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Hardcode numwords in internal vli_add

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Saves 40 bytes
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Manuel Pégourié-Gonnard 2019-11-04 12:37:08 +01:00
parent 78a7e351fe
commit 02d9d21fd6
1 changed files with 17 additions and 17 deletions
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34
tinycrypt/ecc.c
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@ -218,11 +218,11 @@ uECC_word_t uECC_vli_sub(uECC_word_t *result, const uECC_word_t *left,
/* Computes result = left + right, returning carry, in constant time.
* Can modify in place. */
static uECC_word_t uECC_vli_add(uECC_word_t *result, const uECC_word_t *left,
const uECC_word_t *right, wordcount_t num_words)
const uECC_word_t *right)
{
uECC_word_t carry = 0;
wordcount_t i;
for (i = 0; i < num_words; ++i) {
for (i = 0; i < NUM_ECC_WORDS; ++i) {
uECC_word_t sum = left[i] + right[i] + carry;
uECC_word_t val = (sum < left[i]);
carry = cond_set(val, carry, (sum != left[i]));
@ -429,7 +429,7 @@ void uECC_vli_modAdd(uECC_word_t *result, const uECC_word_t *left,
const uECC_word_t *right, const uECC_word_t *mod,
wordcount_t num_words)
{
uECC_word_t carry = uECC_vli_add(result, left, right, num_words);
uECC_word_t carry = uECC_vli_add(result, left, right);
if (carry || uECC_vli_cmp_unsafe(mod, result, num_words) != 1) {
/* result > mod (result = mod + remainder), so subtract mod to get
* remainder. */
@ -445,7 +445,7 @@ void uECC_vli_modSub(uECC_word_t *result, const uECC_word_t *left,
if (l_borrow) {
/* In this case, result == -diff == (max int) - diff. Since -x % d == d - x,
* we can get the correct result from result + mod (with overflow). */
uECC_vli_add(result, result, mod, num_words);
uECC_vli_add(result, result, mod);
}
}
@ -529,7 +529,7 @@ static void vli_modInv_update(uECC_word_t *uv,
uECC_word_t carry = 0;
if (!EVEN(uv)) {
carry = uECC_vli_add(uv, uv, mod, num_words);
carry = uECC_vli_add(uv, uv, mod);
}
uECC_vli_rshift1(uv, num_words);
if (carry) {
@ -565,7 +565,7 @@ void uECC_vli_modInv(uECC_word_t *result, const uECC_word_t *input,
uECC_vli_sub(a, a, b, num_words);
uECC_vli_rshift1(a, num_words);
if (uECC_vli_cmp_unsafe(u, v, num_words) < 0) {
uECC_vli_add(u, u, mod, num_words);
uECC_vli_add(u, u, mod);
}
uECC_vli_sub(u, u, v, num_words);
vli_modInv_update(u, mod, num_words);
@ -573,7 +573,7 @@ void uECC_vli_modInv(uECC_word_t *result, const uECC_word_t *input,
uECC_vli_sub(b, b, a, num_words);
uECC_vli_rshift1(b, num_words);
if (uECC_vli_cmp_unsafe(v, u, num_words) < 0) {
uECC_vli_add(v, v, mod, num_words);
uECC_vli_add(v, v, mod);
}
uECC_vli_sub(v, v, u, num_words);
vli_modInv_update(v, mod, num_words);
@ -610,7 +610,7 @@ void double_jacobian_default(uECC_word_t * X1, uECC_word_t * Y1,
uECC_vli_modAdd(Z1, X1, X1, curve->p, num_words); /* t3 = 2*(x1^2 - z1^4) */
uECC_vli_modAdd(X1, X1, Z1, curve->p, num_words); /* t1 = 3*(x1^2 - z1^4) */
if (uECC_vli_testBit(X1, 0)) {
uECC_word_t l_carry = uECC_vli_add(X1, X1, curve->p, num_words);
uECC_word_t l_carry = uECC_vli_add(X1, X1, curve->p);
uECC_vli_rshift1(X1, num_words);
X1[num_words - 1] |= l_carry << (uECC_WORD_BITS - 1);
} else {
@ -665,8 +665,8 @@ void vli_mmod_fast_secp256r1(unsigned int *result, unsigned int*product)
tmp[5] = product[13];
tmp[6] = product[14];
tmp[7] = product[15];
carry = uECC_vli_add(tmp, tmp, tmp, NUM_ECC_WORDS);
carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
carry = uECC_vli_add(tmp, tmp, tmp);
carry += uECC_vli_add(result, result, tmp);
/* s2 */
tmp[3] = product[12];
@ -674,8 +674,8 @@ void vli_mmod_fast_secp256r1(unsigned int *result, unsigned int*product)
tmp[5] = product[14];
tmp[6] = product[15];
tmp[7] = 0;
carry += uECC_vli_add(tmp, tmp, tmp, NUM_ECC_WORDS);
carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
carry += uECC_vli_add(tmp, tmp, tmp);
carry += uECC_vli_add(result, result, tmp);
/* s3 */
tmp[0] = product[8];
@ -684,7 +684,7 @@ void vli_mmod_fast_secp256r1(unsigned int *result, unsigned int*product)
tmp[3] = tmp[4] = tmp[5] = 0;
tmp[6] = product[14];
tmp[7] = product[15];
carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
carry += uECC_vli_add(result, result, tmp);
/* s4 */
tmp[0] = product[9];
@ -695,7 +695,7 @@ void vli_mmod_fast_secp256r1(unsigned int *result, unsigned int*product)
tmp[5] = product[15];
tmp[6] = product[13];
tmp[7] = product[8];
carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
carry += uECC_vli_add(result, result, tmp);
/* d1 */
tmp[0] = product[11];
@ -740,7 +740,7 @@ void vli_mmod_fast_secp256r1(unsigned int *result, unsigned int*product)
if (carry < 0) {
do {
carry += uECC_vli_add(result, result, curve_secp256r1.p, NUM_ECC_WORDS);
carry += uECC_vli_add(result, result, curve_secp256r1.p);
}
while (carry < 0);
} else {
@ -925,11 +925,11 @@ static uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0,
bitcount_t num_n_bits = NUM_ECC_BITS;
const uECC_Curve curve = uECC_secp256r1();
uECC_word_t carry = uECC_vli_add(k0, k, curve->n, num_n_words) ||
uECC_word_t carry = uECC_vli_add(k0, k, curve->n) ||
(num_n_bits < ((bitcount_t)num_n_words * uECC_WORD_SIZE * 8) &&
uECC_vli_testBit(k0, num_n_bits));
uECC_vli_add(k1, k0, curve->n, num_n_words);
uECC_vli_add(k1, k0, curve->n);
return carry;
}