sharedRuntimeTrans.cpp revision 1472:c18cbe5936b8
1/* 2 * Copyright (c) 2005, 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 "incls/_precompiled.incl" 26#include "incls/_sharedRuntimeTrans.cpp.incl" 27 28// This file contains copies of the fdlibm routines used by 29// StrictMath. It turns out that it is almost always required to use 30// these runtime routines; the Intel CPU doesn't meet the Java 31// specification for sin/cos outside a certain limited argument range, 32// and the SPARC CPU doesn't appear to have sin/cos instructions. It 33// also turns out that avoiding the indirect call through function 34// pointer out to libjava.so in SharedRuntime speeds these routines up 35// by roughly 15% on both Win32/x86 and Solaris/SPARC. 36 37// Enabling optimizations in this file causes incorrect code to be 38// generated; can not figure out how to turn down optimization for one 39// file in the IDE on Windows 40#ifdef WIN32 41# pragma optimize ( "", off ) 42#endif 43 44#include <math.h> 45 46// VM_LITTLE_ENDIAN is #defined appropriately in the Makefiles 47// [jk] this is not 100% correct because the float word order may different 48// from the byte order (e.g. on ARM) 49#ifdef VM_LITTLE_ENDIAN 50# define __HI(x) *(1+(int*)&x) 51# define __LO(x) *(int*)&x 52#else 53# define __HI(x) *(int*)&x 54# define __LO(x) *(1+(int*)&x) 55#endif 56 57double copysign(double x, double y) { 58 __HI(x) = (__HI(x)&0x7fffffff)|(__HI(y)&0x80000000); 59 return x; 60} 61 62/* 63 * ==================================================== 64 * Copyright (c) 1998 Oracle and/or its affiliates. All rights reserved. 65 * 66 * Developed at SunSoft, a Sun Microsystems, Inc. business. 67 * Permission to use, copy, modify, and distribute this 68 * software is freely granted, provided that this notice 69 * is preserved. 70 * ==================================================== 71 */ 72 73/* 74 * scalbn (double x, int n) 75 * scalbn(x,n) returns x* 2**n computed by exponent 76 * manipulation rather than by actually performing an 77 * exponentiation or a multiplication. 78 */ 79 80static const double 81two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */ 82 twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */ 83 hugeX = 1.0e+300, 84 tiny = 1.0e-300; 85 86double scalbn (double x, int n) { 87 int k,hx,lx; 88 hx = __HI(x); 89 lx = __LO(x); 90 k = (hx&0x7ff00000)>>20; /* extract exponent */ 91 if (k==0) { /* 0 or subnormal x */ 92 if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */ 93 x *= two54; 94 hx = __HI(x); 95 k = ((hx&0x7ff00000)>>20) - 54; 96 if (n< -50000) return tiny*x; /*underflow*/ 97 } 98 if (k==0x7ff) return x+x; /* NaN or Inf */ 99 k = k+n; 100 if (k > 0x7fe) return hugeX*copysign(hugeX,x); /* overflow */ 101 if (k > 0) /* normal result */ 102 {__HI(x) = (hx&0x800fffff)|(k<<20); return x;} 103 if (k <= -54) { 104 if (n > 50000) /* in case integer overflow in n+k */ 105 return hugeX*copysign(hugeX,x); /*overflow*/ 106 else return tiny*copysign(tiny,x); /*underflow*/ 107 } 108 k += 54; /* subnormal result */ 109 __HI(x) = (hx&0x800fffff)|(k<<20); 110 return x*twom54; 111} 112 113/* __ieee754_log(x) 114 * Return the logrithm of x 115 * 116 * Method : 117 * 1. Argument Reduction: find k and f such that 118 * x = 2^k * (1+f), 119 * where sqrt(2)/2 < 1+f < sqrt(2) . 