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lightning-sunbird  0.9+nobinonly
Defines | Functions
ecp_fp192.c File Reference
#include "ecp_fp.h"
#include <stdlib.h>
#include "ecp_fpinc.c"

Go to the source code of this file.

Defines

#define ECFP_BSIZE   192
#define ECFP_NUMDOUBLES   8

Functions

void ecfp192_singleReduce (double *d, const EC_group_fp *group)
void ecfp_reduce_192 (double *r, double *x, const EC_group_fp *group)
mp_err ec_group_set_nistp192_fp (ECGroup *group)

Define Documentation

#define ECFP_BSIZE   192

Definition at line 42 of file ecp_fp192.c.

Definition at line 43 of file ecp_fp192.c.


Function Documentation

mp_err ec_group_set_nistp192_fp ( ECGroup *  group)

Definition at line 138 of file ecp_fp192.c.

{
       EC_group_fp *fpg;

       /* Allocate memory for floating point group data */
       fpg = (EC_group_fp *) malloc(sizeof(EC_group_fp));
       if (fpg == NULL) {
              return MP_MEM;
       }

       fpg->numDoubles = ECFP_NUMDOUBLES;
       fpg->primeBitSize = ECFP_BSIZE;
       fpg->orderBitSize = 192;
       fpg->doubleBitSize = 24;
       fpg->numInts = (ECFP_BSIZE + ECL_BITS - 1) / ECL_BITS;
       fpg->aIsM3 = 1;
       fpg->ecfp_singleReduce = &ecfp192_singleReduce;
       fpg->ecfp_reduce = &ecfp_reduce_192;
       fpg->ecfp_tidy = &ecfp_tidy;

       fpg->pt_add_jac_aff = &ecfp192_pt_add_jac_aff;
       fpg->pt_add_jac = &ecfp192_pt_add_jac;
       fpg->pt_add_jm_chud = &ecfp192_pt_add_jm_chud;
       fpg->pt_add_chud = &ecfp192_pt_add_chud;
       fpg->pt_dbl_jac = &ecfp192_pt_dbl_jac;
       fpg->pt_dbl_jm = &ecfp192_pt_dbl_jm;
       fpg->pt_dbl_aff2chud = &ecfp192_pt_dbl_aff2chud;
       fpg->precompute_chud = &ecfp192_precompute_chud;
       fpg->precompute_jac = &ecfp192_precompute_jac;

       group->point_mul = &ec_GFp_point_mul_wNAF_fp;
       group->points_mul = &ec_pts_mul_basic;
       group->extra1 = fpg;
       group->extra_free = &ec_GFp_extra_free_fp;

       ec_set_fp_precision(fpg);
       fpg->bitSize_alpha = ECFP_TWO192 * fpg->alpha[0];

       return MP_OKAY;
}

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void ecfp192_singleReduce ( double *  d,
const EC_group_fp *  group 
)

Definition at line 51 of file ecp_fp192.c.

{
       double q;

       ECFP_ASSERT(group->doubleBitSize == 24);
       ECFP_ASSERT(group->primeBitSize == 192);
       ECFP_ASSERT(group->numDoubles == 8);

       q = d[ECFP_NUMDOUBLES - 1] - ecfp_beta_192;
       q += group->bitSize_alpha;
       q -= group->bitSize_alpha;

       d[ECFP_NUMDOUBLES - 1] -= q;
       d[0] += q * ecfp_twom192;
       d[2] += q * ecfp_twom128;
       ecfp_positiveTidy(d, group);
}

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void ecfp_reduce_192 ( double *  r,
double *  x,
const EC_group_fp *  group 
)

Definition at line 75 of file ecp_fp192.c.

{
       double x8, x9, x10, q;

       ECFP_ASSERT(group->doubleBitSize == 24);
       ECFP_ASSERT(group->primeBitSize == 192);
       ECFP_ASSERT(group->numDoubles == 8);

       /* Tidy just the upper portion, the lower part can wait */
       ecfp_tidyUpper(x, group);

       x8 = x[8] + x[14] * ecfp_twom128;  /* adds bits 16-40 */
       x9 = x[9] + x[15] * ecfp_twom128;  /* adds bits 16-40 */

       /* Tidy up, or we won't have enough bits later to add it in */

       q = x8 + group->alpha[9];
       q -= group->alpha[9];
       x8 -= q;
       x9 += q;

       q = x9 + group->alpha[10];
       q -= group->alpha[10];
       x9 -= q;
       x10 = x[10] + q;

       r[7] = x[7] + x[15] * ecfp_twom192 + x[13] * ecfp_twom128;     /* adds
                                                                                                                 * bits
                                                                                                                 * 0-40 */
       r[6] = x[6] + x[14] * ecfp_twom192 + x[12] * ecfp_twom128;
       r[5] = x[5] + x[13] * ecfp_twom192 + x[11] * ecfp_twom128;
       r[4] = x[4] + x[12] * ecfp_twom192 + x10 * ecfp_twom128;
       r[3] = x[3] + x[11] * ecfp_twom192 + x9 * ecfp_twom128; /* adds bits
                                                                                                          * 0-40 */
       r[2] = x[2] + x10 * ecfp_twom192 + x8 * ecfp_twom128;
       r[1] = x[1] + x9 * ecfp_twom192;   /* adds bits 16-40 */
       r[0] = x[0] + x8 * ecfp_twom192;

       /* 
        * Tidy up just r[group->numDoubles-2] so that the number of
        * reductions is accurate plus or minus one.  (Rather than tidy all to 
        * make it totally accurate) */
       q = r[ECFP_NUMDOUBLES - 2] + group->alpha[ECFP_NUMDOUBLES - 1];
       q -= group->alpha[ECFP_NUMDOUBLES - 1];
       r[ECFP_NUMDOUBLES - 2] -= q;
       r[ECFP_NUMDOUBLES - 1] += q;

       /* Tidy up the excess bits on r[group->numDoubles-1] using reduction */
       /* Use ecfp_beta so we get a positive res */
       q = r[ECFP_NUMDOUBLES - 1] - ecfp_beta_192;
       q += group->bitSize_alpha;
       q -= group->bitSize_alpha;

       r[ECFP_NUMDOUBLES - 1] -= q;
       r[0] += q * ecfp_twom192;
       r[2] += q * ecfp_twom128;

       /* Tidy the result */
       ecfp_tidyShort(r, group);
}

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