1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S --
9 -- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
11 -- GNARL is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNARL; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNARL was developed by the GNARL team at Florida State University. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
34 -- This is a NT (native) version of this package
36 -- This package contains all the GNULL primitives that interface directly
37 -- with the underlying OS.
40 -- Turn off polling, we do not want ATC polling to take place during
41 -- tasking operations. It causes infinite loops and other problems.
43 with System
.Tasking
.Debug
;
44 -- used for Known_Tasks
46 with System
.OS_Primitives
;
47 -- used for Delay_Modes
53 with Interfaces
.C
.Strings
;
56 with System
.Task_Info
;
57 -- used for Unspecified_Task_Info
59 with System
.Interrupt_Management
;
60 -- used for Initialize
62 with System
.Soft_Links
;
63 -- used for Abort_Defer/Undefer
65 -- We use System.Soft_Links instead of System.Tasking.Initialization
66 -- because the later is a higher level package that we shouldn't depend on.
67 -- For example when using the restricted run time, it is replaced by
68 -- System.Tasking.Restricted.Stages.
70 with Unchecked_Deallocation
;
72 package body System
.Task_Primitives
.Operations
is
74 package SSL
renames System
.Soft_Links
;
76 use System
.Tasking
.Debug
;
79 use Interfaces
.C
.Strings
;
80 use System
.OS_Interface
;
81 use System
.Parameters
;
82 use System
.OS_Primitives
;
84 pragma Link_With
("-Xlinker --stack=0x200000,0x1000");
85 -- Change the default stack size (2 MB) for tasking programs on Windows.
86 -- This allows about 1000 tasks running at the same time. Note that
87 -- we set the stack size for non tasking programs on System unit.
88 -- Also note that under Windows XP, we use a Windows XP extension to
89 -- specify the stack size on a per task basis, as done under other OSes.
95 Environment_Task_Id
: Task_Id
;
96 -- A variable to hold Task_Id for the environment task
98 Single_RTS_Lock
: aliased RTS_Lock
;
99 -- This is a lock to allow only one thread of control in the RTS at
100 -- a time; it is used to execute in mutual exclusion from all other tasks.
101 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
103 Time_Slice_Val
: Integer;
104 pragma Import
(C
, Time_Slice_Val
, "__gl_time_slice_val");
106 Dispatching_Policy
: Character;
107 pragma Import
(C
, Dispatching_Policy
, "__gl_task_dispatching_policy");
109 function Get_Policy
(Prio
: System
.Any_Priority
) return Character;
110 pragma Import
(C
, Get_Policy
, "__gnat_get_specific_dispatching");
111 -- Get priority specific dispatching policy
113 Foreign_Task_Elaborated
: aliased Boolean := True;
114 -- Used to identified fake tasks (i.e., non-Ada Threads)
116 ------------------------------------
117 -- The thread local storage index --
118 ------------------------------------
121 pragma Export
(Ada
, TlsIndex
);
122 -- To ensure that this variable won't be local to this package, since
123 -- in some cases, inlining forces this variable to be global anyway.
131 function Is_Valid_Task
return Boolean;
132 pragma Inline
(Is_Valid_Task
);
133 -- Does executing thread have a TCB?
135 procedure Set
(Self_Id
: Task_Id
);
137 -- Set the self id for the current task
141 package body Specific
is
143 function Is_Valid_Task
return Boolean is
145 return TlsGetValue
(TlsIndex
) /= System
.Null_Address
;
148 procedure Set
(Self_Id
: Task_Id
) is
151 Succeeded
:= TlsSetValue
(TlsIndex
, To_Address
(Self_Id
));
152 pragma Assert
(Succeeded
= True);
157 ---------------------------------
158 -- Support for foreign threads --
159 ---------------------------------
161 function Register_Foreign_Thread
(Thread
: Thread_Id
) return Task_Id
;
162 -- Allocate and Initialize a new ATCB for the current Thread
164 function Register_Foreign_Thread
165 (Thread
: Thread_Id
) return Task_Id
is separate;
167 ----------------------------------
168 -- Condition Variable Functions --
169 ----------------------------------
171 procedure Initialize_Cond
(Cond
: access Condition_Variable
);
172 -- Initialize given condition variable Cond
174 procedure Finalize_Cond
(Cond
: access Condition_Variable
);
175 -- Finalize given condition variable Cond
177 procedure Cond_Signal
(Cond
: access Condition_Variable
);
178 -- Signal condition variable Cond
181 (Cond
: access Condition_Variable
;
182 L
: access RTS_Lock
);
183 -- Wait on conditional variable Cond, using lock L
185 procedure Cond_Timed_Wait
186 (Cond
: access Condition_Variable
;
189 Timed_Out
: out Boolean;
190 Status
: out Integer);
191 -- Do timed wait on condition variable Cond using lock L. The duration
192 -- of the timed wait is given by Rel_Time. When the condition is
193 -- signalled, Timed_Out shows whether or not a time out occurred.
