runtime/MathObject.cpp

   1 /*
   2  *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
   3  *  Copyright (C) 2007, 2008, 2013 Apple Inc. All Rights Reserved.
   4  *
   5  *  This library is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU Lesser General Public
   7  *  License as published by the Free Software Foundation; either
   8  *  version 2 of the License, or (at your option) any later version.
   9  *
  10  *  This library is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *  Lesser General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU Lesser General Public
  16  *  License along with this library; if not, write to the Free Software
  17  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  18  *
  19  */
  20
  21 #include "config.h"
  22 #include "MathObject.h"
  23
  24 #include "Lookup.h"
  25 #include "ObjectPrototype.h"
  26 #include "JSCInlines.h"
  27 #include <time.h>
  28 #include <wtf/Assertions.h>
  29 #include <wtf/MathExtras.h>
  30 #include <wtf/RandomNumber.h>
  31 #include <wtf/RandomNumberSeed.h>
  32 #include <wtf/Vector.h>
  33
  34 namespace JSC {
  35
  36 STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(MathObject);
  37
  38 static EncodedJSValue JSC_HOST_CALL mathProtoFuncAbs(ExecState*);
  39 static EncodedJSValue JSC_HOST_CALL mathProtoFuncACos(ExecState*);
  40 static EncodedJSValue JSC_HOST_CALL mathProtoFuncACosh(ExecState*);
  41 static EncodedJSValue JSC_HOST_CALL mathProtoFuncASin(ExecState*);
  42 static EncodedJSValue JSC_HOST_CALL mathProtoFuncASinh(ExecState*);
  43 static EncodedJSValue JSC_HOST_CALL mathProtoFuncATan(ExecState*);
  44 static EncodedJSValue JSC_HOST_CALL mathProtoFuncATanh(ExecState*);
  45 static EncodedJSValue JSC_HOST_CALL mathProtoFuncATan2(ExecState*);
  46 static EncodedJSValue JSC_HOST_CALL mathProtoFuncCbrt(ExecState*);
  47 static EncodedJSValue JSC_HOST_CALL mathProtoFuncCeil(ExecState*);
  48 static EncodedJSValue JSC_HOST_CALL mathProtoFuncCos(ExecState*);
  49 static EncodedJSValue JSC_HOST_CALL mathProtoFuncCosh(ExecState*);
  50 static EncodedJSValue JSC_HOST_CALL mathProtoFuncExp(ExecState*);
  51 static EncodedJSValue JSC_HOST_CALL mathProtoFuncExpm1(ExecState*);
  52 static EncodedJSValue JSC_HOST_CALL mathProtoFuncFloor(ExecState*);
  53 static EncodedJSValue JSC_HOST_CALL mathProtoFuncFround(ExecState*);
  54 static EncodedJSValue JSC_HOST_CALL mathProtoFuncHypot(ExecState*);
  55 static EncodedJSValue JSC_HOST_CALL mathProtoFuncLog(ExecState*);
  56 static EncodedJSValue JSC_HOST_CALL mathProtoFuncLog1p(ExecState*);
  57 static EncodedJSValue JSC_HOST_CALL mathProtoFuncLog10(ExecState*);
  58 static EncodedJSValue JSC_HOST_CALL mathProtoFuncLog2(ExecState*);
  59 static EncodedJSValue JSC_HOST_CALL mathProtoFuncMax(ExecState*);
  60 static EncodedJSValue JSC_HOST_CALL mathProtoFuncMin(ExecState*);
  61 static EncodedJSValue JSC_HOST_CALL mathProtoFuncPow(ExecState*);
  62 static EncodedJSValue JSC_HOST_CALL mathProtoFuncRandom(ExecState*);
  63 static EncodedJSValue JSC_HOST_CALL mathProtoFuncRound(ExecState*);
  64 static EncodedJSValue JSC_HOST_CALL mathProtoFuncSin(ExecState*);
  65 static EncodedJSValue JSC_HOST_CALL mathProtoFuncSinh(ExecState*);
  66 static EncodedJSValue JSC_HOST_CALL mathProtoFuncSqrt(ExecState*);
  67 static EncodedJSValue JSC_HOST_CALL mathProtoFuncTan(ExecState*);
  68 static EncodedJSValue JSC_HOST_CALL mathProtoFuncTanh(ExecState*);
  69 static EncodedJSValue JSC_HOST_CALL mathProtoFuncTrunc(ExecState*);
  70 static EncodedJSValue JSC_HOST_CALL mathProtoFuncIMul(ExecState*);
  71
  72 }
  73
  74 namespace JSC {
  75
  76 const ClassInfo MathObject::s_info = { "Math", &Base::s_info, 0, 0, CREATE_METHOD_TABLE(MathObject) };
  77
  78 MathObject::MathObject(VM& vm, Structure* structure)
  79     : JSNonFinalObject(vm, structure)
  80 {
  81 }
  82
  83 void MathObject::finishCreation(VM& vm, JSGlobalObject* globalObject)
  84 {
