| /* |
| * Copyright (C) 1999-2000 Harri Porten (porten@kde.org) |
| * Copyright (C) 2007, 2008 Apple Inc. All Rights Reserved. |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| * |
| */ |
| |
| #include "config.h" |
| #include "MathObject.h" |
| |
| #include "Lookup.h" |
| #include "ObjectPrototype.h" |
| #include "Operations.h" |
| #include <time.h> |
| #include <wtf/Assertions.h> |
| #include <wtf/MathExtras.h> |
| #include <wtf/RandomNumber.h> |
| #include <wtf/RandomNumberSeed.h> |
| |
| namespace JSC { |
| |
| ASSERT_HAS_TRIVIAL_DESTRUCTOR(MathObject); |
| |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncAbs(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncACos(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncASin(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncATan(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncATan2(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncCeil(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncCos(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncExp(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncFloor(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncLog(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncMax(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncMin(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncPow(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncRandom(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncRound(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncSin(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncSqrt(ExecState*); |
| static EncodedJSValue JSC_HOST_CALL mathProtoFuncTan(ExecState*); |
| |
| } |
| |
| #include "MathObject.lut.h" |
| |
| namespace JSC { |
| |
| const ClassInfo MathObject::s_info = { "Math", Base::s_classinfo(), 0, ExecState::mathTable, CREATE_METHOD_TABLE(MathObject) }; |
| |
| /* Source for MathObject.lut.h |
| @begin mathTable |
| abs mathProtoFuncAbs DontEnum|Function 1 |
| acos mathProtoFuncACos DontEnum|Function 1 |
| asin mathProtoFuncASin DontEnum|Function 1 |
| atan mathProtoFuncATan DontEnum|Function 1 |
| atan2 mathProtoFuncATan2 DontEnum|Function 2 |
| ceil mathProtoFuncCeil DontEnum|Function 1 |
| cos mathProtoFuncCos DontEnum|Function 1 |
| exp mathProtoFuncExp DontEnum|Function 1 |
| floor mathProtoFuncFloor DontEnum|Function 1 |
| log mathProtoFuncLog DontEnum|Function 1 |
| max mathProtoFuncMax DontEnum|Function 2 |
| min mathProtoFuncMin DontEnum|Function 2 |
| pow mathProtoFuncPow DontEnum|Function 2 |
| random mathProtoFuncRandom DontEnum|Function 0 |
| round mathProtoFuncRound DontEnum|Function 1 |
| sin mathProtoFuncSin DontEnum|Function 1 |
| sqrt mathProtoFuncSqrt DontEnum|Function 1 |
| tan mathProtoFuncTan DontEnum|Function 1 |
| @end |
| */ |
| |
| MathObject::MathObject(JSGlobalObject* globalObject, Structure* structure) |
| : JSNonFinalObject(globalObject->globalData(), structure) |
| { |
| } |
| |
| void MathObject::finishCreation(ExecState* exec, JSGlobalObject* globalObject) |
| { |
| Base::finishCreation(globalObject->globalData()); |
| ASSERT(inherits(&s_info)); |
