diff --git a/interp/src/primitives/combinational.rs b/interp/src/primitives/combinational.rs
index ecc907d88d..c67f1438e5 100644
--- a/interp/src/primitives/combinational.rs
+++ b/interp/src/primitives/combinational.rs
@@ -568,3 +568,8 @@ comb_primitive!(StdUnsynSmod[WIDTH](left: WIDTH, right: WIDTH) -> (out: WIDTH) {
             &left.as_signed(),
             &right.as_signed()), WIDTH))
 });
+
+comb_primitive!(StdCat[LEFT_WIDTH, RIGHT_WIDTH, OUT_WIDTH](left: LEFT_WIDTH, right: RIGHT_WIDTH) -> (out: OUT_WIDTH) {
+
+    Ok(Value::concat(left, right))
+});
diff --git a/interp/src/structures/environment.rs b/interp/src/structures/environment.rs
index 51e51f2c24..27e1c40714 100644
--- a/interp/src/structures/environment.rs
+++ b/interp/src/structures/environment.rs
@@ -432,6 +432,8 @@ impl InterpreterState {
                 Box::new(combinational::StdUnsynSmod::new(params, cell_qin))
             }
 
+            "std_cat" => Box::new(combinational::StdCat::new(params, cell_qin)),
+
             p => {
                 return Err(
                     InterpreterError::UnknownPrimitive(p.to_string()).into()