diff --git a/src/serde.ts b/src/serde.ts
new file mode 100644
index 0000000..80f49dc
--- /dev/null
+++ b/src/serde.ts
@@ -0,0 +1,37 @@
+const decodeExp = (arr: number[]) => {
+  let res = BigInt(0);
+
+  let pos = arr.length - 1;
+  arr.forEach(v => {
+    if (pos == 0) {
+      res += BigInt(v);
+      console.log(`val: ${v} res: ${res}`);
+    } else if (pos == arr.length - 1) {
+      console.log('first run');
+      res = BigInt(v << (pos * 8));
+      console.log(res);
+      console.log(`pos: ${pos} val: ${v} res: ${res}`);
+    } else {
+      //res += BigInt(v << (pos * 8));
+      res += BigInt(v) << BigInt(pos * 8);
+      console.log(v << (pos * 8));
+      console.log(`pos: ${pos} val: ${v} res: ${res}`);
+    }
+    pos -= 1;
+  });
+  console.log(res);
+};
+
+const encodeExp = () => {
+  var myVal = 20000;
+  //  var myVal = n58918699885758813231285507404327079076;
+  var bytes = [];
+  bytes[0] = (myVal & 0xff00) >> 8;
+  bytes[1] = myVal & 0x00ff;
+  console.log(bytes);
+  decodeExp(bytes);
+  // console.log((bytes[0] << 8) + bytes[1]);
+  //  console.log((bytes[0] << 8));// + bytes[1]);
+};
+//encodeExp();
+//decodeExp(a);