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

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• Hash : 0e45984f
  Author :
  Date : 2015-06-21T17:33:46
  

  Fixed crash if initialization of EGL failed but was tried again later. The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly uninitialized data structure if loading the library first failed. A later try to use EGL then skipped initialization and assumed it was previously successful because the data structure now already existed. This led to at least one crash in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was dereferenced to make a call to eglBindAPI().

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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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