120 * 121 * 2. Approximation of log(1+f). 122 * Let s = f/(2+f) ; based on log(1+f) = log(1+s) - log(1-s) 123 * = 2s + 2/3 s**3 + 2/5 s**5 + ....., 124 * = 2s + s*R 125 * We use a special Reme algorithm on [0,0.1716] to generate 126 * a polynomial of degree 14 to approximate R The maximum error 127 * of this polynomial approximation is bounded by 2**-58.45. In 128 * other words, 129 * 2 4 6 8 10 12 14 130 * R(z) ~ Lg1*s +Lg2*s +Lg3*s +Lg4*s +Lg5*s +Lg6*s +Lg7*s 131 * (the values of Lg1 to Lg7 are listed in the program) 132 * and 133 * | 2 14 | -58.45 134 * | Lg1*s +...+Lg7*s - R(z) | <= 2 135 * | | 136 * Note that 2s = f - s*f = f - hfsq + s*hfsq, where hfsq = f*f/2. 137 * In order to guarantee error in log below 1ulp, we compute log 138 * by 139 * log(1+f) = f - s*(f - R) (if f is not too large) 140 * log(1+f) = f - (hfsq - s*(hfsq+R)). (better accuracy) 141 * 142 * 3. Finally, log(x) = k*ln2 + log(1+f). 143 * = k*ln2_hi+(f-(hfsq-(s*(hfsq+R)+k*ln2_lo))) 144 * Here ln2 is split into two floating point number: 145 * ln2_hi + ln2_lo, 146 * where n*ln2_hi is always exact for |n| < 2000. 147 * 148 * Special cases: 149 * log(x) is NaN with signal if x < 0 (including -INF) ; 150 * log(+INF) is +INF; log(0) is -INF with signal; 151 * log(NaN) is that NaN with no signal. 152 * 153 * Accuracy: 154 * according to an error analysis, the error is always less than 155 * 1 ulp (unit in the last place). 156 * 157 * Constants: 158 * The hexadecimal values are the intended ones for the following 159 * constants. The decimal values may be used, provided that the 160 * compiler will convert from decimal to binary accurately enough 161 * to produce the hexadecimal values shown. 162 */ 163 164static const double 165ln2_hi = 6.93147180369123816490e-01, /* 3fe62e42 fee00000 */ 166 ln2_lo = 1.90821492927058770002e-10, /* 3dea39ef 35793c76 */ 167 Lg1 = 6.666666666666735130e-01, /* 3FE55555 55555593 */ 168 Lg2 = 3.999999999940941908e-01, /* 3FD99999 9997FA04 */ 169 Lg3 = 2.857142874366239149e-01, /* 3FD24924 94229359 */ 170 Lg4 = 2.222219843214978396e-01, /* 3FCC71C5 1D8E78AF */ 171 Lg5 = 1.818357216161805012e-01, /* 3FC74664 96CB03DE */ 172 Lg6 = 1.531383769920937332e-01, /* 3FC39A09 D078C69F */ 173 Lg7 = 1.479819860511658591e-01; /* 3FC2F112 DF3E5244 */ 174 175static double zero = 0.0; 176 177static double __ieee754_log(double x) { 178 double hfsq,f,s,z,R,w,t1,t2,dk; 179 int k,hx,i,j; 180 unsigned lx; 181 182 hx = __HI(x); /* high word of x */ 