commit b6653f3e27a68387c4d8f6053f88c2f26bbb9c6a
author Gabor Mezei <gabor.mezei@arm.com> Mon May 08 17:32:44 2023 +0200
committer Gabor Mezei <gabor.mezei@arm.com> Fri May 12 12:34:12 2023 +0200
tree 5789ab26b1b2e5216bb1d4f8f7ccc6f081cb46d2
parent dcaf99ebb82f74e9371abcf9521fec428c14d405

Update comments

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>

library/ecp_curves.c

diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index 47f1b34..c506dad 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -5533,7 +5533,6 @@
  * with R about 33 bits, used by the Koblitz curves.
  *
  * 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
 
@@ -5571,6 +5570,10 @@
         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++) {
         /* Copy A1 */
         memcpy(A1, X + P_limbs - adjust, P_limbs * ciL);