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Diffstat (limited to 'translate/grt/grt-processes.adb')
| -rw-r--r-- | translate/grt/grt-processes.adb | 795 |
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diff --git a/translate/grt/grt-processes.adb b/translate/grt/grt-processes.adb new file mode 100644 index 000000000..a4e269bf9 --- /dev/null +++ b/translate/grt/grt-processes.adb @@ -0,0 +1,795 @@ +-- GHDL Run Time (GRT) - processes. +-- Copyright (C) 2002, 2003, 2004, 2005 Tristan Gingold +-- +-- GHDL 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, or (at your option) any later +-- version. +-- +-- GHDL 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 GCC; see the file COPYING. If not, write to the Free +-- Software Foundation, 59 Temple Place - Suite 330, Boston, MA +-- 02111-1307, USA. +with GNAT.Table; +with Ada.Unchecked_Conversion; +with Ada.Unchecked_Deallocation; +with Grt.Stack2; use Grt.Stack2; +with Grt.Disp; +with Grt.Astdio; +with Grt.Signals; use Grt.Signals; +with Grt.Errors; use Grt.Errors; +with Grt.Stacks; use Grt.Stacks; +with Grt.Options; +with Grt.Rtis_Addr; use Grt.Rtis_Addr; +with Grt.Rtis_Utils; +with Grt.Hooks; +with Grt.Disp_Signals; +with Grt.Stdio; +with Grt.Stats; + +package body Grt.Processes is + -- Access to a process subprogram. + type Proc_Acc is access procedure (Self : System.Address); + + -- Simply linked list for sensitivity. + type Sensitivity_El; + type Sensitivity_Acc is access Sensitivity_El; + type Sensitivity_El is record + Sig : Ghdl_Signal_Ptr; + Next : Sensitivity_Acc; + end record; + + Last_Time : Std_Time := Std_Time'Last; + + -- State of a process. + type Process_State is + ( + -- Sensitized process. Its state cannot change. + State_Sensitized, + + -- Verilog process, being suspended. + State_Delayed, + + -- Non-sensitized process being suspended. + State_Wait, + + -- Non-sensitized process being awaked by a wait timeout. This state + -- is transcient. + State_Timeout, + + -- Non-sensitized process waiting until end. + State_Dead); + + type Process_Type is record + -- Stack for the process. + -- This must be the first field of the record (and this is the only + -- part visible). + -- Must be NULL_STACK for sensitized processes. + Stack : Stack_Type; + + -- Subprogram containing process code. + Subprg : Proc_Acc; + + -- Instance (THIS parameter) for the subprogram. + This : System.Address; + + -- Name of the process. + Rti : Rti_Context; + + -- True if the process is resumed and will be run at next cycle. + Resumed : Boolean; + + -- True if the process is postponed. + Postponed : Boolean; + + State : Process_State; + + -- Timeout value for wait. + Timeout : Std_Time; + + -- Sensitivity list. + Sensitivity : Sensitivity_Acc; + end record; + type Process_Acc is access all Process_Type; + + -- Per 'thread' data. + -- The process being executed. + Cur_Proc_Id : Process_Id; + + Cur_Proc : Process_Acc; + pragma Export (C, Cur_Proc, "grt_cur_proc"); + + -- The secondary stack for the thread. + Stack2 : Stack2_Ptr; + + package Process_Table is new GNAT.Table + (Table_Component_Type => Process_Type, + Table_Index_Type => Process_Id, + Table_Low_Bound => 1, + Table_Initial => 1, + Table_Increment => 100); + + procedure Free is new Ada.Unchecked_Deallocation + (Name => Sensitivity_Acc, Object => Sensitivity_El); + + procedure Init is + begin + Process_Table.Init; + end Init; + + function Get_Current_Process_Id return Process_Id + is + begin + return Cur_Proc_Id; + end Get_Current_Process_Id; + + function Get_Nbr_Processes return Natural is + begin + return Natural (Process_Table.Last); + end Get_Nbr_Processes; + + procedure Process_Register (This : System.Address; + Proc : System.Address; + Ctxt : Rti_Context; + State : Process_State; + Postponed : Boolean) + is + function To_Proc_Acc is new Ada.Unchecked_Conversion + (Source => System.Address, Target => Proc_Acc); + Stack : Stack_Type; + begin + if State /= State_Sensitized then + Stack := Stack_Create (Proc, This); + else + Stack := Null_Stack; + end if; + Process_Table.Increment_Last; + Process_Table.Table (Process_Table.Last) := + (Subprg => To_Proc_Acc (Proc), + This => This, + Rti => Ctxt, + Sensitivity => null, + Resumed => True, + Postponed => Postponed, + State => State, + Timeout => Bad_Time, + Stack => Stack); + -- Used to create drivers. + Cur_Proc_Id := Process_Table.Last; + end Process_Register; + + procedure Ghdl_Process_Register + (Instance : System.Address; + Proc : System.Address; + Ctxt : Ghdl_Rti_Access; + Addr : System.Address) + is + begin + Process_Register (Instance, Proc, (Addr, Ctxt), State_Timeout, False); + end Ghdl_Process_Register; + + procedure Ghdl_Sensitized_Process_Register + (Instance : System.Address; + Proc : System.Address; + Ctxt : Ghdl_Rti_Access; + Addr : System.Address) + is + begin + Process_Register (Instance, Proc, (Addr, Ctxt), State_Sensitized, False); + end Ghdl_Sensitized_Process_Register; + + procedure Ghdl_Postponed_Process_Register + (Instance : System.Address; + Proc : System.Address; + Ctxt : Ghdl_Rti_Access; + Addr : System.Address) + is + begin + Process_Register (Instance, Proc, (Addr, Ctxt), State_Timeout, True); + end Ghdl_Postponed_Process_Register; + + procedure Ghdl_Postponed_Sensitized_Process_Register + (Instance : System.Address; + Proc : System.Address; + Ctxt : Ghdl_Rti_Access; + Addr : System.Address) + is + begin + Process_Register (Instance, Proc, (Addr, Ctxt), State_Sensitized, True); + end Ghdl_Postponed_Sensitized_Process_Register; + + procedure Verilog_Process_Register (This : System.Address; + Proc : System.Address; + Ctxt : Rti_Context) + is + function To_Proc_Acc is new Ada.Unchecked_Conversion + (Source => System.Address, Target => Proc_Acc); + begin + Process_Table.Increment_Last; + Process_Table.Table (Process_Table.Last) := + (Rti => Ctxt, + Sensitivity => null, + Resumed => True, + Postponed => False, + State => State_Sensitized, + Timeout => Bad_Time, + Subprg => To_Proc_Acc (Proc), + This => This, + Stack => Null_Stack); + -- Used to create drivers. + Cur_Proc_Id := Process_Table.Last; + end Verilog_Process_Register; + + procedure Ghdl_Initial_Register (Instance : System.Address; + Proc : System.Address) + is + begin + Verilog_Process_Register (Instance, Proc, Null_Context); + end Ghdl_Initial_Register; + + procedure Ghdl_Always_Register (Instance : System.Address; + Proc : System.Address) + is + begin + Verilog_Process_Register (Instance, Proc, Null_Context); + end Ghdl_Always_Register; + + procedure Ghdl_Process_Add_Sensitivity (Sig : Ghdl_Signal_Ptr) + is + begin + Resume_Process_If_Event (Sig, Process_Table.Last); + end Ghdl_Process_Add_Sensitivity; + + procedure Resume_Process (Proc : Process_Id) is + begin + Process_Table.Table (Proc).Resumed := True; + end Resume_Process; + + function Ghdl_Stack2_Allocate (Size : Ghdl_Index_Type) + return System.Address + is + begin + return Grt.Stack2.Allocate (Stack2, Size); + end Ghdl_Stack2_Allocate; + + function Ghdl_Stack2_Mark return Mark_Id is + begin + if Stack2 = Null_Stack2_Ptr then + Stack2 := Grt.Stack2.Create; + end if; + return Grt.Stack2.Mark (Stack2); + end Ghdl_Stack2_Mark; + + procedure