  85     Base::finishCreation(vm);
  86     ASSERT(inherits(info()));
  87
  88     putDirectWithoutTransition(vm, Identifier(&vm, "E"), jsNumber(exp(1.0)), DontDelete | DontEnum | ReadOnly);
  89     putDirectWithoutTransition(vm, Identifier(&vm, "LN2"), jsNumber(log(2.0)), DontDelete | DontEnum | ReadOnly);
  90     putDirectWithoutTransition(vm, Identifier(&vm, "LN10"), jsNumber(log(10.0)), DontDelete | DontEnum | ReadOnly);
  91     putDirectWithoutTransition(vm, Identifier(&vm, "LOG2E"), jsNumber(1.0 / log(2.0)), DontDelete | DontEnum | ReadOnly);
  92     putDirectWithoutTransition(vm, Identifier(&vm, "LOG10E"), jsNumber(0.4342944819032518), DontDelete | DontEnum | ReadOnly);
  93     putDirectWithoutTransition(vm, Identifier(&vm, "PI"), jsNumber(piDouble), DontDelete | DontEnum | ReadOnly);
  94     putDirectWithoutTransition(vm, Identifier(&vm, "SQRT1_2"), jsNumber(sqrt(0.5)), DontDelete | DontEnum | ReadOnly);
  95     putDirectWithoutTransition(vm, Identifier(&vm, "SQRT2"), jsNumber(sqrt(2.0)), DontDelete | DontEnum | ReadOnly);
  96
  97     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "abs"), 1, mathProtoFuncAbs, AbsIntrinsic, DontEnum | Function);
  98     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "acos"), 1, mathProtoFuncACos, NoIntrinsic, DontEnum | Function);
  99     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "asin"), 1, mathProtoFuncASin, NoIntrinsic, DontEnum | Function);
 100     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "atan"), 1, mathProtoFuncATan, NoIntrinsic, DontEnum | Function);
 101     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "acosh"), 1, mathProtoFuncACosh, NoIntrinsic, DontEnum | Function);
 102     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "asinh"), 1, mathProtoFuncASinh, NoIntrinsic, DontEnum | Function);
 103     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "atanh"), 1, mathProtoFuncATanh, NoIntrinsic, DontEnum | Function);
 104     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "atan2"), 2, mathProtoFuncATan2, NoIntrinsic, DontEnum | Function);
 105     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "cbrt"), 1, mathProtoFuncCbrt, NoIntrinsic, DontEnum | Function);
 106     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "ceil"), 1, mathProtoFuncCeil, CeilIntrinsic, DontEnum | Function);
 107     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "cos"), 1, mathProtoFuncCos, CosIntrinsic, DontEnum | Function);
 108     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "cosh"), 1, mathProtoFuncCosh, NoIntrinsic, DontEnum | Function);
 109     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "exp"), 1, mathProtoFuncExp, ExpIntrinsic, DontEnum | Function);
 110     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "expm1"), 1, mathProtoFuncExpm1, NoIntrinsic, DontEnum | Function);
 111     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "floor"), 1, mathProtoFuncFloor, FloorIntrinsic, DontEnum | Function);
 112     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "fround"), 1, mathProtoFuncFround, FRoundIntrinsic, DontEnum | Function);
 113     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "hypot"), 2, mathProtoFuncHypot, NoIntrinsic, DontEnum | Function);
 114     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "log"), 1, mathProtoFuncLog, LogIntrinsic, DontEnum | Function);
 115     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "log10"), 1, mathProtoFuncLog10, NoIntrinsic, DontEnum | Function);
 116     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "log1p"), 1, mathProtoFuncLog1p, NoIntrinsic, DontEnum | Function);
 117     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "log2"), 1, mathProtoFuncLog2, NoIntrinsic, DontEnum | Function);
 118     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "max"), 2, mathProtoFuncMax, MaxIntrinsic, DontEnum | Function);
