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-- Netlist utilities (composed of a few calls).
-- Copyright (C) 2017 Tristan Gingold
--
-- This file is part of GHDL.
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation; either version 2 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
-- MA 02110-1301, USA.
package body Netlists.Utils is
function Get_Nbr_Inputs (Inst : Instance) return Port_Nbr
is
M : constant Module := Get_Module (Inst);
begin
if Is_Self_Instance (Inst) then
return Get_Nbr_Outputs (M);
else
return Get_Nbr_Inputs (M);
end if;
end Get_Nbr_Inputs;
function Get_Nbr_Outputs (Inst : Instance) return Port_Nbr
is
M : constant Module := Get_Module (Inst);
begin
if Is_Self_Instance (Inst) then
return Get_Nbr_Inputs (M);
else
return Get_Nbr_Outputs (M);
end if;
end Get_Nbr_Outputs;
function Get_Nbr_Params (Inst : Instance) return Param_Nbr
is
M : constant Module := Get_Module (Inst);
begin
return Get_Nbr_Params (M);
end Get_Nbr_Params;
function Get_Param_Desc
(Inst : Instance; Param : Param_Idx) return Param_Desc is
begin
return Get_Param_Desc (Get_Module (Inst), Param);
end Get_Param_Desc;
function Get_Id (Inst : Instance) return Module_Id is
begin
return Get_Id (Get_Module (Inst));
end Get_Id;
function Get_Input_Name (M : Module; I : Port_Idx) return Sname is
begin
return Get_Input_Desc (M, I).Name;
end Get_Input_Name;
function Get_Output_Name (M : Module; I : Port_Idx) return Sname is
begin
return Get_Output_Desc (M, I).Name;
end Get_Output_Name;
function Is_Connected (O : Net) return Boolean is
begin
return Get_First_Sink (O) /= No_Input;
end Is_Connected;
function Has_One_Connection (O : Net) return Boolean
is
Inp : Input;
begin
Inp := Get_First_Sink (O);
if Inp = No_Input then
-- No connection.
return False;
end if;
Inp := Get_Next_Sink (Inp);
return Inp = No_Input;
end Has_One_Connection;
procedure Disconnect_And_Free (I : Input)
is
I_Net : constant Net := Get_Driver (I);
Inst : constant Instance := Get_Net_Parent (I_Net);
Nbr_Inputs : Port_Nbr;
Nbr_Outputs : Port_Nbr;
begin
-- First disconnect.
Disconnect (I);
-- Quick check: is output (of I) still used ?
if Is_Connected (I_Net) then
return;
end if;
-- Check that all outputs are unused.
Nbr_Outputs := Get_Nbr_Outputs (Inst);
if Nbr_Outputs > 1 then
for K in 0 .. Nbr_Outputs - 1 loop
if Is_Connected (Get_Output (Inst, K)) then
return;
end if;
end loop;
end if;
-- First disconnect inputs.
Nbr_Inputs := Get_Nbr_Inputs (Inst);
if Nbr_Inputs > 0 then
for K in 0 .. Nbr_Inputs - 1 loop
Disconnect_And_Free (Get_Input (Inst, K));
end loop;
end if;
-- Free Inst
Free_Instance (Inst);
end Disconnect_And_Free;
function Is_Unused_Instance (Inst : Instance) return Boolean
is
Nbr_Outputs : constant Port_Idx := Get_Nbr_Outputs (Inst);
N : Net;
begin
-- An instance without outputs is considered as used.
if Nbr_Outputs = 0 then
return False;
end if;
for Idx in 0 .. Nbr_Outputs - 1 loop
N := Get_Output (Inst, Idx);
if Is_Connected (N) then
-- Connected output.
return False;
end if;
end loop;
-- All outputs are unconnected.
return True;
end Is_Unused_Instance;
procedure Remove_Unused_Instances (M : Module)
is
pragma Assert (Is_Valid (M));
Inst : Instance;
begin
Extract_All_Instances (M, Inst);
-- Add the self instance (the first one).
Append_Instance (M, Inst);
Inst := Get_Next_Instance (Inst);
while Inst /= No_Instance loop
if not (Get_Id (Inst) = Id_Free
or else Is_Unused_Instance (Inst))
then
-- Keep this used instance.
Append_Instance (M, Inst);
end if;
Inst := Get_Next_Instance (Inst);
end loop;
end Remove_Unused_Instances;
procedure Remove_Free_Instances (M : Module)
is
pragma Assert (Is_Valid (M));
Inst : Instance;
begin
Extract_All_Instances (M, Inst);
while Inst /= No_Instance loop
if Get_Id (Inst) /= Id_Free then
Append_Instance (M, Inst);
end if;
Inst := Get_Next_Instance (Inst);
end loop;
end Remove_Free_Instances;
end Netlists.Utils;
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