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s-osprim-mingw.adb (Get_Base_Time): Make sure that the base time is taken at a clock tick boundary.

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2009-12-01  Pascal Obry  <obry@adacore.com>

	* s-osprim-mingw.adb (Get_Base_Time): Make sure that the base time is
	taken at a clock tick boundary.

From-SVN: r154871
This commit is contained in:
Pascal Obry 2009-12-01 10:29:57 +00:00 committed by Arnaud Charlet
parent 4f08579c5e
commit b27dc43154
2 changed files with 36 additions and 12 deletions
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5
gcc/ada/ChangeLog
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@ -1,3 +1,8 @@
2009-12-01 Pascal Obry <obry@adacore.com>
* s-osprim-mingw.adb (Get_Base_Time): Make sure that the base time is
taken at a clock tick boundary.
2009-12-01 Thomas Quinot <quinot@adacore.com>
* g-sechas.ads (GNAT.Secure_Hashes.H."=" on Context): Make abstract.

43
gcc/ada/s-osprim-mingw.adb
View File

@ -156,15 +156,17 @@ package body System.OS_Primitives is
-- Therefore, the elapsed time reported by GetSystemTime between both
-- actions should be null.
Max_Elapsed : constant := 0;
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;
Test_Now : aliased Long_Long_Integer;
Loc_Ticks : aliased LARGE_INTEGER;
Loc_Time : aliased Long_Long_Integer;
Elapsed : Long_Long_Integer;
Current_Max : Long_Long_Integer := Long_Long_Integer'Last;
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
@ -182,8 +184,6 @@ package body System.OS_Primitives is
-- during the runs.
for K in 1 .. 10 loop
GetSystemTimeAsFileTime (Loc_Time'Access);
if QueryPerformanceCounter (Loc_Ticks'Access) = Win32.FALSE then
pragma Assert
(Standard.False,
@ -191,17 +191,36 @@ package body System.OS_Primitives is
null;
end if;
GetSystemTimeAsFileTime (Test_Now'Access);
GetSystemTimeAsFileTime (Ctrl_Time'Access);
Elapsed := Test_Now - Loc_Time;
-- 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 the loop when we have reached the expected precision
exit when Elapsed <= Max_Elapsed;
end if;
exit when Elapsed = Max_Elapsed;
end loop;
Base_Clock := Duration