| |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "E"), jsNumber(exp(1.0)), DontDelete | DontEnum | ReadOnly); |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "LN2"), jsNumber(log(2.0)), DontDelete | DontEnum | ReadOnly); |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "LN10"), jsNumber(log(10.0)), DontDelete | DontEnum | ReadOnly); |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "LOG2E"), jsNumber(1.0 / log(2.0)), DontDelete | DontEnum | ReadOnly); |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "LOG10E"), jsNumber(0.4342944819032518), DontDelete | DontEnum | ReadOnly); // See ECMA-262 15.8.1.5 |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "PI"), jsNumber(piDouble), DontDelete | DontEnum | ReadOnly); |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "SQRT1_2"), jsNumber(sqrt(0.5)), DontDelete | DontEnum | ReadOnly); |
| putDirectWithoutTransition(exec->globalData(), Identifier(exec, "SQRT2"), jsNumber(sqrt(2.0)), DontDelete | DontEnum | ReadOnly); |
| } |
| |
| bool MathObject::getOwnPropertySlot(JSCell* cell, ExecState* exec, PropertyName propertyName, PropertySlot &slot) |
| { |
| return getStaticFunctionSlot<JSObject>(exec, ExecState::mathTable(exec), jsCast<MathObject*>(cell), propertyName, slot); |
| } |
| |
| bool MathObject::getOwnPropertyDescriptor(JSObject* object, ExecState* exec, PropertyName propertyName, PropertyDescriptor& descriptor) |
| { |
| return getStaticFunctionDescriptor<JSObject>(exec, ExecState::mathTable(exec), jsCast<MathObject*>(object), propertyName, descriptor); |
| } |
| |
| // ------------------------------ Functions -------------------------------- |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncAbs(ExecState* exec) |
| { |
| return JSValue::encode(jsNumber(fabs(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncACos(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(acos(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncASin(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(asin(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncATan(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(atan(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncATan2(ExecState* exec) |
| { |
| double arg0 = exec->argument(0).toNumber(exec); |
| double arg1 = exec->argument(1).toNumber(exec); |
| return JSValue::encode(jsDoubleNumber(atan2(arg0, arg1))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncCeil(ExecState* exec) |
| { |
| return JSValue::encode(jsNumber(ceil(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncCos(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(cos(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncExp(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(exp(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncFloor(ExecState* exec) |
| { |
| return JSValue::encode(jsNumber(floor(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncLog(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(log(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncMax(ExecState* exec) |
| { |
| unsigned argsCount = exec->argumentCount(); |
| double result = -std::numeric_limits<double>::infinity(); |
| for (unsigned k = 0; k < argsCount; ++k) { |
| double val = exec->argument(k).toNumber(exec); |
| if (isnan(val)) { |
| result = QNaN; |
| break; |
| } |
| if (val > result || (val == 0 && result == 0 && !signbit(val))) |
| result = val; |
| } |
| return JSValue::encode(jsNumber(result)); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncMin(ExecState* exec) |
| { |
| unsigned argsCount = exec->argumentCount(); |
| double result = +std::numeric_limits<double>::infinity(); |
| for (unsigned k = 0; k < argsCount; ++k) { |
| double val = exec->argument(k).toNumber(exec); |
| if (isnan(val)) { |
| result = QNaN; |
| break; |
| } |
| if (val < result || (val == 0 && result == 0 && signbit(val))) |
