sysdeps/loongarch/fpu/e_scalbf.c

   1 /* scalbf().  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 float
  26 __ieee754_scalbf (float x, float fn)
  27 {
  28   int x_cond;
  29   int fn_cond;
  30   asm volatile ("fclass.s \t%0, %1" : "=f" (x_cond) : "f" (x));
  31   asm volatile ("fclass.s \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(-FLT_MAX < fn && fn < FLT_MAX))
  43     {
  44       float rintf_fn, tmp;
  45
  46       /* rintf_fn = rintf(fn) */
  47       asm volatile ("frint.s \t%0, %1" : "=f" (rintf_fn) : "f" (fn));
  48
  49       if (rintf_fn != fn )
  50           return (x - x) / (x - x);
  51
  52       asm volatile ("ftintrz.w.s \t%0, %1" : "=f" (tmp) : "f" (rintf_fn));
  53       asm volatile ("fscaleb.s \t%0, %1, %2" : "=f" (x) : "f" (x), "f" (tmp));
  54     }
  55   else
  56     asm volatile ("fscaleb.s \t%0, %1, %2" : "=f" (x) : "f" (x), "f" (fn));
  57
  58   return x;
  59 }
  60 libm_alias_finite (__ieee754_scalb, __scalb)