bignum_mod: Updated documentation.
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/library/bignum_mod.h b/library/bignum_mod.h
index c4b763f..60966cc 100644
--- a/library/bignum_mod.h
+++ b/library/bignum_mod.h
@@ -98,10 +98,11 @@
/* Skip 1 as it is slightly easier to accidentally pass to functions. */
/** Montgomery representation. */
MBEDTLS_MPI_MOD_REP_MONTGOMERY = 2,
- /** TODO: document this.
- *
- * Residues are in canonical representation.
- */
+ /* Optimised reduction available. This indicates a coordinate modulus (P)
+ * and one of the following available:
+ * - MBEDTLS_ECP_NIST_OPTIM
+ * - Kobliz Curve.
+ * - Fast Reduction Curve CURVE25519 or CURVE448. */
MBEDTLS_MPI_MOD_REP_OPT_RED,
} mbedtls_mpi_mod_rep_selector;