194 -- Status is only valid if Timed_Out is False, in which case it
195 -- shows whether Cond_Timed_Wait completed successfully.
197 ---------------------
198 -- Initialize_Cond --
199 ---------------------
201 procedure Initialize_Cond
(Cond
: access Condition_Variable
) is
205 hEvent
:= CreateEvent
(null, True, False, Null_Ptr
);
206 pragma Assert
(hEvent
/= 0);
207 Cond
.all := Condition_Variable
(hEvent
);
214 -- No such problem here, DosCloseEventSem has been derived.
215 -- What does such refer to in above comment???
217 procedure Finalize_Cond
(Cond
: access Condition_Variable
) is
220 Result
:= CloseHandle
(HANDLE
(Cond
.all));
221 pragma Assert
(Result
= True);
228 procedure Cond_Signal
(Cond
: access Condition_Variable
) is
231 Result
:= SetEvent
(HANDLE
(Cond
.all));
232 pragma Assert
(Result
= True);
239 -- Pre-assertion: Cond is posted
242 -- Post-assertion: Cond is posted
246 (Cond
: access Condition_Variable
;
253 -- Must reset Cond BEFORE L is unlocked
255 Result_Bool
:= ResetEvent
(HANDLE
(Cond
.all));
256 pragma Assert
(Result_Bool
= True);
259 -- No problem if we are interrupted here: if the condition is signaled,
260 -- WaitForSingleObject will simply not block
262 Result
:= WaitForSingleObject
(HANDLE
(Cond
.all), Wait_Infinite
);
263 pragma Assert
(Result
= 0);
268 ---------------------
269 -- Cond_Timed_Wait --
270 ---------------------
272 -- Pre-assertion: Cond is posted
275 -- Post-assertion: Cond is posted
278 procedure Cond_Timed_Wait
279 (Cond
: access Condition_Variable
;
282 Timed_Out
: out Boolean;
283 Status
: out Integer)
285 Time_Out_Max
: constant DWORD
:= 16#FFFF0000#
;
286 -- NT 4 cannot handle timeout values that are too large,
287 -- e.g. DWORD'Last - 1
294 -- Must reset Cond BEFORE L is unlocked
296 Result
:= ResetEvent
(HANDLE
(Cond
.all));
297 pragma Assert
(Result
= True);
300 -- No problem if we are interrupted here: if the condition is signaled,
301 -- WaitForSingleObject will simply not block
303 if Rel_Time
<= 0.0 then
308 if Rel_Time
>= Duration (Time_Out_Max
) / 1000 then
309 Time_Out
:= Time_Out_Max
;
311 Time_Out
:= DWORD
(Rel_Time
* 1000);
314 Wait_Result
:= WaitForSingleObject
(HANDLE
(Cond
.all), Time_Out
);
316 if Wait_Result
= WAIT_TIMEOUT
then
326 -- Ensure post-condition
329 Result
:= SetEvent
(HANDLE
(Cond
.all));
330 pragma Assert
(Result
= True);
333 Status
:= Integer (Wait_Result
);
340 -- The underlying thread system sets a guard page at the
341 -- bottom of a thread stack, so nothing is needed.
