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jlechner |
------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- S Y S T E M . O S _ I N T E R F A C E --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1991-1994, Florida State University --
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-- Copyright (C) 1995-2005, AdaCore --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNARL; see file COPYING. If not, write --
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-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. --
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-- Extensive contributions were provided by Ada Core Technologies, Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This is the OS/2 version of this package
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pragma Polling (Off);
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-- Turn off polling, we do not want ATC polling to take place during
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-- tasking operations. It causes infinite loops and other problems.
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with Interfaces.OS2Lib.Errors;
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with Interfaces.OS2Lib.Synchronization;
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package body System.OS_Interface is
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use Interfaces;
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use Interfaces.OS2Lib;
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use Interfaces.OS2Lib.Synchronization;
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use Interfaces.OS2Lib.Errors;
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-----------
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-- Yield --
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-----------
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-- Give up the remainder of the time-slice and yield the processor
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-- to other threads of equal priority. Yield will return immediately
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-- without giving up the current time-slice when the only threads
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-- that are ready have a lower priority.
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-- ??? Just giving up the current time-slice seems not to be enough
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-- to get the thread to the end of the ready queue if OS/2 does use
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-- a queue at all. As a partial work-around, we give up two time-slices.
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-- This is the best we can do now, and at least is sufficient for passing
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-- the ACVC 2.0.1 Annex D tests.
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procedure Yield is
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begin
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Delay_For (0);
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Delay_For (0);
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end Yield;
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---------------
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-- Delay_For --
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---------------
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procedure Delay_For (Period : in Duration_In_Millisec) is
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Result : APIRET;
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begin
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pragma Assert (Period >= 0, "GNULLI---Delay_For: negative argument");
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-- ??? DosSleep is not the appropriate function for a delay in real
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-- time. It only gives up some number of scheduled time-slices.
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-- Use a timer instead or block for some semaphore with a time-out.
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Result := DosSleep (ULONG (Period));
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if Result = ERROR_TS_WAKEUP then
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-- Do appropriate processing for interrupted sleep
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-- Can we raise an exception here?
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null;
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end if;
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pragma Assert (Result = NO_ERROR, "GNULLI---Error in Delay_For");
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end Delay_For;
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-----------
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-- Clock --
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-----------
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function Clock return Duration is
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-- Implement conversion from tick count to Duration
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-- using fixed point arithmetic. The frequency of
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-- the Intel 8254 timer chip is 18.2 * 2**16 Hz.
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Tick_Duration : constant := 1.0 / (18.2 * 2**16);
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Tick_Count : aliased QWORD;
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begin
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-- Read nr of clock ticks since boot time
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Must_Not_Fail (DosTmrQueryTime (Tick_Count'Access));
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return Tick_Count * Tick_Duration;
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end Clock;
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end System.OS_Interface;
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