




#include "internal/deprecated.h"



#include <openssl/opensslconf.h>

#include <stdint.h>
#include <string.h>
#include <openssl/err.h>
#include "ec_local.h"

#include "internal/numbers.h"

#ifndef INT128_MAX
# error "Your compiler doesn't appear to support 128-bit integer types"
#endif

typedef uint8_t u8;
typedef uint32_t u32;
typedef uint64_t u64;



typedef u8 felem_bytearray[32];


static const felem_bytearray nistp256_curve_params[5] = {
    {0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x01, 
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
    {0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x01, 
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
     0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfc},
    {0x5a, 0xc6, 0x35, 0xd8, 0xaa, 0x3a, 0x93, 0xe7, 
     0xb3, 0xeb, 0xbd, 0x55, 0x76, 0x98, 0x86, 0xbc,
     0x65, 0x1d, 0x06, 0xb0, 0xcc, 0x53, 0xb0, 0xf6,
     0x3b, 0xce, 0x3c, 0x3e, 0x27, 0xd2, 0x60, 0x4b},
    {0x6b, 0x17, 0xd1, 0xf2, 0xe1, 0x2c, 0x42, 0x47, 
     0xf8, 0xbc, 0xe6, 0xe5, 0x63, 0xa4, 0x40, 0xf2,
     0x77, 0x03, 0x7d, 0x81, 0x2d, 0xeb, 0x33, 0xa0,
     0xf4, 0xa1, 0x39, 0x45, 0xd8, 0x98, 0xc2, 0x96},
    {0x4f, 0xe3, 0x42, 0xe2, 0xfe, 0x1a, 0x7f, 0x9b, 
     0x8e, 0xe7, 0xeb, 0x4a, 0x7c, 0x0f, 0x9e, 0x16,
     0x2b, 0xce, 0x33, 0x57, 0x6b, 0x31, 0x5e, 0xce,
     0xcb, 0xb6, 0x40, 0x68, 0x37, 0xbf, 0x51, 0xf5}
};



#define NLIMBS 4

typedef uint128_t limb;
typedef limb felem[NLIMBS];
typedef limb longfelem[NLIMBS * 2];
typedef u64 smallfelem[NLIMBS];


static const u64 kPrime[4] =
    { 0xfffffffffffffffful, 0xffffffff, 0, 0xffffffff00000001ul };
static const u64 bottom63bits = 0x7ffffffffffffffful;


static void bin32_to_felem(felem out, const u8 in[32])
{
    out[0] = *((u64 *)&in[0]);
    out[1] = *((u64 *)&in[8]);
    out[2] = *((u64 *)&in[16]);
    out[3] = *((u64 *)&in[24]);
}


static void smallfelem_to_bin32(u8 out[32], const smallfelem in)
{
    *((u64 *)&out[0]) = in[0];
    *((u64 *)&out[8]) = in[1];
    *((u64 *)&out[16]) = in[2];
    *((u64 *)&out[24]) = in[3];
}


static int BN_to_felem(felem out, const BIGNUM *bn)
{
    felem_bytearray b_out;
    int num_bytes;

    if (BN_is_negative(bn)) {
        ERR_raise(ERR_LIB_EC, EC_R_BIGNUM_OUT_OF_RANGE);
        return 0;
    }
    num_bytes = BN_bn2lebinpad(bn, b_out, sizeof(b_out));
    if (num_bytes < 0) {
        ERR_raise(ERR_LIB_EC, EC_R_BIGNUM_OUT_OF_RANGE);
        return 0;
    }
    bin32_to_felem(out, b_out);
    return 1;
}


static BIGNUM *smallfelem_to_BN(BIGNUM *out, const smallfelem in)
{
    felem_bytearray b_out;
    smallfelem_to_bin32(b_out, in);
    return BN_lebin2bn(b_out, sizeof(b_out), out);
}



static void smallfelem_one(smallfelem out)
{
    out[0] = 1;
    out[1] = 0;
    out[2] = 0;
    out[3] = 0;
}

static void smallfelem_assign(smallfelem out, const smallfelem in)
{
    out[0] = in[0];
    out[1] = in[1];
    out[2] = in[2];
    out[3] = in[3];
}

static void felem_assign(felem out, const felem in)
{
    out[0] = in[0];
    out[1] = in[1];
    out[2] = in[2];
    out[3] = in[3];
}


static void felem_sum(felem out, const felem in)
{
    out[0] += in[0];
    out[1] += in[1];
    out[2] += in[2];
    out[3] += in[3];
}


static void felem_small_sum(felem out, const smallfelem in)
{
    out[0] += in[0];
    out[1] += in[1];
    out[2] += in[2];
    out[3] += in[3];
}


static void felem_scalar(felem out, const u64 scalar)
{
    out[0] *= scalar;
    out[1] *= scalar;
    out[2] *= scalar;
    out[3] *= scalar;
}


static void longfelem_scalar(longfelem out, const u64 scalar)
{
    out[0] *= scalar;
    out[1] *= scalar;
    out[2] *= scalar;
    out[3] *= scalar;
    out[4] *= scalar;
    out[5] *= scalar;
    out[6] *= scalar;
    out[7] *= scalar;
}

#define two105m41m9 (((limb)1) << 105) - (((limb)1) << 41) - (((limb)1) << 9)
#define two105 (((limb)1) << 105)
#define two105m41p9 (((limb)1) << 105) - (((limb)1) << 41) + (((limb)1) << 9)


static const felem zero105 =
    { two105m41m9, two105, two105m41p9, two105m41p9 };


static void smallfelem_neg(felem out, const smallfelem small)
{
    
    out[0] = zero105[0] - small[0];
    out[1] = zero105[1] - small[1];
    out[2] = zero105[2] - small[2];
    out[3] = zero105[3] - small[3];
}


static void felem_diff(felem out, const felem in)
{
    
    out[0] += zero105[0];
    out[1] += zero105[1];
    out[2] += zero105[2];
    out[3] += zero105[3];

    out[0] -= in[0];
    out[1] -= in[1];
    out[2] -= in[2];
    out[3] -= in[3];
}

#define two107m43m11 (((limb)1) << 107) - (((limb)1) << 43) - (((limb)1) << 11)
#define two107 (((limb)1) << 107)
#define two107m43p11 (((limb)1) << 107) - (((limb)1) << 43) + (((limb)1) << 11)


static const felem zero107 =
    { two107m43m11, two107, two107m43p11, two107m43p11 };


static void felem_diff_zero107(felem out, const felem in)
{
    
    out[0] += zero107[0];
    out[1] += zero107[1];
    out[2] += zero107[2];
    out[3] += zero107[3];

    out[0] -= in[0];
    out[1] -= in[1];
    out[2] -= in[2];
    out[3] -= in[3];
}


static void longfelem_diff(longfelem out, const longfelem in)
{
    static const limb two70m8p6 =
        (((limb) 1) << 70) - (((limb) 1) << 8) + (((limb) 1) << 6);
    static const limb two70p40 = (((limb) 1) << 70) + (((limb) 1) << 40);
    static const limb two70 = (((limb) 1) << 70);
    static const limb two70m40m38p6 =
        (((limb) 1) << 70) - (((limb) 1) << 40) - (((limb) 1) << 38) +
        (((limb) 1) << 6);
    static const limb two70m6 = (((limb) 1) << 70) - (((limb) 1) << 6);

    
    out[0] += two70m8p6;
    out[1] += two70p40;
    out[2] += two70;
    out[3] += two70m40m38p6;
    out[4] += two70m6;
    out[5] += two70m6;
    out[6] += two70m6;
    out[7] += two70m6;

    
    out[0] -= in[0];
    out[1] -= in[1];
    out[2] -= in[2];
    out[3] -= in[3];
    out[4] -= in[4];
    out[5] -= in[5];
    out[6] -= in[6];
    out[7] -= in[7];
}