Ghdl_Stack2_Release (Mark : Mark_Id) is + begin + Grt.Stack2.Release (Stack2, Mark); + end Ghdl_Stack2_Release; + + function To_Acc is new Ada.Unchecked_Conversion + (Source => System.Address, Target => Process_Acc); + + procedure Ghdl_Process_Wait_Add_Sensitivity (Sig : Ghdl_Signal_Ptr) + is + El : Sensitivity_Acc; + begin + El := new Sensitivity_El'(Sig => Sig, + Next => Cur_Proc.Sensitivity); + Cur_Proc.Sensitivity := El; + end Ghdl_Process_Wait_Add_Sensitivity; + + procedure Ghdl_Process_Wait_Set_Timeout (Time : Std_Time) + is + begin + if Time < 0 then + -- LRM93 8.1 + Error ("negative timeout clause"); + end if; + Cur_Proc.Timeout := Current_Time + Time; + end Ghdl_Process_Wait_Set_Timeout; + + function Ghdl_Process_Wait_Suspend return Boolean + is + begin + if Cur_Proc.State = State_Sensitized then + Error ("wait statement in a sensitized process"); + end if; + -- Suspend this process. + Cur_Proc.State := State_Wait; +-- if Cur_Proc.Timeout = Bad_Time then +-- Cur_Proc.Timeout := Std_Time'Last; +-- end if; + Stack_Switch (Main_Stack, Cur_Proc.Stack); + return Cur_Proc.State = State_Timeout; + end Ghdl_Process_Wait_Suspend; + + procedure Ghdl_Process_Wait_Close + is + El : Sensitivity_Acc; + N_El : Sensitivity_Acc; + begin + El := Cur_Proc.Sensitivity; + Cur_Proc.Sensitivity := null; + while El /= null loop + N_El := El.Next; + Free (El); + El := N_El; + end loop; + end Ghdl_Process_Wait_Close; + + procedure Ghdl_Process_Wait_Exit + is + begin + if Cur_Proc.State = State_Sensitized then + Error ("wait statement in a sensitized process"); + end if; + -- Mark this process as dead, in order to kill it. + -- It cannot be killed now, since this code is still in the process. + Cur_Proc.State := State_Dead; + -- Suspend this process. + Stack_Switch (Main_Stack, Cur_Proc.Stack); + end Ghdl_Process_Wait_Exit; + + procedure Ghdl_Process_Wait_Timeout (Time : Std_Time) + is + begin + if Cur_Proc.State = State_Sensitized then + Error ("wait statement in a sensitized process"); + end if; + if Time < 0 then + -- LRM93 8.1 + Error ("negative timeout clause"); + end if; + Cur_Proc.Timeout := Current_Time + Time; + Cur_Proc.State := State_Wait; + -- Suspend this process. + Stack_Switch (Main_Stack, Cur_Proc.Stack); + end Ghdl_Process_Wait_Timeout; + + -- Verilog. + procedure Ghdl_Process_Delay (Del : Ghdl_U32) + is + begin + Cur_Proc.Timeout := Current_Time + Std_Time (Del); + Cur_Proc.State := State_Delayed; + end Ghdl_Process_Delay; + + -- Protected object lock. + -- Note: there is no real locks, since the kernel is single threading. + -- Multi lock is allowed, and rules are just checked. + type Object_Lock is record + -- The owner of the lock. + -- Nul_Process_Id means the lock is free. + Process : Process_Id; + -- Number of times the lock has been acquired. + Count : Natural; + end record; + + type Object_Lock_Acc is access Object_Lock; + type Object_Lock_Acc_Acc is access Object_Lock_Acc; + + function To_Lock_Acc_Acc is new Ada.Unchecked_Conversion + (Source => System.Address, Target => Object_Lock_Acc_Acc); + + procedure Ghdl_Protected_Enter (Obj : System.Address) + is + Lock : Object_Lock_Acc := To_Lock_Acc_Acc (Obj).all; + begin + if Lock.Process = Nul_Process_Id then + if Lock.Count /= 0 then + Internal_Error ("protected_enter"); + end if; + Lock.Process := Get_Current_Process_Id; + Lock.Count := 1; + else + if Lock.Process /= Get_Current_Process_Id then + Internal_Error ("protected_enter(2)"); + end if; + Lock.Count := Lock.Count + 1; + end if; + end Ghdl_Protected_Enter; + + procedure Ghdl_Protected_Leave (Obj : System.Address) + is + Lock : Object_Lock_Acc := To_Lock_Acc_Acc (Obj).all; + begin + if Lock.Process /= Get_Current_Process_Id then + Internal_Error ("protected_leave(1)"); + end if; + + if Lock.Count <= 0 then + Internal_Error ("protected_leave(2)"); + end if; + Lock.Count := Lock.Count - 1; + if Lock.Count = 0 then + Lock.Process := Nul_Process_Id; + end if; + end Ghdl_Protected_Leave; + + procedure Ghdl_Protected_Init (Obj : System.Address) + is + Lock : Object_Lock_Acc_Acc := To_Lock_Acc_Acc (Obj); + begin + Lock.all := new Object_Lock'(Process => Nul_Process_Id, + Count => 0); + end Ghdl_Protected_Init; + + procedure Ghdl_Protected_Fini (Obj : System.Address) + is + procedure Deallocate is new Ada.Unchecked_Deallocation + (Object => Object_Lock, Name => Object_Lock_Acc); + + Lock : Object_Lock_Acc_Acc := To_Lock_Acc_Acc (Obj); + begin + if Lock.all.Count /= 0 or Lock.all.Process /= Nul_Process_Id then + Internal_Error ("protected_fini"); + end if; + Deallocate (Lock.all); + end Ghdl_Protected_Fini; + + function Compute_Next_Time return Std_Time + is + Res : Std_Time; + begin + -- f) The time of the next simulation cycle, Tn, is determined by + -- setting it to the earliest of + -- 1) TIME'HIGH + Res := Std_Time'Last; + + -- 2) The next time at which a driver becomes active, or + Res := Std_Time'Min (Res, Grt.Signals.Find_Next_Time); + + if Res = Current_Time then + return Res; + end if; + + -- 3) The next time at which a process resumes. + for I in Process_Table.First .. Process_Table.Last loop + declare + Proc : Process_Type renames Process_Table.Table (I); + begin + if Proc.State = State_Wait + and then Proc.Timeout < Res + and then Proc.Timeout >= 0 + then + -- No signals to be updated. + Grt.Signals.Flush_Active_List; + + if Proc.Timeout = Current_Time then + -- Can't be better. + return Current_Time; + else + Res := Proc.Timeout; + end if; + end if; + end; + end loop; + + return Res; + end Compute_Next_Time; + + procedure Disp_Process_Name (Stream : Grt.Stdio.FILEs; Proc : Process_Id) + is + begin + Grt.Rtis_Utils.Put (Stream, Process_Table.Table (Proc).Rti); + end Disp_Process_Name; + + type Run_Handler is access function return Integer; + -- pragma Convention (C, Run_Handler); + + function Run_Through_Longjump (Hand : Run_Handler) return Integer; + pragma Import (C, Run_Through_Longjump, "__ghdl_run_through_longjump"); + + -- Run resumed processes. + -- If POSTPONED is true, resume postponed processes, else resume + -- non-posponed processes. + -- Returns one of these values: + -- No process has been run. + Run_None : constant Integer := 1; + -- At least one process was run. + Run_Resumed : constant Integer := 2; + -- Simulation is finished. + Run_Finished : constant Integer := 3; + -- Failure, simulation should stop. + Run_Failure : constant Integer := -1; + + function Run_Processes (Postponed : Boolean) return Integer + is + Status : Integer; + begin + Status := Run_None; + + if Options.Flag_Stats then + Stats.Start_Processes; + end if; + + for I in Process_Table.First .. Process_Table.Last loop + if Process_Table.Table (I).Postponed = Postponed + and Process_Table.Table (I).Resumed + then + if Grt.Options.Trace_Processes then + Grt.Astdio.Put ("run process "); + Disp_Process_Name (Stdio.stdout, I); + Grt.Astdio.Put (" ["); + Grt.Astdio.Put (Stdio.stdout, Process_Table.Table (I).This); + Grt.Astdio.Put ("]"); + Grt.Astdio.New_Line; + end if; + Process_Table.Table (I).Resumed := False; + Status := Run_Resumed; + Cur_Proc_Id := I; + Cur_Proc := To_Acc (Process_Table.Table (I)'Address); + if Cur_Proc.State = State_Sensitized then + Cur_Proc.Subprg.all (Cur_Proc.This); + else + Stack_Switch (Cur_Proc.Stack, Main_Stack); + end if; + if Grt.Options.Checks then + Ghdl_Signal_Internal_Checks; + Grt.Stack2.Check_Empty (Stack2); + end if; + end if; + end loop; + + if Options.Flag_Stats then + Stats.End_Processes; + end if; + return Status; + end Run_Processes; + + function Initialization_Phase return Integer + is + Status : Integer; + begin + -- LRM93 12.6.4 + -- At the beginning of initialization, the current time, Tc, is assumed + -- to be 0 ns. + Current_Time := 0; + + -- The initialization phase consists of the following steps: + -- - The driving value and the effective value of each explicitly + -- declared signal are computed, and the current value of the signal + -- is set to the effective value. This value is assumed to have been + -- the value of the signal for an infinite length of time prior to + -- the start of the simulation. + Init_Signals; + + -- - The value of each implicit signal of the form S'Stable(T) or + -- S'Quiet(T) is set to true. The value of each implicit signal of + -- the form S'Delayed is set to the initial value of its prefix, S. + -- GHDL: already done when the signals are created. + null; + + -- - The value of each implicit GUARD signal is set to the result of + -- evaluating the corresponding guard expression. + null; + + -- - Each nonpostponed process in the model is executed until it + -- suspends. + Status := Run_Processes (Postponed => False); + if Status = Run_Failure then + return Run_Failure; + end if; + + -- - Each postponed process in the model is executed until it suspends. + Status := Run_Processes (Postponed => True); + if Status = Run_Failure then + return Run_Failure; + end if; + + -- - The time of the next simulation cycle (which in this case is the + -- first simulation cycle), Tn, is calculated according to the rules + -- of step f of the simulation cycle, below. + Current_Time := Compute_Next_Time; + + return Run_Resumed; + end Initialization_Phase; + + -- Launch a simulation cycle. + -- Set FINISHED to true if this is the last cycle. + function Simulation_Cycle return Integer + is + Tn : Std_Time; + Status : Integer; + begin + -- LRM93 12.6.4 + -- A simulation cycle consists of the following steps: + -- + -- a) The current time, Tc is set equal to Tn. Simulation is complete + -- when Tn = TIME'HIGH and there are no active drivers or process + -- resumptions at Tn. + -- GHDL: this is done at the last step of the cycle. + null; + + -- b) Each active explicit signal in the model is updated. (Events + -- may occur on signals as a result). + -- c) Each implicit signal in the model is updated. (Events may occur + -- on signals as a result.) + if Options.Flag_Stats then + Stats.Start_Update; + end if; + Update_Signals; + if Options.Flag_Stats then + Stats.End_Update; + end if; + + -- d) For each process P, if P is currently sensitive to a signal S and + -- if an event has occured on S in this simulation cycle, then P + -- resumes. + for I in Process_Table.First .. Process_Table.Last loop + declare + Proc : Process_Type renames Process_Table.Table (I); + El : Sensitivity_Acc; + begin + case Proc.State is + when State_Sensitized => + null; + when State_Delayed => + if Proc.Timeout = Current_Time then + Proc.Timeout := Bad_Time; + Proc.Resumed := True; + Proc.State := State_Sensitized; + end if; + when State_Wait => + if Proc.Timeout = Current_Time then + Proc.Timeout := Bad_Time; + Proc.Resumed := True; + Proc.State := State_Timeout; + else + El := Proc.Sensitivity; + while El /= null loop + if El.Sig.Event then + Proc.Resumed := True; + exit; + else + El := El.Next; + end if; + end loop; + end if; + when State_Timeout => + Internal_Error ("process in timeout"); + when State_Dead => + null; + end case; + end; + end loop; + + -- e) Each nonpostponed that has resumed in the current simulation cycle + -- is executed until it suspends. + Status := Run_Processes (Postponed => False); + if Status = Run_Failure then + return Run_Failure; + end if; + + -- f) The time of the next simulation cycle, Tn, is determined by + -- setting it to the earliest of + -- 1) TIME'HIGH + -- 2) The next time at which a driver becomes active, or + -- 3) The next time at which a process resumes. + -- If Tn = Tc, then the next simulation cycle (if any) will be a + -- delta cycle. + if Options.Flag_Stats then + Stats.Start_Next_Time; + end if; + Tn := Compute_Next_Time; + if Options.Flag_Stats then + Stats.End_Next_Time; + end if; + + -- g) If the next simulation cycle will be a delta cycle, the remainder + -- of the step is skipped. + -- Otherwise, each postponed process that has resumed but has not + -- been executed since its last resumption is executed until it + -- suspends. Then Tn is recalculated according to the rules of + -- step f. It is an error if the execution of any postponed + -- process causes a delta cycle to occur immediatly after the + -- current simulation cycle. + if Tn = Current_Time then + if Current_Time = Last_Time and then Status = Run_None then + return Run_Finished; + else + Current_Delta := Current_Delta + 1; + return Run_Resumed; + end if; + else + Current_Delta := 0; + Status := Run_Processes (Postponed => True); + if Status = Run_Resumed then + Flush_Active_List; + if Options.Flag_Stats then + Stats.Start_Next_Time; + end if; + Tn := Compute_Next_Time; + if Options.Flag_Stats then + Stats.End_Next_Time; + end if; + if Tn = Current_Time then + Error ("postponed process causes a delta cycle"); + end if; + elsif Status = Run_Failure then + return Run_Failure; + end if; + Current_Time := Tn; + return Run_Resumed; + end if; + end Simulation_Cycle; + + function Simulation return Integer + is + use Options; + Status : Integer; + begin + --Put_Line ("grt.processes:" & Process_Id'Image (Process_Table.Last) + -- & " process(es)"); + +-- if Disp_Sig_Types then +-- Grt.Disp.Disp_Signals_Type; +-- end if; + + Grt.Hooks.Call_Start_Hooks; + + Status := Run_Through_Longjump (Initialization_Phase'Access); + if Status /= Run_Resumed then + return -1; + end if; + + Current_Delta := 0; + Nbr_Delta_Cycles := 0; + Nbr_Cycles := 0; + if Trace_Signals then + Grt.Disp_Signals.Disp_All_Signals; + end if; + + if Current_Time /= 0 then + -- This is the end of a cycle. + Cycle_Time := 0; + Grt.Hooks.Call_Cycle_Hooks; + end if; + + loop + Cycle_Time := Current_Time; + if Disp_Time then + Grt.Disp.Disp_Now; + end if; + Status := Run_Through_Longjump (Simulation_Cycle'Access); + exit when Status = Run_Failure; + if Trace_Signals then + Grt.Disp_Signals.Disp_All_Signals; + end if; + + -- Statistics. + if Current_Delta = 0 then + Nbr_Cycles := Nbr_Cycles + 1; + else + Nbr_Delta_Cycles := Nbr_Delta_Cycles + 1; + end if; + + exit when Status = Run_Finished; + if Current_Delta = 0 then + Grt.Hooks.Call_Cycle_Hooks; + end if; + + if Current_Delta >= Stop_Delta then + Error ("simulation stopped by --stop-delta"); + exit; + end if; + if Current_Time > Stop_Time then + Info ("simulation stopped by --stop-time"); + exit; + end if; + end loop; + + Grt.Hooks.Call_Finish_Hooks; + + if Status = Run_Failure then + return -1; + else + return 0; + end if; + end Simulation; + +end Grt.Processes; |