------------------------------------------------------------------------------ -- -- -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- S Y S T E M . O S _ P R I M I T I V E S -- -- -- -- B o d y -- -- -- -- Copyright (C) 1998-2003 Free Software Foundation, Inc. -- -- -- -- GNARL is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNARL is distributed in the hope that it will be useful, but WITH- -- -- OUT 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 distributed with GNARL; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is the NT version of this package with Ada.Exceptions; with Interfaces.C; package body System.OS_Primitives is --------------------------- -- Win32 API Definitions -- --------------------------- -- These definitions are copied from System.OS_Interface because we do not -- want to depend on gnarl here. type DWORD is new Interfaces.C.unsigned_long; type LARGE_INTEGER is delta 1.0 range -2.0**63 .. 2.0**63 - 1.0; type BOOL is new Boolean; for BOOL'Size use Interfaces.C.unsigned_long'Size; procedure GetSystemTimeAsFileTime (lpFileTime : access Long_Long_Integer); pragma Import (Stdcall, GetSystemTimeAsFileTime, "GetSystemTimeAsFileTime"); function QueryPerformanceCounter (lpPerformanceCount : access LARGE_INTEGER) return BOOL; pragma Import (Stdcall, QueryPerformanceCounter, "QueryPerformanceCounter"); function QueryPerformanceFrequency (lpFrequency : access LARGE_INTEGER) return BOOL; pragma Import (Stdcall, QueryPerformanceFrequency, "QueryPerformanceFrequency"); procedure Sleep (dwMilliseconds : DWORD); pragma Import (Stdcall, Sleep, External_Name => "Sleep"); ---------------------------------------- -- Data for the high resolution clock -- ---------------------------------------- -- Declare some pointers to access multi-word data above. This is needed -- to workaround a limitation in the GNU/Linker auto-import feature used -- to build the GNAT runtime DLLs. In fact the Clock and Monotonic_Clock -- routines are inlined and they are using some multi-word variables. -- GNU/Linker will fail to auto-import those variables when building -- libgnarl.dll. The indirection level introduced here has no measurable -- penalties. -- -- Note that access variables below must not be declared as constant -- otherwise the compiler optimization will remove this indirect access. type DA is access all Duration; -- Use to have indirect access to multi-word variables type LIA is access all LARGE_INTEGER; -- Use to have indirect access to multi-word variables type LLIA is access all Long_Long_Integer; -- Use to have indirect access to multi-word variables Tick_Frequency : aliased LARGE_INTEGER; TFA : constant LIA := Tick_Frequency'Access; -- Holds frequency of high-performance counter used by Clock -- Windows NT uses a 1_193_182 Hz counter on PCs. Base_Ticks : aliased LARGE_INTEGER; BTA : constant LIA := Base_Ticks'Access; -- Holds the Tick count for the base time. Base_Monotonic_Ticks : aliased LARGE_INTEGER; BMTA : constant LIA := Base_Monotonic_Ticks'Access; -- Holds the Tick count for the base monotonic time Base_Clock : aliased Duration; BCA : constant DA := Base_Clock'Access; -- Holds the current clock for the standard clock's base time Base_Monotonic_Clock : aliased Duration; BMCA : constant DA := Base_Monotonic_Clock'Access; -- Holds the current clock for monotonic clock's base time Base_Time : aliased Long_Long_Integer; BTiA : constant LLIA := Base_Time'Access; -- Holds the base time used to check for system time change, used with -- the standard clock. procedure Get_Base_Time; -- Retrieve the base time and base ticks. These values will be used by -- clock to compute the current time by adding to it a fraction of the -- performance counter. This is for the implementation of a -- high-resolution clock. Note that this routine does not change the base -- monotonic values used by the monotonic clock. ----------- -- Clock -- ----------- -- This