| result = val; |
| } |
| return JSValue::encode(jsNumber(result)); |
| } |
| |
| #if PLATFORM(IOS) && CPU(ARM_THUMB2) |
| |
| static double fdlibmPow(double x, double y); |
| |
| static ALWAYS_INLINE bool isDenormal(double x) |
| { |
| static const uint64_t signbit = 0x8000000000000000ULL; |
| static const uint64_t minNormal = 0x0001000000000000ULL; |
| return (bitwise_cast<uint64_t>(x) & ~signbit) - 1 < minNormal - 1; |
| } |
| |
| static ALWAYS_INLINE bool isEdgeCase(double x) |
| { |
| static const uint64_t signbit = 0x8000000000000000ULL; |
| static const uint64_t infinity = 0x7fffffffffffffffULL; |
| return (bitwise_cast<uint64_t>(x) & ~signbit) - 1 >= infinity - 1; |
| } |
| |
| static ALWAYS_INLINE double mathPow(double x, double y) |
| { |
| if (!isDenormal(x) && !isDenormal(y)) { |
| double libmResult = pow(x,y); |
| if (libmResult || isEdgeCase(x) || isEdgeCase(y)) |
| return libmResult; |
| } |
| return fdlibmPow(x,y); |
| } |
| |
| #else |
| |
| ALWAYS_INLINE double mathPow(double x, double y) |
| { |
| #if COMPILER(MINGW64) |
| // MinGW-w64 has a custom implementation for pow. |
| // This handles certain special cases that are different. |
| if ((x == 0.0 || isinf(x)) && isfinite(y)) { |
| double f; |
| if (modf(y, &f) != 0.0) |
| return ((x == 0.0) ^ (y > 0.0)) ? std::numeric_limits<double>::infinity() : 0.0; |
| } |
| |
| if (x == 2.0) { |
| int yInt = static_cast<int>(y); |
| if (y == yInt) |
| return ldexp(1.0, yInt); |
| } |
| #endif |
| |
| return pow(x, y); |
| } |
| |
| #endif |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncPow(ExecState* exec) |
| { |
| // ECMA 15.8.2.1.13 |
| |
| double arg = exec->argument(0).toNumber(exec); |
| double arg2 = exec->argument(1).toNumber(exec); |
| |
| if (isnan(arg2)) |
| return JSValue::encode(jsNaN()); |
| if (isinf(arg2) && fabs(arg) == 1) |
| return JSValue::encode(jsNaN()); |
| return JSValue::encode(jsNumber(mathPow(arg, arg2))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncRandom(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(exec->lexicalGlobalObject()->weakRandomNumber())); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncRound(ExecState* exec) |
| { |
| double arg = exec->argument(0).toNumber(exec); |
| double integer = ceil(arg); |
| return JSValue::encode(jsNumber(integer - (integer - arg > 0.5))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncSin(ExecState* exec) |
| { |
| return JSValue::encode(exec->globalData().cachedSin(exec->argument(0).toNumber(exec))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncSqrt(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(sqrt(exec->argument(0).toNumber(exec)))); |
| } |
| |
| EncodedJSValue JSC_HOST_CALL mathProtoFuncTan(ExecState* exec) |
| { |
| return JSValue::encode(jsDoubleNumber(tan(exec->argument(0).toNumber(exec)))); |
| } |
| |
| #if PLATFORM(IOS) && CPU(ARM_THUMB2) |
| |
| // The following code is taken from netlib.org: |
| // http://www.netlib.org/fdlibm/fdlibm.h |
| // http://www.netlib.org/fdlibm/e_pow.c |
| // http://www.netlib.org/fdlibm/s_scalbn.c |
| // |
| // And was originally distributed under the following license: |
| |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunSoft, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| /* |
| * ==================================================== |
| * Copyright (C) 2004 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| /* __ieee754_pow(x,y) return x**y |
| * |
| * n |