#define two64m0 (((limb)1) << 64) - 1
#define two110p32m0 (((limb)1) << 110) + (((limb)1) << 32) - 1
#define two64m46 (((limb)1) << 64) - (((limb)1) << 46)
#define two64m32 (((limb)1) << 64) - (((limb)1) << 32)


static const felem zero110 = { two64m0, two110p32m0, two64m46, two64m32 };


static void felem_shrink(smallfelem out, const felem in)
{
    felem tmp;
    u64 a, b, mask;
    u64 high, low;
    static const u64 kPrime3Test = 0x7fffffff00000001ul; 

    
    tmp[3] = zero110[3] + in[3] + ((u64)(in[2] >> 64));
    

    tmp[2] = zero110[2] + (u64)in[2];
    tmp[0] = zero110[0] + in[0];
    tmp[1] = zero110[1] + in[1];
    

    
    a = tmp[3] >> 64;           
    tmp[3] = (u64)tmp[3];
    tmp[3] -= a;
    tmp[3] += ((limb) a) << 32;
    

    b = a;
    a = tmp[3] >> 64;           
    b += a;                     
    tmp[3] = (u64)tmp[3];
    tmp[3] -= a;
    tmp[3] += ((limb) a) << 32;
    

    
    tmp[0] += b;
    tmp[1] -= (((limb) b) << 32);

    
    high = (u64)(tmp[3] >> 64);
    
    high = 0 - high;
    
    low = (u64)tmp[3];
    mask = 0 - (low >> 63);
    
    low &= bottom63bits;
    low -= kPrime3Test;
    
    low = ~low;
    low = 0 - (low >> 63);
    
    mask = (mask & low) | high;
    tmp[0] -= mask & kPrime[0];
    tmp[1] -= mask & kPrime[1];
    
    tmp[3] -= mask & kPrime[3];
    

    tmp[1] += ((u64)(tmp[0] >> 64));
    tmp[0] = (u64)tmp[0];
    tmp[2] += ((u64)(tmp[1] >> 64));
    tmp[1] = (u64)tmp[1];
    tmp[3] += ((u64)(tmp[2] >> 64));
    tmp[2] = (u64)tmp[2];
    

    out[0] = tmp[0];
    out[1] = tmp[1];
    out[2] = tmp[2];
    out[3] = tmp[3];
}


static void smallfelem_expand(felem out, const smallfelem in)
{
    out[0] = in[0];
    out[1] = in[1];
    out[2] = in[2];
    out[3] = in[3];
}


static void smallfelem_square(longfelem out, const smallfelem small)
{
    limb a;
    u64 high, low;

    a = ((uint128_t) small[0]) * small[0];
    low = a;
    high = a >> 64;
    out[0] = low;
    out[1] = high;

    a = ((uint128_t) small[0]) * small[1];
    low = a;
    high = a >> 64;
    out[1] += low;
    out[1] += low;
    out[2] = high;

    a = ((uint128_t) small[0]) * small[2];
    low = a;
    high = a >> 64;
    out[2] += low;
    out[2] *= 2;
    out[3] = high;

    a = ((uint128_t) small[0]) * small[3];
    low = a;
    high = a >> 64;
    out[3] += low;
    out[4] = high;

    a = ((uint128_t) small[1]) * small[2];
    low = a;
    high = a >> 64;
    out[3] += low;
    out[3] *= 2;
    out[4] += high;

    a = ((uint128_t) small[1]) * small[1];
    low = a;
    high = a >> 64;
    out[2] += low;
    out[3] += high;

    a = ((uint128_t) small[1]) * small[3];
    low = a;
    high = a >> 64;
    out[4] += low;
    out[4] *= 2;
    out[5] = high;

    a = ((uint128_t) small[2]) * small[3];
    low = a;
    high = a >> 64;
    out[5] += low;
    out[5] *= 2;
    out[6] = high;
    out[6] += high;

    a = ((uint128_t) small[2]) * small[2];
    low = a;
    high = a >> 64;
    out[4] += low;
    out[5] += high;

    a = ((uint128_t) small[3]) * small[3];
    low = a;
    high = a >> 64;
    out[6] += low;
    out[7] = high;
}


static void felem_square(longfelem out, const felem in)
{
    u64 small[4];
    felem_shrink(small, in);
    smallfelem_square(out, small);
}


static void smallfelem_mul(longfelem out, const smallfelem small1,
                           const smallfelem small2)
{
    limb a;
    u64 high, low;

    a = ((uint128_t) small1[0]) * small2[0];
    low = a;
    high = a >> 64;
    out[0] = low;
    out[1] = high;

    a = ((uint128_t) small1[0]) * small2[1];
    low = a;
    high = a >> 64;
    out[1] += low;
    out[2] = high;

    a = ((uint128_t) small1[1]) * small2[0];
    low = a;
    high = a >> 64;
    out[1] += low;
    out[2] += high;

    a = ((uint128_t) small1[0]) * small2[2];
    low = a;
    high = a >> 64;
    out[2] += low;
    out[3] = high;

    a = ((uint128_t) small1[1]) * small2[1];
    low = a;
    high = a >> 64;
    out[2] += low;
    out[3] += high;

    a = ((uint128_t) small1[2]) * small2[0];
    low = a;
    high = a >> 64;
    out[2] += low;
    out[3] += high;

    a = ((uint128_t) small1[0]) * small2[3];
    low = a;
    high = a >> 64;
    out[3] += low;
    out[4] = high;

    a = ((uint128_t) small1[1]) * small2[2];
    low = a;
    high = a >> 64;
    out[3] += low;
    out[4] += high;

    a = ((uint128_t) small1[2]) * small2[1];
    low = a;
    high = a >> 64;
    out[3] += low;
    out[4] += high;

    a = ((uint128_t) small1[3]) * small2[0];
    low = a;
    high = a >> 64;
    out[3] += low;
    out[4] += high;

    a = ((uint128_t) small1[1]) * small2[3];
    low = a;
    high = a >> 64;
    out[4] += low;
    out[5] = high;

    a = ((uint128_t) small1[2]) * small2[2];
    low = a;
    high = a >> 64;
    out[4] += low;
    out[5] += high;

    a = ((uint128_t) small1[3]) * small2[1];
    low = a;
    high = a >> 64;
    out[4] += low;
    out[5] += high;

    a = ((uint128_t) small1[2]) * small2[3];
    low = a;
    high = a >> 64;
    out[5] += low;
    out[6] = high;

    a = ((uint128_t) small1[3]) * small2[2];
    low = a;
    high = a >> 64;
    out[5] += low;
    out[6] += high;

    a = ((uint128_t) small1[3]) * small2[3];
    low = a;
    high = a >> 64;
    out[6] += low;
    out[7] = high;
}


static void felem_mul(longfelem out, const felem in1, const felem in2)
{
    smallfelem small1, small2;
    felem_shrink(small1, in1);
    felem_shrink(small2, in2);
    smallfelem_mul(out, small1, small2);
}


static void felem_small_mul(longfelem out, const smallfelem small1,
                            const felem in2)
{
    smallfelem small2;
    felem_shrink(small2, in2);
    smallfelem_mul(out, small1, small2);
}

#define two100m36m4 (((limb)1) << 100) - (((limb)1) << 36) - (((limb)1) << 4)
#define two100 (((limb)1) << 100)
#define two100m36p4 (((limb)1) << 100) - (((limb)1) << 36) + (((limb)1) << 4)

static const felem zero100 =
    { two100m36m4, two100, two100m36p4, two100m36p4 };


static void felem_reduce_(felem out, const longfelem in)
{
    int128_t c;
    
    c = in[4] + (in[5] << 32);
    out[0] += c;
    out[3] -= c;

    c = in[5] - in[7];
    out[1] += c;
    out[2] -= c;

    
    
    out[1] -= (in[4] << 32);
    out[3] += (in[4] << 32);

    
    out[2] -= (in[5] << 32);

    
    out[0] -= in[6];
    out[0] -= (in[6] << 32);
    out[1] += (in[6] << 33);
    out[2] += (in[6] * 2);
    out[3] -= (in[6] << 32);

    
    out[0] -= in[7];
    out[0] -= (in[7] << 32);
    out[2] += (in[7] << 33);
    out[3] += (in[7] * 3);
}


static void felem_reduce(felem out, const longfelem in)
{
    out[0] = zero100[0] + in[0];
    out[1] = zero100[1] + in[1];
    out[2] = zero100[2] + in[2];
    out[3] = zero100[3] + in[3];

    felem_reduce_(out, in);

    
}


static void felem_reduce_zero105(felem out, const longfelem in)
{
    out[0] = zero105[0] + in[0];
    out[1] = zero105[1] + in[1];
    out[2] = zero105[2] + in[2];
    out[3] = zero105[3] + in[3];

    felem_reduce_(out, in);

