/*-
* Copyright (c) 2017, 2023 Steven G. Kargl
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice unmodified, this list of conditions, and the following
*    disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/*
* See ../src/s_sinpi.c for implementation details.
*/

#include <stdint.h>

#include "math.h"
#include "math_private.h"

static const union ieee_ext_u
pi_hi_u = LD80C(0xc90fdaa200000000,   1, 3.14159265346825122833e+00L),
pi_lo_u = LD80C(0x85a308d313198a2e, -33, 1.21542010130123852029e-10L);
#define pi_hi   (pi_hi_u.extu_ld)
#define pi_lo   (pi_lo_u.extu_ld)

#include "k_cospil.h"
#include "k_sinpil.h"

static volatile const double vzero = 0;

long double
sinpil(long double x)
{
       long double ax, hi, lo, s;
       uint64_t lx;
       uint32_t j0;
       uint16_t hx, ix;

       EXTRACT_LDBL80_WORDS(hx, lx, x);
       ix = hx & 0x7fff;
       INSERT_LDBL80_WORDS(ax, ix, lx);

       ENTERI();

       if (ix < 0x3fff) {                      /* |x| < 1 */
               if (ix < 0x3ffd) {              /* |x| < 0.25 */
                       if (ix < 0x3fdd) {      /* |x| < 0x1p-34 */
                               if (x == 0)
                                       RETURNI(x);
                               INSERT_LDBL80_WORDS(hi, hx,
                                   lx & 0xffffffff00000000ull);
                               hi *= 0x1p63L;
                               lo = x * 0x1p63L - hi;
                               s = (pi_lo + pi_hi) * lo + pi_lo * hi +
                                   pi_hi * hi;
                               RETURNI(s * 0x1p-63L);
                       }
                       s = __kernel_sinpil(ax);
                       RETURNI((hx & 0x8000) ? -s : s);
               }

               if (ix < 0x3ffe)                        /* |x| < 0.5 */
                       s = __kernel_cospil(0.5 - ax);
               else if (lx < 0xc000000000000000ull)    /* |x| < 0.75 */
                       s = __kernel_cospil(ax - 0.5);
               else
                       s = __kernel_sinpil(1 - ax);
               RETURNI((hx & 0x8000) ? -s : s);
       }

       if (ix < 0x403e) {                      /* 1 <= |x| < 0x1p63 */
               FFLOORL80(x, j0, ix, lx);       /* Integer part of ax. */
               ax -= x;
               EXTRACT_LDBL80_WORDS(ix, lx, ax);

               if (ix == 0) {
                       s = 0;
               } else {
                       if (ix < 0x3ffe) {              /* |x| < 0.5 */
                               if (ix < 0x3ffd)        /* |x| < 0.25 */
                                       s = __kernel_sinpil(ax);
                               else
                                       s = __kernel_cospil(0.5 - ax);
                       } else {
                                                       /* |x| < 0.75 */
                               if (lx < 0xc000000000000000ull)
                                       s = __kernel_cospil(ax - 0.5);
                               else
                                       s = __kernel_sinpil(1 - ax);
                       }

                       if (j0 > 40)
                               x -= 0x1p40;
                       if (j0 > 30)
                               x -= 0x1p30;
                       j0 = (uint32_t)x;
                       if (j0 & 1) s = -s;
               }
               RETURNI((hx & 0x8000) ? -s : s);
       }

       /* x = +-inf or nan. */
       if (ix >= 0x7fff)
               RETURNI(vzero / vzero);

       /*
        * |x| >= 0x1p63 is always an integer, so return +-0.
        */
       RETURNI(copysignl(0, x));
}