183 lx = __LO(x); /* low word of x */ 184 185 k=0; 186 if (hx < 0x00100000) { /* x < 2**-1022 */ 187 if (((hx&0x7fffffff)|lx)==0) 188 return -two54/zero; /* log(+-0)=-inf */ 189 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */ 190 k -= 54; x *= two54; /* subnormal number, scale up x */ 191 hx = __HI(x); /* high word of x */ 192 } 193 if (hx >= 0x7ff00000) return x+x; 194 k += (hx>>20)-1023; 195 hx &= 0x000fffff; 196 i = (hx+0x95f64)&0x100000; 197 __HI(x) = hx|(i^0x3ff00000); /* normalize x or x/2 */ 198 k += (i>>20); 199 f = x-1.0; 200 if((0x000fffff&(2+hx))<3) { /* |f| < 2**-20 */ 201 if(f==zero) { 202 if (k==0) return zero; 203 else {dk=(double)k; return dk*ln2_hi+dk*ln2_lo;} 204 } 205 R = f*f*(0.5-0.33333333333333333*f); 206 if(k==0) return f-R; else {dk=(double)k; 207 return dk*ln2_hi-((R-dk*ln2_lo)-f);} 208 } 209 s = f/(2.0+f); 210 dk = (double)k; 211 z = s*s; 212 i = hx-0x6147a; 213 w = z*z; 214 j = 0x6b851-hx; 215 t1= w*(Lg2+w*(Lg4+w*Lg6)); 216 t2= z*(Lg1+w*(Lg3+w*(Lg5+w*Lg7))); 217 i |= j; 218 R = t2+t1; 219 if(i>0) { 220 hfsq=0.5*f*f; 221 if(k==0) return f-(hfsq-s*(hfsq+R)); else 222 return dk*ln2_hi-((hfsq-(s*(hfsq+R)+dk*ln2_lo))-f); 223 } else { 224 if(k==0) return f-s*(f-R); else 225 return dk*ln2_hi-((s*(f-R)-dk*ln2_lo)-f); 226 } 227} 228 229JRT_LEAF(jdouble, SharedRuntime::dlog(jdouble x)) 230 return __ieee754_log(x); 231JRT_END 232 233/* __ieee754_log10(x) 234 * Return the base 10 logarithm of x 235 * 236 * Method : 237 * Let log10_2hi = leading 40 bits of log10(2) and 238 * log10_2lo = log10(2) - log10_2hi, 239 * ivln10 = 1/log(10) rounded. 240 * Then 241 * n = ilogb(x), 242 * if(n<0) n = n+1; 243 * x = scalbn(x,-n); 244 * log10(x) := n*log10_2hi + (n*log10_2lo + ivln10*log(x)) 245 * 246 * Note 1: 247 * To guarantee log10(10**n)=n, where 10**n is normal, the rounding 248 * mode must set to Round-to-Nearest. 249 * Note 2: 250 * [1/log(10)] rounded to 53 bits has error .198 ulps; 251 * log10 is monotonic at all binary break points. 252 * 253 * Special cases: 254 * log10(x) is NaN with signal if x < 0; 255 * log10(+INF) is +INF with no signal; log10(0) is -INF with signal; 256 * log10(NaN) is that NaN with no signal; 257 * log10(10**N) = N for N=0,1,...,22. 258 * 259 * Constants: 260 * The hexadecimal values are the intended ones for the following constants. 261 * The decimal values may be used, provided that the compiler will convert 262 * from decimal to binary accurately enough to produce the hexadecimal values 263 * shown. 