| * Method: Let x = 2 * (1+f) |
| * 1. Compute and return log2(x) in two pieces: |
| * log2(x) = w1 + w2, |
| * where w1 has 53-24 = 29 bit trailing zeros. |
| * 2. Perform y*log2(x) = n+y' by simulating muti-precision |
| * arithmetic, where |y'|<=0.5. |
| * 3. Return x**y = 2**n*exp(y'*log2) |
| * |
| * Special cases: |
| * 1. (anything) ** 0 is 1 |
| * 2. (anything) ** 1 is itself |
| * 3. (anything) ** NAN is NAN |
| * 4. NAN ** (anything except 0) is NAN |
| * 5. +-(|x| > 1) ** +INF is +INF |
| * 6. +-(|x| > 1) ** -INF is +0 |
| * 7. +-(|x| < 1) ** +INF is +0 |
| * 8. +-(|x| < 1) ** -INF is +INF |
| * 9. +-1 ** +-INF is NAN |
| * 10. +0 ** (+anything except 0, NAN) is +0 |
| * 11. -0 ** (+anything except 0, NAN, odd integer) is +0 |
| * 12. +0 ** (-anything except 0, NAN) is +INF |
| * 13. -0 ** (-anything except 0, NAN, odd integer) is +INF |
| * 14. -0 ** (odd integer) = -( +0 ** (odd integer) ) |
| * 15. +INF ** (+anything except 0,NAN) is +INF |
| * 16. +INF ** (-anything except 0,NAN) is +0 |
| * 17. -INF ** (anything) = -0 ** (-anything) |
| * 18. (-anything) ** (integer) is (-1)**(integer)*(+anything**integer) |
| * 19. (-anything except 0 and inf) ** (non-integer) is NAN |
| * |
| * Accuracy: |
| * pow(x,y) returns x**y nearly rounded. In particular |
| * pow(integer,integer) |
| * always returns the correct integer provided it is |
| * representable. |
| * |
| * Constants : |
| * The hexadecimal values are the intended ones for the following |
| * constants. The decimal values may be used, provided that the |
| * compiler will convert from decimal to binary accurately enough |
| * to produce the hexadecimal values shown. |
| */ |
| |
| #define __HI(x) *(1+(int*)&x) |
| #define __LO(x) *(int*)&x |
| |
| static const double |
| bp[] = {1.0, 1.5,}, |
| dp_h[] = { 0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */ |
| dp_l[] = { 0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */ |
| zero = 0.0, |
| one = 1.0, |
| two = 2.0, |
| two53 = 9007199254740992.0, /* 0x43400000, 0x00000000 */ |
| huge = 1.0e300, |
| tiny = 1.0e-300, |
| /* for scalbn */ |
| two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */ |
| twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */ |
| /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */ |
| L1 = 5.99999999999994648725e-01, /* 0x3FE33333, 0x33333303 */ |
| L2 = 4.28571428578550184252e-01, /* 0x3FDB6DB6, 0xDB6FABFF */ |
| L3 = 3.33333329818377432918e-01, /* 0x3FD55555, 0x518F264D */ |
| L4 = 2.72728123808534006489e-01, /* 0x3FD17460, 0xA91D4101 */ |
| L5 = 2.30660745775561754067e-01, /* 0x3FCD864A, 0x93C9DB65 */ |
| L6 = 2.06975017800338417784e-01, /* 0x3FCA7E28, 0x4A454EEF */ |
| P1 = 1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */ |
| P2 = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */ |
| P3 = 6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */ |
| P4 = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */ |
| P5 = 4.13813679705723846039e-08, /* 0x3E663769, 0x72BEA4D0 */ |
| lg2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */ |
| lg2_h = 6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */ |
| lg2_l = -1.90465429995776804525e-09, /* 0xBE205C61, 0x0CA86C39 */ |
| ovt = 8.0085662595372944372e-0017, /* -(1024-log2(ovfl+.5ulp)) */ |
| cp = 9.61796693925975554329e-01, /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */ |
| cp_h = 9.61796700954437255859e-01, /* 0x3FEEC709, 0xE0000000 =(float)cp */ |
| cp_l = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h*/ |