342 -- ??? Check the comment above
344 procedure Stack_Guard
(T
: ST
.Task_Id
; On
: Boolean) is
345 pragma Warnings
(Off
, T
);
346 pragma Warnings
(Off
, On
);
356 function Get_Thread_Id
(T
: ST
.Task_Id
) return OSI
.Thread_Id
is
358 return T
.Common
.LL
.Thread
;
365 function Self
return Task_Id
is
366 Self_Id
: constant Task_Id
:= To_Task_Id
(TlsGetValue
(TlsIndex
));
368 if Self_Id
= null then
369 return Register_Foreign_Thread
(GetCurrentThread
);
375 ---------------------
376 -- Initialize_Lock --
377 ---------------------
379 -- Note: mutexes and cond_variables needed per-task basis are
380 -- initialized in Intialize_TCB and the Storage_Error is handled.
381 -- Other mutexes (such as RTS_Lock, Memory_Lock...) used in
382 -- the RTS is initialized before any status change of RTS.
383 -- Therefore raising Storage_Error in the following routines
384 -- should be able to be handled safely.
386 procedure Initialize_Lock
387 (Prio
: System
.Any_Priority
;
391 InitializeCriticalSection
(L
.Mutex
'Access);
392 L
.Owner_Priority
:= 0;
396 procedure Initialize_Lock
(L
: access RTS_Lock
; Level
: Lock_Level
) is
397 pragma Unreferenced
(Level
);
399 InitializeCriticalSection
(CRITICAL_SECTION
(L
.all)'Unrestricted_Access);
406 procedure Finalize_Lock
(L
: access Lock
) is
408 DeleteCriticalSection
(L
.Mutex
'Access);
411 procedure Finalize_Lock
(L
: access RTS_Lock
) is
413 DeleteCriticalSection
(CRITICAL_SECTION
(L
.all)'Unrestricted_Access);
420 procedure Write_Lock
(L
: access Lock
; Ceiling_Violation
: out Boolean) is
422 L
.Owner_Priority
:= Get_Priority
(Self
);
424 if L
.Priority
< L
.Owner_Priority
then
425 Ceiling_Violation
:= True;
429 EnterCriticalSection
(L
.Mutex
'Access);
431 Ceiling_Violation
:= False;
435 (L
: access RTS_Lock
;
436 Global_Lock
: Boolean := False)
439 if not Single_Lock
or else Global_Lock
then
440 EnterCriticalSection
(CRITICAL_SECTION
(L
.all)'Unrestricted_Access);
444 procedure Write_Lock
(T
: Task_Id
) is
446 if not Single_Lock
then
448 (CRITICAL_SECTION
(T
.Common
.LL
.L
)'Unrestricted_Access);
456 procedure Read_Lock
(L
: access Lock
; Ceiling_Violation
: out Boolean) is
458 Write_Lock
(L
, Ceiling_Violation
);
465 procedure Unlock
(L
: access Lock
) is
467 LeaveCriticalSection
(L
.Mutex
'Access);
470 procedure Unlock
(L
: access RTS_Lock
; Global_Lock
: Boolean := False) is
472 if not Single_Lock
or else Global_Lock
then
473 LeaveCriticalSection
(CRITICAL_SECTION
(L
.all)'Unrestricted_Access);
477 procedure Unlock
(T
: Task_Id
) is
479 if not Single_Lock
then
481 (CRITICAL_SECTION
(T
.Common
.LL
.L
)'Unrestricted_Access);
491 Reason
: System
.Tasking
.Task_States
)
493 pragma Unreferenced
(Reason
);
496 pragma Assert
(Self_ID
= Self
);
499 Cond_Wait
(Self_ID
.Common
.LL
.CV
'Access, Single_RTS_Lock
'Access);
501 Cond_Wait
(Self_ID
.Common
.LL
.CV
'Access, Self_ID
.Common
.LL
.L
'Access);
504 if Self_ID
.Deferral_Level
= 0
505 and then Self_ID
.Pending_ATC_Level
< Self_ID
.ATC_Nesting_Level
508 raise Standard
'Abort_Signal;
516 -- This is for use within the run-time system, so abort is
517 -- assumed to be already deferred, and the caller should be
518 -- holding its own ATCB lock.