264 */ 265 266static const double 267ivln10 = 4.34294481903251816668e-01, /* 0x3FDBCB7B, 0x1526E50E */ 268 log10_2hi = 3.01029995663611771306e-01, /* 0x3FD34413, 0x509F6000 */ 269 log10_2lo = 3.69423907715893078616e-13; /* 0x3D59FEF3, 0x11F12B36 */ 270 271static double __ieee754_log10(double x) { 272 double y,z; 273 int i,k,hx; 274 unsigned lx; 275 276 hx = __HI(x); /* high word of x */ 277 lx = __LO(x); /* low word of x */ 278 279 k=0; 280 if (hx < 0x00100000) { /* x < 2**-1022 */ 281 if (((hx&0x7fffffff)|lx)==0) 282 return -two54/zero; /* log(+-0)=-inf */ 283 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */ 284 k -= 54; x *= two54; /* subnormal number, scale up x */ 285 hx = __HI(x); /* high word of x */ 286 } 287 if (hx >= 0x7ff00000) return x+x; 288 k += (hx>>20)-1023; 289 i = ((unsigned)k&0x80000000)>>31; 290 hx = (hx&0x000fffff)|((0x3ff-i)<<20); 291 y = (double)(k+i); 292 __HI(x) = hx; 293 z = y*log10_2lo + ivln10*__ieee754_log(x); 294 return z+y*log10_2hi; 295} 296 297JRT_LEAF(jdouble, SharedRuntime::dlog10(jdouble x)) 298 return __ieee754_log10(x); 299JRT_END 300 301 302/* __ieee754_exp(x) 303 * Returns the exponential of x. 304 * 305 * Method 306 * 1. Argument reduction: 307 * Reduce x to an r so that |r| <= 0.5*ln2 ~ 0.34658. 308 * Given x, find r and integer k such that 309 * 310 * x = k*ln2 + r, |r| <= 0.5*ln2. 311 * 312 * Here r will be represented as r = hi-lo for better 313 * accuracy. 314 * 315 * 2. Approximation of exp(r) by a special rational function on 316 * the interval [0,0.34658]: 317 * Write 318 * R(r**2) = r*(exp(r)+1)/(exp(r)-1) = 2 + r*r/6 - r**4/360 + ... 319 * We use a special Reme algorithm on [0,0.34658] to generate 320 * a polynomial of degree 5 to approximate R. The maximum error 321 * of this polynomial approximation is bounded by 2**-59. In 322 * other words, 323 * R(z) ~ 2.0 + P1*z + P2*z**2 + P3*z**3 + P4*z**4 + P5*z**5 324 * (where z=r*r, and the values of P1 to P5 are listed below) 325 * and 326 * | 5 | -59 327 * | 2.0+P1*z+...+P5*z - R(z) | <= 2 328 * | | 329 * The computation of exp(r) thus becomes 330 * 2*r 331 * exp(r) = 1 + ------- 332 * R - r 333 * r*R1(r) 334 * = 1 + r + ----------- (for better accuracy) 335 * 2 - R1(r) 336 * where 337 * 2 4 10 338 * R1(r) = r - (P1*r + P2*r + ... + P5*r ). 339 * 340 * 3. Scale back to obtain exp(x): 341 * From step 1, we have 342 * exp(x) = 2^k * exp(r) 343 * 344 * Special cases: 345 * exp(INF) is INF, exp(NaN) is NaN; 346 * exp(-INF) is 0, and 347 * for finite argument, only exp(0)=1 is exact. 348 * 349 * Accuracy: 350 * according to an error analysis, the error is always less than 351 * 1 ulp (unit in the last place). 352 * 353 * Misc. info. 354 * For IEEE double 355 * if x > 7.09782712893383973096e+02 then exp(x) overflow 356 * if x < -7.45133219101941108420e+02 then exp(x) underflow 357 * 358 * Constants: 359 * The hexadecimal values are the intended ones for the following 360 * constants. The decimal values may be used, provided that the 361 * compiler will convert from decimal to binary accurately enough 362 * to produce the hexadecimal values shown. 