kc3-lang/SDL/src/libm/k_sin.c

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• Hash : 24c86b55
  Author :
  Date : 2014-09-11T19:24:42
  

  [X11] Reconcile logical keyboard state with physical state on FocusIn
  since the window system doesn't do it for us like other platforms.
  
  This prevents sticky keys and missed keys when going in and out
  of focus, for example Alt would appear to stick if switching away
  from an SDL app with Alt-Tab and had to be pressed again.
  
  CR: Sam
  

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• src/libm/k_sin.c

• /* @(#)k_sin.c 5.1 93/09/24 */
  /*
   * ====================================================
   * 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.
   * ====================================================
   */
  
  #if defined(LIBM_SCCS) && !defined(lint)
  static const char rcsid[] =
      "$NetBSD: k_sin.c,v 1.8 1995/05/10 20:46:31 jtc Exp $";
  #endif
  
  /* __kernel_sin( x, y, iy)
   * kernel sin function on [-pi/4, pi/4], pi/4 ~ 0.7854
   * Input x is assumed to be bounded by ~pi/4 in magnitude.
   * Input y is the tail of x.
   * Input iy indicates whether y is 0. (if iy=0, y assume to be 0).
   *
   * Algorithm
   *	1. Since sin(-x) = -sin(x), we need only to consider positive x.
   *	2. if x < 2^-27 (hx<0x3e400000 0), return x with inexact if x!=0.
   *	3. sin(x) is approximated by a polynomial of degree 13 on
   *	   [0,pi/4]
   *		  	         3            13
   *	   	sin(x) ~ x + S1*x + ... + S6*x
   *	   where
   *
   * 	|sin(x)         2     4     6     8     10     12  |     -58
   * 	|----- - (1+S1*x +S2*x +S3*x +S4*x +S5*x  +S6*x   )| <= 2
   * 	|  x 					           |
   *
   *	4. sin(x+y) = sin(x) + sin'(x')*y
   *		    ~ sin(x) + (1-x*x/2)*y
   *	   For better accuracy, let
   *		     3      2      2      2      2
   *		r = x *(S2+x *(S3+x *(S4+x *(S5+x *S6))))
   *	   then                   3    2
   *		sin(x) = x + (S1*x + (x *(r-y/2)+y))
   */
  
  #include "math_libm.h"
  #include "math_private.h"
  
  #ifdef __STDC__
  static const double
  #else
  static double
  #endif
    half = 5.00000000000000000000e-01,    /* 0x3FE00000, 0x00000000 */
      S1 = -1.66666666666666324348e-01,   /* 0xBFC55555, 0x55555549 */
      S2 = 8.33333333332248946124e-03,    /* 0x3F811111, 0x1110F8A6 */
      S3 = -1.98412698298579493134e-04,   /* 0xBF2A01A0, 0x19C161D5 */
      S4 = 2.75573137070700676789e-06,    /* 0x3EC71DE3, 0x57B1FE7D */
      S5 = -2.50507602534068634195e-08,   /* 0xBE5AE5E6, 0x8A2B9CEB */
      S6 = 1.58969099521155010221e-10;    /* 0x3DE5D93A, 0x5ACFD57C */
  
  #ifdef __STDC__
  double attribute_hidden
  __kernel_sin(double x, double y, int iy)
  #else
  double attribute_hidden
  __kernel_sin(x, y, iy)
       double x, y;
       int iy;                    /* iy=0 if y is zero */
  #endif
  {
      double z, r, v;
      int32_t ix;
      GET_HIGH_WORD(ix, x);
      ix &= 0x7fffffff;           /* high word of x */
      if (ix < 0x3e400000) {      /* |x| < 2**-27 */
          if ((int) x == 0)
              return x;
      }                           /* generate inexact */
      z = x * x;
      v = z * x;
      r = S2 + z * (S3 + z * (S4 + z * (S5 + z * S6)));
      if (iy == 0)
          return x + v * (S1 + z * r);
      else
          return x - ((z * (half * y - v * r) - y) - v * S1);
  }
  

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