520 procedure Timed_Sleep
523 Mode
: ST
.Delay_Modes
;
524 Reason
: System
.Tasking
.Task_States
;
525 Timedout
: out Boolean;
526 Yielded
: out Boolean)
528 pragma Unreferenced
(Reason
);
529 Check_Time
: Duration := Monotonic_Clock
;
534 Local_Timedout
: Boolean;
540 if Mode
= Relative
then
542 Abs_Time
:= Duration'Min (Time
, Max_Sensible_Delay
) + Check_Time
;
544 Rel_Time
:= Time
- Check_Time
;
548 if Rel_Time
> 0.0 then
550 exit when Self_ID
.Pending_ATC_Level
< Self_ID
.ATC_Nesting_Level
551 or else Self_ID
.Pending_Priority_Change
;
554 Cond_Timed_Wait
(Self_ID
.Common
.LL
.CV
'Access,
555 Single_RTS_Lock
'Access, Rel_Time
, Local_Timedout
, Result
);
557 Cond_Timed_Wait
(Self_ID
.Common
.LL
.CV
'Access,
558 Self_ID
.Common
.LL
.L
'Access, Rel_Time
, Local_Timedout
, Result
);
561 Check_Time
:= Monotonic_Clock
;
562 exit when Abs_Time
<= Check_Time
;
564 if not Local_Timedout
then
566 -- Somebody may have called Wakeup for us
572 Rel_Time
:= Abs_Time
- Check_Time
;
581 procedure Timed_Delay
584 Mode
: ST
.Delay_Modes
)
586 Check_Time
: Duration := Monotonic_Clock
;
592 pragma Warnings
(Off
, Integer);
599 Write_Lock
(Self_ID
);
601 if Mode
= Relative
then
603 Abs_Time
:= Time
+ Check_Time
;
605 Rel_Time
:= Time
- Check_Time
;
609 if Rel_Time
> 0.0 then
610 Self_ID
.Common
.State
:= Delay_Sleep
;
613 if Self_ID
.Pending_Priority_Change
then
614 Self_ID
.Pending_Priority_Change
:= False;
615 Self_ID
.Common
.Base_Priority
:= Self_ID
.New_Base_Priority
;
616 Set_Priority
(Self_ID
, Self_ID
.Common
.Base_Priority
);
619 exit when Self_ID
.Pending_ATC_Level
< Self_ID
.ATC_Nesting_Level
;
622 Cond_Timed_Wait
(Self_ID
.Common
.LL
.CV
'Access,
623 Single_RTS_Lock
'Access,
624 Rel_Time
, Timedout
, Result
);
626 Cond_Timed_Wait
(Self_ID
.Common
.LL
.CV
'Access,
627 Self_ID
.Common
.LL
.L
'Access,
628 Rel_Time
, Timedout
, Result
);
631 Check_Time
:= Monotonic_Clock
;
632 exit when Abs_Time
<= Check_Time
;
634 Rel_Time
:= Abs_Time
- Check_Time
;
637 Self_ID
.Common
.State
:= Runnable
;
653 procedure Wakeup
(T
: Task_Id
; Reason
: System
.Tasking
.Task_States
) is
654 pragma Unreferenced
(Reason
);
656 Cond_Signal
(T
.Common
.LL
.CV
'Access);
663 procedure Yield
(Do_Yield
: Boolean := True) is
674 type Prio_Array_Type
is array (System
.Any_Priority
) of Integer;
675 pragma Atomic_Components
(Prio_Array_Type
);
677 Prio_Array
: Prio_Array_Type
;
678 -- Global array containing the id of the currently running task for
681 -- Note: we assume that we are on a single processor with run-til-blocked
684 procedure Set_Priority
686 Prio
: System
.Any_Priority
;
687 Loss_Of_Inheritance
: Boolean := False)
690 Array_Item
: Integer;
693 Res
:= SetThreadPriority
694 (T
.Common
.LL
.Thread
, Interfaces
.C
.int
(Underlying_Priorities
(Prio
)));
695 pragma Assert
(Res
= True);
697 if Dispatching_Policy
= 'F' or else Get_Policy
(Prio
) = 'F' then
699 -- Annex D requirement [RM D.2.2 par. 9]:
700 -- If the task drops its priority due to the loss of inherited
701 -- priority, it is added at the head of the ready queue for its
702 -- new active priority.
