930e5ccc3e
R=rtoy@chromium.org BUG=v8:3479 LOG=N Review URL: https://codereview.chromium.org/465353002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23238 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
281 lines
8.6 KiB
C++
281 lines
8.6 KiB
C++
// The following is adapted from fdlibm (http://www.netlib.org/fdlibm).
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//
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// ====================================================
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// Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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//
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// Developed at SunSoft, a Sun Microsystems, Inc. business.
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// Permission to use, copy, modify, and distribute this
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// software is freely granted, provided that this notice
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// is preserved.
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// ====================================================
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//
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// The original source code covered by the above license above has been
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// modified significantly by Google Inc.
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// Copyright 2014 the V8 project authors. All rights reserved.
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#include "src/v8.h"
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#include "src/double.h"
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#include "third_party/fdlibm/fdlibm.h"
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namespace v8 {
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namespace fdlibm {
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#ifdef _MSC_VER
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inline double scalbn(double x, int y) { return _scalb(x, y); }
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#endif // _MSC_VER
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const double MathConstants::constants[] = {
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6.36619772367581382433e-01, // invpio2 0
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1.57079632673412561417e+00, // pio2_1 1
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6.07710050650619224932e-11, // pio2_1t 2
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6.07710050630396597660e-11, // pio2_2 3
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2.02226624879595063154e-21, // pio2_2t 4
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2.02226624871116645580e-21, // pio2_3 5
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8.47842766036889956997e-32, // pio2_3t 6
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-1.66666666666666324348e-01, // S1 7 coefficients for sin
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8.33333333332248946124e-03, // 8
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-1.98412698298579493134e-04, // 9
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2.75573137070700676789e-06, // 10
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-2.50507602534068634195e-08, // 11
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1.58969099521155010221e-10, // S6 12
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4.16666666666666019037e-02, // C1 13 coefficients for cos
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-1.38888888888741095749e-03, // 14
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2.48015872894767294178e-05, // 15
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-2.75573143513906633035e-07, // 16
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2.08757232129817482790e-09, // 17
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-1.13596475577881948265e-11, // C6 18
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3.33333333333334091986e-01, // T0 19 coefficients for tan
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1.33333333333201242699e-01, // 20
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5.39682539762260521377e-02, // 21
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2.18694882948595424599e-02, // 22
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8.86323982359930005737e-03, // 23
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3.59207910759131235356e-03, // 24
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1.45620945432529025516e-03, // 25
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5.88041240820264096874e-04, // 26
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2.46463134818469906812e-04, // 27
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7.81794442939557092300e-05, // 28
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7.14072491382608190305e-05, // 29
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-1.85586374855275456654e-05, // 30
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2.59073051863633712884e-05, // T12 31
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7.85398163397448278999e-01, // pio4 32
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3.06161699786838301793e-17, // pio4lo 33
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6.93147180369123816490e-01, // ln2_hi 34
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1.90821492927058770002e-10, // ln2_lo 35
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1.80143985094819840000e+16, // 2^54 36
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6.666666666666666666e-01, // 2/3 37
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6.666666666666735130e-01, // LP1 38 coefficients for log1p
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3.999999999940941908e-01, // 39
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2.857142874366239149e-01, // 40
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2.222219843214978396e-01, // 41
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1.818357216161805012e-01, // 42
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1.531383769920937332e-01, // 43
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1.479819860511658591e-01, // LP7 44
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7.09782712893383973096e+02, // 45 overflow threshold for expm1
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1.44269504088896338700e+00, // 1/ln2 46
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-3.33333333333331316428e-02, // Q1 47 coefficients for expm1
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1.58730158725481460165e-03, // 48
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-7.93650757867487942473e-05, // 49
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4.00821782732936239552e-06, // 50
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-2.01099218183624371326e-07 // Q5 51
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};
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// Table of constants for 2/pi, 396 Hex digits (476 decimal) of 2/pi
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static const int two_over_pi[] = {
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0xA2F983, 0x6E4E44, 0x1529FC, 0x2757D1, 0xF534DD, 0xC0DB62, 0x95993C,
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0x439041, 0xFE5163, 0xABDEBB, 0xC561B7, 0x246E3A, 0x424DD2, 0xE00649,
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0x2EEA09, 0xD1921C, 0xFE1DEB, 0x1CB129, 0xA73EE8, 0x8235F5, 0x2EBB44,
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0x84E99C, 0x7026B4, 0x5F7E41, 0x3991D6, 0x398353, 0x39F49C, 0x845F8B,
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0xBDF928, 0x3B1FF8, 0x97FFDE, 0x05980F, 0xEF2F11, 0x8B5A0A, 0x6D1F6D,
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0x367ECF, 0x27CB09, 0xB74F46, 0x3F669E, 0x5FEA2D, 0x7527BA, 0xC7EBE5,
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0xF17B3D, 0x0739F7, 0x8A5292, 0xEA6BFB, 0x5FB11F, 0x8D5D08, 0x560330,
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0x46FC7B, 0x6BABF0, 0xCFBC20, 0x9AF436, 0x1DA9E3, 0x91615E, 0xE61B08,
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0x659985, 0x5F14A0, 0x68408D, 0xFFD880, 0x4D7327, 0x310606, 0x1556CA,
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0x73A8C9, 0x60E27B, 0xC08C6B};
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static const double zero = 0.0;
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static const double two24 = 1.6777216e+07;
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static const double one = 1.0;
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static const double twon24 = 5.9604644775390625e-08;
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static const double PIo2[] = {
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1.57079625129699707031e+00, // 0x3FF921FB, 0x40000000
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7.54978941586159635335e-08, // 0x3E74442D, 0x00000000
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5.39030252995776476554e-15, // 0x3CF84698, 0x80000000
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3.28200341580791294123e-22, // 0x3B78CC51, 0x60000000
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1.27065575308067607349e-29, // 0x39F01B83, 0x80000000
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1.22933308981111328932e-36, // 0x387A2520, 0x40000000
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2.73370053816464559624e-44, // 0x36E38222, 0x80000000
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2.16741683877804819444e-51 // 0x3569F31D, 0x00000000
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};
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int __kernel_rem_pio2(double* x, double* y, int e0, int nx) {
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static const int32_t jk = 3;
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double fw;
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int32_t jx = nx - 1;
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int32_t jv = (e0 - 3) / 24;
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if (jv < 0) jv = 0;
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int32_t q0 = e0 - 24 * (jv + 1);
