libgcc/config/lm32/_modsi3.c

/* _modsi3 for Lattice Mico32.
   Contributed by Jon Beniston <jon@beniston.com> 
   
   Copyright (C) 2009-2021 Free Software Foundation, Inc.

   This file is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 3, or (at your option) any
   later version.
   
   This file is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.
   
   Under Section 7 of GPL version 3, you are granted additional
   permissions described in the GCC Runtime Library Exception, version
   3.1, as published by the Free Software Foundation.
   
   You should have received a copy of the GNU General Public License and
   a copy of the GCC Runtime Library Exception along with this program;
   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
   <http://www.gnu.org/licenses/>. */

#include "libgcc_lm32.h"

/* Signed integer modulus.  */

SItype
__modsi3 (SItype a, SItype b)
{
  int neg = 0;
  SItype res;
  int cfg;

  if (b == 0)
    {
      /* Raise divide by zero exception.  */
      int eba, sr;
      /* Save interrupt enable.  */
      __asm__ __volatile__ ("rcsr %0, IE":"=r" (sr));
      sr = (sr & 1) << 1;
      __asm__ __volatile__ ("wcsr IE, %0"::"r" (sr));
      /* Branch to exception handler.  */
      __asm__ __volatile__ ("rcsr %0, EBA":"=r" (eba));
      eba += 32 * 5;
      __asm__ __volatile__ ("mv ea, ra");
      __asm__ __volatile__ ("b %0"::"r" (eba));
      __builtin_unreachable ();
    }

  if (a < 0)
    {
      a = -a;
      neg = 1;
    }

  if (b < 0)
    b = -b;

__asm__ ("rcsr %0, CFG":"=r" (cfg));
  if (cfg & 2)
  __asm__ ("modu %0, %1, %2": "=r" (res):"r" (a), "r" (b));
  else
    res = __udivmodsi4 (a, b, 1);

  if (neg)
    res = -res;

  return res;
}