diff --git a/include/mbedtls/sha512.h b/include/mbedtls/sha512.h
index a348fc1b5..c10794814 100644
--- a/include/mbedtls/sha512.h
+++ b/include/mbedtls/sha512.h
@@ -101,8 +101,8 @@ void mbedtls_sha512_clone( mbedtls_sha512_context *dst,
  * \param is384    Determines which function to use. This must be
  *                 either \c 0 for SHA-512, or \c 1 for SHA-384.
  *
- * \note           When \c MBEDTLS_SHA384_C is defined,
- *                 \p is384 must be \c 1, or the function will return
+ * \note           When \c MBEDTLS_SHA384_C is not defined,
+ *                 \p is384 must be \c 0, or the function will return
  *                 #MBEDTLS_ERR_SHA512_BAD_INPUT_DATA.
  *
  * \return         \c 0 on success.
@@ -175,8 +175,8 @@ int mbedtls_internal_sha512_process( mbedtls_sha512_context *ctx,
  * \param is384    Determines which function to use. This must be either
  *                 \c 0 for SHA-512, or \c 1 for SHA-384.
  *
- * \note           When \c MBEDTLS_SHA384_C is defined, \p is384 must
- *                 be \c 1, or the function will return
+ * \note           When \c MBEDTLS_SHA384_C is not defined, \p is384 must
+ *                 be \c 0, or the function will return
  *                 #MBEDTLS_ERR_SHA512_BAD_INPUT_DATA.
  *
  * \return         \c 0 on success.