Rip out non-endomorphism code
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@@ -140,19 +140,16 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
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secp256k1_fe Z;
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int skew_1;
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#ifdef USE_ENDOMORPHISM
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secp256k1_ge pre_a_lam[ECMULT_TABLE_SIZE(WINDOW_A)];
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int wnaf_lam[1 + WNAF_SIZE(WINDOW_A - 1)];
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int skew_lam;
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secp256k1_scalar q_1, q_lam;
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#endif
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int wnaf_1[1 + WNAF_SIZE(WINDOW_A - 1)];
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int i;
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/* build wnaf representation for q. */
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int rsize = size;
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#ifdef USE_ENDOMORPHISM
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if (size > 128) {
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rsize = 128;
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/* split q into q_1 and q_lam (where q = q_1 + q_lam*lambda, and q_1 and q_lam are ~128 bit) */
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@@ -160,12 +157,9 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
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skew_1 = secp256k1_wnaf_const(wnaf_1, &q_1, WINDOW_A - 1, 128);
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skew_lam = secp256k1_wnaf_const(wnaf_lam, &q_lam, WINDOW_A - 1, 128);
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} else
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#endif
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{
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skew_1 = secp256k1_wnaf_const(wnaf_1, scalar, WINDOW_A - 1, size);
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#ifdef USE_ENDOMORPHISM
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skew_lam = 0;
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#endif
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}
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/* Calculate odd multiples of a.
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@@ -179,14 +173,12 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
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for (i = 0; i < ECMULT_TABLE_SIZE(WINDOW_A); i++) {
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secp256k1_fe_normalize_weak(&pre_a[i].y);
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}
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#ifdef USE_ENDOMORPHISM
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if (size > 128) {
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for (i = 0; i < ECMULT_TABLE_SIZE(WINDOW_A); i++) {
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secp256k1_ge_mul_lambda(&pre_a_lam[i], &pre_a[i]);
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}
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}
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#endif
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/* first loop iteration (separated out so we can directly set r, rather
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* than having it start at infinity, get doubled several times, then have
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@@ -195,14 +187,12 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
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VERIFY_CHECK(i != 0);
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ECMULT_CONST_TABLE_GET_GE(&tmpa, pre_a, i, WINDOW_A);
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secp256k1_gej_set_ge(r, &tmpa);
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#ifdef USE_ENDOMORPHISM
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if (size > 128) {
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i = wnaf_lam[WNAF_SIZE_BITS(rsize, WINDOW_A - 1)];
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VERIFY_CHECK(i != 0);
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ECMULT_CONST_TABLE_GET_GE(&tmpa, pre_a_lam, i, WINDOW_A);
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secp256k1_gej_add_ge(r, r, &tmpa);
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}
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#endif
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/* remaining loop iterations */
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for (i = WNAF_SIZE_BITS(rsize, WINDOW_A - 1) - 1; i >= 0; i--) {
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int n;
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@@ -215,14 +205,12 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
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ECMULT_CONST_TABLE_GET_GE(&tmpa, pre_a, n, WINDOW_A);
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VERIFY_CHECK(n != 0);
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secp256k1_gej_add_ge(r, r, &tmpa);
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#ifdef USE_ENDOMORPHISM
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if (size > 128) {
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n = wnaf_lam[i];
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ECMULT_CONST_TABLE_GET_GE(&tmpa, pre_a_lam, n, WINDOW_A);
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VERIFY_CHECK(n != 0);
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secp256k1_gej_add_ge(r, r, &tmpa);
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}
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#endif
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}
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secp256k1_fe_mul(&r->z, &r->z, &Z);
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@@ -231,43 +219,35 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
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/* Correct for wNAF skew */
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secp256k1_ge correction = *a;
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secp256k1_ge_storage correction_1_stor;
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#ifdef USE_ENDOMORPHISM
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secp256k1_ge_storage correction_lam_stor;
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#endif
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secp256k1_ge_storage a2_stor;
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secp256k1_gej tmpj;
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secp256k1_gej_set_ge(&tmpj, &correction);
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secp256k1_gej_double_var(&tmpj, &tmpj, NULL);
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secp256k1_ge_set_gej(&correction, &tmpj);
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secp256k1_ge_to_storage(&correction_1_stor, a);
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#ifdef USE_ENDOMORPHISM
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if (size > 128) {
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secp256k1_ge_to_storage(&correction_lam_stor, a);
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}
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#endif
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secp256k1_ge_to_storage(&a2_stor, &correction);
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/* For odd numbers this is 2a (so replace it), for even ones a (so no-op) */
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secp256k1_ge_storage_cmov(&correction_1_stor, &a2_stor, skew_1 == 2);
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#ifdef USE_ENDOMORPHISM
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if (size > 128) {
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secp256k1_ge_storage_cmov(&correction_lam_stor, &a2_stor, skew_lam == 2);
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}
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#endif
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/* Apply the correction */
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secp256k1_ge_from_storage(&correction, &correction_1_stor);
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secp256k1_ge_neg(&correction, &correction);
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secp256k1_gej_add_ge(r, r, &correction);
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#ifdef USE_ENDOMORPHISM
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if (size > 128) {
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secp256k1_ge_from_storage(&correction, &correction_lam_stor);
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secp256k1_ge_neg(&correction, &correction);
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secp256k1_ge_mul_lambda(&correction, &correction);
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secp256k1_gej_add_ge(r, r, &correction);
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}
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#endif
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}
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}
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