source: git/factory/ffops.h @ 2dd068

// emacs edit mode for this file is -*- C++ -*-
// $Id: ffops.h,v 1.0 1996-05-17 10:59:40 stobbe Exp $

#ifndef INCL_FFOPS_H
#define INCL_FFOPS_H

/*
$Log: not supported by cvs2svn $
*/

#include "cf_globals.h"
#include "cf_switches.h"

extern int ff_prime;
extern int ff_halfprime;
extern short * ff_invtab;

int ff_newinv ( const int );
void ff_setprime ( const int );

inline int ff_norm ( const int a )
{
  int n = a % ff_prime;
  if ( n < 0 )
    return n + ff_prime;
  else
    return n;
}

inline int ff_symmetric( const int a )
{
    if ( cf_glob_switches.isOn( SW_SYMMETRIC_FF ) )
        return ( a > ff_halfprime ) ? a - ff_prime : a;
    else
        return a;
}

inline int ff_longnorm ( const long a )
{
  int n = (int)(a % (long)ff_prime);
  if ( n < 0 )
    return n + ff_prime;
  else
    return n;
}

inline int ff_add ( const int a, const int b )
{
  return ff_norm( a + b );
}

inline int ff_sub ( const int a, const int b )
{
  return ff_norm( a - b );
}

inline int ff_neg ( const int a )
{
  return ff_norm( -a );
}

inline int ff_mul ( const int a, const int b )
{
  return ff_longnorm ( (long)a * (long)b );
}

inline int ff_inv ( const int a )
{
  register b;
  if ( (b = (int)(ff_invtab[a])) )
    return b;
  else
    return ff_newinv( a );
}

inline int ff_div ( const int a, const int b )
{
  return ff_mul( a, ff_inv( b ) );
}

#endif /* INCL_FFOPS_H */