yuzu-emu/mbedtls
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Update comments

Browse source 
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
This commit is contained in:
Gabor Mezei 2023-05-08 17:32:44 +02:00
parent dcaf99ebb8
commit b6653f3e27
No known key found for this signature in database
GPG key ID: FEE76C0CF8C6267D
1 changed files with 4 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
library/ecp_curves.c
View file

@ -5533,7 +5533,6 @@ cleanup:
* with R about 33 bits, used by the Koblitz curves. * with R about 33 bits, used by the Koblitz curves.
* *
* Write N as A0 + 2^224 A1, return A0 + R * A1. * Write N as A0 + 2^224 A1, return A0 + R * A1.
* Actually do two passes, since R is big.
*/ */
#define P_KOBLITZ_R (8 / sizeof(mbedtls_mpi_uint)) // Limbs in R #define P_KOBLITZ_R (8 / sizeof(mbedtls_mpi_uint)) // Limbs in R
@ -5571,6 +5570,10 @@ static inline int ecp_mod_koblitz(mbedtls_mpi_uint *X,
mask = ((mbedtls_mpi_uint) 1 << shift) - 1; mask = ((mbedtls_mpi_uint) 1 << shift) - 1;
} }
/* Two pass is needed for reducing the value of `A0 + R * A1` and
* need an additional one to reduce the possible overflow during
* the addition.
*/
for (size_t pass = 0; pass < 3; pass++) { for (size_t pass = 0; pass < 3; pass++) {
/* Copy A1 */ /* Copy A1 */
memcpy(A1, X + P_limbs - adjust, P_limbs * ciL); memcpy(A1, X + P_limbs - adjust, P_limbs * ciL);