704 if Loss_Of_Inheritance
705 and then Prio
< T
.Common
.Current_Priority
707 Array_Item
:= Prio_Array
(T
.Common
.Base_Priority
) + 1;
708 Prio_Array
(T
.Common
.Base_Priority
) := Array_Item
;
711 -- Let some processes a chance to arrive
715 -- Then wait for our turn to proceed
717 exit when Array_Item
= Prio_Array
(T
.Common
.Base_Priority
)
718 or else Prio_Array
(T
.Common
.Base_Priority
) = 1;
721 Prio_Array
(T
.Common
.Base_Priority
) :=
722 Prio_Array
(T
.Common
.Base_Priority
) - 1;
726 T
.Common
.Current_Priority
:= Prio
;
733 function Get_Priority
(T
: Task_Id
) return System
.Any_Priority
is
735 return T
.Common
.Current_Priority
;
742 -- There were two paths were we needed to call Enter_Task :
743 -- 1) from System.Task_Primitives.Operations.Initialize
744 -- 2) from System.Tasking.Stages.Task_Wrapper
746 -- The thread initialisation has to be done only for the first case.
748 -- This is because the GetCurrentThread NT call does not return the real
749 -- thread handler but only a "pseudo" one. It is not possible to release
750 -- the thread handle and free the system ressources from this "pseudo"
751 -- handle. So we really want to keep the real thread handle set in
752 -- System.Task_Primitives.Operations.Create_Task during thread creation.
754 procedure Enter_Task
(Self_ID
: Task_Id
) is
755 procedure Init_Float
;
756 pragma Import
(C
, Init_Float
, "__gnat_init_float");
757 -- Properly initializes the FPU for x86 systems
760 Specific
.Set
(Self_ID
);
763 Self_ID
.Common
.LL
.Thread_Id
:= GetCurrentThreadId
;
767 for J
in Known_Tasks
'Range loop
768 if Known_Tasks
(J
) = null then
769 Known_Tasks
(J
) := Self_ID
;
770 Self_ID
.Known_Tasks_Index
:= J
;
782 function New_ATCB
(Entry_Num
: Task_Entry_Index
) return Task_Id
is
784 return new Ada_Task_Control_Block
(Entry_Num
);
791 function Is_Valid_Task
return Boolean renames Specific
.Is_Valid_Task
;
793 -----------------------------
794 -- Register_Foreign_Thread --
795 -----------------------------
797 function Register_Foreign_Thread
return Task_Id
is
799 if Is_Valid_Task
then
802 return Register_Foreign_Thread
(GetCurrentThread
);
804 end Register_Foreign_Thread
;
810 procedure Initialize_TCB
(Self_ID
: Task_Id
; Succeeded
: out Boolean) is
812 -- Initialize thread ID to 0, this is needed to detect threads that
813 -- are not yet activated.
815 Self_ID
.Common
.LL
.Thread
:= 0;
817 Initialize_Cond
(Self_ID
.Common
.LL
.CV
'Access);
819 if not Single_Lock
then
820 Initialize_Lock
(Self_ID
.Common
.LL
.L
'Access, ATCB_Level
);
830 procedure Create_Task
832 Wrapper
: System
.Address
;
833 Stack_Size
: System
.Parameters
.Size_Type
;
834 Priority
: System
.Any_Priority
;
835 Succeeded
: out Boolean)
837 Initial_Stack_Size
: constant := 1024;
838 -- We set the initial stack size to 1024. On Windows version prior to XP
839 -- there is no way to fix a task stack size. Only the initial stack size
840 -- can be set, the operating system will raise the task stack size if
843 function Is_Windows_XP
return Integer;
844 pragma Import
(C
, Is_Windows_XP
, "__gnat_is_windows_xp");
845 -- Returns 1 if running on Windows XP
848 TaskId
: aliased DWORD
;
849 pTaskParameter
: System
.OS_Interface
.PVOID
;
851 Entry_Point
: PTHREAD_START_ROUTINE
;
854 pTaskParameter
:= To_Address
(T
);
856 Entry_Point
:= To_PTHREAD_START_ROUTINE
(Wrapper
);
858 if Is_Windows_XP
= 1 then
859 hTask
:= CreateThread
864 DWORD
(Create_Suspended
) or
865 DWORD
(Stack_Size_Param_Is_A_Reservation
),
866 TaskId
'Unchecked_Access);
868 hTask
:= CreateThread
873 DWORD
(Create_Suspended
),
874 TaskId
'Unchecked_Access);
877 -- Step 1: Create the thread in blocked mode
883 -- Step 2: set its TCB
885 T
.Common
.LL
.Thread
:= hTask
;
887 -- Step 3: set its priority (child has inherited priority from parent)
889 Set_Priority
(T
, Priority
);
891 if Time_Slice_Val
= 0
892 or else Dispatching_Policy
= 'F'
893 or else Get_Policy
(Priority
) = 'F'
895 -- Here we need Annex D semantics so we disable the NT priority
896 -- boost. A priority boost is temporarily given by the system to a
897 -- thread when it is taken out of a wait state.
