deps/v8/third_party/fdlibm/fdlibm.cc
// The following is adapted from fdlibm (http://www.netlib.org/fdlibm).
//
// ====================================================
// 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.
// ====================================================
//
// The original source code covered by the above license above has been
// modified significantly by Google Inc.
// Copyright 2014 the V8 project authors. All rights reserved.
#include "src/v8.h"
#include "src/double.h"
#include "third_party/fdlibm/fdlibm.h"
namespace v8 {
namespace fdlibm {
#ifdef _MSC_VER
inline double scalbn(double x, int y) { return _scalb(x, y); }
#endif // _MSC_VER
const double TrigonometricConstants::constants[] = {
6.36619772367581382433e-01, // invpio2 0
1.57079632673412561417e+00, // pio2_1 1
6.07710050650619224932e-11, // pio2_1t 2
6.07710050630396597660e-11, // pio2_2 3
2.02226624879595063154e-21, // pio2_2t 4
2.02226624871116645580e-21, // pio2_3 5
8.47842766036889956997e-32, // pio2_3t 6
-1.66666666666666324348e-01, // S1 7
8.33333333332248946124e-03, // 8
-1.98412698298579493134e-04, // 9
2.75573137070700676789e-06, // 10
-2.50507602534068634195e-08, // 11
1.58969099521155010221e-10, // S6 12
4.16666666666666019037e-02, // C1 13
-1.38888888888741095749e-03, // 14
2.48015872894767294178e-05, // 15
-2.75573143513906633035e-07, // 16
2.08757232129817482790e-09, // 17
-1.13596475577881948265e-11, // C6 18
3.33333333333334091986e-01, // T0 19
1.33333333333201242699e-01, // 20
5.39682539762260521377e-02, // 21
2.18694882948595424599e-02, // 22
8.86323982359930005737e-03, // 23
3.59207910759131235356e-03, // 24
1.45620945432529025516e-03, // 25
5.88041240820264096874e-04, // 26
2.46463134818469906812e-04, // 27
7.81794442939557092300e-05, // 28
7.14072491382608190305e-05, // 29
-1.85586374855275456654e-05, // 30
2.59073051863633712884e-05, // T12 31
7.85398163397448278999e-01, // pio4 32
3.06161699786838301793e-17, // pio4lo 33
};
// Table of constants for 2/pi, 396 Hex digits (476 decimal) of 2/pi
static const int two_over_pi[] = {
0xA2F983, 0x6E4E44, 0x1529FC, 0x2757D1, 0xF534DD, 0xC0DB62, 0x95993C,
0x439041, 0xFE5163, 0xABDEBB, 0xC561B7, 0x246E3A, 0x424DD2, 0xE00649,
0x2EEA09, 0xD1921C, 0xFE1DEB, 0x1CB129, 0xA73EE8, 0x8235F5, 0x2EBB44,
0x84E99C, 0x7026B4, 0x5F7E41, 0x3991D6, 0x398353, 0x39F49C, 0x845F8B,
0xBDF928, 0x3B1FF8, 0x97FFDE, 0x05980F, 0xEF2F11, 0x8B5A0A, 0x6D1F6D,
0x367ECF, 0x27CB09, 0xB74F46, 0x3F669E, 0x5FEA2D, 0x7527BA, 0xC7EBE5,
0xF17B3D, 0x0739F7, 0x8A5292, 0xEA6BFB, 0x5FB11F, 0x8D5D08, 0x560330,
0x46FC7B, 0x6BABF0, 0xCFBC20, 0x9AF436, 0x1DA9E3, 0x91615E, 0xE61B08,
0x659985, 0x5F14A0, 0x68408D, 0xFFD880, 0x4D7327, 0x310606, 0x1556CA,
0x73A8C9, 0x60E27B, 0xC08C6B};
static const double zero = 0.0;
static const double two24 = 1.6777216e+07;
static const double one = 1.0;
static const double twon24 = 5.9604644775390625e-08;
static const double PIo2[] = {
1.57079625129699707031e+00, // 0x3FF921FB, 0x40000000
7.54978941586159635335e-08, // 0x3E74442D, 0x00000000
5.39030252995776476554e-15, // 0x3CF84698, 0x80000000
3.28200341580791294123e-22, // 0x3B78CC51, 0x60000000
1.27065575308067607349e-29, // 0x39F01B83, 0x80000000
1.22933308981111328932e-36, // 0x387A2520, 0x40000000
2.73370053816464559624e-44, // 0x36E38222, 0x80000000