    
}


static void subtract_u64(u64 *result, u64 *carry, u64 v)
{
    uint128_t r = *result;
    r -= v;
    *carry = (r >> 64) & 1;
    *result = (u64)r;
}


static void felem_contract(smallfelem out, const felem in)
{
    unsigned i;
    u64 all_equal_so_far = 0, result = 0, carry;

    felem_shrink(out, in);
    

    all_equal_so_far--;
    
    for (i = 3; i < 4; i--) {
        u64 equal;
        uint128_t a = ((uint128_t) kPrime[i]) - out[i];
        
        result |= all_equal_so_far & ((u64)(a >> 64));

        
        equal = kPrime[i] ^ out[i];
        equal--;
        equal &= equal << 32;
        equal &= equal << 16;
        equal &= equal << 8;
        equal &= equal << 4;
        equal &= equal << 2;
        equal &= equal << 1;
        equal = 0 - (equal >> 63);

        all_equal_so_far &= equal;
    }

    
    result |= all_equal_so_far;

    
    subtract_u64(&out[0], &carry, result & kPrime[0]);
    subtract_u64(&out[1], &carry, carry);
    subtract_u64(&out[2], &carry, carry);
    subtract_u64(&out[3], &carry, carry);

    subtract_u64(&out[1], &carry, result & kPrime[1]);
    subtract_u64(&out[2], &carry, carry);
    subtract_u64(&out[3], &carry, carry);

    subtract_u64(&out[2], &carry, result & kPrime[2]);
    subtract_u64(&out[3], &carry, carry);

    subtract_u64(&out[3], &carry, result & kPrime[3]);
}

static void smallfelem_square_contract(smallfelem out, const smallfelem in)
{
    longfelem longtmp;
    felem tmp;

    smallfelem_square(longtmp, in);
    felem_reduce(tmp, longtmp);
    felem_contract(out, tmp);
}

static void smallfelem_mul_contract(smallfelem out, const smallfelem in1,
                                    const smallfelem in2)
{
    longfelem longtmp;
    felem tmp;

    smallfelem_mul(longtmp, in1, in2);
    felem_reduce(tmp, longtmp);
    felem_contract(out, tmp);
}


static limb smallfelem_is_zero(const smallfelem small)
{
    limb result;
    u64 is_p;

    u64 is_zero = small[0] | small[1] | small[2] | small[3];
    is_zero--;
    is_zero &= is_zero << 32;
    is_zero &= is_zero << 16;
    is_zero &= is_zero << 8;
    is_zero &= is_zero << 4;
    is_zero &= is_zero << 2;
    is_zero &= is_zero << 1;
    is_zero = 0 - (is_zero >> 63);

    is_p = (small[0] ^ kPrime[0]) |
        (small[1] ^ kPrime[1]) |
        (small[2] ^ kPrime[2]) | (small[3] ^ kPrime[3]);
    is_p--;
    is_p &= is_p << 32;
    is_p &= is_p << 16;
    is_p &= is_p << 8;
    is_p &= is_p << 4;
    is_p &= is_p << 2;
    is_p &= is_p << 1;
    is_p = 0 - (is_p >> 63);

    is_zero |= is_p;

    result = is_zero;
    result |= ((limb) is_zero) << 64;
    return result;
}

static int smallfelem_is_zero_int(const void *small)
{
    return (int)(smallfelem_is_zero(small) & ((limb) 1));
}


static void felem_inv(felem out, const felem in)
{
    felem ftmp, ftmp2;
    
    felem e2, e4, e8, e16, e32, e64;
    longfelem tmp;
    unsigned i;

    felem_square(tmp, in);
    felem_reduce(ftmp, tmp);    
    felem_mul(tmp, in, ftmp);
    felem_reduce(ftmp, tmp);    
    felem_assign(e2, ftmp);
    felem_square(tmp, ftmp);
    felem_reduce(ftmp, tmp);    
    felem_square(tmp, ftmp);
    felem_reduce(ftmp, tmp);    
    felem_mul(tmp, ftmp, e2);
    felem_reduce(ftmp, tmp);    
    felem_assign(e4, ftmp);
    felem_square(tmp, ftmp);
    felem_reduce(ftmp, tmp);    
    felem_square(tmp, ftmp);
    felem_reduce(ftmp, tmp);    
    felem_square(tmp, ftmp);
    felem_reduce(ftmp, tmp);    
    felem_square(tmp, ftmp);
    felem_reduce(ftmp, tmp);    
    felem_mul(tmp, ftmp, e4);
    felem_reduce(ftmp, tmp);    
    felem_assign(e8, ftmp);
    for (i = 0; i < 8; i++) {
        felem_square(tmp, ftmp);
        felem_reduce(ftmp, tmp);
    }                           
    felem_mul(tmp, ftmp, e8);
    felem_reduce(ftmp, tmp);    
    felem_assign(e16, ftmp);
    for (i = 0; i < 16; i++) {
        felem_square(tmp, ftmp);
        felem_reduce(ftmp, tmp);
    }                           
    felem_mul(tmp, ftmp, e16);
    felem_reduce(ftmp, tmp);    
    felem_assign(e32, ftmp);
    for (i = 0; i < 32; i++) {
        felem_square(tmp, ftmp);
        felem_reduce(ftmp, tmp);
    }                           
    felem_assign(e64, ftmp);
    felem_mul(tmp, ftmp, in);
    felem_reduce(ftmp, tmp);    
    for (i = 0; i < 192; i++) {
        felem_square(tmp, ftmp);
        felem_reduce(ftmp, tmp);
    }                           

    felem_mul(tmp, e64, e32);
    felem_reduce(ftmp2, tmp);   
    for (i = 0; i < 16; i++) {
        felem_square(tmp, ftmp2);
        felem_reduce(ftmp2, tmp);
    }                           
    felem_mul(tmp, ftmp2, e16);
    felem_reduce(ftmp2, tmp);   
    for (i = 0; i < 8; i++) {
        felem_square(tmp, ftmp2);
        felem_reduce(ftmp2, tmp);
    }                           
    felem_mul(tmp, ftmp2, e8);
    felem_reduce(ftmp2, tmp);   
    for (i = 0; i < 4; i++) {
        felem_square(tmp, ftmp2);
        felem_reduce(ftmp2, tmp);
    }                           
    felem_mul(tmp, ftmp2, e4);
    felem_reduce(ftmp2, tmp);   
    felem_square(tmp, ftmp2);
    felem_reduce(ftmp2, tmp);   
    felem_square(tmp, ftmp2);
    felem_reduce(ftmp2, tmp);   
    felem_mul(tmp, ftmp2, e2);
    felem_reduce(ftmp2, tmp);   
    felem_square(tmp, ftmp2);
    felem_reduce(ftmp2, tmp);   
    felem_square(tmp, ftmp2);
    felem_reduce(ftmp2, tmp);   
    felem_mul(tmp, ftmp2, in);
    felem_reduce(ftmp2, tmp);   

    felem_mul(tmp, ftmp2, ftmp);
    felem_reduce(out, tmp);     
}

static void smallfelem_inv_contract(smallfelem out, const smallfelem in)
{
    felem tmp;

    smallfelem_expand(tmp, in);
    felem_inv(tmp, tmp);
    felem_contract(out, tmp);
}




static void
point_double(felem x_out, felem y_out, felem z_out,
             const felem x_in, const felem y_in, const felem z_in)
{
    longfelem tmp, tmp2;
    felem delta, gamma, beta, alpha, ftmp, ftmp2;
    smallfelem small1, small2;

    felem_assign(ftmp, x_in);
    
    felem_assign(ftmp2, x_in);
    

    
    felem_square(tmp, z_in);
    felem_reduce(delta, tmp);
    

    
    felem_square(tmp, y_in);
    felem_reduce(gamma, tmp);
    
    felem_shrink(small1, gamma);

    
    felem_small_mul(tmp, small1, x_in);
    felem_reduce(beta, tmp);
    

    
    felem_diff(ftmp, delta);
    
    felem_sum(ftmp2, delta);
    
    felem_scalar(ftmp2, 3);
    
    felem_mul(tmp, ftmp, ftmp2);
    felem_reduce(alpha, tmp);
    
    felem_shrink(small2, alpha);

    
    smallfelem_square(tmp, small2);
    felem_reduce(x_out, tmp);
    felem_assign(ftmp, beta);
    felem_scalar(ftmp, 8);
    
    felem_diff(x_out, ftmp);
    

    
    felem_sum(delta, gamma);
    
    felem_assign(ftmp, y_in);
    felem_sum(ftmp, z_in);
    
    felem_square(tmp, ftmp);
    felem_reduce(z_out, tmp);
    felem_diff(z_out, delta);
    

    
    felem_scalar(beta, 4);
    
    felem_diff_zero107(beta, x_out);
    
    felem_small_mul(tmp, small2, beta);
    
    smallfelem_square(tmp2, small1);
    
    longfelem_scalar(tmp2, 8);
    
    longfelem_diff(tmp, tmp2);
    
    felem_reduce_zero105(y_out, tmp);
    
