diff --git a/src/fields/generic_common_impl.h b/src/fields/generic_common_impl.h
index c98f11b..58b971e 100644
--- a/src/fields/generic_common_impl.h
+++ b/src/fields/generic_common_impl.h
@@ -44,7 +44,7 @@ template<typename I, int B, uint32_t MOD, typename F, typename T, const F* SQR,
     inline constexpr Elem Qrt(Elem a) const { return QRT->template Map<O>(a); }
 
     /** Compute the inverse of x1. */
-    Elem Inv(Elem a) const { return InvExtGCD<I, O, B, MOD>(a); }
+    Elem Inv(Elem a) const { return InvExtGCD<I, O>(a, B, MOD); }
 
     /** Generate a random field element. */
     Elem FromSeed(uint64_t seed) const {
diff --git a/src/int_utils.h b/src/int_utils.h
index cbf983f..7e18024 100644
--- a/src/int_utils.h
+++ b/src/int_utils.h
@@ -211,13 +211,13 @@ template<typename I, int N, typename L, typename F, int K> struct GFMulHelper
 template<typename I, int N, typename L, typename F> inline constexpr I GFMul(const I& a, const I& b) { return GFMulHelper<I, N, L, F, N>::Run(a, b); }
 
 /** Compute the inverse of x using an extgcd algorithm. */
-template<typename I, typename F, int BITS, uint32_t MOD>
-inline I InvExtGCD(I x)
+template<typename I, typename F>
+inline I InvExtGCD(I x, int bits, uint32_t mod)
 {
     if (F::IsZero(x)) return x;
     I t(0), newt(1);
-    I r(MOD), newr = x;
-    int rlen = BITS + 1, newrlen = F::Bits(newr, BITS);
+    I r(mod), newr = x;
+    int rlen = bits + 1, newrlen = F::Bits(newr, bits);
     while (newr) {
         int q = rlen - newrlen;
         r ^= F::Shift(newr, q);