1  /* scalb().  LoongArch version.
       2     Copyright (C) 2022-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #define NO_MATH_REDIRECT
      20  #include <math.h>
      21  #include <libm-alias-finite.h>
      22  #include <fpu_control.h>
      23  #include <float.h>
      24  
      25  double
      26  __ieee754_scalb (double x, double fn)
      27  {
      28    int x_cond;
      29    int fn_cond;
      30    asm volatile ("fclass.d \t%0, %1" : "=f" (x_cond) : "f" (x));
      31    asm volatile ("fclass.d \t%0, %1" : "=f" (fn_cond) : "f" (fn));
      32  
      33    if (__glibc_unlikely(( x_cond | fn_cond) & _FCLASS_NAN))
      34        return x * fn;
      35    else if (__glibc_unlikely(fn_cond & _FCLASS_INF))
      36      {
      37        if (!(fn_cond & _FCLASS_MINF))
      38  	  return x * fn;
      39        else
      40  	  return x / -fn;
      41      }
      42    else if (__glibc_likely(-DBL_MAX < fn && fn < DBL_MAX))
      43      {
      44        double rint_fn, tmp;
      45  
      46        /* rint_fn = rint(fn) */
      47        asm volatile ("frint.d \t%0, %1" : "=f" (rint_fn) : "f" (fn));
      48  
      49        if (rint_fn != fn )
      50  	  return (x - x) / (x - x);
      51  
      52        asm volatile ("ftintrz.l.d \t%0, %1" : "=f" (tmp) : "f" (rint_fn));
      53        asm volatile ("fscaleb.d \t%0, %1, %2" : "=f" (x) : "f" (x), "f" (tmp));
      54      }
      55    else
      56      asm volatile ("fscaleb.d \t%0, %1, %2" : "=f" (x) : "f" (x), "f" (fn));
      57  
      58    return x;
      59  }
      60  libm_alias_finite (__ieee754_scalb, __scalb)