diff --git a/library/ecp.c b/library/ecp.c
index 086acb3..538d2cf 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -2930,7 +2930,7 @@
 
 #if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED)
 #if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
-#define ECP_MPI_INIT(s, n, p) { s, (n), (mbedtls_mpi_uint *) (p) }
+#define ECP_MPI_INIT(_s, _n, _p) { .s = (_s), .n = (_n), .p = (mbedtls_mpi_uint *) (_p) }
 #define ECP_MPI_INIT_ARRAY(x)   \
     ECP_MPI_INIT(1, sizeof(x) / sizeof(mbedtls_mpi_uint), x)
 /*