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

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• Hash : 70438be2
  Author :
  Date : 2014-12-03T10:55:23
  

  WinRT: fixed bug whereby SDL would override an app's default orientation
  
  WinRT apps can set a default, preferred orientation via a .appxmanifest file.
  SDL was overriding this on app startup, and making the app use all possible
  orientations (landscape and portrait).
  
  Thanks to Eric Wing for the heads up on this!
  

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• src/libm/s_tan.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.
   * ====================================================
   */
  
  /* tan(x)
   * Return tangent function of x.
   *
   * kernel function:
   *	__kernel_tan		... tangent function on [-pi/4,pi/4]
   *	__ieee754_rem_pio2	... argument reduction routine
   *
   * Method.
   *      Let S,C and T denote the sin, cos and tan respectively on
   *	[-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
   *	in [-pi/4 , +pi/4], and let n = k mod 4.
   *	We have
   *
   *          n        sin(x)      cos(x)        tan(x)
   *     ----------------------------------------------------------
   *	    0	       S	   C		 T
   *	    1	       C	  -S		-1/T
   *	    2	      -S	  -C		 T
   *	    3	      -C	   S		-1/T
   *     ----------------------------------------------------------
   *
   * Special cases:
   *      Let trig be any of sin, cos, or tan.
   *      trig(+-INF)  is NaN, with signals;
   *      trig(NaN)    is that NaN;
   *
   * Accuracy:
   *	TRIG(x) returns trig(x) nearly rounded
   */
  
  #include "math_libm.h"
  #include "math_private.h"
  
  double tan(double x)
  {
  	double y[2],z=0.0;
  	int32_t n, ix;
  
      /* High word of x. */
  	GET_HIGH_WORD(ix,x);
  
      /* |x| ~< pi/4 */
  	ix &= 0x7fffffff;
  	if(ix <= 0x3fe921fb) return __kernel_tan(x,z,1);
  
      /* tan(Inf or NaN) is NaN */
  	else if (ix>=0x7ff00000) return x-x;		/* NaN */
  
      /* argument reduction needed */
  	else {
  	    n = __ieee754_rem_pio2(x,y);
  	    return __kernel_tan(y[0],y[1],1-((n&1)<<1)); /*   1 -- n even
  							-1 -- n odd */
  	}
  }
  libm_hidden_def(tan)
  

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