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secp256k1
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Remove the non-storage cmov

This commit is contained in:
Pieter Wuille 2015-01-25 00:56:22 -04:00
parent 55422b6aaf
commit fcc48c4561
4 changed files with 12 additions and 42 deletions
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1
src/field.h
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@ -117,7 +117,6 @@ static void secp256k1_fe_to_storage(secp256k1_fe_storage_t *r, const secp256k1_f
static void secp256k1_fe_from_storage(secp256k1_fe_t *r, const secp256k1_fe_storage_t*);
/** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. */
static void secp256k1_fe_cmov(secp256k1_fe_t *r, const secp256k1_fe_t *a, int flag);
static void secp256k1_fe_storage_cmov(secp256k1_fe_storage_t *r, const secp256k1_fe_storage_t *a, int flag);
#endif

20
src/field_10x26_impl.h
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@ -1063,26 +1063,6 @@ static void secp256k1_fe_sqr(secp256k1_fe_t *r, const secp256k1_fe_t *a) {
#endif
}
static void secp256k1_fe_cmov(secp256k1_fe_t *r, const secp256k1_fe_t *a, int flag) {
uint32_t mask0 = flag + ~((uint32_t)0), mask1 = ~mask0;
r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);
r->n[1] = (r->n[1] & mask0) | (a->n[1] & mask1);
r->n[2] = (r->n[2] & mask0) | (a->n[2] & mask1);
r->n[3] = (r->n[3] & mask0) | (a->n[3] & mask1);
r->n[4] = (r->n[4] & mask0) | (a->n[4] & mask1);
r->n[5] = (r->n[5] & mask0) | (a->n[5] & mask1);
r->n[6] = (r->n[6] & mask0) | (a->n[6] & mask1);
r->n[7] = (r->n[7] & mask0) | (a->n[7] & mask1);
r->n[8] = (r->n[8] & mask0) | (a->n[8] & mask1);
r->n[9] = (r->n[9] & mask0) | (a->n[9] & mask1);
#ifdef VERIFY
if (flag) {
r->magnitude = a->magnitude;
r->normalized = a->normalized;
}
#endif
}
static inline void secp256k1_fe_storage_cmov(secp256k1_fe_storage_t *r, const secp256k1_fe_storage_t *a, int flag) {
uint32_t mask0 = flag + ~((uint32_t)0), mask1 = ~mask0;
r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);

15
src/field_5x52_impl.h
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@ -398,21 +398,6 @@ static void secp256k1_fe_sqr(secp256k1_fe_t *r, const secp256k1_fe_t *a) {
#endif
}
static void secp256k1_fe_cmov(secp256k1_fe_t *r, const secp256k1_fe_t *a, int flag) {
uint64_t mask0 = flag + ~((uint64_t)0), mask1 = ~mask0;
r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);
r->n[1] = (r->n[1] & mask0) | (a->n[1] & mask1);
r->n[2] = (r->n[2] & mask0) | (a->n[2] & mask1);
r->n[3] = (r->n[3] & mask0) | (a->n[3] & mask1);
r->n[4] = (r->n[4] & mask0) | (a->n[4] & mask1);
#ifdef VERIFY
if (flag) {
r->magnitude = a->magnitude;
r->normalized = a->normalized;
}
#endif
}
static inline void secp256k1_fe_storage_cmov(secp256k1_fe_storage_t *r, const secp256k1_fe_storage_t *a, int flag) {
uint64_t mask0 = flag + ~((uint64_t)0), mask1 = ~mask0;
r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);

18
src/tests.c
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@ -685,12 +685,18 @@ void run_field_misc(void) {
z = x;
secp256k1_fe_add(&z,&y);
secp256k1_fe_normalize(&z);
/* Test the conditional move. */
secp256k1_fe_cmov(&z, &x, 0);
CHECK(secp256k1_fe_equal_var(&x, &z) == 0);
CHECK(secp256k1_fe_cmp_var(&x, &z) != 0);
secp256k1_fe_cmov(&y, &x, 1);
CHECK(secp256k1_fe_equal_var(&x, &y));
/* Test storage conversion and conditional moves. */
secp256k1_fe_storage_t xs, ys, zs;
secp256k1_fe_to_storage(&xs, &x);
secp256k1_fe_to_storage(&ys, &y);
secp256k1_fe_to_storage(&zs, &z);
secp256k1_fe_storage_cmov(&zs, &xs, 0);
CHECK(memcmp(&xs, &zs, sizeof(xs)) != 0);
secp256k1_fe_storage_cmov(&ys, &xs, 1);
CHECK(memcmp(&xs, &ys, sizeof(xs)) == 0);
secp256k1_fe_from_storage(&x, &xs);
secp256k1_fe_from_storage(&y, &ys);
secp256k1_fe_from_storage(&z, &zs);
/* Test that mul_int, mul, and add agree. */
secp256k1_fe_add(&y, &x);
secp256k1_fe_add(&y, &x);