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Rewrite EC_window_bits_for_scalar_size into a function.

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The compiler should be plenty smart enough to decide whether to inline a
static function called only once. We don't need to resort to so
unreadable a ternary chain.

Change-Id: Iacc8e0c4147fc69008806a0cc36d9e632169601a
Reviewed-on: https://boringssl-review.googlesource.com/12466
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
David Benjamin 2016-11-27 08:45:45 -05:00 committed by Adam Langley
parent c6d09e83c7
commit bfe5f08170
1 changed files with 25 additions and 8 deletions
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33
crypto/ec/wnaf.c
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@ -217,12 +217,29 @@ err:
* sometimes smaller windows will give better performance
* (thus the boundaries should be increased)
*/
#define EC_window_bits_for_scalar_size(b) \
((size_t)((b) >= 2000 ? 6 : (b) >= 800 ? 5 : (b) >= 300 \
? 4 \
: (b) >= 70 ? 3 : (b) >= 20 \
? 2 \
: 1))
static size_t window_bits_for_scalar_size(size_t b) {
if (b >= 2000) {
return 6;
}
if (b >= 800) {
return 5;
}
if (b >= 300) {
return 4;
}
if (b >= 70) {
return 3;
}
if (b >= 20) {
return 2;
}
return 1;
}
int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
const EC_POINT *p, const BIGNUM *p_scalar, BN_CTX *ctx) {
@ -294,7 +311,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
size_t bits;
bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(g_scalar);
wsize[i] = EC_window_bits_for_scalar_size(bits);
wsize[i] = window_bits_for_scalar_size(bits);
num_val += (size_t)1 << (wsize[i] - 1);
wNAF[i + 1] = NULL; /* make sure we always have a pivot */
wNAF[i] =
@ -364,7 +381,7 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
}
}
#if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
#if 1 /* optional; window_bits_for_scalar_size assumes we do this step */
if (!EC_POINTs_make_affine(group, num_val, val, ctx)) {
goto err;
}