}


static void
point_double_small(smallfelem x_out, smallfelem y_out, smallfelem z_out,
                   const smallfelem x_in, const smallfelem y_in,
                   const smallfelem z_in)
{
    felem felem_x_out, felem_y_out, felem_z_out;
    felem felem_x_in, felem_y_in, felem_z_in;

    smallfelem_expand(felem_x_in, x_in);
    smallfelem_expand(felem_y_in, y_in);
    smallfelem_expand(felem_z_in, z_in);
    point_double(felem_x_out, felem_y_out, felem_z_out,
                 felem_x_in, felem_y_in, felem_z_in);
    felem_shrink(x_out, felem_x_out);
    felem_shrink(y_out, felem_y_out);
    felem_shrink(z_out, felem_z_out);
}


static void copy_conditional(felem out, const felem in, limb mask)
{
    unsigned i;
    for (i = 0; i < NLIMBS; ++i) {
        const limb tmp = mask & (in[i] ^ out[i]);
        out[i] ^= tmp;
    }
}


static void copy_small_conditional(felem out, const smallfelem in, limb mask)
{
    unsigned i;
    const u64 mask64 = mask;
    for (i = 0; i < NLIMBS; ++i) {
        out[i] = ((limb) (in[i] & mask64)) | (out[i] & ~mask);
    }
}


static void point_add(felem x3, felem y3, felem z3,
                      const felem x1, const felem y1, const felem z1,
                      const int mixed, const smallfelem x2,
                      const smallfelem y2, const smallfelem z2)
{
    felem ftmp, ftmp2, ftmp3, ftmp4, ftmp5, ftmp6, x_out, y_out, z_out;
    longfelem tmp, tmp2;
    smallfelem small1, small2, small3, small4, small5;
    limb x_equal, y_equal, z1_is_zero, z2_is_zero;
    limb points_equal;

    felem_shrink(small3, z1);

    z1_is_zero = smallfelem_is_zero(small3);
    z2_is_zero = smallfelem_is_zero(z2);

    
    smallfelem_square(tmp, small3);
    felem_reduce(ftmp, tmp);
    
    felem_shrink(small1, ftmp);

    if (!mixed) {
        
        smallfelem_square(tmp, z2);
        felem_reduce(ftmp2, tmp);
        
        felem_shrink(small2, ftmp2);

        felem_shrink(small5, x1);

        
        smallfelem_mul(tmp, small5, small2);
        felem_reduce(ftmp3, tmp);
        

        
        felem_assign(ftmp5, z1);
        felem_small_sum(ftmp5, z2);
        

        
        felem_square(tmp, ftmp5);
        felem_reduce(ftmp5, tmp);
        
        felem_sum(ftmp2, ftmp);
        
        felem_diff(ftmp5, ftmp2);
        

        
        smallfelem_mul(tmp, small2, z2);
        felem_reduce(ftmp2, tmp);

        
        felem_mul(tmp, y1, ftmp2);
        felem_reduce(ftmp6, tmp);
        
    } else {
        

        
        felem_assign(ftmp3, x1);
        

        
        felem_assign(ftmp5, z1);
        felem_scalar(ftmp5, 2);
        

        
        felem_assign(ftmp6, y1);
        
    }

    
    smallfelem_mul(tmp, x2, small1);
    felem_reduce(ftmp4, tmp);

    
    felem_diff_zero107(ftmp4, ftmp3);
    
    felem_shrink(small4, ftmp4);

    x_equal = smallfelem_is_zero(small4);

    
    felem_small_mul(tmp, small4, ftmp5);
    felem_reduce(z_out, tmp);
    

    
    smallfelem_mul(tmp, small1, small3);
    felem_reduce(ftmp, tmp);

    
    felem_small_mul(tmp, y2, ftmp);
    felem_reduce(ftmp5, tmp);

    
    felem_diff_zero107(ftmp5, ftmp6);
    
    felem_scalar(ftmp5, 2);
    
    felem_shrink(small1, ftmp5);
    y_equal = smallfelem_is_zero(small1);

    
    points_equal = (x_equal & y_equal & (~z1_is_zero) & (~z2_is_zero));

    if (points_equal) {
        
        point_double(x3, y3, z3, x1, y1, z1);
        return;
    }

    
    felem_assign(ftmp, ftmp4);
    felem_scalar(ftmp, 2);
    
    felem_square(tmp, ftmp);
    felem_reduce(ftmp, tmp);

    
    felem_mul(tmp, ftmp4, ftmp);
    felem_reduce(ftmp2, tmp);

    
    felem_mul(tmp, ftmp3, ftmp);
    felem_reduce(ftmp4, tmp);

    
    smallfelem_square(tmp, small1);
    felem_reduce(x_out, tmp);
    felem_assign(ftmp3, ftmp4);
    felem_scalar(ftmp4, 2);
    felem_sum(ftmp4, ftmp2);
    
    felem_diff(x_out, ftmp4);
    

    
    felem_diff_zero107(ftmp3, x_out);
    
    felem_small_mul(tmp, small1, ftmp3);
    felem_mul(tmp2, ftmp6, ftmp2);
    longfelem_scalar(tmp2, 2);
    
    longfelem_diff(tmp, tmp2);
    
    felem_reduce_zero105(y_out, tmp);
    

    copy_small_conditional(x_out, x2, z1_is_zero);
    copy_conditional(x_out, x1, z2_is_zero);
    copy_small_conditional(y_out, y2, z1_is_zero);
    copy_conditional(y_out, y1, z2_is_zero);
    copy_small_conditional(z_out, z2, z1_is_zero);
    copy_conditional(z_out, z1, z2_is_zero);
    felem_assign(x3, x_out);
    felem_assign(y3, y_out);
    felem_assign(z3, z_out);
}


static void point_add_small(smallfelem x3, smallfelem y3, smallfelem z3,
                            smallfelem x1, smallfelem y1, smallfelem z1,
                            smallfelem x2, smallfelem y2, smallfelem z2)
{
    felem felem_x3, felem_y3, felem_z3;
    felem felem_x1, felem_y1, felem_z1;
    smallfelem_expand(felem_x1, x1);
    smallfelem_expand(felem_y1, y1);
    smallfelem_expand(felem_z1, z1);
    point_add(felem_x3, felem_y3, felem_z3, felem_x1, felem_y1, felem_z1, 0,
              x2, y2, z2);
    felem_shrink(x3, felem_x3);
    felem_shrink(y3, felem_y3);
    felem_shrink(z3, felem_z3);
}




