA, 0x1BB341FE */
duke@435 725 2.18694882948595424599e-02, /* 0x3F9664F4, 0x8406D637 */
duke@435 726 8.86323982359930005737e-03, /* 0x3F8226E3, 0xE96E8493 */
duke@435 727 3.59207910759131235356e-03, /* 0x3F6D6D22, 0xC9560328 */
duke@435 728 1.45620945432529025516e-03, /* 0x3F57DBC8, 0xFEE08315 */
duke@435 729 5.88041240820264096874e-04, /* 0x3F4344D8, 0xF2F26501 */
duke@435 730 2.46463134818469906812e-04, /* 0x3F3026F7, 0x1A8D1068 */
duke@435 731 7.81794442939557092300e-05, /* 0x3F147E88, 0xA03792A6 */
duke@435 732 7.14072491382608190305e-05, /* 0x3F12B80F, 0x32F0A7E9 */
duke@435 733 -1.85586374855275456654e-05, /* 0xBEF375CB, 0xDB605373 */
duke@435 734 2.59073051863633712884e-05, /* 0x3EFB2A70, 0x74BF7AD4 */
duke@435 735 };
duke@435 736
duke@435 737 static double __kernel_tan(double x, double y, int iy)
duke@435 738 {
duke@435 739 double z,r,v,w,s;
duke@435 740 int ix,hx;
duke@435 741 hx = __HI(x); /* high word of x */
duke@435 742 ix = hx&0x7fffffff; /* high word of |x| */
duke@435 743 if(ix<0x3e300000) { /* x < 2**-28 */
duke@435 744 if((int)x==0) { /* generate inexact */
duke@435 745 if (((ix | __LO(x)) | (iy + 1)) == 0)
duke@435 746 return one / fabsd(x);
duke@435 747 else {
duke@435 748 if (iy == 1)
duke@435 749 return x;
duke@435 750 else { /* compute -1 / (x+y) carefully */
duke@435 751 double a, t;
duke@435 752
duke@435 753 z = w = x + y;
duke@435 754 __LO(z) = 0;
duke@435 755 v = y - (z - x);
duke@435 756 t = a = -one / w;
duke@435 757 __LO(t) = 0;
duke@435 758 s = one + t * z;
duke@435 759 return t + a * (s + t * v);
duke@435 760 }
duke@435 761 }
duke@435 762 }
duke@435 763 }
duke@435 764 if(ix>=0x3FE59428) { /* |x|>=0.6744 */
duke@435 765 if(hx<0) {x = -x; y = -y;}
duke@435 766 z = pio4-x;
duke@435 767 w = pio4lo-y;
duke@435 768 x = z+w; y = 0.0;
duke@435 769 }
duke@435 770 z = x*x;
duke@435 771 w = z*z;
duke@435 772 /* Break x^5*(T[1]+x^2*T[2]+...) into
duke@435 773 * x^5(T[1]+x^4*T[3]+...+x^20*T[11]) +
duke@435 774 * x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12]))
duke@435 775 */
duke@435 776 r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11]))));
duke@435 777 v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12])))));
duke@435 778 s = z*x;
duke@435 779 r = y + z*(s*(r+v)+y);
duke@435 780 r += T[0]*s;
duke@435 781 w = x+r;
duke@435 782 if(ix>=0x3FE59428) {
duke@435 783 v = (double)iy;
duke@435 784 return (double)(1-((hx>>30)&2))*(v-2.0*(x-(w*w/(w+v)-r)));
duke@435 785 }
duke@435 786 if(iy==1) return w;
duke@435 787 else { /* if allow error up to 2 ulp,
duke@435 788 simply return -1.0/(x+r) here */
duke@435 789 /* compute -1.0/(x+r) accurately */
duke@435 790 double a,t;
duke@435 791 z = w;
duke@435 792 __LO(z) = 0;
duke@435 793 v = r-(z - x); /* z+v = r+x */
duke@435 794 t = a = -1.0/w; /* a = -1.0/w */
duke@435 795 __LO(t) = 0;
duke@435 796 s = 1.0+t*z;
duke@435 797 return t+a*(s+t*v);
duke@435 798 }
duke@435 799 }
duke@435 800
duke@435 801
duke@435 802 //----------------------------------------------------------------------
duke@435 803 //
duke@435 804 // Routines for new sin/cos implementation
duke@435 805 //
duke@435 806 //----------------------------------------------------------------------
duke@435 807
duke@435 808 /* sin(x)
duke@435 809 * Return sine function of x.