 119     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "min"), 2, mathProtoFuncMin, MinIntrinsic, DontEnum | Function);
 120     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "pow"), 2, mathProtoFuncPow, PowIntrinsic, DontEnum | Function);
 121     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "random"), 0, mathProtoFuncRandom, NoIntrinsic, DontEnum | Function);
 122     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "round"), 1, mathProtoFuncRound, RoundIntrinsic, DontEnum | Function);
 123     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "sin"), 1, mathProtoFuncSin, SinIntrinsic, DontEnum | Function);
 124     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "sinh"), 1, mathProtoFuncSinh, NoIntrinsic, DontEnum | Function);
 125     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "sqrt"), 1, mathProtoFuncSqrt, SqrtIntrinsic, DontEnum | Function);
 126     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "tan"), 1, mathProtoFuncTan, NoIntrinsic, DontEnum | Function);
 127     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "tanh"), 1, mathProtoFuncTanh, NoIntrinsic, DontEnum | Function);
 128     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "trunc"), 1, mathProtoFuncTrunc, NoIntrinsic, DontEnum | Function);
 129     putDirectNativeFunctionWithoutTransition(vm, globalObject, Identifier(&vm, "imul"), 1, mathProtoFuncIMul, IMulIntrinsic, DontEnum | Function);
 130 }
 131
 132 // ------------------------------ Functions --------------------------------
 133
 134 EncodedJSValue JSC_HOST_CALL mathProtoFuncAbs(ExecState* exec)
 135 {
 136     return JSValue::encode(jsNumber(fabs(exec->argument(0).toNumber(exec))));
 137 }
 138
 139 EncodedJSValue JSC_HOST_CALL mathProtoFuncACos(ExecState* exec)
 140 {
 141     return JSValue::encode(jsDoubleNumber(acos(exec->argument(0).toNumber(exec))));
 142 }
 143
 144 EncodedJSValue JSC_HOST_CALL mathProtoFuncASin(ExecState* exec)
 145 {
 146     return JSValue::encode(jsDoubleNumber(asin(exec->argument(0).toNumber(exec))));
 147 }
 148
 149 EncodedJSValue JSC_HOST_CALL mathProtoFuncATan(ExecState* exec)
 150 {
 151     return JSValue::encode(jsDoubleNumber(atan(exec->argument(0).toNumber(exec))));
 152 }
 153
 154 EncodedJSValue JSC_HOST_CALL mathProtoFuncATan2(ExecState* exec)
 155 {
 156     double arg0 = exec->argument(0).toNumber(exec);
 157     double arg1 = exec->argument(1).toNumber(exec);
 158     return JSValue::encode(jsDoubleNumber(atan2(arg0, arg1)));
 159 }
 160
 161 EncodedJSValue JSC_HOST_CALL mathProtoFuncCeil(ExecState* exec)
 162 {
 163     return JSValue::encode(jsNumber(ceil(exec->argument(0).toNumber(exec))));
 164 }
 165
 166 EncodedJSValue JSC_HOST_CALL mathProtoFuncCos(ExecState* exec)
 167 {
 168     return JSValue::encode(jsDoubleNumber(cos(exec->argument(0).toNumber(exec))));
 169 }
 170
 171 EncodedJSValue JSC_HOST_CALL mathProtoFuncExp(ExecState* exec)
 172 {
 173     return JSValue::encode(jsDoubleNumber(exp(exec->argument(0).toNumber(exec))));
 174 }
 175
 176 EncodedJSValue JSC_HOST_CALL mathProtoFuncFloor(ExecState* exec)
 177 {
 178     return JSValue::encode(jsNumber(floor(exec->argument(0).toNumber(exec))));
 179 }
 180
 181 EncodedJSValue JSC_HOST_CALL mathProtoFuncHypot(ExecState* exec)
 182 {
 183     unsigned argsCount = exec->argumentCount();
 184     double max = 0;
 185     Vector<double, 8> args;
 186     args.reserveInitialCapacity(argsCount);
 187     for (unsigned i = 0; i < argsCount; ++i) {
 188         args.uncheckedAppend(exec->uncheckedArgument(i).toNumber(exec));
 189         if (exec->hadException())
 190             return JSValue::encode(jsNull());
 191         if (std::isinf(args[i]))
 192             return JSValue::encode(jsDoubleNumber(+std::numeric_limits<double>::infinity()));
 193         max = std::max(fabs(args[i]), max);
 194     }
 195     if (!max)
 196         max = 1;
 197     // Kahan summation algorithm significantly reduces the numerical error in the total obtained.
