diff --git a/engine/runtime-language-arrow/src/main/java/org/enso/interpreter/arrow/runtime/ByteBufferDirect.java b/engine/runtime-language-arrow/src/main/java/org/enso/interpreter/arrow/runtime/ByteBufferDirect.java
index a5462418b8473..faa667835bd22 100644
--- a/engine/runtime-language-arrow/src/main/java/org/enso/interpreter/arrow/runtime/ByteBufferDirect.java
+++ b/engine/runtime-language-arrow/src/main/java/org/enso/interpreter/arrow/runtime/ByteBufferDirect.java
@@ -184,7 +184,7 @@ public int capacity() throws UnsupportedMessageException {
   public boolean isNull(int index) {
     var bufferIndex = index >> 3;
     var slot = bitmapBuffer.get(bufferIndex);
-    var byteIndex = index & ~(1 << 3);
+    var byteIndex = index & byteMask;
     var mask = 1 << byteIndex;
     return (slot & mask) == 0;
   }
@@ -192,7 +192,7 @@ public boolean isNull(int index) {
   public void setNull(int index) {
     var bufferIndex = index >> 3;
     var slot = bitmapBuffer.get(bufferIndex);
-    var byteIndex = index & ~(1 << 3);
+    var byteIndex = index & byteMask;
     var mask = ~(1 << byteIndex);
     bitmapBuffer.put(bufferIndex, (byte) (slot & mask));
   }
@@ -201,12 +201,17 @@ private void setValidityBitmap(int index0, int unitSize) {
     var index = index0 / unitSize;
     var bufferIndex = index >> 3;
     var slot = bitmapBuffer.get(bufferIndex);
-    var byteIndex = index & ~(1 << 3);
+
+    var byteIndex = index & byteMask;
+    var test = index & byteMask;
+
     var mask = 1 << byteIndex;
     var updated = (slot | mask);
     bitmapBuffer.put(bufferIndex, (byte) (updated));
   }
 
+  private static final int byteMask = ~(~(1 << 3) + 1); // 7
+
   @Override
   public void close() throws Exception {
     this.dataBuffer.clear();