bignum_mod_raw: Updated documentation for mpi_mod_raw_mul
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/library/bignum_mod_raw.c b/library/bignum_mod_raw.c
index d29896c..8f7270a 100644
--- a/library/bignum_mod_raw.c
+++ b/library/bignum_mod_raw.c
@@ -132,13 +132,13 @@
{
/* Standard (A * B) multiplication stored into pre-allocated T
* buffer of fixed limb size of (2N + 1).
-
+ *
* The space may not not fully filled by when
- * MBEDTLS_MPI_MOD_REP_OPT_RED is used, with most
- * curves using (2N) limbs.
+ * MBEDTLS_MPI_MOD_REP_OPT_RED is used, where we only need
+ * (2N) or (2N-1) limbs (depending on limb size and curve).
*
* The 521-bit Weierstrass curve is the only
- * that which requires a limb size of (2N + 1). */
+ * that which requires a limb size of (2N). */
const size_t T_limbs = (N->bits == 521) ?
BITS_TO_LIMBS(N->bits * 2) + 1 :
BITS_TO_LIMBS(N->bits * 2);