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Diffstat (limited to 'gcc/ada/5wosprim.adb')
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diff --git a/gcc/ada/5wosprim.adb b/gcc/ada/5wosprim.adb new file mode 100644 index 00000000000..a86325a8b69 --- /dev/null +++ b/gcc/ada/5wosprim.adb @@ -0,0 +1,228 @@ +------------------------------------------------------------------------------ +-- -- +-- 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 -- +-- -- +-- $Revision: 1.13 $ -- +-- -- +-- Copyright (C) 1998-2001 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. It is -- +-- now maintained by Ada Core Technologies Inc. in cooperation with Florida -- +-- State University (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +-- This is the NT version of this package + +with Ada.Exceptions; +with System.OS_Interface; + +package body System.OS_Primitives is + + use System.OS_Interface; + + --------------------------------------- + -- Data for the high resolution clock -- + --------------------------------------- + + Tick_Frequency : aliased LARGE_INTEGER; + -- 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; + -- Holds the Tick count for the base time. + + Base_Clock : Duration; + -- Holds the current clock for the standard clock's base time + + Base_Monotonic_Clock : Duration; + -- Holds the current clock for monotonic clock's base time + + Base_Time : aliased Long_Long_Integer; + -- Holds the base time used to check for system time change, used with + -- the standard clock. + + procedure Get_Base_Time; + -- Retrieve the base time. This base time 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. + + ----------- + -- 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 := 1E7; + 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 (abs (Now - Base_Time) / Hundreds_Nano_In_Sec); + + Elap_Secs_Tick := + Duration (Long_Long_Float (Current_Ticks - Base_Ticks) / + Long_Long_Float (Tick_Frequency)); + + -- 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 NNTP 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 - Base_Ticks) / + Long_Long_Float (Tick_Frequency)); + end if; + + return Base_Clock + Elap_Secs_Tick; + end Clock; + + ------------------- + -- Get_Base_Time -- + ------------------- + + procedure Get_Base_Time is + use System.OS_Interface; + + -- 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 - Base_Ticks) / + Long_Long_Float (Tick_Frequency)); + + return Base_Monotonic_Clock + 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; + + Base_Monotonic_Clock := Base_Clock; +end System.OS_Primitives; |