kc3-lang/SDL/src/libm/s_scalbn.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_scalbn.c

• /* @(#)s_scalbn.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: s_scalbn.c,v 1.8 1995/05/10 20:48:08 jtc Exp $";
  #endif
  
  /*
   * scalbn (double x, int n)
   * scalbn(x,n) returns x* 2**n  computed by  exponent
   * manipulation rather than by actually performing an
   * exponentiation or a multiplication.
   */
  
  #include "math_libm.h"
  #include "math_private.h"
  
  libm_hidden_proto(copysign)
  #ifdef __STDC__
       static const double
  #else
       static double
  #endif
         two54 = 1.80143985094819840000e+16,      /* 0x43500000, 0x00000000 */
           twom54 = 5.55111512312578270212e-17,   /* 0x3C900000, 0x00000000 */
           huge_val = 1.0e+300, tiny = 1.0e-300;
  
  libm_hidden_proto(scalbn)
  #ifdef __STDC__
       double scalbn(double x, int n)
  #else
       double scalbn(x, n)
       double x;
       int n;
  #endif
  {
      int32_t k, hx, lx;
      EXTRACT_WORDS(hx, lx, x);
      k = (hx & 0x7ff00000) >> 20;        /* extract exponent */
      if (k == 0) {               /* 0 or subnormal x */
          if ((lx | (hx & 0x7fffffff)) == 0)
              return x;           /* +-0 */
          x *= two54;
          GET_HIGH_WORD(hx, x);
          k = ((hx & 0x7ff00000) >> 20) - 54;
          if (n < -50000)
              return tiny * x;    /* underflow */
      }
      if (k == 0x7ff)
          return x + x;           /* NaN or Inf */
      k = k + n;
      if (k > 0x7fe)
          return huge_val * copysign(huge_val, x);        /* overflow  */
      if (k > 0) {                /* normal result */
          SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
          return x;
      }
      if (k <= -54) {
          if (n > 50000)          /* in case integer overflow in n+k */
              return huge_val * copysign(huge_val, x);    /* overflow */
          else
              return tiny * copysign(tiny, x);    /* underflow */
      }
      k += 54;                    /* subnormal result */
      SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
      return x * twom54;
  }
  
  libm_hidden_def(scalbn)
  

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