static const smallfelem gmul[2][16][3] = {
    {{{0, 0, 0, 0},
      {0, 0, 0, 0},
      {0, 0, 0, 0}},
     {{0xf4a13945d898c296, 0x77037d812deb33a0, 0xf8bce6e563a440f2,
       0x6b17d1f2e12c4247},
      {0xcbb6406837bf51f5, 0x2bce33576b315ece, 0x8ee7eb4a7c0f9e16,
       0x4fe342e2fe1a7f9b},
      {1, 0, 0, 0}},
     {{0x90e75cb48e14db63, 0x29493baaad651f7e, 0x8492592e326e25de,
       0x0fa822bc2811aaa5},
      {0xe41124545f462ee7, 0x34b1a65050fe82f5, 0x6f4ad4bcb3df188b,
       0xbff44ae8f5dba80d},
      {1, 0, 0, 0}},
     {{0x93391ce2097992af, 0xe96c98fd0d35f1fa, 0xb257c0de95e02789,
       0x300a4bbc89d6726f},
      {0xaa54a291c08127a0, 0x5bb1eeada9d806a5, 0x7f1ddb25ff1e3c6f,
       0x72aac7e0d09b4644},
      {1, 0, 0, 0}},
     {{0x57c84fc9d789bd85, 0xfc35ff7dc297eac3, 0xfb982fd588c6766e,
       0x447d739beedb5e67},
      {0x0c7e33c972e25b32, 0x3d349b95a7fae500, 0xe12e9d953a4aaff7,
       0x2d4825ab834131ee},
      {1, 0, 0, 0}},
     {{0x13949c932a1d367f, 0xef7fbd2b1a0a11b7, 0xddc6068bb91dfc60,
       0xef9519328a9c72ff},
      {0x196035a77376d8a8, 0x23183b0895ca1740, 0xc1ee9807022c219c,
       0x611e9fc37dbb2c9b},
      {1, 0, 0, 0}},
     {{0xcae2b1920b57f4bc, 0x2936df5ec6c9bc36, 0x7dea6482e11238bf,
       0x550663797b51f5d8},
      {0x44ffe216348a964c, 0x9fb3d576dbdefbe1, 0x0afa40018d9d50e5,
       0x157164848aecb851},
      {1, 0, 0, 0}},
     {{0xe48ecafffc5cde01, 0x7ccd84e70d715f26, 0xa2e8f483f43e4391,
       0xeb5d7745b21141ea},
      {0xcac917e2731a3479, 0x85f22cfe2844b645, 0x0990e6a158006cee,
       0xeafd72ebdbecc17b},
      {1, 0, 0, 0}},
     {{0x6cf20ffb313728be, 0x96439591a3c6b94a, 0x2736ff8344315fc5,
       0xa6d39677a7849276},
      {0xf2bab833c357f5f4, 0x824a920c2284059b, 0x66b8babd2d27ecdf,
       0x674f84749b0b8816},
      {1, 0, 0, 0}},
     {{0x2df48c04677c8a3e, 0x74e02f080203a56b, 0x31855f7db8c7fedb,
       0x4e769e7672c9ddad},
      {0xa4c36165b824bbb0, 0xfb9ae16f3b9122a5, 0x1ec0057206947281,
       0x42b99082de830663},
      {1, 0, 0, 0}},
     {{0x6ef95150dda868b9, 0xd1f89e799c0ce131, 0x7fdc1ca008a1c478,
       0x78878ef61c6ce04d},
      {0x9c62b9121fe0d976, 0x6ace570ebde08d4f, 0xde53142c12309def,
       0xb6cb3f5d7b72c321},
      {1, 0, 0, 0}},
     {{0x7f991ed2c31a3573, 0x5b82dd5bd54fb496, 0x595c5220812ffcae,
       0x0c88bc4d716b1287},
      {0x3a57bf635f48aca8, 0x7c8181f4df2564f3, 0x18d1b5b39c04e6aa,
       0xdd5ddea3f3901dc6},
      {1, 0, 0, 0}},
     {{0xe96a79fb3e72ad0c, 0x43a0a28c42ba792f, 0xefe0a423083e49f3,
       0x68f344af6b317466},
      {0xcdfe17db3fb24d4a, 0x668bfc2271f5c626, 0x604ed93c24d67ff3,
       0x31b9c405f8540a20},
      {1, 0, 0, 0}},
     {{0xd36b4789a2582e7f, 0x0d1a10144ec39c28, 0x663c62c3edbad7a0,
       0x4052bf4b6f461db9},
      {0x235a27c3188d25eb, 0xe724f33999bfcc5b, 0x862be6bd71d70cc8,
       0xfecf4d5190b0fc61},
      {1, 0, 0, 0}},
     {{0x74346c10a1d4cfac, 0xafdf5cc08526a7a4, 0x123202a8f62bff7a,
       0x1eddbae2c802e41a},
      {0x8fa0af2dd603f844, 0x36e06b7e4c701917, 0x0c45f45273db33a0,
       0x43104d86560ebcfc},
      {1, 0, 0, 0}},
     {{0x9615b5110d1d78e5, 0x66b0de3225c4744b, 0x0a4a46fb6aaf363a,
       0xb48e26b484f7a21c},
      {0x06ebb0f621a01b2d, 0xc004e4048b7b0f98, 0x64131bcdfed6f668,
       0xfac015404d4d3dab},
      {1, 0, 0, 0}}},
    {{{0, 0, 0, 0},
      {0, 0, 0, 0},
      {0, 0, 0, 0}},
     {{0x3a5a9e22185a5943, 0x1ab919365c65dfb6, 0x21656b32262c71da,
       0x7fe36b40af22af89},
      {0xd50d152c699ca101, 0x74b3d5867b8af212, 0x9f09f40407dca6f1,
       0xe697d45825b63624},
      {1, 0, 0, 0}},
     {{0xa84aa9397512218e, 0xe9a521b074ca0141, 0x57880b3a18a2e902,
       0x4a5b506612a677a6},
      {0x0beada7a4c4f3840, 0x626db15419e26d9d, 0xc42604fbe1627d40,
       0xeb13461ceac089f1},
      {1, 0, 0, 0}},
     {{0xf9faed0927a43281, 0x5e52c4144103ecbc, 0xc342967aa815c857,
       0x0781b8291c6a220a},
      {0x5a8343ceeac55f80, 0x88f80eeee54a05e3, 0x97b2a14f12916434,
       0x690cde8df0151593},
      {1, 0, 0, 0}},
     {{0xaee9c75df7f82f2a, 0x9e4c35874afdf43a, 0xf5622df437371326,
       0x8a535f566ec73617},
      {0xc5f9a0ac223094b7, 0xcde533864c8c7669, 0x37e02819085a92bf,
       0x0455c08468b08bd7},
      {1, 0, 0, 0}},
     {{0x0c0a6e2c9477b5d9, 0xf9a4bf62876dc444, 0x5050a949b6cdc279,
       0x06bada7ab77f8276},
      {0xc8b4aed1ea48dac9, 0xdebd8a4b7ea1070f, 0x427d49101366eb70,
       0x5b476dfd0e6cb18a},
      {1, 0, 0, 0}},
     {{0x7c5c3e44278c340a, 0x4d54606812d66f3b, 0x29a751b1ae23c5d8,
       0x3e29864e8a2ec908},
      {0x142d2a6626dbb850, 0xad1744c4765bd780, 0x1f150e68e322d1ed,
       0x239b90ea3dc31e7e},
      {1, 0, 0, 0}},
     {{0x78c416527a53322a, 0x305dde6709776f8e, 0xdbcab759f8862ed4,
       0x820f4dd949f72ff7},
      {0x6cc544a62b5debd4, 0x75be5d937b4e8cc4, 0x1b481b1b215c14d3,
       0x140406ec783a05ec},
      {1, 0, 0, 0}},
     {{0x6a703f10e895df07, 0xfd75f3fa01876bd8, 0xeb5b06e70ce08ffe,
       0x68f6b8542783dfee},
      {0x90c76f8a78712655, 0xcf5293d2f310bf7f, 0xfbc8044dfda45028,
       0xcbe1feba92e40ce6},
      {1, 0, 0, 0}},
     {{0xe998ceea4396e4c1, 0xfc82ef0b6acea274, 0x230f729f2250e927,
       0xd0b2f94d2f420109},
      {0x4305adddb38d4966, 0x10b838f8624c3b45, 0x7db2636658954e7a,
       0x971459828b0719e5},
      {1, 0, 0, 0}},
     {{0x4bd6b72623369fc9, 0x57f2929e53d0b876, 0xc2d5cba4f2340687,
       0x961610004a866aba},
      {0x49997bcd2e407a5e, 0x69ab197d92ddcb24, 0x2cf1f2438fe5131c,
       0x7acb9fadcee75e44},
      {1, 0, 0, 0}},
     {{0x254e839423d2d4c0, 0xf57f0c917aea685b, 0xa60d880f6f75aaea,
       0x24eb9acca333bf5b},
      {0xe3de4ccb1cda5dea, 0xfeef9341c51a6b4f, 0x743125f88bac4c4d,
       0x69f891c5acd079cc},
      {1, 0, 0, 0}},
     {{0xeee44b35702476b5, 0x7ed031a0e45c2258, 0xb422d1e7bd6f8514,
       0xe51f547c5972a107},
      {0xa25bcd6fc9cf343d, 0x8ca922ee097c184e, 0xa62f98b3a9fe9a06,
       0x1c309a2b25bb1387},
      {1, 0, 0, 0}},
     {{0x9295dbeb1967c459, 0xb00148833472c98e, 0xc504977708011828,
       0x20b87b8aa2c4e503},
      {0x3063175de057c277, 0x1bd539338fe582dd, 0x0d11adef5f69a044,
       0xf5c6fa49919776be},
      {1, 0, 0, 0}},
     {{0x8c944e760fd59e11, 0x3876cba1102fad5f, 0xa454c3fad83faa56,
       0x1ed7d1b9332010b9},
      {0xa1011a270024b889, 0x05e4d0dcac0cd344, 0x52b520f0eb6a2a24,
       0x3a2b03f03217257a},
      {1, 0, 0, 0}},
     {{0xf20fc2afdf1d043d, 0xf330240db58d5a62, 0xfc7d229ca0058c3b,
       0x15fee545c78dd9f6},
      {0x501e82885bc98cda, 0x41ef80e5d046ac04, 0x557d9f49461210fb,
       0x4ab5b6b2b8753f81},
      {1, 0, 0, 0}}}
};


