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Tidy up BN_mod_mul_montgomery.

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This matches bn_mod_mul_montgomery_small and removes a bit of
unnecessary stuttering.

Change-Id: Ife249c6e8754aef23c144dbfdea5daaf7ed9f48a
Reviewed-on: https://boringssl-review.googlesource.com/25248
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
David Benjamin 2018-01-19 09:52:16 -05:00 committed by Adam Langley
parent 2ccdf584aa
commit 9a5bfc0350
1 changed files with 28 additions and 35 deletions
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63
crypto/fipsmodule/bn/montgomery.c
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@ -126,10 +126,6 @@
#define OPENSSL_BN_ASM_MONT
#endif
static int bn_mod_mul_montgomery_fallback(BIGNUM *r, const BIGNUM *a,
const BIGNUM *b,
const BN_MONT_CTX *mont, BN_CTX *ctx);
BN_MONT_CTX *BN_MONT_CTX_new(void) {
BN_MONT_CTX *ret = OPENSSL_malloc(sizeof(BN_MONT_CTX));
@ -375,37 +371,6 @@ int bn_one_to_montgomery(BIGNUM *r, const BN_MONT_CTX *mont, BN_CTX *ctx) {
return BN_from_montgomery(r, &mont->RR, mont, ctx);
}
int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BN_MONT_CTX *mont, BN_CTX *ctx) {
#if !defined(OPENSSL_BN_ASM_MONT)
return bn_mod_mul_montgomery_fallback(r, a, b, mont, ctx);
#else
int num = mont->N.top;
// |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
if (num < (128 / BN_BITS2) ||
a->top != num ||
b->top != num) {
return bn_mod_mul_montgomery_fallback(r, a, b, mont, ctx);
}
if (!bn_wexpand(r, num)) {
return 0;
}
if (!bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
// The check above ensures this won't happen.
assert(0);
OPENSSL_PUT_ERROR(BN, ERR_R_INTERNAL_ERROR);
return 0;
}
r->neg = a->neg ^ b->neg;
r->top = num;
bn_correct_top(r);
return 1;
#endif
}
static int bn_mod_mul_montgomery_fallback(BIGNUM *r, const BIGNUM *a,
const BIGNUM *b,
const BN_MONT_CTX *mont,
@ -440,6 +405,34 @@ err:
return ret;
}
int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BN_MONT_CTX *mont, BN_CTX *ctx) {
#if defined(OPENSSL_BN_ASM_MONT)
// |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
int num = mont->N.top;
if (num >= (128 / BN_BITS2) &&
a->top == num &&
b->top == num) {
if (!bn_wexpand(r, num)) {
return 0;
}
if (!bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
// The check above ensures this won't happen.
assert(0);
OPENSSL_PUT_ERROR(BN, ERR_R_INTERNAL_ERROR);
return 0;
}
r->neg = a->neg ^ b->neg;
r->top = num;
bn_correct_top(r);
return 1;
}
#endif
return bn_mod_mul_montgomery_fallback(r, a, b, mont, ctx);
}
int bn_to_montgomery_small(BN_ULONG *r, size_t num_r, const BN_ULONG *a,
size_t num_a, const BN_MONT_CTX *mont) {
return bn_mod_mul_montgomery_small(r, num_r, a, num_a, mont->RR.d,