ecmult_const_impl.h File Reference

#include "scalar.h"
#include "group.h"
#include "ecmult_const.h"
#include "ecmult_impl.h"

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Macros
#define	ECMULT_CONST_TABLE_GET_GE(r, pre, n, w)

Macro Definition Documentation

ECMULT_CONST_TABLE_GET_GE

#define ECMULT_CONST_TABLE_GET_GE	(		r,
			pre,
			n,
			w )

Value:

    do { \
    int m = 0; \
      \
    int mask = (n) >> (sizeof(n) * CHAR_BIT - 1); \
    int abs_n = ((n) + mask) ^ mask; \
    int idx_n = abs_n >> 1; \
    secp256k1_fe neg_y; \
    VERIFY_CHECK(((n) & 1) == 1); \
    VERIFY_CHECK((n) >= -((1 << ((w)-1)) - 1)); \
    VERIFY_CHECK((n) <=  ((1 << ((w)-1)) - 1)); \
    VERIFY_SETUP(secp256k1_fe_clear(&(r)->x)); \
    VERIFY_SETUP(secp256k1_fe_clear(&(r)->y)); \
      \
    (r)->x = (pre)[m].x; \
    (r)->y = (pre)[m].y; \
    for (m = 1; m < ECMULT_TABLE_SIZE(w); m++) { \
          \
        secp256k1_fe_cmov(&(r)->x, &(pre)[m].x, m == idx_n); \
        secp256k1_fe_cmov(&(r)->y, &(pre)[m].y, m == idx_n); \
    } \
    (r)->infinity = 0; \
    secp256k1_fe_negate(&neg_y, &(r)->y, 1); \
    secp256k1_fe_cmov(&(r)->y, &neg_y, (n) != abs_n); \
} while(0)

Definition at line 29 of file ecmult_const_impl.h.