3 files changed, 51 insertions, 0 deletions
diff --git a/src/synth/synth-ieee-numeric_std.adb b/src/synth/synth-ieee-numeric_std.adb
index 4d8aa46a9..5319a3113 100644
--- a/src/synth/synth-ieee-numeric_std.adb
+++ b/src/synth/synth-ieee-numeric_std.adb
@@ -112,4 +112,35 @@ package body Synth.Ieee.Numeric_Std is
       end loop;
       return Res;
    end Add_Sgn_Int;
+
+   function Add_Uns_Nat (L : Std_Logic_Vector; R : Uns64)
+                        return Std_Logic_Vector
+   is
+      pragma Assert (L'First = 1);
+      subtype Res_Type is Std_Logic_Vector (1 .. L'Last);
+      V : Uns64;
+      Res : Res_Type;
+      Lb, Rb, Carry : Sl_X01;
+   begin
+      if L'Last < 1 then
+         return Null_Vec;
+      end if;
+      V := R;
+      Carry := '0';
+      for I in Res'Range loop
+         Lb := Sl_To_X01 (L (I));
+         Rb := Uns_To_01 (V and 1);
+         if Lb = 'X' then
+            --assert NO_WARNING
+            --  report "NUMERIC_STD.""+"": non logical value detected"
+            --  severity warning;
+            Res := (others => 'X');
+            exit;
+         end if;
+         Res (I) := Compute_Sum (Carry, Rb, Lb);
+         Carry := Compute_Carry (Carry, Rb, Lb);
+         V := Shift_Right (V, 1);
+      end loop;
+      return Res;
+   end Add_Uns_Nat;
 end Synth.Ieee.Numeric_Std;
diff --git a/src/synth/synth-ieee-numeric_std.ads b/src/synth/synth-ieee-numeric_std.ads
index 824c3fe00..340dac3d6 100644
--- a/src/synth/synth-ieee-numeric_std.ads
+++ b/src/synth/synth-ieee-numeric_std.ads
@@ -27,4 +27,6 @@ package Synth.Ieee.Numeric_Std is
 
    function Add_Sgn_Int (L : Std_Logic_Vector; R : Int64)
                         return Std_Logic_Vector;
+   function Add_Uns_Nat (L : Std_Logic_Vector; R : Uns64)
+                        return Std_Logic_Vector;
 end Synth.Ieee.Numeric_Std;
diff --git a/src/synth/synth-static_oper.adb b/src/synth/synth-static_oper.adb
index fb79af54c..645456db0 100644
--- a/src/synth/synth-static_oper.adb
+++ b/src/synth/synth-static_oper.adb
@@ -123,6 +123,21 @@ package body Synth.Static_Oper is
       end;
    end Synth_Add_Sgn_Int;
 
+   function Synth_Add_Uns_Nat (L, R : Value_Acc; Loc : Syn_Src)
+                              return Value_Acc
+   is
+      pragma Unreferenced (Loc);
+      L_Arr : Std_Logic_Vector (1 .. Natural (L.Arr.Len));
+      R_Val : constant Uns64 := Uns64 (R.Scal);
+   begin
+      To_Std_Logic_Vector (L, L_Arr);
+      declare
+         Res_Arr : constant Std_Logic_Vector := Add_Uns_Nat (L_Arr, R_Val);
+      begin
+         return To_Value_Acc (Res_Arr, L.Typ.Vec_El);
+      end;
+   end Synth_Add_Uns_Nat;
+
    function Synth_Static_Dyadic_Predefined (Syn_Inst : Synth_Instance_Acc;
                                             Imp : Node;
                                             Left : Value_Acc;
@@ -224,6 +239,9 @@ package body Synth.Static_Oper is
          when Iir_Predefined_Ieee_Numeric_Std_Add_Sgn_Int =>
             return Synth_Add_Sgn_Int (Left, Right, Expr);
 
+         when Iir_Predefined_Ieee_Numeric_Std_Add_Uns_Nat =>
+            return Synth_Add_Uns_Nat (Left, Right, Expr);
+
          when others =>
             Error_Msg_Synth
               (+Expr, "synth_static_dyadic_predefined: unhandled "