text: /* origin: FreeBSD /usr/src/lib/msun/src/s_sin.c */
  /*
   * ====================================================
   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   *
   * Developed at SunPro, a Sun Microsystems, Inc. business.
   * Permission to use, copy, modify, and distribute this
   * software is freely granted, provided that this notice
   * is preserved.
   * ====================================================
   */
  
  #define _GNU_SOURCE
  #include "libm.h"
  
  void sincos(double x, double *sin, double *cos)
  {
  	double y[2], s, c;
  	uint32_t ix;
  	unsigned n;
  
  	GET_HIGH_WORD(ix, x);
  	ix &= 0x7fffffff;
  
  	/* |x| ~< pi/4 */
  	if (ix <= 0x3fe921fb) {
  		/* if |x| < 2**-27 * sqrt(2) */
  		if (ix < 0x3e46a09e) {
  			/* raise inexact if x!=0 and underflow if subnormal */
  			FORCE_EVAL(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f);
  			*sin = x;
  			*cos = 1.0;
  			return;
  		}
  		*sin = __sin(x, 0.0, 0);
  		*cos = __cos(x, 0.0);
  		return;
  	}
  
  	/* sincos(Inf or NaN) is NaN */
  	if (ix >= 0x7ff00000) {
  		*sin = *cos = x - x;
  		return;
  	}
  
  	/* argument reduction needed */
  	n = __rem_pio2(x, y);
  	s = __sin(y[0], y[1], 1);
  	c = __cos(y[0], y[1]);
  	switch (n&3) {
  	case 0:
  		*sin = s;
  		*cos = c;
  		break;
  	case 1:
  		*sin = c;
  		*cos = -s;
  		break;
  	case 2:
  		*sin = -s;
  		*cos = -c;
  		break;
  	case 3:
  	default:
  		*sin = -c;
  		*cos = s;
  		break;
  	}
  }
  