 198     double sum = 0;
 199     double compensation = 0;
 200     for (double argument : args) {
 201         double scaledArgument = argument / max;
 202         double summand = scaledArgument * scaledArgument - compensation;
 203         double preliminary = sum + summand;
 204         compensation = (preliminary - sum) - summand;
 205         sum = preliminary;
 206     }
 207     return JSValue::encode(jsDoubleNumber(sqrt(sum) * max));
 208 }
 209
 210 EncodedJSValue JSC_HOST_CALL mathProtoFuncLog(ExecState* exec)
 211 {
 212     return JSValue::encode(jsDoubleNumber(log(exec->argument(0).toNumber(exec))));
 213 }
 214
 215 EncodedJSValue JSC_HOST_CALL mathProtoFuncMax(ExecState* exec)
 216 {
 217     unsigned argsCount = exec->argumentCount();
 218     double result = -std::numeric_limits<double>::infinity();
 219     for (unsigned k = 0; k < argsCount; ++k) {
 220         double val = exec->uncheckedArgument(k).toNumber(exec);
 221         if (std::isnan(val)) {
 222             result = PNaN;
 223         } else if (val > result || (!val && !result && !std::signbit(val)))
 224             result = val;
 225     }
 226     return JSValue::encode(jsNumber(result));
 227 }
 228
 229 EncodedJSValue JSC_HOST_CALL mathProtoFuncMin(ExecState* exec)
 230 {
 231     unsigned argsCount = exec->argumentCount();
 232     double result = +std::numeric_limits<double>::infinity();
 233     for (unsigned k = 0; k < argsCount; ++k) {
 234         double val = exec->uncheckedArgument(k).toNumber(exec);
 235         if (std::isnan(val)) {
 236             result = PNaN;
 237         } else if (val < result || (!val && !result && std::signbit(val)))
 238             result = val;
 239     }
 240     return JSValue::encode(jsNumber(result));
 241 }
 242
 243 #if PLATFORM(IOS) && CPU(ARM_THUMB2)
 244
 245 static double fdlibmPow(double x, double y);
 246
 247 static ALWAYS_INLINE bool isDenormal(double x)
 248 {
 249         static const uint64_t signbit = 0x8000000000000000ULL;
 250         static const uint64_t minNormal = 0x0001000000000000ULL;
 251         return (bitwise_cast<uint64_t>(x) & ~signbit) - 1 < minNormal - 1;
 252 }
 253
 254 static ALWAYS_INLINE bool isEdgeCase(double x)
 255 {
 256         static const uint64_t signbit = 0x8000000000000000ULL;
 257         static const uint64_t infinity = 0x7fffffffffffffffULL;
 258         return (bitwise_cast<uint64_t>(x) & ~signbit) - 1 >= infinity - 1;
 259 }
 260
 261 static ALWAYS_INLINE double mathPow(double x, double y)
 262 {
 263     if (!isDenormal(x) && !isDenormal(y)) {
 264         double libmResult = pow(x,y);
 265         if (libmResult || isEdgeCase(x) || isEdgeCase(y))
 266             return libmResult;
 267     }
 268     return fdlibmPow(x,y);
 269 }
 270
 271 #else
 272
 273 ALWAYS_INLINE double mathPow(double x, double y)
 274 {
 275     return pow(x, y);
 276 }
 277
 278 #endif
 279
 280 EncodedJSValue JSC_HOST_CALL mathProtoFuncPow(ExecState* exec)
 281 {
 282     // ECMA 15.8.2.1.13
 283
 284     double arg = exec->argument(0).toNumber(exec);
 285     double arg2 = exec->argument(1).toNumber(exec);
 286
 287     if (std::isnan(arg2))
 288         return JSValue::encode(jsNaN());
 289     if (std::isinf(arg2) && fabs(arg) == 1)
 290         return JSValue::encode(jsNaN());
 291     return JSValue::encode(jsNumber(mathPow(arg, arg2)));
 292 }
 293
 294 EncodedJSValue JSC_HOST_CALL mathProtoFuncRandom(ExecState* exec)
 295 {
 296     return JSValue::encode(jsDoubleNumber(exec->lexicalGlobalObject()->weakRandomNumber()));
 297 }
 298
 299 EncodedJSValue JSC_HOST_CALL mathProtoFuncRound(ExecState* exec)
 300 {
 301     double arg = exec->argument(0).toNumber(exec);
 302     double integer = ceil(arg);
 303     return JSValue::encode(jsNumber(integer - (integer - arg > 0.5)));
 304 }
 305
 306 EncodedJSValue JSC_HOST_CALL mathProtoFuncSin(ExecState* exec)
 307 {
 308     return JSValue::encode(jsDoubleNumber(sin(exec->argument(0).toNumber(exec))));
 309 }
 310
 311 EncodedJSValue JSC_HOST_CALL mathProtoFuncSqrt(ExecState* exec)
 312 {
 313     return JSValue::encode(jsDoubleNumber(sqrt(exec->argument(0).toNumber(exec))));
 314 }
 315
 316 EncodedJSValue JSC_HOST_CALL mathProtoFuncTan(ExecState* exec)
 317 {
 318     return JSValue::encode(jsDoubleNumber(tan(exec->argument(0).toNumber(exec))));