899 SetThreadPriorityBoost
(hTask
, DisablePriorityBoost
=> True);
902 -- Step 4: Now, start it for good:
904 Result
:= ResumeThread
(hTask
);
905 pragma Assert
(Result
= 1);
907 Succeeded
:= Result
= 1;
914 procedure Finalize_TCB
(T
: Task_Id
) is
915 Self_ID
: Task_Id
:= T
;
918 Is_Self
: constant Boolean := T
= Self
;
920 procedure Free
is new
921 Unchecked_Deallocation
(Ada_Task_Control_Block
, Task_Id
);
924 if not Single_Lock
then
925 Finalize_Lock
(T
.Common
.LL
.L
'Access);
928 Finalize_Cond
(T
.Common
.LL
.CV
'Access);
930 if T
.Known_Tasks_Index
/= -1 then
931 Known_Tasks
(T
.Known_Tasks_Index
) := null;
934 if Self_ID
.Common
.LL
.Thread
/= 0 then
936 -- This task has been activated. Wait for the thread to terminate
937 -- then close it. this is needed to release system ressources.
939 Result
:= WaitForSingleObject
(T
.Common
.LL
.Thread
, Wait_Infinite
);
940 pragma Assert
(Result
/= WAIT_FAILED
);
941 Succeeded
:= CloseHandle
(T
.Common
.LL
.Thread
);
942 pragma Assert
(Succeeded
= True);
956 procedure Exit_Task
is
965 procedure Abort_Task
(T
: Task_Id
) is
966 pragma Unreferenced
(T
);
971 ----------------------
972 -- Environment_Task --
973 ----------------------
975 function Environment_Task
return Task_Id
is
977 return Environment_Task_Id
;
978 end Environment_Task
;
984 procedure Lock_RTS
is
986 Write_Lock
(Single_RTS_Lock
'Access, Global_Lock
=> True);
993 procedure Unlock_RTS
is
995 Unlock
(Single_RTS_Lock
'Access, Global_Lock
=> True);
1002 procedure Initialize
(Environment_Task
: Task_Id
) is
1004 pragma Unreferenced
(Discard
);
1007 Environment_Task_Id
:= Environment_Task
;
1008 OS_Primitives
.Initialize
;
1009 Interrupt_Management
.Initialize
;
1011 if Time_Slice_Val
= 0 or else Dispatching_Policy
= 'F' then
1013 -- Here we need Annex D semantics, switch the current process to the
1014 -- High_Priority_Class.
1017 OS_Interface
.SetPriorityClass
1018 (GetCurrentProcess
, High_Priority_Class
);
1020 -- ??? In theory it should be possible to use the priority class
1021 -- Realtime_Priority_Class but we suspect a bug in the NT scheduler
1022 -- which prevents (in some obscure cases) a thread to get on top of
1023 -- the running queue by another thread of lower priority. For
1024 -- example cxd8002 ACATS test freeze.
