1  /* s_floorf.c -- float version of s_floor.c.
       2   */
       3  
       4  /*
       5   * ====================================================
       6   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
       7   *
       8   * Developed at SunPro, a Sun Microsystems, Inc. business.
       9   * Permission to use, copy, modify, and distribute this
      10   * software is freely granted, provided that this notice
      11   * is preserved.
      12   * ====================================================
      13   */
      14  
      15  /*
      16   * floorf(x)
      17   * Return x rounded toward -inf to integral value
      18   * Method:
      19   *	Bit twiddling.
      20   */
      21  
      22  #define NO_MATH_REDIRECT
      23  #include <math.h>
      24  #include <math_private.h>
      25  #include <libm-alias-float.h>
      26  #include <math-use-builtins.h>
      27  
      28  float
      29  __floorf (float x)
      30  {
      31  #if USE_FLOORF_BUILTIN
      32    return __builtin_floorf (x);
      33  #else
      34    /* Use generic implementation.  */
      35    int32_t i0, j0;
      36    uint32_t i;
      37    GET_FLOAT_WORD (i0, x);
      38    j0 = ((i0 >> 23) & 0xff) - 0x7f;
      39    if (j0 < 23)
      40      {
      41        if (j0 < 0)
      42  	{
      43  	  /* return 0 * sign (x) if |x| < 1  */
      44  	  if (i0 >= 0)
      45  	    i0 = 0;
      46  	  else if ((i0 & 0x7fffffff) != 0)
      47  	    i0 = 0xbf800000;
      48  	}
      49        else
      50  	{
      51  	  i = (0x007fffff) >> j0;
      52  	  if ((i0 & i) == 0)
      53  	    return x;		/* x is integral  */
      54  	  if (i0 < 0)
      55  	    i0 += (0x00800000) >> j0;
      56  	  i0 &= (~i);
      57  	}
      58      }
      59    else
      60      {
      61        if (__glibc_unlikely (j0 == 0x80))
      62  	return x + x;		/* inf or NaN  */
      63        else
      64  	return x;		/* x is integral  */
      65      }
      66    SET_FLOAT_WORD (x, i0);
      67    return x;
      68  #endif /* ! USE_FLOORF_BUILTIN  */
      69  }
      70  #ifndef __floorf
      71  libm_alias_float (__floor, floor)
      72  #endif