 319 }
 320
 321 EncodedJSValue JSC_HOST_CALL mathProtoFuncIMul(ExecState* exec)
 322 {
 323     int32_t left = exec->argument(0).toInt32(exec);
 324     if (exec->hadException())
 325         return JSValue::encode(jsNull());
 326     int32_t right = exec->argument(1).toInt32(exec);
 327     return JSValue::encode(jsNumber(left * right));
 328 }
 329
 330 EncodedJSValue JSC_HOST_CALL mathProtoFuncACosh(ExecState* exec)
 331 {
 332     return JSValue::encode(jsDoubleNumber(acosh(exec->argument(0).toNumber(exec))));
 333 }
 334
 335 EncodedJSValue JSC_HOST_CALL mathProtoFuncASinh(ExecState* exec)
 336 {
 337     return JSValue::encode(jsDoubleNumber(asinh(exec->argument(0).toNumber(exec))));
 338 }
 339
 340 EncodedJSValue JSC_HOST_CALL mathProtoFuncATanh(ExecState* exec)
 341 {
 342     return JSValue::encode(jsDoubleNumber(atanh(exec->argument(0).toNumber(exec))));
 343 }
 344
 345 EncodedJSValue JSC_HOST_CALL mathProtoFuncCbrt(ExecState* exec)
 346 {
 347     return JSValue::encode(jsDoubleNumber(cbrt(exec->argument(0).toNumber(exec))));
 348 }
 349
 350 EncodedJSValue JSC_HOST_CALL mathProtoFuncCosh(ExecState* exec)
 351 {
 352     return JSValue::encode(jsDoubleNumber(cosh(exec->argument(0).toNumber(exec))));
 353 }
 354
 355 EncodedJSValue JSC_HOST_CALL mathProtoFuncExpm1(ExecState* exec)
 356 {
 357     return JSValue::encode(jsDoubleNumber(expm1(exec->argument(0).toNumber(exec))));
 358 }
 359
 360 EncodedJSValue JSC_HOST_CALL mathProtoFuncFround(ExecState* exec)
 361 {
 362     return JSValue::encode(jsDoubleNumber(static_cast<float>(exec->argument(0).toNumber(exec))));
 363 }
 364
 365 EncodedJSValue JSC_HOST_CALL mathProtoFuncLog1p(ExecState* exec)
 366 {
 367     double value = exec->argument(0).toNumber(exec);
 368     if (value == 0)
 369         return JSValue::encode(jsDoubleNumber(value));
 370     return JSValue::encode(jsDoubleNumber(log1p(value)));
 371 }
 372
 373 EncodedJSValue JSC_HOST_CALL mathProtoFuncLog10(ExecState* exec)
 374 {
 375     return JSValue::encode(jsDoubleNumber(log10(exec->argument(0).toNumber(exec))));
 376 }
 377
 378 EncodedJSValue JSC_HOST_CALL mathProtoFuncLog2(ExecState* exec)
 379 {
 380     return JSValue::encode(jsDoubleNumber(log2(exec->argument(0).toNumber(exec))));
 381 }
 382
 383 EncodedJSValue JSC_HOST_CALL mathProtoFuncSinh(ExecState* exec)
 384 {
 385     return JSValue::encode(jsDoubleNumber(sinh(exec->argument(0).toNumber(exec))));
 386 }
 387
 388 EncodedJSValue JSC_HOST_CALL mathProtoFuncTanh(ExecState* exec)
 389 {
 390     return JSValue::encode(jsDoubleNumber(tanh(exec->argument(0).toNumber(exec))));
 391 }
 392
 393 EncodedJSValue JSC_HOST_CALL mathProtoFuncTrunc(ExecState*exec)
 394 {
 395     return JSValue::encode(jsNumber(exec->argument(0).toIntegerPreserveNaN(exec)));
 396 }
 397
 398
 399 #if PLATFORM(IOS) && CPU(ARM_THUMB2)
 400
 401 // The following code is taken from netlib.org:
 402 //   http://www.netlib.org/fdlibm/fdlibm.h
 403 //   http://www.netlib.org/fdlibm/e_pow.c
 404 //   http://www.netlib.org/fdlibm/s_scalbn.c
 405 //
 406 // And was originally distributed under the following license:
 407
 408 /*
 409  * ====================================================
 410  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 411  *
 412  * Developed at SunSoft, a Sun Microsystems, Inc. business.
 413  * Permission to use, copy, modify, and distribute this
 414  * software is freely granted, provided that this notice
 415  * is preserved.
 416  * ====================================================
 417  */
 418 /*
 419  * ====================================================
 420  * Copyright (C) 2004 by Sun Microsystems, Inc. All rights reserved.
 421  *
 422  * Permission to use, copy, modify, and distribute this
 423  * software is freely granted, provided that this notice
 424  * is preserved.
 425  * ====================================================
 426  */
 427
 428 /* __ieee754_pow(x,y) return x**y
 429  *
 430  *              n
 431  * Method:  Let x =  2   * (1+f)
 432  *    1. Compute and return log2(x) in two pieces:
 433  *        log2(x) = w1 + w2,
 434  *       where w1 has 53-24 = 29 bit trailing zeros.
 435  *    2. Perform y*log2(x) = n+y' by simulating muti-precision
 436  *       arithmetic, where |y'|<=0.5.
