diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/synth/netlists-inference.adb | 224 |
1 files changed, 153 insertions, 71 deletions
diff --git a/src/synth/netlists-inference.adb b/src/synth/netlists-inference.adb index 8786d42eb..44a419eff 100644 --- a/src/synth/netlists-inference.adb +++ b/src/synth/netlists-inference.adb @@ -318,6 +318,156 @@ package body Netlists.Inference is and then Get_Input_Net (Inst, 0) = Prev_Val; end Is_Prev_FF_Value; + function Infere_FF_Else (Ctxt : Context_Acc; + Prev_Val : Net; + Off : Uns32; + Last_Mux : Instance; + Clk : Net; + Clk_Enable : Net; + Stmt : Synth.Source.Syn_Src) return Net; + + procedure Infere_FF_Mux (Ctxt : Context_Acc; + Prev_Val : Net; + Off : Uns32; + Last_Mux : Instance; + Stmt : Synth.Source.Syn_Src; + Els : out Net; + Data : out Net) + is + Mux_Loc : constant Location_Type := Get_Location (Last_Mux); + Sel : constant Input := Get_Mux2_Sel (Last_Mux); + I0 : constant Input := Get_Mux2_I0 (Last_Mux); + I1 : constant Input := Get_Mux2_I1 (Last_Mux); + Els_Inst : Instance; + Els_Clk : Net; + Els_En : Net; + begin + -- There must be no 'else' part for clock expression. + Els := Get_Driver (I0); + if Is_Prev_FF_Value (Els, Prev_Val, Off) then + -- The loop. + Els := No_Net; + else + Els_Inst := Get_Net_Parent (Els); + if Get_Id (Els_Inst) = Id_Mux2 then + Extract_Clock (Ctxt, Get_Driver (Get_Mux2_Sel (Els_Inst)), + Els_Clk, Els_En); + else + Els_Clk := No_Net; + end if; + if Els_Clk = No_Net then + Error_Msg_Synth + (Mux_Loc, "clocked logic requires clocked logic on else part"); + Els := No_Net; + else + Els := Infere_FF_Else (Ctxt, Prev_Val, Off, Els_Inst, + Els_Clk, Els_En, Stmt); + end if; + end if; + + Disconnect (Sel); + -- Don't try to free driver of I0 as this is Prev_Val or a selection + -- of it. + Disconnect (I0); + Data := Get_Driver (I1); + -- Don't try to free driver of I1 as it is reconnected. + Disconnect (I1); + end Infere_FF_Mux; + + function Infere_FF_Create (Ctxt : Context_Acc; + Rst : Net; + Rst_Val : Net; + Init : Net; + Clk : Net; + Data : Net; + Els : Net; + Loc : Location_Type) return Net + is + Res : Net; + begin + if Rst = No_Net then + pragma Assert (Rst_Val = No_Net); + if Els = No_Net then + if Init /= No_Net then + Res := Build_Idff (Ctxt, Clk, D => Data, Init => Init); + else + Res := Build_Dff (Ctxt, Clk, D => Data); + end if; + else + if Init /= No_Net then + Res := Build_Midff (Ctxt, Clk, D => Data, + Els => Els, Init => Init); + else + Res := Build_Mdff (Ctxt, Clk, D => Data, Els => Els); + end if; + end if; + else + if Els /= No_Net then + Error_Msg_Synth + (Loc, "synchronous code does not expect else part"); + end if; + + if Init /= No_Net then + Res := Build_Iadff (Ctxt, Clk, D => Data, + Rst => Rst, Rst_Val => Rst_Val, + Init => Init); + else + Res := Build_Adff (Ctxt, Clk, D => Data, + Rst => Rst, Rst_Val => Rst_Val); + end if; + end if; + + Set_Location (Res, Loc); + + return Res; + end Infere_FF_Create; + + function Infere_FF_Else (Ctxt : Context_Acc; + Prev_Val : Net; + Off : Uns32; + Last_Mux : Instance; + Clk : Net; + Clk_Enable : Net; + Stmt : Synth.Source.Syn_Src) return Net + is + Mux_Loc : constant Location_Type := Get_Location (Last_Mux); + Data : Net; + Res : Net; + Els : Net; + begin + -- Create and