363 */ 364 365static const double 366one = 1.0, 367 halF[2] = {0.5,-0.5,}, 368 twom1000= 9.33263618503218878990e-302, /* 2**-1000=0x01700000,0*/ 369 o_threshold= 7.09782712893383973096e+02, /* 0x40862E42, 0xFEFA39EF */ 370 u_threshold= -7.45133219101941108420e+02, /* 0xc0874910, 0xD52D3051 */ 371 ln2HI[2] ={ 6.93147180369123816490e-01, /* 0x3fe62e42, 0xfee00000 */ 372 -6.93147180369123816490e-01,},/* 0xbfe62e42, 0xfee00000 */ 373 ln2LO[2] ={ 1.90821492927058770002e-10, /* 0x3dea39ef, 0x35793c76 */ 374 -1.90821492927058770002e-10,},/* 0xbdea39ef, 0x35793c76 */ 375 invln2 = 1.44269504088896338700e+00, /* 0x3ff71547, 0x652b82fe */ 376 P1 = 1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */ 377 P2 = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */ 378 P3 = 6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */ 379 P4 = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */ 380 P5 = 4.13813679705723846039e-08; /* 0x3E663769, 0x72BEA4D0 */ 381 382static double __ieee754_exp(double x) { 383 double y,hi=0,lo=0,c,t; 384 int k=0,xsb; 385 unsigned hx; 386 387 hx = __HI(x); /* high word of x */ 388 xsb = (hx>>31)&1; /* sign bit of x */ 389 hx &= 0x7fffffff; /* high word of |x| */ 390 391 /* filter out non-finite argument */ 392 if(hx >= 0x40862E42) { /* if |x|>=709.78... */ 393 if(hx>=0x7ff00000) { 394 if(((hx&0xfffff)|__LO(x))!=0) 395 return x+x; /* NaN */ 396 else return (xsb==0)? x:0.0; /* exp(+-inf)={inf,0} */ 397 } 398 if(x > o_threshold) return hugeX*hugeX; /* overflow */ 399 if(x < u_threshold) return twom1000*twom1000; /* underflow */ 400 } 401 402 /* argument reduction */ 403 if(hx > 0x3fd62e42) { /* if |x| > 0.5 ln2 */ 404 if(hx < 0x3FF0A2B2) { /* and |x| < 1.5 ln2 */ 405 hi = x-ln2HI[xsb]; lo=ln2LO[xsb]; k = 1-xsb-xsb; 406 } else { 407 k = (int)(invln2*x+halF[xsb]); 408 t = k; 409 hi = x - t*ln2HI[0]; /* t*ln2HI is exact here */ 410 lo = t*ln2LO[0]; 411 } 412 x = hi - lo; 413 } 414 else if(hx < 0x3e300000) { /* when |x|<2**-28 */ 415 if(hugeX+x>one) return one+x;/* trigger inexact */ 416 } 417 else k = 0; 418 419 /* x is now in primary range */ 420 t = x*x; 421 c = x - t*(P1+t*(P2+t*(P3+t*(P4+t*P5)))); 422 if(k==0) return one-((x*c)/(c-2.0)-x); 423 else y = one-((lo-(x*c)/(2.0-c))-hi); 424 if(k >= -1021) { 425 __HI(y) += (k<<20); /* add k to y's exponent */ 426 return y; 427 } else { 428 __HI(y) += ((k+1000)<<20);/* add k to y's exponent */ 429 return y*twom1000; 430 } 431} 432 433JRT_LEAF(jdouble, SharedRuntime::dexp(jdouble x)) 434 return __ieee754_exp(x); 435JRT_END 436 437/* __ieee754_pow(x,y) return x**y 438 * 439 * n 440 * Method: Let x = 2 * (1+f) 441 * 1. Compute and return log2(x) in two pieces: 442 * log2(x) = w1 + w2, 443 * where w1 has 53-24 = 29 bit trailing zeros. 444 * 2. Perform y*log2(x) = n+y' by simulating muti-precision 445 * arithmetic, where |y'|<=0.5. 