#ifndef modq_h
#define modq_h

#include "crypto_int16.h"
#include "crypto_int32.h"
#include "crypto_uint16.h"

typedef crypto_int16 modq;

/* input between -9000000 and 9000000 */
/* output between -2295 and 2295 */
static inline modq modq_freeze(crypto_int32 a)
{
  a -= 4591 * ((228 * a) >> 20);
  a -= 4591 * ((58470 * a + 134217728) >> 28);
  return a;
}

static inline modq modq_minusproduct(modq a,modq b,modq c)
{
  crypto_int32 A = a;
  crypto_int32 B = b;
  crypto_int32 C = c;
  return modq_freeze(A - B * C);
}

static inline modq modq_plusproduct(modq a,modq b,modq c)
{
  crypto_int32 A = a;
  crypto_int32 B = b;
  crypto_int32 C = c;
  return modq_freeze(A + B * C);
}

static inline modq modq_product(modq a,modq b)
{
  crypto_int32 A = a;
  crypto_int32 B = b;
  return modq_freeze(A * B);
}

static inline modq modq_square(modq a)
{
  crypto_int32 A = a;
  return modq_freeze(A * A);
}

static inline modq modq_sum(modq a,modq b)
{
  crypto_int32 A = a;
  crypto_int32 B = b;
  return modq_freeze(A + B);
}

static inline modq modq_reciprocal(modq a1)
{
  modq a2 = modq_square(a1);
  modq a3 = modq_product(a2,a1);
  modq a4 = modq_square(a2);
  modq a8 = modq_square(a4);
  modq a16 = modq_square(a8);
  modq a32 = modq_square(a16);
  modq a35 = modq_product(a32,a3);
  modq a70 = modq_square(a35);
  modq a140 = modq_square(a70);
  modq a143 = modq_product(a140,a3);
  modq a286 = modq_square(a143);
  modq a572 = modq_square(a286);
  modq a1144 = modq_square(a572);
  modq a1147 = modq_product(a1144,a3);
  modq a2294 = modq_square(a1147);
  modq a4588 = modq_square(a2294);
  modq a4589 = modq_product(a4588,a1);
  return a4589;
}

static inline modq modq_quotient(modq num,modq den)
{
  return modq_product(num,modq_reciprocal(den));
}

/* -1 if x is nonzero, 0 otherwise */
static inline int modq_nonzero_mask(modq x)
{
  crypto_int32 r = (crypto_uint16) x;
  r = -r;
  r >>= 30;
  return r;
}

#endif