diff options
| -rw-r--r-- | src/synth/netlists-memories.adb | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/src/synth/netlists-memories.adb b/src/synth/netlists-memories.adb index ccce168ec..8e62137e6 100644 --- a/src/synth/netlists-memories.adb +++ b/src/synth/netlists-memories.adb @@ -438,7 +438,8 @@ package body Netlists.Memories is -- Return True iff MUX_INP is a mux2 input whose output is connected to a -- dff to create a DFF with enable (the other mux2 input is connected to -- the dff output). - function Is_Enable_Dff (Mux_Inp : Input) return Boolean + procedure Is_Enable_Dff + (Mux_Inp : Input; Res : out Boolean; Inv : out Boolean) is Mux_Inst : constant Instance := Get_Input_Parent (Mux_Inp); pragma Assert (Get_Id (Mux_Inst) = Id_Mux2); @@ -446,40 +447,50 @@ package body Netlists.Memories is Inp : Input; Dff_Inst : Instance; Dff_Out : Net; + Prt : Port_Idx; begin + Inv := False; + Res := False; + Inp := Get_First_Sink (Mux_Out); if Inp = No_Input or else Get_Next_Sink (Inp) /= No_Input then -- The output of the mux must be connected to one input. - return False; + return; end if; -- Check if the mux is before a dff. Dff_Inst := Get_Input_Parent (Inp); if Get_Id (Dff_Inst) /= Id_Dff then - return False; + return; end if; Dff_Out := Get_Output (Dff_Inst, 0); if Mux_Inp = Get_Input (Mux_Inst, 1) then - return Skip_Signal (Get_Input_Net (Mux_Inst, 2)) = Dff_Out; + -- Loop on sel = 1 (so enable is inverted). + Inv := True; + Prt := 2; else - return Skip_Signal (Get_Input_Net (Mux_Inst, 1)) = Dff_Out; + -- Loop on sel = 0. + Prt := 1; end if; + Res := Skip_Signal (Get_Input_Net (Mux_Inst, Prt)) = Dff_Out; end Is_Enable_Dff; - -- INST is a Dyn_Extract. - -- If INST is followed by a dff or a dff+enable (with mux2), return the - -- dff in LAST_INST, the clock in CLK and the enable in EN. + -- EXTR_INST is a Dyn_Extract. + -- If EXTR_INST is followed by a dff or a dff+enable (with mux2), + -- return the dff in LAST_INST, the clock in CLK and the enable in EN. procedure Extract_Extract_Dff (Ctxt : Context_Acc; - Inst : Instance; + Extr_Inst : Instance; Last_Inst : out Instance; Clk : out Net; En : out Net) is - Val : constant Net := Get_Output (Inst, 0); + Val : constant Net := Get_Output (Extr_Inst, 0); Inp : Input; Iinst : Instance; + Is_Dff : Boolean; + Is_Inv : Boolean; begin Inp := Get_First_Sink (Val); if Get_Next_Sink (Inp) = No_Input then @@ -500,7 +511,13 @@ package body Netlists.Memories is Last_Inst := Iinst; return; end; - elsif Get_Id (Iinst) = Id_Mux2 and then Is_Enable_Dff (Inp) then + end if; + if Get_Id (Iinst) = Id_Mux2 then + Is_Enable_Dff (Inp, Is_Dff, Is_Inv); + else + Is_Dff := False; + end if; + if Is_Dff then declare Mux_Out : constant Net := Get_Output (Iinst, 0); Mux_En_Inp : constant Input := Get_Input (Iinst, 0); @@ -508,12 +525,11 @@ package body Netlists.Memories is Mux_I1_Inp : constant Input := Get_Input (Iinst, 2); Dff_Din : constant Input := Get_First_Sink (Mux_Out); Dff_Inst : constant Instance := Get_Input_Parent (Dff_Din); - Dff_Out : constant Net := Get_Output (Dff_Inst, 0); Clk_Inp : constant Input := Get_Input (Dff_Inst, 0); begin Clk := Get_Driver (Clk_Inp); En := Get_Driver (Mux_En_Inp); - if Dff_Out = Get_Driver (Mux_I1_Inp) then + if Is_Inv then En := Build_Monadic (Ctxt, Id_Not, En); Copy_Location (En, Iinst); end if; @@ -529,7 +545,7 @@ package body Netlists.Memories is end if; end if; - Last_Inst := Inst; + Last_Inst := Extr_Inst; Clk := No_Net; En := No_Net; end Extract_Extract_Dff; |