 437  *    3. Return x**y = 2**n*exp(y'*log2)
 438  *
 439  * Special cases:
 440  *    1.  (anything) ** 0  is 1
 441  *    2.  (anything) ** 1  is itself
 442  *    3.  (anything) ** NAN is NAN
 443  *    4.  NAN ** (anything except 0) is NAN
 444  *    5.  +-(|x| > 1) **  +INF is +INF
 445  *    6.  +-(|x| > 1) **  -INF is +0
 446  *    7.  +-(|x| < 1) **  +INF is +0
 447  *    8.  +-(|x| < 1) **  -INF is +INF
 448  *    9.  +-1         ** +-INF is NAN
 449  *    10. +0 ** (+anything except 0, NAN)               is +0
 450  *    11. -0 ** (+anything except 0, NAN, odd integer)  is +0
 451  *    12. +0 ** (-anything except 0, NAN)               is +INF
 452  *    13. -0 ** (-anything except 0, NAN, odd integer)  is +INF
 453  *    14. -0 ** (odd integer) = -( +0 ** (odd integer) )
 454  *    15. +INF ** (+anything except 0,NAN) is +INF
 455  *    16. +INF ** (-anything except 0,NAN) is +0
 456  *    17. -INF ** (anything)  = -0 ** (-anything)
 457  *    18. (-anything) ** (integer) is (-1)**(integer)*(+anything**integer)
 458  *    19. (-anything except 0 and inf) ** (non-integer) is NAN
 459  *
 460  * Accuracy:
 461  *    pow(x,y) returns x**y nearly rounded. In particular
 462  *            pow(integer,integer)
 463  *    always returns the correct integer provided it is
 464  *    representable.
 465  *
 466  * Constants :
 467  * The hexadecimal values are the intended ones for the following
 468  * constants. The decimal values may be used, provided that the
 469  * compiler will convert from decimal to binary accurately enough
 470  * to produce the hexadecimal values shown.
 471  */
 472
 473 #define __HI(x) *(1+(int*)&x)
 474 #define __LO(x) *(int*)&x
 475
 476 static const double
 477 bp[] = {1.0, 1.5,},
 478 dp_h[] = { 0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */
 479 dp_l[] = { 0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */
 480 zero    =  0.0,
 481 one    =  1.0,
 482 two    =  2.0,
 483 two53    =  9007199254740992.0,    /* 0x43400000, 0x00000000 */
 484 huge    =  1.0e300,
 485 tiny    =  1.0e-300,
 486         /* for scalbn */
 487 two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
 488 twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
 489     /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */
 490 L1  =  5.99999999999994648725e-01, /* 0x3FE33333, 0x33333303 */
 491 L2  =  4.28571428578550184252e-01, /* 0x3FDB6DB6, 0xDB6FABFF */
 492 L3  =  3.33333329818377432918e-01, /* 0x3FD55555, 0x518F264D */
 493 L4  =  2.72728123808534006489e-01, /* 0x3FD17460, 0xA91D4101 */
 494 L5  =  2.30660745775561754067e-01, /* 0x3FCD864A, 0x93C9DB65 */
 495 L6  =  2.06975017800338417784e-01, /* 0x3FCA7E28, 0x4A454EEF */
 496 P1   =  1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */
 497 P2   = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */
 498 P3   =  6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */
 499 P4   = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */
 500 P5   =  4.13813679705723846039e-08, /* 0x3E663769, 0x72BEA4D0 */
 501 lg2  =  6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */
 502 lg2_h  =  6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */
 503 lg2_l  = -1.90465429995776804525e-09, /* 0xBE205C61, 0x0CA86C39 */
 504 ovt =  8.0085662595372944372e-0017, /* -(1024-log2(ovfl+.5ulp)) */
 505 cp    =  9.61796693925975554329e-01, /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */
 506 cp_h  =  9.61796700954437255859e-01, /* 0x3FEEC709, 0xE0000000 =(float)cp */
 507 cp_l  = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h*/
 508 ivln2    =  1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */
 509 ivln2_h  =  1.44269502162933349609e+00, /* 0x3FF71547, 0x60000000 =24b 1/ln2*/
 510 ivln2_l  =  1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
 511
 512 inline double fdlibmScalbn (double x, int n)
 513 {
 514     int  k,hx,lx;
 515     hx = __HI(x);
 516     lx = __LO(x);
 517         k = (hx&0x7ff00000)>>20;        /* extract exponent */
 518         if (k==0) {                /* 0 or subnormal x */
 519             if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
 520         x *= two54;
