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

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• Hash : b72938c8
  Author :
  Date : 2015-04-20T12:22:44
  

  Windows: Always set the system timer resolution to 1ms by default.
  
  An existing hint lets apps that don't need the timer resolution changed avoid
  this, to save battery, etc, but this fixes several problems in timing, audio
  callbacks not firing fast enough, etc.
  
  Fixes Bugzilla #2944.
  

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• src/libm/s_floor.c

• /* @(#)s_floor.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_floor.c,v 1.8 1995/05/10 20:47:20 jtc Exp $";
  #endif
  
  /*
   * floor(x)
   * Return x rounded toward -inf to integral value
   * Method:
   *	Bit twiddling.
   * Exception:
   *	Inexact flag raised if x not equal to floor(x).
   */
  
  #include "math_libm.h"
  #include "math_private.h"
  
  #ifdef __STDC__
  static const double huge_val = 1.0e300;
  #else
  static double huge_val = 1.0e300;
  #endif
  
  libm_hidden_proto(floor)
  #ifdef __STDC__
       double floor(double x)
  #else
       double floor(x)
       double x;
  #endif
  {
      int32_t i0, i1, j0;
      u_int32_t i, j;
      EXTRACT_WORDS(i0, i1, x);
      j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
      if (j0 < 20) {
          if (j0 < 0) {           /* raise inexact if x != 0 */
              if (huge_val + x > 0.0) {       /* return 0*sign(x) if |x|<1 */
                  if (i0 >= 0) {
                      i0 = i1 = 0;
                  } else if (((i0 & 0x7fffffff) | i1) != 0) {
                      i0 = 0xbff00000;
                      i1 = 0;
                  }
              }
          } else {
              i = (0x000fffff) >> j0;
              if (((i0 & i) | i1) == 0)
                  return x;       /* x is integral */
              if (huge_val + x > 0.0) {       /* raise inexact flag */
                  if (i0 < 0)
                      i0 += (0x00100000) >> j0;
                  i0 &= (~i);
                  i1 = 0;
              }
          }
      } else if (j0 > 51) {
          if (j0 == 0x400)
              return x + x;       /* inf or NaN */
          else
              return x;           /* x is integral */
      } else {
          i = ((u_int32_t) (0xffffffff)) >> (j0 - 20);
          if ((i1 & i) == 0)
              return x;           /* x is integral */
          if (huge_val + x > 0.0) {   /* raise inexact flag */
              if (i0 < 0) {
                  if (j0 == 20)
                      i0 += 1;
                  else {
                      j = i1 + (1 << (52 - j0));
                      if (j < (u_int32_t) i1)
                          i0 += 1;        /* got a carry */
                      i1 = j;
                  }
              }
              i1 &= (~i);
          }
      }
      INSERT_WORDS(x, i0, i1);
      return x;
  }
  
  libm_hidden_def(floor)
  

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