diff --git a/src/leb128/containers_leb128.ml b/src/leb128/containers_leb128.ml
index f250a5eb..d43f3121 100644
--- a/src/leb128/containers_leb128.ml
+++ b/src/leb128/containers_leb128.ml
@@ -60,7 +60,7 @@ module Decode = struct
     Int64.to_int v, n_consumed
 
   let[@inline] decode_zigzag (v : int64) : int64 =
-    Int64.(logxor (shift_right v 1) (neg (logand v Int64.one)))
+    Int64.(logxor (shift_right_logical v 1) (sub 0L (logand v 1L)))
 
   let[@inline] i64 sl off : int64 * int =
     let v, n_consumed = u64 sl off in
diff --git a/tests/leb128/t_leb128.ml b/tests/leb128/t_leb128.ml
index 90f9fd30..f89d5611 100644
--- a/tests/leb128/t_leb128.ml
+++ b/tests/leb128/t_leb128.ml
@@ -72,7 +72,7 @@ true
 
 t @@ fun () ->
 let buf = Buf.create () in
-Leb128.Encode.u64 buf 1L;
+Leb128.Encode.u64 buf 0L;
 let slice = Buf.to_slice buf in
 let v, n = Leb128.Decode.u64 slice 0 in
 assert_equal ~printer:Int64.to_string 0L v;