diff --git a/library/bignum.c b/library/bignum.c
index 699d2c6..d915ade 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -2063,6 +2063,7 @@
     size_t window_bitsize;
     size_t i, j, nblimbs;
     size_t bufsize, nbits;
+    size_t exponent_bits_in_window = 0;
     mbedtls_mpi_uint ei, mm, state;
     mbedtls_mpi RR, T, W[(size_t) 1 << MBEDTLS_MPI_WINDOW_SIZE], WW, Apos;
     int neg;
@@ -2236,7 +2237,6 @@
     nblimbs = E->n;
     bufsize = 0;
     nbits   = 0;
-    size_t exponent_bits_in_window = 0;
     state   = 0;
 
     while (1) {