diff --git a/packages/taler-wallet-core/src/crypto/primitives/nacl-fast.ts b/packages/taler-wallet-core/src/crypto/primitives/nacl-fast.ts
index c2d40691a..315e2bba9 100644
--- a/packages/taler-wallet-core/src/crypto/primitives/nacl-fast.ts
+++ b/packages/taler-wallet-core/src/crypto/primitives/nacl-fast.ts
@@ -1548,7 +1548,7 @@ function modL(r: Uint8Array, x: Float64Array): void {
     carry = 0;
     for (j = i - 32, k = i - 12; j < k; ++j) {
       x[j] += carry - 16 * x[i] * L[j - (i - 32)];
-      carry = (x[j] + 128) >> 8;
+      carry = Math.floor((x[j] + 128) / 256);
       x[j] -= carry * 256;
     }
     x[j] += carry;