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ec2_mult.c readability update.

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This commit is contained in:
Andy Polyakov 2008-10-28 13:53:51 +00:00
parent f1455b3063
commit ea71ec1b11
1 changed files with 10 additions and 9 deletions
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19
crypto/ec/ec2_mult.c
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@ -216,8 +216,8 @@ static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r,
const EC_POINT *point, BN_CTX *ctx) const EC_POINT *point, BN_CTX *ctx)
{ {
BIGNUM *x1, *x2, *z1, *z2; BIGNUM *x1, *x2, *z1, *z2;
int ret = 0, i, j; int ret = 0, i;
BN_ULONG mask; BN_ULONG mask,word;
if (r == point) if (r == point)
{ {
@ -251,22 +251,24 @@ static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r,
if (!BN_GF2m_add(x2, x2, &group->b)) goto err; /* x2 = x^4 + b */ if (!BN_GF2m_add(x2, x2, &group->b)) goto err; /* x2 = x^4 + b */
/* find top most bit and go one past it */ /* find top most bit and go one past it */
i = scalar->top - 1; j = BN_BITS2 - 1; i = scalar->top - 1;
mask = BN_TBIT; mask = BN_TBIT;
while (!(scalar->d[i] & mask)) { mask >>= 1; j--; } word = scalar->d[i];
mask >>= 1; j--; while (!(word & mask)) mask >>= 1;
mask >>= 1;
/* if top most bit was at word break, go to next word */ /* if top most bit was at word break, go to next word */
if (!mask) if (!mask)
{ {
i--; j = BN_BITS2 - 1; i--;
mask = BN_TBIT; mask = BN_TBIT;
} }
for (; i >= 0; i--) for (; i >= 0; i--)
{ {
for (; j >= 0; j--) word = scalar->d[i];
while (mask)
{ {
if (scalar->d[i] & mask) if (word & mask)
{ {
if (!gf2m_Madd(group, &point->X, x1, z1, x2, z2, ctx)) goto err; if (!gf2m_Madd(group, &point->X, x1, z1, x2, z2, ctx)) goto err;
if (!gf2m_Mdouble(group, x2, z2, ctx)) goto err; if (!gf2m_Mdouble(group, x2, z2, ctx)) goto err;
@ -278,7 +280,6 @@ static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r,
} }
mask >>= 1; mask >>= 1;
} }
j = BN_BITS2 - 1;
mask = BN_TBIT; mask = BN_TBIT;
} }