#ifndef RMODULO2M_H
#define RMODULO2M_H
/****************************************
*  Computer Algebra System SINGULAR     *
****************************************/
/* $Id$ */
/*
* ABSTRACT: numbers modulo 2^m
*/
#ifdef HAVE_RINGS
#include "coeffs.h"
#include "rintegers.h"

#ifndef NATNUMBER
#define NATNUMBER unsigned long
#endif


BOOLEAN nr2mInitChar    (coeffs r, void*);

extern int nr2mExp;
extern NATNUMBER nr2mModul; /* for storing 2^m - 1, i.e., the
                               bit pattern '11..1' of length m */

number  nr2mCopy        (number a, const coeffs r);
BOOLEAN nr2mGreaterZero (number k, const coeffs r);
number  nr2mMult        (number a, number b, const coeffs r);
number  nr2mInit        (int i, const coeffs r);
int     nr2mInt         (number &n, const coeffs r);
number  nr2mAdd         (number a, number b, const coeffs r);
number  nr2mSub         (number a, number b, const coeffs r);
void    nr2mPower       (number a, int i, number * result, const coeffs r);
BOOLEAN nr2mIsZero      (number a, const coeffs r);
BOOLEAN nr2mIsOne       (number a, const coeffs r);
BOOLEAN nr2mIsMOne      (number a, const coeffs r);
BOOLEAN nr2mIsUnit      (number a, const coeffs r);
number  nr2mGetUnit     (number a, const coeffs r);
number  nr2mDiv         (number a, number b, const coeffs r);
number  nr2mIntDiv      (number a,number b, const coeffs r);
number  nr2mMod         (number a,number b, const coeffs r);
number  nr2mNeg         (number c, const coeffs r);
number  nr2mInvers      (number c, const coeffs r);
BOOLEAN nr2mGreater     (number a, number b, const coeffs r);
BOOLEAN nr2mDivBy       (number a, number b, const coeffs r);
int     nr2mDivComp     (number a, number b, const coeffs r);
BOOLEAN nr2mEqual       (number a, number b, const coeffs r);
number  nr2mLcm         (number a, number b, const coeffs r);
number  nr2mGcd         (number a, number b, const coeffs r);
number  nr2mExtGcd      (number a, number b, number *s, number *t, const coeffs r);
nMapFunc nr2mSetMap     (const coeffs src, const coeffs dst);
void    nr2mWrite       (number &a, const coeffs r);
const char *  nr2mRead  (const char *s, number *a, const coeffs r);
char *  nr2mName        (number n, const coeffs r);
#ifdef LDEBUG
BOOLEAN nr2mDBTest      (number a, const char *f, const int l, const coeffs r);
#endif
void    nr2mSetExp(int c, const coeffs r);
void    nr2mInitExp(int c, const coeffs r);


static inline number nr2mMultM(number a, number b, const coeffs r)
{
  return (number)
    ((((NATNUMBER) a) * ((NATNUMBER) b)) & ((NATNUMBER) r->nr2mModul));
}

static inline number nr2mAddM(number a, number b, const coeffs r)
{
  return (number)
    ((((NATNUMBER) a) + ((NATNUMBER) b)) & ((NATNUMBER) r->nr2mModul));
}

static inline number nr2mSubM(number a, number b, const coeffs r)
{
  return (number)((NATNUMBER)a<(NATNUMBER)b ?
                       r->nr2mModul-(NATNUMBER)b+(NATNUMBER)a + 1: (NATNUMBER)a-(NATNUMBER)b);
}

#define nr2mNegM(A,r) (number)(r->nr2mModul-(NATNUMBER)(A) + 1)
#define nr2mEqualM(A,B)  ((A)==(B))

#endif
#endif