1  /* ceil().  RISC-V version.
       2     Copyright (C) 2017-2023 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 <fenv_private.h>
      22  #include <libm-alias-double.h>
      23  #include <stdint.h>
      24  
      25  double
      26  __ceil (double x)
      27  {
      28    int flags = riscv_getflags ();
      29    bool nan = isnan (x);
      30    double mag = fabs (x);
      31  
      32    if (nan)
      33      return x + x;
      34  
      35    if (mag < (1ULL << __DBL_MANT_DIG__))
      36      {
      37        int64_t i;
      38        double new_x;
      39  
      40        asm volatile ("fcvt.l.d %0, %1, rup" : "=r" (i) : "f" (x));
      41        asm volatile ("fcvt.d.l %0, %1, rup" : "=f" (new_x) : "r" (i));
      42  
      43        /* ceil(-0) == -0, and in general we'll always have the same
      44  	 sign as our input.  */
      45        x = copysign (new_x, x);
      46  
      47        riscv_setflags (flags);
      48      }
      49  
      50    return x;
      51  }
      52  
      53  libm_alias_double (__ceil, ceil)