implementation of clock provides high resolution timer values -- using QueryPerformanceCounter. This call return a 64 bits values (based -- on the 8253 16 bits counter). This counter is updated every 1/1_193_182 -- times per seconds. The call to QueryPerformanceCounter takes 6 -- microsecs to complete. function Clock return Duration is Max_Shift : constant Duration := 2.0; Hundreds_Nano_In_Sec : constant Long_Long_Float := 1.0E7; Current_Ticks : aliased LARGE_INTEGER; Elap_Secs_Tick : Duration; Elap_Secs_Sys : Duration; Now : aliased Long_Long_Integer; begin if not QueryPerformanceCounter (Current_Ticks'Access) then return 0.0; end if; GetSystemTimeAsFileTime (Now'Access); Elap_Secs_Sys := Duration (Long_Long_Float (abs (Now - BTiA.all)) / Hundreds_Nano_In_Sec); Elap_Secs_Tick := Duration (Long_Long_Float (Current_Ticks - BTA.all) / Long_Long_Float (TFA.all)); -- If we have a shift of more than Max_Shift seconds we resynchonize the -- Clock. This is probably due to a manual Clock adjustment, an DST -- adjustment or an NTP synchronisation. And we want to adjust the -- time for this system (non-monotonic) clock. if abs (Elap_Secs_Sys - Elap_Secs_Tick) > Max_Shift then Get_Base_Time; Elap_Secs_Tick := Duration (Long_Long_Float (Current_Ticks - BTA.all) / Long_Long_Float (TFA.all)); end if; return BCA.all + Elap_Secs_Tick; end Clock; ------------------- -- Get_Base_Time -- ------------------- procedure Get_Base_Time is -- The resolution for GetSystemTime is 1 millisecond. -- The time to get both base times should take less than 1 millisecond. -- Therefore, the elapsed time reported by GetSystemTime between both -- actions should be null. Max_Elapsed : constant := 0; Test_Now : aliased Long_Long_Integer; epoch_1970 : constant := 16#19D_B1DE_D53E_8000#; -- win32 UTC epoch system_time_ns : constant := 100; -- 100 ns per tick Sec_Unit : constant := 10#1#E9; begin -- Here we must be sure that both of these calls are done in a short -- amount of time. Both are base time and should in theory be taken -- at the very same time. loop GetSystemTimeAsFileTime (Base_Time'Access); if not QueryPerformanceCounter (Base_Ticks'Access) then pragma Assert (Standard.False, "Could not query high performance counter in Clock"); null; end if; GetSystemTimeAsFileTime (Test_Now'Access); exit when Test_Now - Base_Time = Max_Elapsed; end loop; Base_Clock := Duration (Long_Long_Float ((Base_Time - epoch_1970) * system_time_ns) / Long_Long_Float (Sec_Unit)); end Get_Base_Time; --------------------- -- Monotonic_Clock -- --------------------- function Monotonic_Clock return Duration is Current_Ticks : aliased LARGE_INTEGER; Elap_Secs_Tick : Duration; begin if not QueryPerformanceCounter (Current_Ticks'Access) then return 0.0; end if; Elap_Secs_Tick := Duration (Long_Long_Float (Current_Ticks - BMTA.all) / Long_Long_Float (TFA.all)); return BMCA.all + Elap_Secs_Tick; end Monotonic_Clock; ----------------- -- Timed_Delay -- ----------------- procedure Timed_Delay (Time : Duration; Mode : Integer) is Rel_Time : Duration; Abs_Time : Duration; Check_Time : Duration := Monotonic_Clock; begin if Mode = Relative then Rel_Time := Time; Abs_Time := Time + Check_Time; else Rel_Time := Time - Check_Time; Abs_Time := Time; end if; if Rel_Time > 0.0 then loop Sleep (DWORD (Rel_Time * 1000.0)); Check_Time := Monotonic_Clock; exit when Abs_Time <= Check_Time; Rel_Time := Abs_Time - Check_Time; end loop; end if; end Timed_Delay; -- Package elaboration, get starting time as base begin if not QueryPerformanceFrequency (Tick_Frequency'Access) then Ada.Exceptions.Raise_Exception (Program_Error'Identity, "cannot get high performance counter frequency"); end if; Get_Base_Time; -- Keep base clock and ticks for the monotonic clock. These values should -- never be changed to ensure proper behavior of the monotonic clock. Base_Monotonic_Clock := Base_Clock; Base_Monotonic_Ticks := Base_Ticks; end System.OS_Primitives;