446 * 3. Return x**y = 2**n*exp(y'*log2) 447 * 448 * Special cases: 449 * 1. (anything) ** 0 is 1 450 * 2. (anything) ** 1 is itself 451 * 3. (anything) ** NAN is NAN 452 * 4. NAN ** (anything except 0) is NAN 453 * 5. +-(|x| > 1) ** +INF is +INF 454 * 6. +-(|x| > 1) ** -INF is +0 455 * 7. +-(|x| < 1) ** +INF is +0 456 * 8. +-(|x| < 1) ** -INF is +INF 457 * 9. +-1 ** +-INF is NAN 458 * 10. +0 ** (+anything except 0, NAN) is +0 459 * 11. -0 ** (+anything except 0, NAN, odd integer) is +0 460 * 12. +0 ** (-anything except 0, NAN) is +INF 461 * 13. -0 ** (-anything except 0, NAN, odd integer) is +INF 462 * 14. -0 ** (odd integer) = -( +0 ** (odd integer) ) 463 * 15. +INF ** (+anything except 0,NAN) is +INF 464 * 16. +INF ** (-anything except 0,NAN) is +0 465 * 17. -INF ** (anything) = -0 ** (-anything) 466 * 18. (-anything) ** (integer) is (-1)**(integer)*(+anything**integer) 467 * 19. (-anything except 0 and inf) ** (non-integer) is NAN 468 * 469 * Accuracy: 470 * pow(x,y) returns x**y nearly rounded. In particular 471 * pow(integer,integer) 472 * always returns the correct integer provided it is 473 * representable. 474 * 475 * Constants : 476 * The hexadecimal values are the intended ones for the following 477 * constants. The decimal values may be used, provided that the 478 * compiler will convert from decimal to binary accurately enough 479 * to produce the hexadecimal values shown. 480 */ 481 482static const double 483bp[] = {1.0, 1.5,}, 484 dp_h[] = { 0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */ 485 dp_l[] = { 0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */ 486 zeroX = 0.0, 487 two = 2.0, 488 two53 = 9007199254740992.0, /* 0x43400000, 0x00000000 */ 489 /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */ 490 L1X = 5.99999999999994648725e-01, /* 0x3FE33333, 0x33333303 */ 491 L2X = 4.28571428578550184252e-01, /* 0x3FDB6DB6, 0xDB6FABFF */ 492 L3X = 3.33333329818377432918e-01, /* 0x3FD55555, 0x518F264D */ 493 L4X = 2.72728123808534006489e-01, /* 0x3FD17460, 0xA91D4101 */ 494 L5X = 2.30660745775561754067e-01, /* 0x3FCD864A, 0x93C9DB65 */ 495 L6X = 2.06975017800338417784e-01, /* 0x3FCA7E28, 0x4A454EEF */ 496 lg2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */ 497 lg2_h = 6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */ 498 lg2_l = -1.90465429995776804525e-09, /* 0xBE205C61, 0x0CA86C39 */ 499 ovt = 8.0085662595372944372e-0017, /* -(1024-log2(ovfl+.5ulp)) */ 500 cp = 9.61796693925975554329e-01, /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */ 501 cp_h = 9.61796700954437255859e-01, /* 0x3FEEC709, 0xE0000000 =(float)cp */ 502 cp_l = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h*/ 503 ivln2 = 1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */ 504 ivln2_h = 1.44269502162933349609e+00, /* 0x3FF71547, 0x60000000 =24b 1/ln2*/ 505 ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/ 506 507double __ieee754_pow(double x, double y) { 508 double z,ax,z_h,z_l,p_h,p_l; 509 double y1,t1,t2,r,s,t,u,v,w; 510 int i0,i1,i,j,k,yisint,n; 511 int hx,hy,ix,iy; 512 unsigned lx,ly; 513 514 i0 = ((*(int*)&one)>>29)^1; i1=1-i0; 515 hx = __HI(x); lx = __LO(x); 516 hy = __HI(y); ly = __LO(y); 517 ix = hx&0x7fffffff; iy = hy&0x7fffffff; 518 519 /* y==zero: x**0 = 1 */ 520 if((iy|ly)==0) return one; 521 522 /* +-NaN return x+y */ 523 if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) || 524 iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0))) 525 return x+y; 526 527 /* determine if y is an odd int when x < 0 528 * yisint = 0 ... y is not an integer 529 * yisint = 1 ... y is an odd int 530 * yisint = 2 ... y is an even int 531 */ 532 yisint = 0; 533 if(hx<0) { 534 if(iy>=0x43400000) yisint = 2; /* even integer y */ 535 else if(iy>=0x3ff00000) { 536 k = (iy>>20)-0x3ff; /* exponent */ 537 if(k>20) { 538 j = ly>>(52-k); 539 if((unsigned)(j<<(52-k))==ly) yisint = 2-(j&1); 540 } else if(ly==0) { 541 j = iy>>(20-k); 542 if((j<<(20-k))==iy) yisint = 2-(j&1); 543 } 544 } 545 } 546 547 /* special value of y */ 548 if(ly==0) { 549 if (iy==0x7ff00000) { /* y is +-inf */ 550 if(((ix-0x3ff00000)|lx)==0) 551 return y - y; /* inf**+-1 is NaN */ 552 else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */ 553 return (hy>=0)? y: zeroX; 554 else /* (|x|<1)**-,+inf = inf,0 */ 555 return (hy<0)?-y: zeroX; 556 } 557 if(iy==0x3ff00000) { /* y is +-1 */ 558 if(hy<0) return one/x; else return x; 559 } 560 if(hy==0x40000000) return x*x; /* y is 2 */ 561 if(hy==0x3fe00000) { /* y is 0.5 */ 562 if(hx>=0) /* x >= +0 */ 563 return sqrt(x); 564 } 565 } 566 567 ax = fabsd(x); 568 /* special value of x */ 569 if(lx==0) { 570 if(ix==0x7ff00000||ix==0||ix==0x3ff00000){ 571 z = ax; /*x is +-0,+-inf,+-1*/ 572 if(hy<0) z = one/z; /* z = (1/|x|) */ 573 if(hx<0) { 574 if(((ix-0x3ff00000)|yisint)==0) { 575 z = (z-z)/(z-z); /* (-1)**non-int is NaN */ 576 } else if(yisint==1) 577 z = -1.0*z; /* (x<0)**odd = -(|x|**odd) */ 578 } 579 return z; 580 } 581 } 582 583 n = (hx>>31)+1; 584 585 /* (x<0)**(non-int) is NaN */ 586 if((n|yisint)==0) return (x-x)/(x-x); 587 588 s = one; /* s (sign of result -ve**odd) = -1 else = 1 */ 589 if((n|(yisint-1))==0) s = -one;/* (-ve)**(odd int) */ 590 591 /* |y| is huge */ 592 if(iy>0x41e00000) { /* if |y| > 2**31 */ 593 if(iy>0x43f00000){ /* if |y| > 2**64, must o/uflow */ 594 if(ix<=0x3fefffff) return (hy<0)? hugeX*hugeX:tiny*tiny; 595 if(ix>=0x3ff00000) return (hy>0)? hugeX*hugeX:tiny*tiny; 596 } 597 /* over/underflow if x is not close to one */ 598 if(ix<0x3fefffff) return (hy<0)? s*hugeX*hugeX:s*tiny*tiny; 599 if(ix>0x3ff00000) return (hy>0)? s*hugeX*hugeX:s*tiny*tiny; 600 /* now |1-x| is tiny <= 2**-20, suffice to compute 601 log(x) by x-x^2/2+x^3/3-x^4/4 */ 602 t = ax-one; /* t has 20 trailing zeros */ 603 w = (t*t)*(0.5-t*(0.3333333333333333333333-t*0.25)); 604 u = ivln2_h*t; /* ivln2_h has 21 sig. bits */ 605 v = t*ivln2_l-w*ivln2; 606 t1 = u+v; 607 __LO(t1) = 0; 608 t2 = v-(t1-u); 609 } else { 610 double ss,s2,s_h,s_l,t_h,t_l; 611 n = 0; 612 /* take care subnormal