| ivln2 = 1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */ |
| ivln2_h = 1.44269502162933349609e+00, /* 0x3FF71547, 0x60000000 =24b 1/ln2*/ |
| ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/ |
| |
| inline double fdlibmScalbn (double x, int n) |
| { |
| int k,hx,lx; |
| hx = __HI(x); |
| lx = __LO(x); |
| k = (hx&0x7ff00000)>>20; /* extract exponent */ |
| if (k==0) { /* 0 or subnormal x */ |
| if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */ |
| x *= two54; |
| hx = __HI(x); |
| k = ((hx&0x7ff00000)>>20) - 54; |
| if (n< -50000) return tiny*x; /*underflow*/ |
| } |
| if (k==0x7ff) return x+x; /* NaN or Inf */ |
| k = k+n; |
| if (k > 0x7fe) return huge*copysign(huge,x); /* overflow */ |
| if (k > 0) /* normal result */ |
| {__HI(x) = (hx&0x800fffff)|(k<<20); return x;} |
| if (k <= -54) { |
| if (n > 50000) /* in case integer overflow in n+k */ |
| return huge*copysign(huge,x); /*overflow*/ |
| else return tiny*copysign(tiny,x); /*underflow*/ |
| } |
| k += 54; /* subnormal result */ |
| __HI(x) = (hx&0x800fffff)|(k<<20); |
| return x*twom54; |
| } |
| |
| double fdlibmPow(double x, double y) |
| { |
| double z,ax,z_h,z_l,p_h,p_l; |
| double y1,t1,t2,r,s,t,u,v,w; |
| int i0,i1,i,j,k,yisint,n; |
| int hx,hy,ix,iy; |
| unsigned lx,ly; |
| |
| i0 = ((*(int*)&one)>>29)^1; i1=1-i0; |
| hx = __HI(x); lx = __LO(x); |
| hy = __HI(y); ly = __LO(y); |
| ix = hx&0x7fffffff; iy = hy&0x7fffffff; |
| |
| /* y==zero: x**0 = 1 */ |
| if((iy|ly)==0) return one; |
| |
| /* +-NaN return x+y */ |
| if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) || |
| iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0))) |
| return x+y; |
| |
| /* determine if y is an odd int when x < 0 |
| * yisint = 0 ... y is not an integer |
| * yisint = 1 ... y is an odd int |
| * yisint = 2 ... y is an even int |
| */ |
| yisint = 0; |
| if(hx<0) { |
| if(iy>=0x43400000) yisint = 2; /* even integer y */ |
| else if(iy>=0x3ff00000) { |
| k = (iy>>20)-0x3ff; /* exponent */ |
| if(k>20) { |
| j = ly>>(52-k); |
| if(static_cast<unsigned>(j<<(52-k))==ly) yisint = 2-(j&1); |
| } else if(ly==0) { |
| j = iy>>(20-k); |
| if((j<<(20-k))==iy) yisint = 2-(j&1); |
| } |
| } |
| } |
| |
| /* special value of y */ |
| if(ly==0) { |
| if (iy==0x7ff00000) { /* y is +-inf */ |
| if(((ix-0x3ff00000)|lx)==0) |
| return y - y; /* inf**+-1 is NaN */ |
| else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */ |
| return (hy>=0)? y: zero; |
| else /* (|x|<1)**-,+inf = inf,0 */ |
| return (hy<0)?-y: zero; |
| } |
| if(iy==0x3ff00000) { /* y is +-1 */ |
| if(hy<0) return one/x; else return x; |
| } |
| if(hy==0x40000000) return x*x; /* y is 2 */ |
| if(hy==0x3fe00000) { /* y is 0.5 */ |
| if(hx>=0) /* x >= +0 */ |
| return sqrt(x); |
| } |
| } |
| |
| ax = fabs(x); |
| /* special value of x */ |
| if(lx==0) { |
| if(ix==0x7ff00000||ix==0||ix==0x3ff00000){ |
| z = ax; /*x is +-0,+-inf,+-1*/ |
| if(hy<0) z = one/z; /* z = (1/|x|) */ |
| if(hx<0) { |
| if(((ix-0x3ff00000)|yisint)==0) { |
| z = (z-z)/(z-z); /* (-1)**non-int is NaN */ |
| } else if(yisint==1) |
| z = -z; /* (x<0)**odd = -(|x|**odd) */ |
| } |
| return z; |
| } |
| } |
| |
| n = (hx>>31)+1; |
| |
| /* (x<0)**(non-int) is NaN */ |
| if((n|yisint)==0) return (x-x)/(x-x); |
| |
| s = one; /* s (sign of result -ve**odd) = -1 else = 1 */ |
| if((n|(yisint-1))==0) s = -one;/* (-ve)**(odd int) */ |
| |
| /* |y| is huge */ |
| if(iy>0x41e00000) { /* if |y| > 2**31 */ |
