kc3-lang/SDL/src/libm/e_atan2.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/e_atan2.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.
   * ====================================================
   */
  
  /* __ieee754_atan2(y,x)
   * Method :
   *	1. Reduce y to positive by atan2(y,x)=-atan2(-y,x).
   *	2. Reduce x to positive by (if x and y are unexceptional):
   *		ARG (x+iy) = arctan(y/x)   	   ... if x > 0,
   *		ARG (x+iy) = pi - arctan[y/(-x)]   ... if x < 0,
   *
   * Special cases:
   *
   *	ATAN2((anything), NaN ) is NaN;
   *	ATAN2(NAN , (anything) ) is NaN;
   *	ATAN2(+-0, +(anything but NaN)) is +-0  ;
   *	ATAN2(+-0, -(anything but NaN)) is +-pi ;
   *	ATAN2(+-(anything but 0 and NaN), 0) is +-pi/2;
   *	ATAN2(+-(anything but INF and NaN), +INF) is +-0 ;
   *	ATAN2(+-(anything but INF and NaN), -INF) is +-pi;
   *	ATAN2(+-INF,+INF ) is +-pi/4 ;
   *	ATAN2(+-INF,-INF ) is +-3pi/4;
   *	ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-pi/2;
   *
   * Constants:
   * The hexadecimal values are the intended ones for the following
   * constants. The decimal values may be used, provided that the
   * compiler will convert from decimal to binary accurately enough
   * to produce the hexadecimal values shown.
   */
  
  #include "math_libm.h"
  #include "math_private.h"
  
  static const double
  tiny  = 1.0e-300,
  zero  = 0.0,
  pi_o_4  = 7.8539816339744827900E-01, /* 0x3FE921FB, 0x54442D18 */
  pi_o_2  = 1.5707963267948965580E+00, /* 0x3FF921FB, 0x54442D18 */
  pi      = 3.1415926535897931160E+00, /* 0x400921FB, 0x54442D18 */
  pi_lo   = 1.2246467991473531772E-16; /* 0x3CA1A626, 0x33145C07 */
  
  double attribute_hidden __ieee754_atan2(double y, double x)
  {
  	double z;
  	int32_t k,m,hx,hy,ix,iy;
  	u_int32_t lx,ly;
  
  	EXTRACT_WORDS(hx,lx,x);
  	ix = hx&0x7fffffff;
  	EXTRACT_WORDS(hy,ly,y);
  	iy = hy&0x7fffffff;
  	if(((ix|((lx|-(int32_t)lx)>>31))>0x7ff00000)||
  	   ((iy|((ly|-(int32_t)ly)>>31))>0x7ff00000))	/* x or y is NaN */
  	   return x+y;
  	if(((hx-0x3ff00000)|lx)==0) return atan(y);   /* x=1.0 */
  	m = ((hy>>31)&1)|((hx>>30)&2);	/* 2*sign(x)+sign(y) */
  
      /* when y = 0 */
  	if((iy|ly)==0) {
  	    switch(m) {
  		case 0:
  		case 1: return y; 	/* atan(+-0,+anything)=+-0 */
  		case 2: return  pi+tiny;/* atan(+0,-anything) = pi */
  		case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */
  	    }
  	}
      /* when x = 0 */
  	if((ix|lx)==0) return (hy<0)?  -pi_o_2-tiny: pi_o_2+tiny;
  
      /* when x is INF */
  	if(ix==0x7ff00000) {
  	    if(iy==0x7ff00000) {
  		switch(m) {
  		    case 0: return  pi_o_4+tiny;/* atan(+INF,+INF) */
  		    case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */
  		    case 2: return  3.0*pi_o_4+tiny;/* atan(+INF,-INF) */
  		    case 3: return -3.0*pi_o_4-tiny;/* atan(-INF,-INF) */
  		}
  	    } else {
  		switch(m) {
  		    case 0: return  zero  ;	/* atan(+...,+INF) */
  		    case 1: return -zero  ;	/* atan(-...,+INF) */
  		    case 2: return  pi+tiny  ;	/* atan(+...,-INF) */
  		    case 3: return -pi-tiny  ;	/* atan(-...,-INF) */
  		}
  	    }
  	}
      /* when y is INF */
  	if(iy==0x7ff00000) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
  
      /* compute y/x */
  	k = (iy-ix)>>20;
  	if(k > 60) z=pi_o_2+0.5*pi_lo; 	/* |y/x| >  2**60 */
  	else if(hx<0&&k<-60) z=0.0; 	/* |y|/x < -2**60 */
  	else z=atan(fabs(y/x));		/* safe to do y/x */
  	switch (m) {
  	    case 0: return       z  ;	/* atan(+,+) */
  	    case 1: {
  	    	      u_int32_t zh;
  		      GET_HIGH_WORD(zh,z);
  		      SET_HIGH_WORD(z,zh ^ 0x80000000);
  		    }
  		    return       z  ;	/* atan(-,+) */
  	    case 2: return  pi-(z-pi_lo);/* atan(+,-) */
  	    default: /* case 3 */
  	    	    return  (z-pi_lo)-pi;/* atan(-,-) */
  	}
  }
  

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