number */ 613 if(ix<0x00100000) 614 {ax *= two53; n -= 53; ix = __HI(ax); } 615 n += ((ix)>>20)-0x3ff; 616 j = ix&0x000fffff; 617 /* determine interval */ 618 ix = j|0x3ff00000; /* normalize ix */ 619 if(j<=0x3988E) k=0; /* |x|<sqrt(3/2) */ 620 else if(j<0xBB67A) k=1; /* |x|<sqrt(3) */ 621 else {k=0;n+=1;ix -= 0x00100000;} 622 __HI(ax) = ix; 623 624 /* compute ss = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */ 625 u = ax-bp[k]; /* bp[0]=1.0, bp[1]=1.5 */ 626 v = one/(ax+bp[k]); 627 ss = u*v; 628 s_h = ss; 629 __LO(s_h) = 0; 630 /* t_h=ax+bp[k] High */ 631 t_h = zeroX; 632 __HI(t_h)=((ix>>1)|0x20000000)+0x00080000+(k<<18); 633 t_l = ax - (t_h-bp[k]); 634 s_l = v*((u-s_h*t_h)-s_h*t_l); 635 /* compute log(ax) */ 636 s2 = ss*ss; 637 r = s2*s2*(L1X+s2*(L2X+s2*(L3X+s2*(L4X+s2*(L5X+s2*L6X))))); 638 r += s_l*(s_h+ss); 639 s2 = s_h*s_h; 640 t_h = 3.0+s2+r; 641 __LO(t_h) = 0; 642 t_l = r-((t_h-3.0)-s2); 643 /* u+v = ss*(1+...) */ 644 u = s_h*t_h; 645 v = s_l*t_h+t_l*ss; 646 /* 2/(3log2)*(ss+...) */ 647 p_h = u+v; 648 __LO(p_h) = 0; 649 p_l = v-(p_h-u); 650 z_h = cp_h*p_h; /* cp_h+cp_l = 2/(3*log2) */ 651 z_l = cp_l*p_h+p_l*cp+dp_l[k]; 652 /* log2(ax) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */ 653 t = (double)n; 654 t1 = (((z_h+z_l)+dp_h[k])+t); 655 __LO(t1) = 0; 656 t2 = z_l-(((t1-t)-dp_h[k])-z_h); 657 } 658 659 /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */ 660 y1 = y; 661 __LO(y1) = 0; 662 p_l = (y-y1)*t1+y*t2; 663 p_h = y1*t1; 664 z = p_l+p_h; 665 j = __HI(z); 666 i = __LO(z); 667 if (j>=0x40900000) { /* z >= 1024 */ 668 if(((j-0x40900000)|i)!=0) /* if z > 1024 */ 669 return s*hugeX*hugeX; /* overflow */ 670 else { 671 if(p_l+ovt>z-p_h) return s*hugeX*hugeX; /* overflow */ 672 } 673 } else if((j&0x7fffffff)>=0x4090cc00 ) { /* z <= -1075 */ 674 if(((j-0xc090cc00)|i)!=0) /* z < -1075 */ 675 return s*tiny*tiny; /* underflow */ 676 else { 677 if(p_l<=z-p_h) return s*tiny*tiny; /* underflow */ 678 } 679 } 680 /* 681 * compute 2**(p_h+p_l) 682 */ 683 i = j&0x7fffffff; 684 k = (i>>20)-0x3ff; 685 n = 0; 686 if(i>0x3fe00000) { /* if |z| > 0.5, set n = [z+0.5] */ 687 n = j+(0x00100000>>(k+1)); 688 k = ((n&0x7fffffff)>>20)-0x3ff; /* new k for n */ 689 t = zeroX; 690 __HI(t) = (n&~(0x000fffff>>k)); 691 n = ((n&0x000fffff)|0x00100000)>>(20-k); 692 if(j<0) n = -n; 693 p_h -= t; 694 } 695 t = p_l+p_h; 696 __LO(t) = 0; 697 u = t*lg2_h; 698 v = (p_l-(t-p_h))*lg2+t*lg2_l; 699 z = u+v; 700 w = v-(z-u); 701 t = z*z; 702 t1 = z - t*(P1+t*(P2+t*(P3+t*(P4+t*P5)))); 703 r = (z*t1)/(t1-two)-(w+z*w); 704 z = one-(r-z); 705 j = __HI(z); 706 j += (n<<20); 707 if((j>>20)<=0) z = scalbn(z,n); /* subnormal output */ 708 else __HI(z) += (n<<20); 709 return s*z; 710} 711 712 713JRT_LEAF(jdouble, SharedRuntime::dpow(jdouble x, jdouble y)) 714 return __ieee754_pow(x, y); 715JRT_END 716 717#ifdef WIN32 718# pragma optimize ( "", on ) 719#endif 720