| if(iy>0x43f00000){ /* if |y| > 2**64, must o/uflow */ |
| if(ix<=0x3fefffff) return (hy<0)? huge*huge:tiny*tiny; |
| if(ix>=0x3ff00000) return (hy>0)? huge*huge:tiny*tiny; |
| } |
| /* over/underflow if x is not close to one */ |
| if(ix<0x3fefffff) return (hy<0)? s*huge*huge:s*tiny*tiny; |
| if(ix>0x3ff00000) return (hy>0)? s*huge*huge:s*tiny*tiny; |
| /* now |1-x| is tiny <= 2**-20, suffice to compute |
| log(x) by x-x^2/2+x^3/3-x^4/4 */ |
| t = ax-one; /* t has 20 trailing zeros */ |
| w = (t*t)*(0.5-t*(0.3333333333333333333333-t*0.25)); |
| u = ivln2_h*t; /* ivln2_h has 21 sig. bits */ |
| v = t*ivln2_l-w*ivln2; |
| t1 = u+v; |
| __LO(t1) = 0; |
| t2 = v-(t1-u); |
| } else { |
| double ss,s2,s_h,s_l,t_h,t_l; |
| n = 0; |
| /* take care subnormal number */ |
| if(ix<0x00100000) |
| {ax *= two53; n -= 53; ix = __HI(ax); } |
| n += ((ix)>>20)-0x3ff; |
| j = ix&0x000fffff; |
| /* determine interval */ |
| ix = j|0x3ff00000; /* normalize ix */ |
| if(j<=0x3988E) k=0; /* |x|<sqrt(3/2) */ |
| else if(j<0xBB67A) k=1; /* |x|<sqrt(3) */ |
| else {k=0;n+=1;ix -= 0x00100000;} |
| __HI(ax) = ix; |
| |
| /* compute ss = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */ |
| u = ax-bp[k]; /* bp[0]=1.0, bp[1]=1.5 */ |
| v = one/(ax+bp[k]); |
| ss = u*v; |
| s_h = ss; |
| __LO(s_h) = 0; |
| /* t_h=ax+bp[k] High */ |
| t_h = zero; |
| __HI(t_h)=((ix>>1)|0x20000000)+0x00080000+(k<<18); |
| t_l = ax - (t_h-bp[k]); |
| s_l = v*((u-s_h*t_h)-s_h*t_l); |
| /* compute log(ax) */ |
| s2 = ss*ss; |
| r = s2*s2*(L1+s2*(L2+s2*(L3+s2*(L4+s2*(L5+s2*L6))))); |
| r += s_l*(s_h+ss); |
| s2 = s_h*s_h; |
| t_h = 3.0+s2+r; |
| __LO(t_h) = 0; |
| t_l = r-((t_h-3.0)-s2); |
| /* u+v = ss*(1+...) */ |
| u = s_h*t_h; |
| v = s_l*t_h+t_l*ss; |
| /* 2/(3log2)*(ss+...) */ |
| p_h = u+v; |
| __LO(p_h) = 0; |
| p_l = v-(p_h-u); |
| z_h = cp_h*p_h; /* cp_h+cp_l = 2/(3*log2) */ |
| z_l = cp_l*p_h+p_l*cp+dp_l[k]; |
| /* log2(ax) = (ss+..)*2/(3*log2) = n + dp_h + z_h + z_l */ |
| t = (double)n; |
| t1 = (((z_h+z_l)+dp_h[k])+t); |
| __LO(t1) = 0; |
| t2 = z_l-(((t1-t)-dp_h[k])-z_h); |
| } |
| |
| /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */ |
| y1 = y; |
| __LO(y1) = 0; |
| p_l = (y-y1)*t1+y*t2; |
| p_h = y1*t1; |
| z = p_l+p_h; |
| j = __HI(z); |
| i = __LO(z); |
| if (j>=0x40900000) { /* z >= 1024 */ |
| if(((j-0x40900000)|i)!=0) /* if z > 1024 */ |
| return s*huge*huge; /* overflow */ |
| else { |
| if(p_l+ovt>z-p_h) return s*huge*huge; /* overflow */ |
| } |
| } else if((j&0x7fffffff)>=0x4090cc00 ) { /* z <= -1075 */ |
| if(((j-0xc090cc00)|i)!=0) /* z < -1075 */ |
| return s*tiny*tiny; /* underflow */ |
| else { |
| if(p_l<=z-p_h) return s*tiny*tiny; /* underflow */ |
| } |
| } |
| /* |
| * compute 2**(p_h+p_l) |
| */ |
| i = j&0x7fffffff; |
| k = (i>>20)-0x3ff; |
| n = 0; |
| if(i>0x3fe00000) { /* if |z| > 0.5, set n = [z+0.5] */ |
| n = j+(0x00100000>>(k+1)); |
| k = ((n&0x7fffffff)>>20)-0x3ff; /* new k for n */ |
| t = zero; |
| __HI(t) = (n&~(0x000fffff>>k)); |
| n = ((n&0x000fffff)|0x00100000)>>(20-k); |
| if(j<0) n = -n; |
| p_h -= t; |
| } |
| t = p_l+p_h; |
| __LO(t) = 0; |
| u = t*lg2_h; |
| v = (p_l-(t-p_h))*lg2+t*lg2_l; |
| z = u+v; |
| w = v-(z-u); |
| t = z*z; |
| t1 = z - t*(P1+t*(P2+t*(P3+t*(P4+t*P5)))); |
| r = (z*t1)/(t1-two)-(w+z*w); |
| z = one-(r-z); |
| j = __HI(z); |
| j += (n<<20); |
| if((j>>20)<=0) z = fdlibmScalbn(z,n); /* subnormal output */ |
| else __HI(z) += (n<<20); |
| return s*z; |
| } |
| |
| #endif |
| |
| } // namespace JSC |