2.16741683877804819444e-51 // 0x3569F31D, 0x00000000
};
int __kernel_rem_pio2(double* x, double* y, int e0, int nx) {
static const int32_t jk = 3;
double fw;
int32_t jx = nx - 1;
int32_t jv = (e0 - 3) / 24;
if (jv < 0) jv = 0;
int32_t q0 = e0 - 24 * (jv + 1);
int32_t m = jx + jk;
double f[10];
for (int i = 0, j = jv - jx; i <= m; i++, j++) {
f[i] = (j < 0) ? zero : static_cast<double>(two_over_pi[j]);
}
double q[10];
for (int i = 0; i <= jk; i++) {
fw = 0.0;
for (int j = 0; j <= jx; j++) fw += x[j] * f[jx + i - j];
q[i] = fw;
}
int32_t jz = jk;
recompute:
int32_t iq[10];
double z = q[jz];
for (int i = 0, j = jz; j > 0; i++, j--) {
fw = static_cast<double>(static_cast<int32_t>(twon24 * z));
iq[i] = static_cast<int32_t>(z - two24 * fw);
z = q[j - 1] + fw;
}
z = scalbn(z, q0);
z -= 8.0 * std::floor(z * 0.125);
int32_t n = static_cast<int32_t>(z);
z -= static_cast<double>(n);
int32_t ih = 0;
if (q0 > 0) {
int32_t i = (iq[jz - 1] >> (24 - q0));
n += i;
iq[jz - 1] -= i << (24 - q0);
ih = iq[jz - 1] >> (23 - q0);
} else if (q0 == 0) {
ih = iq[jz - 1] >> 23;
} else if (z >= 0.5) {
ih = 2;
}
if (ih > 0) {
n += 1;
int32_t carry = 0;
for (int i = 0; i < jz; i++) {
int32_t j = iq[i];
if (carry == 0) {
if (j != 0) {
carry = 1;
iq[i] = 0x1000000 - j;
}
} else {
iq[i] = 0xffffff - j;
}
}
if (q0 == 1) {
iq[jz - 1] &= 0x7fffff;
} else if (q0 == 2) {
iq[jz - 1] &= 0x3fffff;
}
if (ih == 2) {
z = one - z;
if (carry != 0) z -= scalbn(one, q0);
}
}
if (z == zero) {
int32_t j = 0;
for (int i = jz - 1; i >= jk; i--) j |= iq[i];
if (j == 0) {
int32_t k = 1;
while (iq[jk - k] == 0) k++;
for (int i = jz + 1; i <= jz + k; i++) {
f[jx + i] = static_cast<double>(two_over_pi[jv + i]);
for (j = 0, fw = 0.0; j <= jx; j++) fw += x[j] * f[jx + i - j];
q[i] = fw;
}
jz += k;
goto recompute;
}
}
if (z == 0.0) {
jz -= 1;
q0 -= 24;
while (iq[jz] == 0) {
jz--;
q0 -= 24;
}
} else {
z = scalbn(z, -q0);
if (z >= two24) {
fw = static_cast<double>(static_cast<int32_t>(twon24 * z));
iq[jz] = static_cast<int32_t>(z - two24 * fw);
jz += 1;
q0 += 24;
iq[jz] = static_cast<int32_t>(fw);
} else {
iq[jz] = static_cast<int32_t>(z);
}
}
fw = scalbn(one, q0);
for (int i = jz; i >= 0; i--) {
q[i] = fw * static_cast<double>(iq[i]);
fw *= twon24;
}
double fq[10];
for (int i = jz; i >= 0; i--) {
fw = 0.0;
for (int k = 0; k <= jk && k <= jz - i; k++) fw += PIo2[k] * q[i + k];
fq[jz - i] = fw;
}
fw = 0.0;
for (int i = jz; i >= 0; i--) fw += fq[i];
y[0] = (ih == 0) ? fw : -fw;
fw = fq[0] - fw;
for (int i = 1; i <= jz; i++) fw += fq[i];
y[1] = (ih == 0) ? fw : -fw;
return n & 7;
}
int rempio2(double x, double* y) {
int32_t hx = static_cast<int32_t>(internal::double_to_uint64(x) >> 32);
int32_t ix = hx & 0x7fffffff;
if (ix >= 0x7ff00000) {
*y = base::OS::nan_value();
return 0;
}
int32_t e0 = (ix >> 20) - 1046;
uint64_t zi = internal::double_to_uint64(x) & 0xFFFFFFFFu;
zi |= static_cast<uint64_t>(ix - (e0 << 20)) << 32;
double z = internal::uint64_to_double(zi);
double tx[3];
for (int i = 0; i < 2; i++) {
tx[i] = static_cast<double>(static_cast<int32_t>(z));
z = (z - tx[i]) * two24;
}
tx[2] = z;
int nx = 3;
while (tx[nx - 1] == zero) nx--;
int n = __kernel_rem_pio2(tx, y, e0, nx);
if (hx < 0) {
y[0] = -y[0];
y[1] = -y[1];
return -n;
}
return n;
}
}
} // namespace v8::internal