diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index 1f9dc71..3d3ec60 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -44,15 +44,15 @@
 #define ECP_VALIDATE(cond)        \
     MBEDTLS_INTERNAL_VALIDATE(cond)
 
-#define ECP_MPI_INIT(_s, _n, _p) { .s = (_s), .n = (_n), .p = (mbedtls_mpi_uint *) (_p) }
+#define ECP_MPI_INIT(_p, _n) { .p = (mbedtls_mpi_uint *) (_p), .s = 1, .n = (_n) }
 
 #define ECP_MPI_INIT_ARRAY(x)   \
-    ECP_MPI_INIT(1, sizeof(x) / sizeof(mbedtls_mpi_uint), x)
+    ECP_MPI_INIT(x, sizeof(x) / sizeof(mbedtls_mpi_uint))
 
 #define ECP_POINT_INIT_XY_Z0(x, y) { \
-        ECP_MPI_INIT_ARRAY(x), ECP_MPI_INIT_ARRAY(y), ECP_MPI_INIT(1, 0, NULL) }
+        ECP_MPI_INIT_ARRAY(x), ECP_MPI_INIT_ARRAY(y), ECP_MPI_INIT(NULL, 0) }
 #define ECP_POINT_INIT_XY_Z1(x, y) { \
-        ECP_MPI_INIT_ARRAY(x), ECP_MPI_INIT_ARRAY(y), ECP_MPI_INIT(1, 1, mpi_one) }
+        ECP_MPI_INIT_ARRAY(x), ECP_MPI_INIT_ARRAY(y), ECP_MPI_INIT(mpi_one, 1) }
 
 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) ||   \
     defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) ||   \