return the DFF. + + -- 1. Remove the mux that creates the loop (will be replaced by the + -- dff). + Infere_FF_Mux (Ctxt, Prev_Val, Off, Last_Mux, Stmt, Els, Data); + + Free_Instance (Last_Mux); + + if Off = 0 + and then Can_Infere_RAM (Data, Prev_Val) + then + -- Maybe it is a RAM. + Data := Infere_RAM (Ctxt, Data, Clk_Enable); + elsif Clk_Enable /= No_Net then + -- If there is a condition with the clock, that's an enable which + -- keep the previous value if the condition is false. Add the mux + -- for it. + declare + Prev : Net; + begin + Prev := Build2_Extract (Ctxt, Prev_Val, Off, Get_Width (Data)); + + Data := Build_Mux2 (Ctxt, Clk_Enable, Prev, Data); + Copy_Location (Data, Clk_Enable); + end; + end if; + + -- Create the FF. + Res := Infere_FF_Create (Ctxt, No_Net, No_Net, No_Net, Clk, Data, + Els, Mux_Loc); + return Res; + end Infere_FF_Else; + -- LAST_MUX is the mux whose input 0 is the loop and clock for selector. function Infere_FF (Ctxt : Context_Acc; Prev_Val : Net; @@ -342,45 +492,7 @@ package body Netlists.Inference is -- 1. Remove the mux that creates the loop (will be replaced by the -- dff). - declare - Sel : constant Input := Get_Mux2_Sel (Last_Mux); - I0 : constant Input := Get_Mux2_I0 (Last_Mux); - I1 : constant Input := Get_Mux2_I1 (Last_Mux); - Els_Inst : Instance; - Els_Clk : Net; - Els_En : Net; - begin - -- There must be no 'else' part for clock expression. - Els := Get_Driver (I0); - if Is_Prev_FF_Value (Els, Prev_Val, Off) then - -- The loop. - Els := No_Net; - else - Els_Inst := Get_Net_Parent (Els); - if Get_Id (Els_Inst) = Id_Mux2 then - Extract_Clock (Ctxt, Get_Driver (Get_Mux2_Sel (Els_Inst)), - Els_Clk, Els_En); - else - Els_Clk := No_Net; - end if; - if Els_Clk = No_Net then - Error_Msg_Synth - (+Stmt, "clocked logic requires clocked logic on else part"); - Els := No_Net; - else - Els := Infere_FF (Ctxt, Prev_Val, Off, Els_Inst, - Els_Clk, Els_En, Stmt); - end if; - end if; - - Disconnect (Sel); - -- Don't try to free driver of I0 as this is Prev_Val or a selection - -- of it. - Disconnect (I0); - Data := Get_Driver (I1); - -- Don't try to free driver of I1 as it is reconnected. - Disconnect (I1); - end; + Infere_FF_Mux (Ctxt, Prev_Val, Off, Last_Mux, Stmt, Els, Data); -- If the signal declaration has an initial value, get it. Sig := Get_Net_Parent (Prev_Val); @@ -514,38 +626,8 @@ package body Netlists.Inference is end if; -- Create the FF. - if Rst = No_Net then - pragma Assert (Rst_Val = No_Net); - if Els = No_Net then - if Init /= No_Net then - Res := Build_Idff (Ctxt, Clk, D => Data, Init => Init); - else - Res := Build_Dff (Ctxt, Clk, D => Data); - end if; - else - if Init /= No_Net then - raise Internal_Error; - else - Res := Build_Mdff (Ctxt, Clk, D => Data, Els => Els); - end if; - end if; - else - if Els /= No_Net then - Error_Msg_Synth - (+Stmt, "synchronous code does not expect else part"); - end if; - - if Init /= No_Net then - Res := Build_Iadff (Ctxt, Clk, D => Data, - Rst => Rst, Rst_Val => Rst_Val, - Init => Init); - else - Res := Build_Adff (Ctxt, Clk, D => Data, - Rst => Rst, Rst_Val => Rst_Val); - end if; - end if; - Set_Location (Res, Mux_Loc); - + Res := Infere_FF_Create (Ctxt, Rst, Rst_Val, Init, Clk, Data, + Els, Mux_Loc); return Res; end Infere_FF; |