 521         hx = __HI(x);
 522         k = ((hx&0x7ff00000)>>20) - 54;
 523             if (n< -50000) return tiny*x;     /*underflow*/
 524         }
 525         if (k==0x7ff) return x+x;        /* NaN or Inf */
 526         k = k+n;
 527         if (k >  0x7fe) return huge*copysign(huge,x); /* overflow  */
 528         if (k > 0)                 /* normal result */
 529         {__HI(x) = (hx&0x800fffff)|(k<<20); return x;}
 530         if (k <= -54) {
 531             if (n > 50000)     /* in case integer overflow in n+k */
 532         return huge*copysign(huge,x);    /*overflow*/
 533         else return tiny*copysign(tiny,x);     /*underflow*/
 534         }
 535         k += 54;                /* subnormal result */
 536         __HI(x) = (hx&0x800fffff)|(k<<20);
 537         return x*twom54;
 538 }
 539
 540 double fdlibmPow(double x, double y)
 541 {
 542     double z,ax,z_h,z_l,p_h,p_l;
 543     double y1,t1,t2,r,s,t,u,v,w;
 544     int i0,i1,i,j,k,yisint,n;
 545     int hx,hy,ix,iy;
 546     unsigned lx,ly;
 547
 548     i0 = ((*(int*)&one)>>29)^1; i1=1-i0;
 549     hx = __HI(x); lx = __LO(x);
 550     hy = __HI(y); ly = __LO(y);
 551     ix = hx&0x7fffffff;  iy = hy&0x7fffffff;
 552
 553     /* y==zero: x**0 = 1 */
 554     if((iy|ly)==0) return one;
 555
 556     /* +-NaN return x+y */
 557     if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) ||
 558        iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0)))
 559         return x+y;
 560
 561     /* determine if y is an odd int when x < 0
 562      * yisint = 0    ... y is not an integer
 563      * yisint = 1    ... y is an odd int
 564      * yisint = 2    ... y is an even int
 565      */
 566     yisint  = 0;
 567     if(hx<0) {
 568         if(iy>=0x43400000) yisint = 2; /* even integer y */
 569         else if(iy>=0x3ff00000) {
 570         k = (iy>>20)-0x3ff;       /* exponent */
 571         if(k>20) {
 572             j = ly>>(52-k);
 573             if(static_cast<unsigned>(j<<(52-k))==ly) yisint = 2-(j&1);
 574         } else if(ly==0) {
 575             j = iy>>(20-k);
 576             if((j<<(20-k))==iy) yisint = 2-(j&1);
 577         }
 578         }
 579     }
 580
 581     /* special value of y */
 582     if(ly==0) {
 583         if (iy==0x7ff00000) {    /* y is +-inf */
 584             if(((ix-0x3ff00000)|lx)==0)
 585             return  y - y;    /* inf**+-1 is NaN */
 586             else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */
 587             return (hy>=0)? y: zero;
 588             else            /* (|x|<1)**-,+inf = inf,0 */
 589             return (hy<0)?-y: zero;
 590         }
 591         if(iy==0x3ff00000) {    /* y is  +-1 */
 592         if(hy<0) return one/x; else return x;
 593         }
 594         if(hy==0x40000000) return x*x; /* y is  2 */
 595         if(hy==0x3fe00000) {    /* y is  0.5 */
 596         if(hx>=0)    /* x >= +0 */
 597         return sqrt(x);
 598         }
 599     }
 600
 601     ax   = fabs(x);
 602     /* special value of x */
 603     if(lx==0) {
 604         if(ix==0x7ff00000||ix==0||ix==0x3ff00000){
 605         z = ax;            /*x is +-0,+-inf,+-1*/
 606         if(hy<0) z = one/z;    /* z = (1/|x|) */
 607         if(hx<0) {
 608             if(((ix-0x3ff00000)|yisint)==0) {
 609             z = (z-z)/(z-z); /* (-1)**non-int is NaN */
 610             } else if(yisint==1)
 611             z = -z;        /* (x<0)**odd = -(|x|**odd) */
 612         }
 613         return z;
 614         }
 615     }
 616
 617     n = (hx>>31)+1;
 618
 619     /* (x<0)**(non-int) is NaN */
 620     if((n|yisint)==0) return (x-x)/(x-x);
 621
 622     s = one; /* s (sign of result -ve**odd) = -1 else = 1 */
 623     if((n|(yisint-1))==0) s = -one;/* (-ve)**(odd int) */
 624
 625     /* |y| is huge */
 626     if(iy>0x41e00000) { /* if |y| > 2**31 */
 627         if(iy>0x43f00000){    /* if |y| > 2**64, must o/uflow */
 628         if(ix<=0x3fefffff) return (hy<0)? huge*huge:tiny*tiny;
 629         if(ix>=0x3ff00000) return (hy>0)? huge*huge:tiny*tiny;
 630         }
 631     /* over/underflow if x is not close to one */
 632         if(ix<0x3fefffff) return (hy<0)? s*huge*huge:s*tiny*tiny;