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int32_t m = jx + jk;
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double f[10];
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for (int i = 0, j = jv - jx; i <= m; i++, j++) {
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f[i] = (j < 0) ? zero : static_cast<double>(two_over_pi[j]);
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}
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double q[10];
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for (int i = 0; i <= jk; i++) {
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fw = 0.0;
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for (int j = 0; j <= jx; j++) fw += x[j] * f[jx + i - j];
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q[i] = fw;
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}
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int32_t jz = jk;
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recompute:
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int32_t iq[10];
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double z = q[jz];
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for (int i = 0, j = jz; j > 0; i++, j--) {
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fw = static_cast<double>(static_cast<int32_t>(twon24 * z));
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iq[i] = static_cast<int32_t>(z - two24 * fw);
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z = q[j - 1] + fw;
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}
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z = scalbn(z, q0);
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z -= 8.0 * std::floor(z * 0.125);
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int32_t n = static_cast<int32_t>(z);
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z -= static_cast<double>(n);
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int32_t ih = 0;
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if (q0 > 0) {
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int32_t i = (iq[jz - 1] >> (24 - q0));
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n += i;
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iq[jz - 1] -= i << (24 - q0);
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ih = iq[jz - 1] >> (23 - q0);
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} else if (q0 == 0) {
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ih = iq[jz - 1] >> 23;
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} else if (z >= 0.5) {
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ih = 2;
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}
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if (ih > 0) {
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n += 1;
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int32_t carry = 0;
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for (int i = 0; i < jz; i++) {
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int32_t j = iq[i];
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if (carry == 0) {
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if (j != 0) {
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carry = 1;
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iq[i] = 0x1000000 - j;
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}
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} else {
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iq[i] = 0xffffff - j;
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}
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}
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if (q0 == 1) {
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iq[jz - 1] &= 0x7fffff;
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} else if (q0 == 2) {
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iq[jz - 1] &= 0x3fffff;
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}
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if (ih == 2) {
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z = one - z;
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if (carry != 0) z -= scalbn(one, q0);
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}
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}
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if (z == zero) {
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int32_t j = 0;
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for (int i = jz - 1; i >= jk; i--) j |= iq[i];
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if (j == 0) {
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int32_t k = 1;
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while (iq[jk - k] == 0) k++;
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for (int i = jz + 1; i <= jz + k; i++) {
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f[jx + i] = static_cast<double>(two_over_pi[jv + i]);
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for (j = 0, fw = 0.0; j <= jx; j++) fw += x[j] * f[jx + i - j];
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q[i] = fw;
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}
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jz += k;
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goto recompute;
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}
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}
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if (z == 0.0) {
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jz -= 1;
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q0 -= 24;
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while (iq[jz] == 0) {
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jz--;
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q0 -= 24;
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}
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} else {
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z = scalbn(z, -q0);
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if (z >= two24) {
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fw = static_cast<double>(static_cast<int32_t>(twon24 * z));
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iq[jz] = static_cast<int32_t>(z - two24 * fw);
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jz += 1;
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q0 += 24;
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iq[jz] = static_cast<int32_t>(fw);
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} else {
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iq[jz] = static_cast<int32_t>(z);
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}
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}
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fw = scalbn(one, q0);
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for (int i = jz; i >= 0; i--) {
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q[i] = fw * static_cast<double>(iq[i]);
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fw *= twon24;
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}
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double fq[10];
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for (int i = jz; i >= 0; i--) {
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fw = 0.0;
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for (int k = 0; k <= jk && k <= jz - i; k++) fw += PIo2[k] * q[i + k];
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fq[jz - i] = fw;
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}
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fw = 0.0;
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for (int i = jz; i >= 0; i--) fw += fq[i];
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y[0] = (ih == 0) ? fw : -fw;
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fw = fq[0] - fw;
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for (int i = 1; i <= jz; i++) fw += fq[i];
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y[1] = (ih == 0) ? fw : -fw;
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return n & 7;
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}
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int rempio2(double x, double* y) {
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int32_t hx = static_cast<int32_t>(internal::double_to_uint64(x) >> 32);
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int32_t ix = hx & 0x7fffffff;
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if (ix >= 0x7ff00000) {
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*y = base::OS::nan_value();
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return 0;
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}
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int32_t e0 = (ix >> 20) - 1046;
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uint64_t zi = internal::double_to_uint64(x) & 0xFFFFFFFFu;
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zi |= static_cast<uint64_t>(ix - (e0 << 20)) << 32;
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double z = internal::uint64_to_double(zi);
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double tx[3];
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for (int i = 0; i < 2; i++) {
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tx[i] = static_cast<double>(static_cast<int32_t>(z));
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z = (z - tx[i]) * two24;
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}
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tx[2] = z;
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int nx = 3;
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while (tx[nx - 1] == zero) nx--;
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int n = __kernel_rem_pio2(tx, y, e0, nx);
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if (hx < 0) {
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y[0] = -y[0];
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y[1] = -y[1];
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return -n;
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}
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return n;
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}
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}
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} // namespace v8::internal
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