static void select_point(const u64 idx, unsigned int size,
                         const smallfelem pre_comp[16][3], smallfelem out[3])
{
    unsigned i, j;
    u64 *outlimbs = &out[0][0];

    memset(out, 0, sizeof(*out) * 3);

    for (i = 0; i < size; i++) {
        const u64 *inlimbs = (u64 *)&pre_comp[i][0][0];
        u64 mask = i ^ idx;
        mask |= mask >> 4;
        mask |= mask >> 2;
        mask |= mask >> 1;
        mask &= 1;
        mask--;
        for (j = 0; j < NLIMBS * 3; j++)
            outlimbs[j] |= inlimbs[j] & mask;
    }
}


static char get_bit(const felem_bytearray in, int i)
{
    if ((i < 0) || (i >= 256))
        return 0;
    return (in[i >> 3] >> (i & 7)) & 1;
}


static void batch_mul(felem x_out, felem y_out, felem z_out,
                      const felem_bytearray scalars[],
                      const unsigned num_points, const u8 *g_scalar,
                      const int mixed, const smallfelem pre_comp[][17][3],
                      const smallfelem g_pre_comp[2][16][3])
{
    int i, skip;
    unsigned num, gen_mul = (g_scalar != NULL);
    felem nq[3], ftmp;
    smallfelem tmp[3];
    u64 bits;
    u8 sign, digit;

    
    memset(nq, 0, sizeof(nq));

    
    skip = 1;                   
    for (i = (num_points ? 255 : 31); i >= 0; --i) {
        
        if (!skip)
            point_double(nq[0], nq[1], nq[2], nq[0], nq[1], nq[2]);

        
        if (gen_mul && (i <= 31)) {
            
            bits = get_bit(g_scalar, i + 224) << 3;
            bits |= get_bit(g_scalar, i + 160) << 2;
            bits |= get_bit(g_scalar, i + 96) << 1;
            bits |= get_bit(g_scalar, i + 32);
            
            select_point(bits, 16, g_pre_comp[1], tmp);

            if (!skip) {
                
                point_add(nq[0], nq[1], nq[2],
                          nq[0], nq[1], nq[2], 1, tmp[0], tmp[1], tmp[2]);
            } else {
                smallfelem_expand(nq[0], tmp[0]);
                smallfelem_expand(nq[1], tmp[1]);
                smallfelem_expand(nq[2], tmp[2]);
                skip = 0;
            }

            
            bits = get_bit(g_scalar, i + 192) << 3;
            bits |= get_bit(g_scalar, i + 128) << 2;
            bits |= get_bit(g_scalar, i + 64) << 1;
            bits |= get_bit(g_scalar, i);
            
            select_point(bits, 16, g_pre_comp[0], tmp);
            
            point_add(nq[0], nq[1], nq[2],
                      nq[0], nq[1], nq[2], 1, tmp[0], tmp[1], tmp[2]);
        }

        
        if (num_points && (i % 5 == 0)) {
            
            for (num = 0; num < num_points; ++num) {
                bits = get_bit(scalars[num], i + 4) << 5;
                bits |= get_bit(scalars[num], i + 3) << 4;
                bits |= get_bit(scalars[num], i + 2) << 3;
                bits |= get_bit(scalars[num], i + 1) << 2;
                bits |= get_bit(scalars[num], i) << 1;
                bits |= get_bit(scalars[num], i - 1);
                ossl_ec_GFp_nistp_recode_scalar_bits(&sign, &digit, bits);

                
                select_point(digit, 17, pre_comp[num], tmp);
                smallfelem_neg(ftmp, tmp[1]); 
                copy_small_conditional(ftmp, tmp[1], (((limb) sign) - 1));
                felem_contract(tmp[1], ftmp);

                if (!skip) {
                    point_add(nq[0], nq[1], nq[2],
                              nq[0], nq[1], nq[2],
                              mixed, tmp[0], tmp[1], tmp[2]);
                } else {
                    smallfelem_expand(nq[0], tmp[0]);
                    smallfelem_expand(nq[1], tmp[1]);
                    smallfelem_expand(nq[2], tmp[2]);
                    skip = 0;
                }
            }
        }
    }
    felem_assign(x_out, nq[0]);
    felem_assign(y_out, nq[1]);
    felem_assign(z_out, nq[2]);
}


struct nistp256_pre_comp_st {
    smallfelem g_pre_comp[2][16][3];
    CRYPTO_REF_COUNT references;
};

const EC_METHOD *EC_GFp_nistp256_method(void)
{
    static const EC_METHOD ret = {
        EC_FLAGS_DEFAULT_OCT,
        NID_X9_62_prime_field,
        ossl_ec_GFp_nistp256_group_init,
        ossl_ec_GFp_simple_group_finish,
        ossl_ec_GFp_simple_group_clear_finish,
        ossl_ec_GFp_nist_group_copy,
        ossl_ec_GFp_nistp256_group_set_curve,
        ossl_ec_GFp_simple_group_get_curve,
        ossl_ec_GFp_simple_group_get_degree,
        ossl_ec_group_simple_order_bits,
        ossl_ec_GFp_simple_group_check_discriminant,
        ossl_ec_GFp_simple_point_init,
        ossl_ec_GFp_simple_point_finish,
        ossl_ec_GFp_simple_point_clear_finish,
        ossl_ec_GFp_simple_point_copy,
        ossl_ec_GFp_simple_point_set_to_infinity,
        ossl_ec_GFp_simple_point_set_affine_coordinates,
        ossl_ec_GFp_nistp256_point_get_affine_coordinates,
        0  ,
        0  ,
        0  ,
        ossl_ec_GFp_simple_add,
        ossl_ec_GFp_simple_dbl,
        ossl_ec_GFp_simple_invert,
        ossl_ec_GFp_simple_is_at_infinity,
        ossl_ec_GFp_simple_is_on_curve,
        ossl_ec_GFp_simple_cmp,
        ossl_ec_GFp_simple_make_affine,
        ossl_ec_GFp_simple_points_make_affine,
        ossl_ec_GFp_nistp256_points_mul,
        ossl_ec_GFp_nistp256_precompute_mult,
        ossl_ec_GFp_nistp256_have_precompute_mult,
        ossl_ec_GFp_nist_field_mul,
        ossl_ec_GFp_nist_field_sqr,
        0  ,
        ossl_ec_GFp_simple_field_inv,
        0  ,
        0  ,
        0,                      
        ossl_ec_key_simple_priv2oct,
        ossl_ec_key_simple_oct2priv,
        0, 
        ossl_ec_key_simple_generate_key,
        ossl_ec_key_simple_check_key,
        ossl_ec_key_simple_generate_public_key,
        0, 
        0, 
        ossl_ecdh_simple_compute_key,
        ossl_ecdsa_simple_sign_setup,
        ossl_ecdsa_simple_sign_sig,
        ossl_ecdsa_simple_verify_sig,
        0, 
        0, 
        0, 
        0, 
        0  
    };

    return &ret;
}




static NISTP256_PRE_COMP *nistp256_pre_comp_new(void)
{
    NISTP256_PRE_COMP *ret = OPENSSL_zalloc(sizeof(*ret));

    if (ret == NULL)
        return ret;

    if (!CRYPTO_NEW_REF(&ret->references, 1)) {
        OPENSSL_free(ret);
        return NULL;
    }
    return ret;
}

NISTP256_PRE_COMP *EC_nistp256_pre_comp_dup(NISTP256_PRE_COMP *p)
{
    int i;
    if (p != NULL)
        CRYPTO_UP_REF(&p->references, &i);
    return p;
}

void EC_nistp256_pre_comp_free(NISTP256_PRE_COMP *pre)
{
    int i;

    if (pre == NULL)
        return;

    CRYPTO_DOWN_REF(&pre->references, &i);
    REF_PRINT_COUNT("EC_nistp256", pre);
    if (i > 0)
        return;
    REF_ASSERT_ISNT(i < 0);

    CRYPTO_FREE_REF(&pre->references);
    OPENSSL_free(pre);
}




int ossl_ec_GFp_nistp256_group_init(EC_GROUP *group)
{
    int ret;
    ret = ossl_ec_GFp_simple_group_init(group);
    group->a_is_minus3 = 1;
    return ret;
}

int ossl_ec_GFp_nistp256_group_set_curve(EC_GROUP *group, const BIGNUM *p,
                                         const BIGNUM *a, const BIGNUM *b,
                                         BN_CTX *ctx)
{
    int ret = 0;
    BIGNUM *curve_p, *curve_a, *curve_b;
#ifndef FIPS_MODULE
    BN_CTX *new_ctx = NULL;

    if (ctx == NULL)
        ctx = new_ctx = BN_CTX_new();
#endif
    if (ctx == NULL)
        return 0;