1027 TlsIndex
:= TlsAlloc
;
1029 -- Initialize the lock used to synchronize chain of all ATCBs
1031 Initialize_Lock
(Single_RTS_Lock
'Access, RTS_Lock_Level
);
1033 Environment_Task
.Common
.LL
.Thread
:= GetCurrentThread
;
1034 Enter_Task
(Environment_Task
);
1037 ---------------------
1038 -- Monotonic_Clock --
1039 ---------------------
1041 function Monotonic_Clock
return Duration
1042 renames System
.OS_Primitives
.Monotonic_Clock
;
1048 function RT_Resolution
return Duration is
1050 return 0.000_001
; -- 1 micro-second
1057 procedure Initialize
(S
: in out Suspension_Object
) is
1059 -- Initialize internal state. It is always initialized to False (ARM
1065 -- Initialize internal mutex
1067 InitializeCriticalSection
(S
.L
'Access);
1069 -- Initialize internal condition variable
1071 S
.CV
:= CreateEvent
(null, True, False, Null_Ptr
);
1072 pragma Assert
(S
.CV
/= 0);
1079 procedure Finalize
(S
: in out Suspension_Object
) is
1082 -- Destroy internal mutex
1084 DeleteCriticalSection
(S
.L
'Access);
1086 -- Destroy internal condition variable
1088 Result
:= CloseHandle
(S
.CV
);
1089 pragma Assert
(Result
= True);
1096 function Current_State
(S
: Suspension_Object
) return Boolean is
1098 -- We do not want to use lock on this read operation. State is marked
1099 -- as Atomic so that we ensure that the value retrieved is correct.
1108 procedure Set_False
(S
: in out Suspension_Object
) is
1110 SSL
.Abort_Defer
.all;
1112 EnterCriticalSection
(S
.L
'Access);
1116 LeaveCriticalSection
(S
.L
'Access);
1118 SSL
.Abort_Undefer
.all;
1125 procedure Set_True
(S
: in out Suspension_Object
) is
1128 SSL
.Abort_Defer
.all;
1130 EnterCriticalSection
(S
.L
'Access);
1132 -- If there is already a task waiting on this suspension object then
1133 -- we resume it, leaving the state of the suspension object to False,
1134 -- as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
1135 -- the state to True.
1141 Result
:= SetEvent
(S
.CV
);
1142 pragma Assert
(Result
= True);
1147 LeaveCriticalSection
(S
.L
'Access);
1149 SSL
.Abort_Undefer
.all;
1152 ------------------------
1153 -- Suspend_Until_True --
1154 ------------------------
1156 procedure Suspend_Until_True
(S
: in out Suspension_Object
) is
1160 SSL
.Abort_Defer
.all;
1162 EnterCriticalSection
(S
.L
'Access);
1165 -- Program_Error must be raised upon calling Suspend_Until_True
1166 -- if another task is already waiting on that suspension object
1167 -- (ARM D.10 par. 10).
1169 LeaveCriticalSection
(S
.L
'Access);
1171 SSL
.Abort_Undefer
.all;
1173 raise Program_Error
;
1175 -- Suspend the task if the state is False. Otherwise, the task
1176 -- continues its execution, and the state of the suspension object
1177 -- is set to False (ARM D.10 par. 9).
1182 LeaveCriticalSection
(S
.L
'Access);
1184 SSL
.Abort_Undefer
.all;
1188 -- Must reset CV BEFORE L is unlocked
1190 Result_Bool
:= ResetEvent
(S
.CV
);
1191 pragma Assert
(Result_Bool
= True);
1193 LeaveCriticalSection
(S
.L
'Access);
1195 SSL
.Abort_Undefer
.all;
1197 Result
:= WaitForSingleObject
(S
.CV
, Wait_Infinite
);
1198 pragma Assert
(Result
= 0);
1201 end Suspend_Until_True
;
1207 -- Dummy versions. The only currently working versions is for solaris
1210 function Check_Exit
(Self_ID
: ST
.Task_Id
) return Boolean is
1211 pragma Unreferenced
(Self_ID
);
1216 --------------------
1217 -- Check_No_Locks --
1218 --------------------
1220 function Check_No_Locks
(Self_ID
: ST
.Task_Id
) return Boolean is
1221 pragma Unreferenced
(Self_ID
);
1230 function Suspend_Task
1232 Thread_Self
: Thread_Id
) return Boolean
1235 if T
.Common
.LL
.Thread
/= Thread_Self
then
1236 return SuspendThread
(T
.Common
.LL
.Thread
) = NO_ERROR
;
1246 function Resume_Task
1248 Thread_Self
: Thread_Id
) return Boolean
1251 if T
.Common
.LL
.Thread
/= Thread_Self
then
1252 return ResumeThread
(T
.Common
.LL
.Thread
) = NO_ERROR
;
1258 end System
.Task_Primitives
.Operations
;