Files
MP-SPDZ/Math/Zp_Data.h
2016-09-02 19:16:51 +01:00

130 lines
3.8 KiB
C++

// (C) 2016 University of Bristol. See License.txt
#ifndef _Zp_Data
#define _Zp_Data
/* Class to define helper information for a Zp element
*
* Basically the data needed for Montgomery operations
*
* Almost all data is public as this is basically a container class
*
*/
#include "Math/bigint.h"
#include "Tools/random.h"
#include <smmintrin.h>
#include <iostream>
using namespace std;
#ifndef MAX_MOD_SZ
#ifdef LargeM
#define MAX_MOD_SZ 20
#else
#define MAX_MOD_SZ 3
#endif
#endif
class modp;
class Zp_Data
{
bool montgomery; // True if we are using Montgomery arithmetic
mp_limb_t R[MAX_MOD_SZ],R2[MAX_MOD_SZ],R3[MAX_MOD_SZ],pi;
mp_limb_t prA[MAX_MOD_SZ];
int t; // More Montgomery data
void Mont_Mult(mp_limb_t* z,const mp_limb_t* x,const mp_limb_t* y) const;
public:
bigint pr;
mp_limb_t mask;
void assign(const Zp_Data& Zp);
void init(const bigint& p,bool mont=true);
int get_t() const { return t; }
const mp_limb_t* get_prA() const { return prA; }
// This one does nothing, needed so as to make vectors of Zp_Data
Zp_Data() : montgomery(0), pi(0), mask(0) { t=1; }
// The main init funciton
Zp_Data(const bigint& p,bool mont=true)
{ init(p,mont); }
Zp_Data(const Zp_Data& Zp) { assign(Zp); }
Zp_Data& operator=(const Zp_Data& Zp)
{ if (this!=&Zp) { assign(Zp); }
return *this;
}
~Zp_Data() { ; }
template <int T>
void Add(mp_limb_t* ans,const mp_limb_t* x,const mp_limb_t* y) const;
void Add(mp_limb_t* ans,const mp_limb_t* x,const mp_limb_t* y) const;
void Sub(mp_limb_t* ans,const mp_limb_t* x,const mp_limb_t* y) const;
__m128i get_random128(PRNG& G);
friend void to_bigint(bigint& ans,const modp& x,const Zp_Data& ZpD,bool reduce);
friend void to_modp(modp& ans,int x,const Zp_Data& ZpD);
friend void to_modp(modp& ans,const bigint& x,const Zp_Data& ZpD);
friend void Add(modp& ans,const modp& x,const modp& y,const Zp_Data& ZpD);
friend void Sub(modp& ans,const modp& x,const modp& y,const Zp_Data& ZpD);
friend void Mul(modp& ans,const modp& x,const modp& y,const Zp_Data& ZpD);
friend void Sqr(modp& ans,const modp& x,const Zp_Data& ZpD);
friend void Negate(modp& ans,const modp& x,const Zp_Data& ZpD);
friend void Inv(modp& ans,const modp& x,const Zp_Data& ZpD);
friend void Power(modp& ans,const modp& x,int exp,const Zp_Data& ZpD);
friend void Power(modp& ans,const modp& x,const bigint& exp,const Zp_Data& ZpD);
friend void assignOne(modp& x,const Zp_Data& ZpD);
friend void assignZero(modp& x,const Zp_Data& ZpD);
friend bool isZero(const modp& x,const Zp_Data& ZpD);
friend bool isOne(const modp& x,const Zp_Data& ZpD);
friend bool areEqual(const modp& x,const modp& y,const Zp_Data& ZpD);
friend class modp;
friend ostream& operator<<(ostream& s,const Zp_Data& ZpD);
friend istream& operator>>(istream& s,Zp_Data& ZpD);
};
template<>
inline void Zp_Data::Add<2>(mp_limb_t* ans,const mp_limb_t* x,const mp_limb_t* y) const
{
__uint128_t a, b, p;
memcpy(&a, x, sizeof(__uint128_t));
memcpy(&b, y, sizeof(__uint128_t));
memcpy(&p, prA, sizeof(__uint128_t));
__uint128_t c = a + b;
asm goto ("jc %l[sub]" :::: sub);
if (c >= p)
sub:
c -= p;
memcpy(ans, &c, sizeof(__uint128_t));
}
template<>
inline void Zp_Data::Add<0>(mp_limb_t* ans,const mp_limb_t* x,const mp_limb_t* y) const
{
mp_limb_t carry = mpn_add_n(ans,x,y,t);
if (carry!=0 || mpn_cmp(ans,prA,t)>=0)
{ mpn_sub_n(ans,ans,prA,t); }
}
inline void Zp_Data::Add(mp_limb_t* ans,const mp_limb_t* x,const mp_limb_t* y) const
{
if (t == 2)
return Add<2>(ans, x, y);
else
return Add<0>(ans, x, y);
}
#endif