github.com/afumu/libc@v0.0.6/musl/src/math/__sinl.c (about)

     1  /* origin: FreeBSD /usr/src/lib/msun/ld80/k_sinl.c */
     2  /* origin: FreeBSD /usr/src/lib/msun/ld128/k_sinl.c */
     3  /*
     4   * ====================================================
     5   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
     6   * Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans.
     7   *
     8   * Developed at SunSoft, a Sun Microsystems, Inc. business.
     9   * Permission to use, copy, modify, and distribute this
    10   * software is freely granted, provided that this notice
    11   * is preserved.
    12   * ====================================================
    13   */
    14  
    15  #include "libm.h"
    16  
    17  #if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
    18  #if LDBL_MANT_DIG == 64
    19  /*
    20   * ld80 version of __sin.c.  See __sin.c for most comments.
    21   */
    22  /*
    23   * Domain [-0.7854, 0.7854], range ~[-1.89e-22, 1.915e-22]
    24   * |sin(x)/x - s(x)| < 2**-72.1
    25   *
    26   * See __cosl.c for more details about the polynomial.
    27   */
    28  static const long double
    29  S1 = -0.166666666666666666671L;   /* -0xaaaaaaaaaaaaaaab.0p-66 */
    30  static const double
    31  S2 =  0.0083333333333333332,      /*  0x11111111111111.0p-59 */
    32  S3 = -0.00019841269841269427,     /* -0x1a01a01a019f81.0p-65 */
    33  S4 =  0.0000027557319223597490,   /*  0x171de3a55560f7.0p-71 */
    34  S5 = -0.000000025052108218074604, /* -0x1ae64564f16cad.0p-78 */
    35  S6 =  1.6059006598854211e-10,     /*  0x161242b90243b5.0p-85 */
    36  S7 = -7.6429779983024564e-13,     /* -0x1ae42ebd1b2e00.0p-93 */
    37  S8 =  2.6174587166648325e-15;     /*  0x179372ea0b3f64.0p-101 */
    38  #define POLY(z) (S2+z*(S3+z*(S4+z*(S5+z*(S6+z*(S7+z*S8))))))
    39  #elif LDBL_MANT_DIG == 113
    40  /*
    41   * ld128 version of __sin.c.  See __sin.c for most comments.
    42   */
    43  /*
    44   * Domain [-0.7854, 0.7854], range ~[-1.53e-37, 1.659e-37]
    45   * |sin(x)/x - s(x)| < 2**-122.1
    46   *
    47   * See __cosl.c for more details about the polynomial.
    48   */
    49  static const long double
    50  S1 = -0.16666666666666666666666666666666666606732416116558L,
    51  S2 =  0.0083333333333333333333333333333331135404851288270047L,
    52  S3 = -0.00019841269841269841269841269839935785325638310428717L,
    53  S4 =  0.27557319223985890652557316053039946268333231205686e-5L,
    54  S5 = -0.25052108385441718775048214826384312253862930064745e-7L,
    55  S6 =  0.16059043836821614596571832194524392581082444805729e-9L,
    56  S7 = -0.76471637318198151807063387954939213287488216303768e-12L,
    57  S8 =  0.28114572543451292625024967174638477283187397621303e-14L;
    58  static const double
    59  S9  = -0.82206352458348947812512122163446202498005154296863e-17,
    60  S10 =  0.19572940011906109418080609928334380560135358385256e-19,
    61  S11 = -0.38680813379701966970673724299207480965452616911420e-22,
    62  S12 =  0.64038150078671872796678569586315881020659912139412e-25;
    63  #define POLY(z) (S2+z*(S3+z*(S4+z*(S5+z*(S6+z*(S7+z*(S8+ \
    64  	z*(S9+z*(S10+z*(S11+z*S12))))))))))
    65  #endif
    66  
    67  long double __sinl(long double x, long double y, int iy)
    68  {
    69  	long double z,r,v;
    70  
    71  	z = x*x;
    72  	v = z*x;
    73  	r = POLY(z);
    74  	if (iy == 0)
    75  		return x+v*(S1+z*r);
    76  	return x-((z*(0.5*y-v*r)-y)-v*S1);
    77  }
    78  #endif