synth: add Get_Input_Instance.

4 files changed, 21 insertions, 10 deletions

diff --git a/src/synth/netlists-gates.ads b/src/synth/netlists-gates.ads
index 506fae353..4a2a7ca33 100644
--- a/src/synth/netlists-gates.ads
+++ b/src/synth/netlists-gates.ads
@@ -157,6 +157,8 @@ package Netlists.Gates is
    Id_Extract : constant Module_Id := 68;
 
    --  OUT := IN0[IN1+OFF+WD-1:IN1+OFF]
+   --  Input0: the memory
+   --  Input1: then index
    Id_Dyn_Extract : constant Module_Id := 69;
 
    --  Like Insert but for dynamic values.
diff --git a/src/synth/netlists-memories.adb b/src/synth/netlists-memories.adb
index 401f1b20c..27887c8a9 100644
--- a/src/synth/netlists-memories.adb
+++ b/src/synth/netlists-memories.adb
@@ -347,9 +347,7 @@ package body Netlists.Memories is
             when Id_Memidx =>
                return Res + 1;
             when Id_Addidx =>
-               if Get_Id (Get_Net_Parent (Get_Input_Net (Inst, 1)))
-                 /= Id_Memidx
-               then
+               if Get_Id (Get_Input_Instance (Inst, 1)) /= Id_Memidx then
                   raise Internal_Error;
                end if;
                Res := Res + 1;
@@ -403,7 +401,7 @@ package body Netlists.Memories is
                   Indexes (P) := (Inst => Inst, Addr => No_Net);
                   exit;
                when Id_Addidx =>
-                  Inst2 := Get_Net_Parent (Get_Input_Net (Inst, 0));
+                  Inst2 := Get_Input_Instance (Inst, 0);
                   if Get_Id (Inst2) /= Id_Memidx then
                      raise Internal_Error;
                   end if;
@@ -494,7 +492,7 @@ package body Netlists.Memories is
                   Remove_Instance (Inst);
                   exit;
                when Id_Addidx =>
-                  Inst2 := Get_Net_Parent (Get_Input_Net (Inst, 0));
+                  Inst2 := Get_Input_Instance (Inst, 0);
                   if Get_Id (Inst2) /= Id_Memidx then
                      raise Internal_Error;
                   end if;
@@ -916,7 +914,7 @@ package body Netlists.Memories is
                end if;
                Set_Mark_Flag (Inst, True);
                Last := Inst;
-               Inst := Get_Net_Parent (Get_Input_Net (Inst, 0));
+               Inst := Get_Input_Instance (Inst, 0);
             when Id_Isignal
               | Id_Signal
               | Id_Const_Bit =>
@@ -1393,7 +1391,7 @@ package body Netlists.Memories is
    is
       Inst : Instance;
    begin
-      Inst := Get_Net_Parent (Get_Input_Net (Sig, 0));
+      Inst := Get_Input_Instance (Sig, 0);
 
       --  Skip dff/idff.
       --  FIXME: that should be considered as an implicit mux.
@@ -1401,7 +1399,7 @@ package body Netlists.Memories is
       case Get_Id (Inst) is
          when Id_Dff
            | Id_Idff =>
-            Inst := Get_Net_Parent (Get_Input_Net (Inst, 1));
+            Inst := Get_Input_Instance (Inst, 1);
          when others =>
             null;
       end case;
@@ -1415,7 +1413,7 @@ package body Netlists.Memories is
             when Id_Dyn_Insert
               | Id_Dyn_Insert_En =>
                --  Skip the dyn_insert.
-               Inst := Get_Net_Parent (Get_Input_Net (Inst, 0));
+               Inst := Get_Input_Instance (Inst, 0);
             when Id_Signal
               | Id_Isignal =>
                --  Should be done.
@@ -1436,7 +1434,7 @@ package body Netlists.Memories is
             return True;
          when Id_Signal
            | Id_Isignal =>
-            return Is_Const_Input (Get_Net_Parent (Get_Input_Net (Inst, 0)));
+            return Is_Const_Input (Get_Input_Instance (Inst, 0));
          when others =>
             --  FIXME: handle other consts ?
             return False;
diff --git a/src/synth/netlists-utils.adb b/src/synth/netlists-utils.adb
index d3861215e..722cafc1a 100644
--- a/src/synth/netlists-utils.adb
+++ b/src/synth/netlists-utils.adb
@@ -103,6 +103,12 @@ package body Netlists.Utils is
       return Get_Driver (Get_Input (Inst, Idx));
    end Get_Input_Net;
 
+   function Get_Input_Instance (Inst : Instance; Idx : Port_Idx)
+                               return Instance is
+   begin
+      return Get_Net_Parent (Get_Input_Net (Inst, Idx));
+   end Get_Input_Instance;
+
    function Is_Const_Module (Id : Module_Id) return Boolean is
    begin
       case Id is
diff --git a/src/synth/netlists-utils.ads b/src/synth/netlists-utils.ads
index b8ccb3e93..f8749749f 100644
--- a/src/synth/netlists-utils.ads
+++ b/src/synth/netlists-utils.ads
@@ -42,8 +42,13 @@ package Netlists.Utils is
    function Get_Input_Width (M : Module; I : Port_Idx) return Width;
    function Get_Output_Width (M : Module; I : Port_Idx) return Width;
 
+   --  Return the net (driver) connected to input IDX of INSTANCE.
    function Get_Input_Net (Inst : Instance; Idx : Port_Idx) return Net;
 
+   --  Return the instance that drives input IDX of INST.
+   function Get_Input_Instance (Inst : Instance; Idx : Port_Idx)
+                               return Instance;
+
    --  Return True iff ID describe a constant.
    function Is_Const_Module (Id : Module_Id) return Boolean;
    function Is_Const_Net (N : Net) return Boolean;