netlists: add id_nop gate.

6 files changed, 36 insertions, 11 deletions

diff --git a/src/synth/ghdlsynth_gates.h b/src/synth/ghdlsynth_gates.h
index adc1e87b9..77c8c3a69 100644
--- a/src/synth/ghdlsynth_gates.h
+++ b/src/synth/ghdlsynth_gates.h
@@ -62,6 +62,7 @@ enum Module_Id {
    Id_Iadff = 59,
    Id_Mdff = 60,
    Id_Midff = 61,
+   Id_Nop = 60,
    Id_Utrunc = 64,
    Id_Strunc = 65,
    Id_Uextend = 66,
diff --git a/src/synth/netlists-builders.adb b/src/synth/netlists-builders.adb
index 6262295de..78954af95 100644
--- a/src/synth/netlists-builders.adb
+++ b/src/synth/netlists-builders.adb
@@ -417,10 +417,8 @@ package body Netlists.Builders is
    procedure Create_Objects_Module (Ctxt : Context_Acc)
    is
       Outputs : Port_Desc_Array (0 .. 0);
-      Inputs : Port_Desc_Array (0 .. 0);
       Inputs2 : Port_Desc_Array (0 .. 1);
    begin
-      Inputs := (0 => Create_Input ("i"));
       Inputs2 := (0 => Create_Input ("i"),
                   1 => Create_Input ("init"));
       Outputs := (0 => Create_Output ("o"));
@@ -428,7 +426,7 @@ package body Netlists.Builders is
       Ctxt.M_Output := New_User_Module
         (Ctxt.Design, New_Sname_Artificial (Name_Output, No_Sname),
          Id_Output, 1, 1, 0);
-      Set_Ports_Desc (Ctxt.M_Output, Inputs, Outputs);
+      Set_Ports_Desc (Ctxt.M_Output, Inputs2 (0 .. 0), Outputs);
 
       Ctxt.M_Ioutput := New_User_Module
         (Ctxt.Design,
@@ -439,7 +437,7 @@ package body Netlists.Builders is
       Ctxt.M_Signal := New_User_Module
         (Ctxt.Design, New_Sname_Artificial (Name_Signal, No_Sname),
          Id_Signal, 1, 1, 0);
-      Set_Ports_Desc (Ctxt.M_Signal, Inputs, Outputs);
+      Set_Ports_Desc (Ctxt.M_Signal, Inputs2 (0 .. 0), Outputs);
 
       Ctxt.M_Isignal := New_User_Module
         (Ctxt.Design,
@@ -450,7 +448,12 @@ package body Netlists.Builders is
       Ctxt.M_Port := New_User_Module
         (Ctxt.Design, New_Sname_Artificial (Name_Port, No_Sname),
          Id_Port, 1, 1, 0);
-      Set_Ports_Desc (Ctxt.M_Port, Inputs, Outputs);
+      Set_Ports_Desc (Ctxt.M_Port, Inputs2 (0 .. 0), Outputs);
+
+      Ctxt.M_Nop := New_User_Module
+        (Ctxt.Design, New_Sname_Artificial (Get_Identifier ("nop"), No_Sname),
+         Id_Nop, 1, 1, 0);
+      Set_Ports_Desc (Ctxt.M_Nop, Inputs2 (0 .. 0), Outputs);
    end Create_Objects_Module;
 
    procedure Create_Dff_Modules (Ctxt : Context_Acc)
@@ -1301,6 +1304,19 @@ package body Netlists.Builders is
       return O;
    end Build_Port;
 
+   function Build_Nop (Ctxt : Context_Acc; I : Net) return Net
+   is
+      Wd : constant Width := Get_Width (I);
+      Inst : Instance;
+      O : Net;
+   begin
+      Inst := New_Internal_Instance (Ctxt, Ctxt.M_Nop);
+      Connect (Get_Input (Inst, 0), I);
+      O := Get_Output (Inst, 0);
+      Set_Width (O, Wd);
+      return O;
+   end Build_Nop;
+
    function Build_Dff (Ctxt : Context_Acc;
                        Clk : Net;
                        D : Net) return Net
@@ -1522,5 +1538,4 @@ package body Netlists.Builders is
       Set_Width (O, W);
       return O;
    end Build_Formal_Input;
-
 end Netlists.Builders;
diff --git a/src/synth/netlists-builders.ads b/src/synth/netlists-builders.ads
index b9aa7757c..f686c6390 100644
--- a/src/synth/netlists-builders.ads
+++ b/src/synth/netlists-builders.ads
@@ -193,10 +193,12 @@ package Netlists.Builders is
                         D : Net;
                         Els : Net) return Net;
    function Build_Midff (Ctxt : Context_Acc;
-                        Clk : Net;
-                        D : Net;
-                        Els : Net;
-                        Init : Net) return Net;
+                         Clk : Net;
+                         D : Net;
+                         Els : Net;
+                         Init : Net) return Net;
+
+   function Build_Nop (Ctxt : Context_Acc; I : Net) return Net;
 private
    type Module_Arr is array (Module_Id range <>) of Module;
 
@@ -220,6 +222,7 @@ private
       M_Edge : Module;
       M_Mux2 : Module;
       M_Mux4 : Module;
+      M_Nop : Module;
       M_Output : Module;
       M_Ioutput : Module;
       M_Signal : Module;
diff --git a/src/synth/netlists-cleanup.adb b/src/synth/netlists-cleanup.adb
index 230e61e10..24889cd6c 100644
--- a/src/synth/netlists-cleanup.adb
+++ b/src/synth/netlists-cleanup.adb
@@ -127,7 +127,8 @@ package body Netlists.Cleanup is
          case Get_Id (Inst) is
             when Id_Output
               | Id_Ioutput
-              | Id_Port =>
+              | Id_Port
+              | Id_Nop =>
                declare
                   Inp : Input;
                   In_Drv : Net;
diff --git a/src/synth/netlists-disp_vhdl.adb b/src/synth/netlists-disp_vhdl.adb
index 423a9ed96..f4e8e49f7 100644
--- a/src/synth/netlists-disp_vhdl.adb
+++ b/src/synth/netlists-disp_vhdl.adb
@@ -763,6 +763,8 @@ package body Netlists.Disp_Vhdl is
             Disp_Template ("  \o0 <= \i0; -- (isignal)" & NL, Inst);
          when Id_Port =>
             Disp_Template ("  \o0 <= \i0; -- (port)" & NL, Inst);
+         when Id_Nop =>
+            Disp_Template ("  \o0 <= \i0; -- (nop)" & NL, Inst);
          when Id_Not =>
             Disp_Template ("  \o0 <= not \i0;" & NL, Inst);
          when Id_Neg =>
diff --git a/src/synth/netlists-gates.ads b/src/synth/netlists-gates.ads
index b60420c22..b7577f85c 100644
--- a/src/synth/netlists-gates.ads
+++ b/src/synth/netlists-gates.ads
@@ -172,6 +172,9 @@ package Netlists.Gates is
    --  Output:  0: Q
    Id_Midff : constant Module_Id := 61;
 
+   --  Temporary gate, O = I
+   Id_Nop : constant Module_Id := 60;
+
    --  Width change: truncate or extend.  Sign is know in order to possibly
    --  detect loss of value.
    Id_Utrunc : constant Module_Id := 64;