diff --git a/index.js b/index.js
index 8a9af47..4c9a0a6 100644
--- a/index.js
+++ b/index.js
@@ -17,7 +17,7 @@ function decode(buffer) {
     do {
       byte = buffer.readUInt8(bytesRead);
       bytesRead += 1;
-      tagCode = (tagCode << 8) | (byte & 0x7f);
+      tagCode = (tagCode << 7) | (byte & 0x7f);
     } while (byte & 0x80);
   }