 633         if(ix>0x3ff00000) return (hy>0)? s*huge*huge:s*tiny*tiny;
 634     /* now |1-x| is tiny <= 2**-20, suffice to compute
 635        log(x) by x-x^2/2+x^3/3-x^4/4 */
 636         t = ax-one;        /* t has 20 trailing zeros */
 637         w = (t*t)*(0.5-t*(0.3333333333333333333333-t*0.25));
 638         u = ivln2_h*t;    /* ivln2_h has 21 sig. bits */
 639         v = t*ivln2_l-w*ivln2;
 640         t1 = u+v;
 641         __LO(t1) = 0;
 642         t2 = v-(t1-u);
 643     } else {
 644         double ss,s2,s_h,s_l,t_h,t_l;
 645         n = 0;
 646     /* take care subnormal number */
 647         if(ix<0x00100000)
 648         {ax *= two53; n -= 53; ix = __HI(ax); }
 649         n  += ((ix)>>20)-0x3ff;
 650         j  = ix&0x000fffff;
 651     /* determine interval */
 652         ix = j|0x3ff00000;        /* normalize ix */
 653         if(j<=0x3988E) k=0;        /* |x|<sqrt(3/2) */
 654         else if(j<0xBB67A) k=1;    /* |x|<sqrt(3)   */
 655         else {k=0;n+=1;ix -= 0x00100000;}
 656         __HI(ax) = ix;
 657
 658     /* compute ss = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */
 659         u = ax-bp[k];        /* bp[0]=1.0, bp[1]=1.5 */
 660         v = one/(ax+bp[k]);
 661         ss = u*v;
 662         s_h = ss;
 663         __LO(s_h) = 0;
 664     /* t_h=ax+bp[k] High */
 665         t_h = zero;
 666         __HI(t_h)=((ix>>1)|0x20000000)+0x00080000+(k<<18);
 667         t_l = ax - (t_h-bp[k]);
 668         s_l = v*((u-s_h*t_h)-s_h*t_l);
 669     /* compute log(ax) */
 670         s2 = ss*ss;
 671         r = s2*s2*(L1+s2*(L2+s2*(L3+s2*(L4+s2*(L5+s2*L6)))));
 672         r += s_l*(s_h+ss);
 673         s2  = s_h*s_h;
 674         t_h = 3.0+s2+r;
 675         __LO(t_h) = 0;
 676         t_l = r-((t_h-3.0)-s2);
 677     /* u+v = ss*(1+...) */
 678         u = s_h*t_h;
 679         v = s_l*t_h+t_l*ss;
 680     /* 2/(3log2)*(ss+...) */
 681         p_h = u+v;
 682         __LO(p_h) = 0;
 683         p_l = v-(p_h-u);
 684         z_h = cp_h*p_h;        /* cp_h+cp_l = 2/(3*log2) */
 685         z_l = cp_l*p_h+p_l*cp+dp_l[k];
 686     /* log2(ax) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */
 687         t = (double)n;
 688         t1 = (((z_h+z_l)+dp_h[k])+t);
 689         __LO(t1) = 0;
 690         t2 = z_l-(((t1-t)-dp_h[k])-z_h);
 691     }
 692
 693     /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */
 694     y1  = y;
 695     __LO(y1) = 0;
 696     p_l = (y-y1)*t1+y*t2;
 697     p_h = y1*t1;
 698     z = p_l+p_h;
 699     j = __HI(z);
 700     i = __LO(z);
 701     if (j>=0x40900000) {                /* z >= 1024 */
 702         if(((j-0x40900000)|i)!=0)            /* if z > 1024 */
 703         return s*huge*huge;            /* overflow */
 704         else {
 705         if(p_l+ovt>z-p_h) return s*huge*huge;    /* overflow */
 706         }
 707     } else if((j&0x7fffffff)>=0x4090cc00 ) {    /* z <= -1075 */
 708         if(((j-0xc090cc00)|i)!=0)         /* z < -1075 */
 709         return s*tiny*tiny;        /* underflow */
 710         else {
 711         if(p_l<=z-p_h) return s*tiny*tiny;    /* underflow */
 712         }
 713     }
 714     /*
 715      * compute 2**(p_h+p_l)
 716      */
 717     i = j&0x7fffffff;
 718     k = (i>>20)-0x3ff;
 719     n = 0;
 720     if(i>0x3fe00000) {        /* if |z| > 0.5, set n = [z+0.5] */
 721         n = j+(0x00100000>>(k+1));
 722         k = ((n&0x7fffffff)>>20)-0x3ff;    /* new k for n */
 723         t = zero;
 724         __HI(t) = (n&~(0x000fffff>>k));
 725         n = ((n&0x000fffff)|0x00100000)>>(20-k);
 726         if(j<0) n = -n;
 727         p_h -= t;
 728     }
 729     t = p_l+p_h;
 730     __LO(t) = 0;
 731     u = t*lg2_h;
 732     v = (p_l-(t-p_h))*lg2+t*lg2_l;
 733     z = u+v;
 734     w = v-(z-u);
 735     t  = z*z;
 736     t1  = z - t*(P1+t*(P2+t*(P3+t*(P4+t*P5))));
 737     r  = (z*t1)/(t1-two)-(w+z*w);
 738     z  = one-(r-z);
 739     j  = __HI(z);
 740     j += (n<<20);
 741     if((j>>20)<=0) z = fdlibmScalbn(z,n);    /* subnormal output */
 742     else __HI(z) += (n<<20);
 743     return s*z;
 744 }
 745
 746 #endif
 747
 748 } // namespace JSC