diff --git a/src/Core__BigInt.mjs b/src/Core__BigInt.mjs
index 88c19a2e..56b7eda6 100644
--- a/src/Core__BigInt.mjs
+++ b/src/Core__BigInt.mjs
@@ -5,12 +5,12 @@ function toInt(t) {
   return Number(t) | 0;
 }
 
-function exp(x, y) {
-  return (x ** y);
+function lnot(x) {
+  return x ^ -1n;
 }
 
 export {
   toInt ,
-  exp ,
+  lnot ,
 }
 /* No side effect */
diff --git a/test/TempTests.mjs b/test/TempTests.mjs
index 4239421f..47409903 100644
--- a/test/TempTests.mjs
+++ b/test/TempTests.mjs
@@ -4,6 +4,7 @@ import * as Core__Int from "../src/Core__Int.mjs";
 import * as IntlTests from "./intl/IntlTests.mjs";
 import * as Core__Dict from "../src/Core__Dict.mjs";
 import * as Core__JSON from "../src/Core__JSON.mjs";
+import * as Caml_bigint from "rescript/lib/es6/caml_bigint.js";
 import * as Caml_option from "rescript/lib/es6/caml_option.js";
 import * as Core__Array from "../src/Core__Array.mjs";
 import * as Core__Float from "../src/Core__Float.mjs";
@@ -143,7 +144,7 @@ console.info("BigInt");
 
 console.info("---");
 
-console.log(BigInt(1) / BigInt(12.0));
+console.log(Caml_bigint.div(BigInt(1), BigInt(12.0)));
 
 console.info("");