1  /* Multiply by integral power of radix.
       2  
       3     Copyright (C) 2011-2023 Free Software Foundation, Inc.
       4  
       5     This file is part of the GNU C Library.
       6  
       7     The GNU C Library is free software; you can redistribute it and/or
       8     modify it under the terms of the GNU Lesser General Public
       9     License as published by the Free Software Foundation; either
      10     version 2.1 of the License, or (at your option) any later version.
      11  
      12     The GNU C Library is distributed in the hope that it will be useful,
      13     but WITHOUT ANY WARRANTY; without even the implied warranty of
      14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15     Lesser General Public License for more details.
      16  
      17     You should have received a copy of the GNU Lesser General Public
      18     License along with the GNU C Library; if not, see
      19     <https://www.gnu.org/licenses/>.  */
      20  
      21  #include <math.h>
      22  #include <math_private.h>
      23  #include <libm-alias-finite.h>
      24  
      25  static FLOAT
      26  __attribute__ ((noinline))
      27  invalid_fn (FLOAT x, FLOAT fn)
      28  {
      29    if (M_SUF (rint) (fn) != fn)
      30      return (fn - fn) / (fn - fn);
      31    else if (fn > M_LIT (65000.0))
      32      return M_SUF (__scalbn) (x, 65000);
      33    else
      34      return M_SUF (__scalbn) (x,-65000);
      35  }
      36  
      37  
      38  FLOAT
      39  M_DECL_FUNC (__ieee754_scalb) (FLOAT x, FLOAT fn)
      40  {
      41    if (__glibc_unlikely (isnan (x)))
      42      return x * fn;
      43    if (__glibc_unlikely (!isfinite (fn)))
      44      {
      45        if (isnan (fn) || fn > M_LIT (0.0))
      46  	return x * fn;
      47        if (x == M_LIT (0.0))
      48  	return x;
      49        return x / -fn;
      50      }
      51    if (__glibc_unlikely (M_FABS (fn) >= M_LIT (0x1p31)
      52  			|| (FLOAT) (int) fn != fn))
      53      return invalid_fn (x, fn);
      54  
      55    return M_SCALBN (x, (int) fn);
      56  }
      57  declare_mgen_finite_alias (__ieee754_scalb, __scalb)