duke@435 810 *
duke@435 811 * kernel function:
duke@435 812 * __kernel_sin ... sine function on [-pi/4,pi/4]
duke@435 813 * __kernel_cos ... cose function on [-pi/4,pi/4]
duke@435 814 * __ieee754_rem_pio2 ... argument reduction routine
duke@435 815 *
duke@435 816 * Method.
duke@435 817 * Let S,C and T denote the sin, cos and tan respectively on
duke@435 818 * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
duke@435 819 * in [-pi/4 , +pi/4], and let n = k mod 4.
duke@435 820 * We have
duke@435 821 *
duke@435 822 * n sin(x) cos(x) tan(x)
duke@435 823 * ----------------------------------------------------------
duke@435 824 * 0 S C T
duke@435 825 * 1 C -S -1/T
duke@435 826 * 2 -S -C T
duke@435 827 * 3 -C S -1/T
duke@435 828 * ----------------------------------------------------------
duke@435 829 *
duke@435 830 * Special cases:
duke@435 831 * Let trig be any of sin, cos, or tan.
duke@435 832 * trig(+-INF) is NaN, with signals;
duke@435 833 * trig(NaN) is that NaN;
duke@435 834 *
duke@435 835 * Accuracy:
duke@435 836 * TRIG(x) returns trig(x) nearly rounded
duke@435 837 */
duke@435 838
duke@435 839 JRT_LEAF(jdouble, SharedRuntime::dsin(jdouble x))
duke@435 840 double y[2],z=0.0;
duke@435 841 int n, ix;
duke@435 842
duke@435 843 /* High word of x. */
duke@435 844 ix = __HI(x);
duke@435 845
duke@435 846 /* |x| ~< pi/4 */
duke@435 847 ix &= 0x7fffffff;
duke@435 848 if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0);
duke@435 849
duke@435 850 /* sin(Inf or NaN) is NaN */
duke@435 851 else if (ix>=0x7ff00000) return x-x;
duke@435 852
duke@435 853 /* argument reduction needed */
duke@435 854 else {
duke@435 855 n = __ieee754_rem_pio2(x,y);
duke@435 856 switch(n&3) {
duke@435 857 case 0: return __kernel_sin(y[0],y[1],1);
duke@435 858 case 1: return __kernel_cos(y[0],y[1]);
duke@435 859 case 2: return -__kernel_sin(y[0],y[1],1);
duke@435 860 default:
duke@435 861 return -__kernel_cos(y[0],y[1]);
duke@435 862 }
duke@435 863 }
duke@435 864 JRT_END
duke@435 865
duke@435 866 /* cos(x)
duke@435 867 * Return cosine function of x.
duke@435 868 *
duke@435 869 * kernel function:
duke@435 870 * __kernel_sin ... sine function on [-pi/4,pi/4]
duke@435 871 * __kernel_cos ... cosine function on [-pi/4,pi/4]
duke@435 872 * __ieee754_rem_pio2 ... argument reduction routine
duke@435 873 *
duke@435 874 * Method.
duke@435 875 * Let S,C and T denote the sin, cos and tan respectively on
duke@435 876 * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
duke@435 877 * in [-pi/4 , +pi/4], and let n = k mod 4.
duke@435 878 * We have
duke@435 879 *
duke@435 880 * n sin(x) cos(x) tan(x)
duke@435 881 * ----------------------------------------------------------
duke@435 882 * 0 S C T
duke@435 883 * 1 C -S -1/T
duke@435 884 * 2 -S -C T
duke@435 885 * 3 -C S -1/T
duke@435 886 * ----------------------------------------------------------
duke@435 887 *
duke@435 888 * Special cases:
duke@435 889 * Let trig be any of sin, cos, or tan.
