-- --
-- S Y S T E M . O S _ P R I M I T I V E S --
-- --
--- B o d y --
+-- B o d y --
-- --
--- Copyright (C) 1998-2005 Free Software Foundation, Inc. --
+-- Copyright (C) 1998-2009, 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- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
+-- sion. GNAT 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, 51 Franklin Street, Fifth Floor, --
--- Boston, MA 02110-1301, USA. --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
--- 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. --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception, --
+-- version 3.1, as published by the Free Software Foundation. --
+-- --
+-- You should have received a copy of the GNU General Public License and --
+-- a copy of the GCC Runtime Library Exception along with this program; --
+-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
+-- <http://www.gnu.org/licenses/>. --
-- --
-- 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;
+with System.Win32.Ext;
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");
+ use System.Win32;
+ use System.Win32.Ext;
----------------------------------------
-- Data for the high resolution clock --
-- 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.
Base_Ticks : aliased LARGE_INTEGER;
BTA : constant LIA := Base_Ticks'Access;
- -- Holds the Tick count for the base time.
+ -- Holds the Tick count for the base time
Base_Monotonic_Ticks : aliased LARGE_INTEGER;
BMTA : constant LIA := Base_Monotonic_Ticks'Access;
Now : aliased Long_Long_Integer;
begin
- if not QueryPerformanceCounter (Current_Ticks'Access) then
+ if QueryPerformanceCounter (Current_Ticks'Access) = Win32.FALSE then
return 0.0;
end if;
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
+ -- If we have a shift of more than Max_Shift seconds we resynchronize
+ -- 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
-------------------
procedure Get_Base_Time is
- -- The resolution for GetSystemTime is 1 millisecond.
+
+ -- 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;
+ Max_Elapsed : constant LARGE_INTEGER :=
+ LARGE_INTEGER (Tick_Frequency / 100_000);
+ -- Look for a precision of 0.01 ms
+
+ Loc_Ticks, Ctrl_Ticks : aliased LARGE_INTEGER;
+ Loc_Time, Ctrl_Time : aliased Long_Long_Integer;
+ Elapsed : LARGE_INTEGER;
+ Current_Max : LARGE_INTEGER := LARGE_INTEGER'Last;
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);
+ -- The goal of the following loop is to synchronize the system time
+ -- with the Win32 performance counter by getting a base offset for both.
+ -- Using these offsets it is then possible to compute actual time using
+ -- a performance counter which has a better precision than the Win32
+ -- time API.
+
+ -- Try at most 10th times to reach the best synchronisation (below 1
+ -- millisecond) otherwise the runtime will use the best value reached
+ -- during the runs.
- if not QueryPerformanceCounter (Base_Ticks'Access) then
+ for K in 1 .. 10 loop
+ if QueryPerformanceCounter (Loc_Ticks'Access) = Win32.FALSE then
pragma Assert
(Standard.False,
"Could not query high performance counter in Clock");
null;
end if;
- GetSystemTimeAsFileTime (Test_Now'Access);
+ GetSystemTimeAsFileTime (Ctrl_Time'Access);
+
+ -- Scan for clock tick, will take upto 16ms/1ms depending on PC.
+ -- This cannot be an infinite loop or the system hardware is badly
+ -- dammaged.
+
+ loop
+ GetSystemTimeAsFileTime (Loc_Time'Access);
+
+ if QueryPerformanceCounter (Ctrl_Ticks'Access) = Win32.FALSE then
+ pragma Assert
+ (Standard.False,
+ "Could not query high performance counter in Clock");
+ null;
+ end if;
+
+ exit when Loc_Time /= Ctrl_Time;
+ Loc_Ticks := Ctrl_Ticks;
+ end loop;
+
+ -- Check elapsed Performance Counter between samples
+ -- to choose the best one.
+
+ Elapsed := Ctrl_Ticks - Loc_Ticks;
+
+ if Elapsed < Current_Max then
+ Base_Time := Loc_Time;
+ Base_Ticks := Loc_Ticks;
+ Current_Max := Elapsed;
- exit when Test_Now - Base_Time = Max_Elapsed;
+ -- Exit the loop when we have reached the expected precision
+
+ exit when Elapsed <= Max_Elapsed;
+ end if;
end loop;
Base_Clock := Duration
Current_Ticks : aliased LARGE_INTEGER;
Elap_Secs_Tick : Duration;
begin
- if not QueryPerformanceCounter (Current_Ticks'Access) then
+ if QueryPerformanceCounter (Current_Ticks'Access) = Win32.FALSE then
return 0.0;
+ else
+ Elap_Secs_Tick :=
+ Duration (Long_Long_Float (Current_Ticks - BMTA.all) /
+ Long_Long_Float (TFA.all));
+ return BMCA.all + Elap_Secs_Tick;
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;
-----------------
-----------------
procedure Timed_Delay (Time : Duration; Mode : Integer) is
+
+ function Mode_Clock return Duration;
+ pragma Inline (Mode_Clock);
+ -- Return the current clock value using either the monotonic clock or
+ -- standard clock depending on the Mode value.
+
+ ----------------
+ -- Mode_Clock --
+ ----------------
+
+ function Mode_Clock return Duration is
+ begin
+ case Mode is
+ when Absolute_RT =>
+ return Monotonic_Clock;
+ when others =>
+ return Clock;
+ end case;
+ end Mode_Clock;
+
+ -- Local Variables
+
+ Base_Time : constant Duration := Mode_Clock;
+ -- Base_Time is used to detect clock set backward, in this case we
+ -- cannot ensure the delay accuracy.
+
Rel_Time : Duration;
Abs_Time : Duration;
- Check_Time : Duration := Monotonic_Clock;
+ Check_Time : Duration := Base_Time;
+
+ -- Start of processing for Timed Delay
begin
if Mode = Relative then
if Rel_Time > 0.0 then
loop
Sleep (DWORD (Rel_Time * 1000.0));
- Check_Time := Monotonic_Clock;
+ Check_Time := Mode_Clock;
- exit when Abs_Time <= Check_Time;
+ exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
Rel_Time := Abs_Time - Check_Time;
end loop;
end if;
end Timed_Delay;
--- Package elaboration, get starting time as base
+ ----------------
+ -- Initialize --
+ ----------------
+
+ Initialized : Boolean := False;
+
+ procedure Initialize is
+ begin
+ if Initialized then
+ return;
+ end if;
+
+ Initialized := True;
+
+ -- Get starting time as base
+
+ if QueryPerformanceFrequency (Tick_Frequency'Access) = Win32.FALSE then
+ raise Program_Error with
+ "cannot get high performance counter frequency";
+ end if;
-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;
- 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.
- -- 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 Initialize;
- Base_Monotonic_Clock := Base_Clock;
- Base_Monotonic_Ticks := Base_Ticks;
end System.OS_Primitives;
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