    BN_CTX_start(ctx);
    curve_p = BN_CTX_get(ctx);
    curve_a = BN_CTX_get(ctx);
    curve_b = BN_CTX_get(ctx);
    if (curve_b == NULL)
        goto err;
    BN_bin2bn(nistp256_curve_params[0], sizeof(felem_bytearray), curve_p);
    BN_bin2bn(nistp256_curve_params[1], sizeof(felem_bytearray), curve_a);
    BN_bin2bn(nistp256_curve_params[2], sizeof(felem_bytearray), curve_b);
    if ((BN_cmp(curve_p, p)) || (BN_cmp(curve_a, a)) || (BN_cmp(curve_b, b))) {
        ERR_raise(ERR_LIB_EC, EC_R_WRONG_CURVE_PARAMETERS);
        goto err;
    }
    group->field_mod_func = BN_nist_mod_256;
    ret = ossl_ec_GFp_simple_group_set_curve(group, p, a, b, ctx);
 err:
    BN_CTX_end(ctx);
#ifndef FIPS_MODULE
    BN_CTX_free(new_ctx);
#endif
    return ret;
}


int ossl_ec_GFp_nistp256_point_get_affine_coordinates(const EC_GROUP *group,
                                                      const EC_POINT *point,
                                                      BIGNUM *x, BIGNUM *y,
                                                      BN_CTX *ctx)
{
    felem z1, z2, x_in, y_in;
    smallfelem x_out, y_out;
    longfelem tmp;

    if (EC_POINT_is_at_infinity(group, point)) {
        ERR_raise(ERR_LIB_EC, EC_R_POINT_AT_INFINITY);
        return 0;
    }
    if ((!BN_to_felem(x_in, point->X)) || (!BN_to_felem(y_in, point->Y)) ||
        (!BN_to_felem(z1, point->Z)))
        return 0;
    felem_inv(z2, z1);
    felem_square(tmp, z2);
    felem_reduce(z1, tmp);
    felem_mul(tmp, x_in, z1);
    felem_reduce(x_in, tmp);
    felem_contract(x_out, x_in);
    if (x != NULL) {
        if (!smallfelem_to_BN(x, x_out)) {
            ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
            return 0;
        }
    }
    felem_mul(tmp, z1, z2);
    felem_reduce(z1, tmp);
    felem_mul(tmp, y_in, z1);
    felem_reduce(y_in, tmp);
    felem_contract(y_out, y_in);
    if (y != NULL) {
        if (!smallfelem_to_BN(y, y_out)) {
            ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
            return 0;
        }
    }
    return 1;
}


static void make_points_affine(size_t num, smallfelem points[][3],
                               smallfelem tmp_smallfelems[])
{
    
    ossl_ec_GFp_nistp_points_make_affine_internal(num,
                                                  points,
                                                  sizeof(smallfelem),
                                                  tmp_smallfelems,
                                                  (void (*)(void *))smallfelem_one,
                                                  smallfelem_is_zero_int,
                                                  (void (*)(void *, const void *))
                                                  smallfelem_assign,
                                                  (void (*)(void *, const void *))
                                                  smallfelem_square_contract,
                                                  (void (*)
                                                   (void *, const void *,
                                                    const void *))
                                                  smallfelem_mul_contract,
                                                  (void (*)(void *, const void *))
                                                  smallfelem_inv_contract,
                                                  
                                                  (void (*)(void *, const void *))
                                                  smallfelem_assign);
}


int ossl_ec_GFp_nistp256_points_mul(const EC_GROUP *group, EC_POINT *r,
                                    const BIGNUM *scalar, size_t num,
                                    const EC_POINT *points[],
                                    const BIGNUM *scalars[], BN_CTX *ctx)
{
    int ret = 0;
    int j;
    int mixed = 0;
    BIGNUM *x, *y, *z, *tmp_scalar;
    felem_bytearray g_secret;
    felem_bytearray *secrets = NULL;
    smallfelem (*pre_comp)[17][3] = NULL;
    smallfelem *tmp_smallfelems = NULL;
    unsigned i;
    int num_bytes;
    int have_pre_comp = 0;
    size_t num_points = num;
    smallfelem x_in, y_in, z_in;
    felem x_out, y_out, z_out;
    NISTP256_PRE_COMP *pre = NULL;
    const smallfelem(*g_pre_comp)[16][3] = NULL;
    EC_POINT *generator = NULL;
    const EC_POINT *p = NULL;
    const BIGNUM *p_scalar = NULL;

    BN_CTX_start(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    z = BN_CTX_get(ctx);
    tmp_scalar = BN_CTX_get(ctx);
    if (tmp_scalar == NULL)
        goto err;

    if (scalar != NULL) {
        pre = group->pre_comp.nistp256;
        if (pre)
            
            g_pre_comp = (const smallfelem(*)[16][3])pre->g_pre_comp;
        else
            
            g_pre_comp = &gmul[0];
        generator = EC_POINT_new(group);
        if (generator == NULL)
            goto err;
        
        if (!smallfelem_to_BN(x, g_pre_comp[0][1][0]) ||
            !smallfelem_to_BN(y, g_pre_comp[0][1][1]) ||
            !smallfelem_to_BN(z, g_pre_comp[0][1][2])) {
            ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
            goto err;
        }
        if (!ossl_ec_GFp_simple_set_Jprojective_coordinates_GFp(group,
                                                                generator,
                                                                x, y, z, ctx))
            goto err;
        if (0 == EC_POINT_cmp(group, generator, group->generator, ctx))
            
            have_pre_comp = 1;
        else
            
            num_points++;
    }
    if (num_points > 0) {
        if (num_points >= 3) {
            
            mixed = 1;
        }
        secrets = OPENSSL_malloc(sizeof(*secrets) * num_points);
        pre_comp = OPENSSL_malloc(sizeof(*pre_comp) * num_points);
        if (mixed)
            tmp_smallfelems =
              OPENSSL_malloc(sizeof(*tmp_smallfelems) * (num_points * 17 + 1));
        if ((secrets == NULL) || (pre_comp == NULL)
            || (mixed && (tmp_smallfelems == NULL)))
            goto err;

        
        memset(secrets, 0, sizeof(*secrets) * num_points);
        memset(pre_comp, 0, sizeof(*pre_comp) * num_points);
        for (i = 0; i < num_points; ++i) {
            if (i == num) {
                
                p = EC_GROUP_get0_generator(group);
                p_scalar = scalar;
            } else {
                
                p = points[i];
                p_scalar = scalars[i];
            }
            if ((p_scalar != NULL) && (p != NULL)) {
                
                if ((BN_num_bits(p_scalar) > 256)
                    || (BN_is_negative(p_scalar))) {
                    
                    if (!BN_nnmod(tmp_scalar, p_scalar, group->order, ctx)) {
                        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
                        goto err;
                    }
                    num_bytes = BN_bn2lebinpad(tmp_scalar,
                                               secrets[i], sizeof(secrets[i]));
                } else {
                    num_bytes = BN_bn2lebinpad(p_scalar,
                                               secrets[i], sizeof(secrets[i]));
                }
                if (num_bytes < 0) {
                    ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
                    goto err;
                }
                
                if ((!BN_to_felem(x_out, p->X)) ||
                    (!BN_to_felem(y_out, p->Y)) ||
                    (!BN_to_felem(z_out, p->Z)))
                    goto err;
                felem_shrink(pre_comp[i][1][0], x_out);
                felem_shrink(pre_comp[i][1][1], y_out);
                felem_shrink(pre_comp[i][1][2], z_out);
                for (j = 2; j <= 16; ++j) {
                    if (j & 1) {
                        point_add_small(pre_comp[i][j][0], pre_comp[i][j][1],
                                        pre_comp[i][j][2], pre_comp[i][1][0],
                                        pre_comp[i][1][1], pre_comp[i][1][2],
                                        pre_comp[i][j - 1][0],
                                        pre_comp[i][j - 1][1],
                                        pre_comp[i][j - 1][2]);
                    } else {
                        point_double_small(pre_comp[i][j][0],
                                           pre_comp[i][j][1],
                                           pre_comp[i][j][2],
                                           pre_comp[i][j / 2][0],
                                           pre_comp[i][j / 2][1],
                                           pre_comp[i][j / 2][2]);
                    }
                }
            }
        }
        if (mixed)
            make_points_affine(num_points * 17, pre_comp[0], tmp_smallfelems);
    }