duke@435 890 * trig(+-INF) is NaN, with signals;
duke@435 891 * trig(NaN) is that NaN;
duke@435 892 *
duke@435 893 * Accuracy:
duke@435 894 * TRIG(x) returns trig(x) nearly rounded
duke@435 895 */
duke@435 896
duke@435 897 JRT_LEAF(jdouble, SharedRuntime::dcos(jdouble x))
duke@435 898 double y[2],z=0.0;
duke@435 899 int n, ix;
duke@435 900
duke@435 901 /* High word of x. */
duke@435 902 ix = __HI(x);
duke@435 903
duke@435 904 /* |x| ~< pi/4 */
duke@435 905 ix &= 0x7fffffff;
duke@435 906 if(ix <= 0x3fe921fb) return __kernel_cos(x,z);
duke@435 907
duke@435 908 /* cos(Inf or NaN) is NaN */
duke@435 909 else if (ix>=0x7ff00000) return x-x;
duke@435 910
duke@435 911 /* argument reduction needed */
duke@435 912 else {
duke@435 913 n = __ieee754_rem_pio2(x,y);
duke@435 914 switch(n&3) {
duke@435 915 case 0: return __kernel_cos(y[0],y[1]);
duke@435 916 case 1: return -__kernel_sin(y[0],y[1],1);
duke@435 917 case 2: return -__kernel_cos(y[0],y[1]);
duke@435 918 default:
duke@435 919 return __kernel_sin(y[0],y[1],1);
duke@435 920 }
duke@435 921 }
duke@435 922 JRT_END
duke@435 923
duke@435 924 /* tan(x)
duke@435 925 * Return tangent function of x.
duke@435 926 *
duke@435 927 * kernel function:
duke@435 928 * __kernel_tan ... tangent function on [-pi/4,pi/4]
duke@435 929 * __ieee754_rem_pio2 ... argument reduction routine
duke@435 930 *
duke@435 931 * Method.
duke@435 932 * Let S,C and T denote the sin, cos and tan respectively on
duke@435 933 * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
duke@435 934 * in [-pi/4 , +pi/4], and let n = k mod 4.
duke@435 935 * We have
duke@435 936 *
duke@435 937 * n sin(x) cos(x) tan(x)
duke@435 938 * ----------------------------------------------------------
duke@435 939 * 0 S C T
duke@435 940 * 1 C -S -1/T
duke@435 941 * 2 -S -C T
duke@435 942 * 3 -C S -1/T
duke@435 943 * ----------------------------------------------------------
duke@435 944 *
duke@435 945 * Special cases:
duke@435 946 * Let trig be any of sin, cos, or tan.
duke@435 947 * trig(+-INF) is NaN, with signals;
duke@435 948 * trig(NaN) is that NaN;
duke@435 949 *
duke@435 950 * Accuracy:
duke@435 951 * TRIG(x) returns trig(x) nearly rounded
duke@435 952 */
duke@435 953
duke@435 954 JRT_LEAF(jdouble, SharedRuntime::dtan(jdouble x))
duke@435 955 double y[2],z=0.0;
duke@435 956 int n, ix;
duke@435 957
duke@435 958 /* High word of x. */
duke@435 959 ix = __HI(x);
duke@435 960
duke@435 961 /* |x| ~< pi/4 */
duke@435 962 ix &= 0x7fffffff;
duke@435 963 if(ix <= 0x3fe921fb) return __kernel_tan(x,z,1);
duke@435 964
duke@435 965 /* tan(Inf or NaN) is NaN */
duke@435 966 else if (ix>=0x7ff00000) return x-x; /* NaN */
duke@435 967
duke@435 968 /* argument reduction needed */
duke@435 969 else {
duke@435 970 n = __ieee754_rem_pio2(x,y);
duke@435 971 return __kernel_tan(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
duke@435 972 -1 -- n odd */
duke@435 973 }
duke@435 974 JRT_END
duke@435 975
duke@435 976
duke@435 977 #ifdef WIN32
duke@435 978 # pragma optimize ( "", on )
duke@435 979 #endif

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