    
    if ((scalar != NULL) && (have_pre_comp)) {
        memset(g_secret, 0, sizeof(g_secret));
        
        if ((BN_num_bits(scalar) > 256) || (BN_is_negative(scalar))) {
            
            if (!BN_nnmod(tmp_scalar, scalar, group->order, ctx)) {
                ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
                goto err;
            }
            num_bytes = BN_bn2lebinpad(tmp_scalar, g_secret, sizeof(g_secret));
        } else {
            num_bytes = BN_bn2lebinpad(scalar, g_secret, sizeof(g_secret));
        }
        
        batch_mul(x_out, y_out, z_out,
                  (const felem_bytearray(*))secrets, num_points,
                  g_secret,
                  mixed, (const smallfelem(*)[17][3])pre_comp, g_pre_comp);
    } else {
        
        batch_mul(x_out, y_out, z_out,
                  (const felem_bytearray(*))secrets, num_points,
                  NULL, mixed, (const smallfelem(*)[17][3])pre_comp, NULL);
    }
    
    felem_contract(x_in, x_out);
    felem_contract(y_in, y_out);
    felem_contract(z_in, z_out);
    if ((!smallfelem_to_BN(x, x_in)) || (!smallfelem_to_BN(y, y_in)) ||
        (!smallfelem_to_BN(z, z_in))) {
        ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
        goto err;
    }
    ret = ossl_ec_GFp_simple_set_Jprojective_coordinates_GFp(group, r, x, y, z,
                                                             ctx);

 err:
    BN_CTX_end(ctx);
    EC_POINT_free(generator);
    OPENSSL_free(secrets);
    OPENSSL_free(pre_comp);
    OPENSSL_free(tmp_smallfelems);
    return ret;
}

int ossl_ec_GFp_nistp256_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
{
    int ret = 0;
    NISTP256_PRE_COMP *pre = NULL;
    int i, j;
    BIGNUM *x, *y;
    EC_POINT *generator = NULL;
    smallfelem tmp_smallfelems[32];
    felem x_tmp, y_tmp, z_tmp;
#ifndef FIPS_MODULE
    BN_CTX *new_ctx = NULL;
#endif

    
    EC_pre_comp_free(group);

#ifndef FIPS_MODULE
    if (ctx == NULL)
        ctx = new_ctx = BN_CTX_new();
#endif
    if (ctx == NULL)
        return 0;

    BN_CTX_start(ctx);
    x = BN_CTX_get(ctx);
    y = BN_CTX_get(ctx);
    if (y == NULL)
        goto err;
    
    if (group->generator == NULL)
        goto err;
    generator = EC_POINT_new(group);
    if (generator == NULL)
        goto err;
    BN_bin2bn(nistp256_curve_params[3], sizeof(felem_bytearray), x);
    BN_bin2bn(nistp256_curve_params[4], sizeof(felem_bytearray), y);
    if (!EC_POINT_set_affine_coordinates(group, generator, x, y, ctx))
        goto err;
    if ((pre = nistp256_pre_comp_new()) == NULL)
        goto err;
    
    if (0 == EC_POINT_cmp(group, generator, group->generator, ctx)) {
        memcpy(pre->g_pre_comp, gmul, sizeof(pre->g_pre_comp));
        goto done;
    }
    if ((!BN_to_felem(x_tmp, group->generator->X)) ||
        (!BN_to_felem(y_tmp, group->generator->Y)) ||
        (!BN_to_felem(z_tmp, group->generator->Z)))
        goto err;
    felem_shrink(pre->g_pre_comp[0][1][0], x_tmp);
    felem_shrink(pre->g_pre_comp[0][1][1], y_tmp);
    felem_shrink(pre->g_pre_comp[0][1][2], z_tmp);
    
    for (i = 1; i <= 8; i <<= 1) {
        point_double_small(pre->g_pre_comp[1][i][0], pre->g_pre_comp[1][i][1],
                           pre->g_pre_comp[1][i][2], pre->g_pre_comp[0][i][0],
                           pre->g_pre_comp[0][i][1],
                           pre->g_pre_comp[0][i][2]);
        for (j = 0; j < 31; ++j) {
            point_double_small(pre->g_pre_comp[1][i][0],
                               pre->g_pre_comp[1][i][1],
                               pre->g_pre_comp[1][i][2],
                               pre->g_pre_comp[1][i][0],
                               pre->g_pre_comp[1][i][1],
                               pre->g_pre_comp[1][i][2]);
        }
        if (i == 8)
            break;
        point_double_small(pre->g_pre_comp[0][2 * i][0],
                           pre->g_pre_comp[0][2 * i][1],
                           pre->g_pre_comp[0][2 * i][2],
                           pre->g_pre_comp[1][i][0], pre->g_pre_comp[1][i][1],
                           pre->g_pre_comp[1][i][2]);
        for (j = 0; j < 31; ++j) {
            point_double_small(pre->g_pre_comp[0][2 * i][0],
                               pre->g_pre_comp[0][2 * i][1],
                               pre->g_pre_comp[0][2 * i][2],
                               pre->g_pre_comp[0][2 * i][0],
                               pre->g_pre_comp[0][2 * i][1],
                               pre->g_pre_comp[0][2 * i][2]);
        }
    }
    for (i = 0; i < 2; i++) {
        
        memset(pre->g_pre_comp[i][0], 0, sizeof(pre->g_pre_comp[i][0]));
        
        
        point_add_small(pre->g_pre_comp[i][6][0], pre->g_pre_comp[i][6][1],
                        pre->g_pre_comp[i][6][2], pre->g_pre_comp[i][4][0],
                        pre->g_pre_comp[i][4][1], pre->g_pre_comp[i][4][2],
                        pre->g_pre_comp[i][2][0], pre->g_pre_comp[i][2][1],
                        pre->g_pre_comp[i][2][2]);
        
        point_add_small(pre->g_pre_comp[i][10][0], pre->g_pre_comp[i][10][1],
                        pre->g_pre_comp[i][10][2], pre->g_pre_comp[i][8][0],
                        pre->g_pre_comp[i][8][1], pre->g_pre_comp[i][8][2],
                        pre->g_pre_comp[i][2][0], pre->g_pre_comp[i][2][1],
                        pre->g_pre_comp[i][2][2]);
        
        point_add_small(pre->g_pre_comp[i][12][0], pre->g_pre_comp[i][12][1],
                        pre->g_pre_comp[i][12][2], pre->g_pre_comp[i][8][0],
                        pre->g_pre_comp[i][8][1], pre->g_pre_comp[i][8][2],
                        pre->g_pre_comp[i][4][0], pre->g_pre_comp[i][4][1],
                        pre->g_pre_comp[i][4][2]);
        
        point_add_small(pre->g_pre_comp[i][14][0], pre->g_pre_comp[i][14][1],
                        pre->g_pre_comp[i][14][2], pre->g_pre_comp[i][12][0],
                        pre->g_pre_comp[i][12][1], pre->g_pre_comp[i][12][2],
                        pre->g_pre_comp[i][2][0], pre->g_pre_comp[i][2][1],
                        pre->g_pre_comp[i][2][2]);
        for (j = 1; j < 8; ++j) {
            
            point_add_small(pre->g_pre_comp[i][2 * j + 1][0],
                            pre->g_pre_comp[i][2 * j + 1][1],
                            pre->g_pre_comp[i][2 * j + 1][2],
                            pre->g_pre_comp[i][2 * j][0],
                            pre->g_pre_comp[i][2 * j][1],
                            pre->g_pre_comp[i][2 * j][2],
                            pre->g_pre_comp[i][1][0],
                            pre->g_pre_comp[i][1][1],
                            pre->g_pre_comp[i][1][2]);
        }
    }
    make_points_affine(31, &(pre->g_pre_comp[0][1]), tmp_smallfelems);

 done:
    SETPRECOMP(group, nistp256, pre);
    pre = NULL;
    ret = 1;

 err:
    BN_CTX_end(ctx);
    EC_POINT_free(generator);
#ifndef FIPS_MODULE
    BN_CTX_free(new_ctx);
#endif
    EC_nistp256_pre_comp_free(pre);
    return ret;
}

int ossl_ec_GFp_nistp256_have_precompute_mult(const EC_GROUP *group)
{
    return HAVEPRECOMP(group, nistp256);
}
