-- C954001.A
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-- C954001.A
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--
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--
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-- Grant of Unlimited Rights
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-- Grant of Unlimited Rights
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--
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--
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-- Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
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-- Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
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-- F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained
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-- F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained
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-- unlimited rights in the software and documentation contained herein.
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-- unlimited rights in the software and documentation contained herein.
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-- Unlimited rights are defined in DFAR 252.227-7013(a)(19). By making
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-- Unlimited rights are defined in DFAR 252.227-7013(a)(19). By making
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-- this public release, the Government intends to confer upon all
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-- this public release, the Government intends to confer upon all
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-- recipients unlimited rights equal to those held by the Government.
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-- recipients unlimited rights equal to those held by the Government.
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-- These rights include rights to use, duplicate, release or disclose the
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-- These rights include rights to use, duplicate, release or disclose the
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-- released technical data and computer software in whole or in part, in
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-- released technical data and computer software in whole or in part, in
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-- any manner and for any purpose whatsoever, and to have or permit others
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-- any manner and for any purpose whatsoever, and to have or permit others
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-- to do so.
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-- to do so.
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--
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--
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-- DISCLAIMER
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-- DISCLAIMER
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--
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--
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-- ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
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-- ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
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-- DISCLOSED ARE AS IS. THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED
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-- DISCLOSED ARE AS IS. THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED
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-- WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
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-- WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
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-- SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE
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-- SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE
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-- OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
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-- OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
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-- PARTICULAR PURPOSE OF SAID MATERIAL.
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-- PARTICULAR PURPOSE OF SAID MATERIAL.
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--*
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--*
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--
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--
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-- OBJECTIVE:
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-- OBJECTIVE:
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-- Check that a requeue statement within an entry_body with parameters
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-- Check that a requeue statement within an entry_body with parameters
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-- may requeue the entry call to a protected entry with a subtype-
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-- may requeue the entry call to a protected entry with a subtype-
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-- conformant parameter profile. Check that, if the call is queued on the
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-- conformant parameter profile. Check that, if the call is queued on the
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-- new entry's queue, the original caller remains blocked after the
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-- new entry's queue, the original caller remains blocked after the
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-- requeue, but the entry_body containing the requeue is completed.
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-- requeue, but the entry_body containing the requeue is completed.
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--
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--
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-- TEST DESCRIPTION:
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-- TEST DESCRIPTION:
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-- Declare a protected object which simulates a disk device. Declare an
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-- Declare a protected object which simulates a disk device. Declare an
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-- entry that requeues the caller to a second entry if the disk head is
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-- entry that requeues the caller to a second entry if the disk head is
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-- not in the proper location, but first sets the second entry's barrier
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-- not in the proper location, but first sets the second entry's barrier
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-- to false. Declare a procedure which sets the second entry's barrier
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-- to false. Declare a procedure which sets the second entry's barrier
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-- to true.
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-- to true.
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--
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--
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-- Declare a task which calls the first entry such that the requeue is
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-- Declare a task which calls the first entry such that the requeue is
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-- called. This task should be queued on the second entry and remain
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-- called. This task should be queued on the second entry and remain
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-- blocked, and the first entry should be complete. Call the procedure
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-- blocked, and the first entry should be complete. Call the procedure
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-- which releases the second entry's queue. The second entry should
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-- which releases the second entry's queue. The second entry should
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-- complete, after which the task should complete.
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-- complete, after which the task should complete.
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--
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--
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--
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--
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-- CHANGE HISTORY:
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-- CHANGE HISTORY:
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-- 06 Dec 94 SAIC ACVC 2.0
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-- 06 Dec 94 SAIC ACVC 2.0
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--
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--
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--!
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--!
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package C954001_0 is -- Disk management abstraction.
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package C954001_0 is -- Disk management abstraction.
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-- Simulate a read-only disk device with a head that may be moved to
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-- Simulate a read-only disk device with a head that may be moved to
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-- different tracks. If a read request is issued for the current
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-- different tracks. If a read request is issued for the current
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-- track, the request can be satisfied immediately. Otherwise, the head
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-- track, the request can be satisfied immediately. Otherwise, the head
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-- must be moved to the correct track, during which time the calling task
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-- must be moved to the correct track, during which time the calling task
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-- is blocked. When the head reaches the correct track, the disk generates
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-- is blocked. When the head reaches the correct track, the disk generates
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-- an interrupt, after which the request can be satisfied, and the
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-- an interrupt, after which the request can be satisfied, and the
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-- calling task can proceed.
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-- calling task can proceed.
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Buffer_Size : constant := 100;
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Buffer_Size : constant := 100;
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type Disk_Buffer is new String (1 .. Buffer_Size);
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type Disk_Buffer is new String (1 .. Buffer_Size);
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type Disk_Track is new Natural;
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type Disk_Track is new Natural;
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type Disk_Address is record
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type Disk_Address is record
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Track : Disk_Track;
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Track : Disk_Track;
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-- Additional components.
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-- Additional components.
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end record;
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end record;
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Initial_Track : constant Disk_Track := 0;
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Initial_Track : constant Disk_Track := 0;
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New_Track : constant Disk_Track := 5;
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New_Track : constant Disk_Track := 5;
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--==============================================--
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--==============================================--
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protected Disk_Device is
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protected Disk_Device is
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entry Read (Where : Disk_Address; -- Read data from disk
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entry Read (Where : Disk_Address; -- Read data from disk
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Data : out Disk_Buffer); -- track.
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Data : out Disk_Buffer); -- track.
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procedure Disk_Interrupt; -- Handle interrupt
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procedure Disk_Interrupt; -- Handle interrupt
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-- from disk.
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-- from disk.
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function TC_Track return Disk_Track; -- Return current track.
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function TC_Track return Disk_Track; -- Return current track.
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function TC_Pending_Queued return Boolean; -- True when there is
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function TC_Pending_Queued return Boolean; -- True when there is
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-- an entry in queue
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-- an entry in queue
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private
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private
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entry Pending_Read (Where : Disk_Address; -- Wait for head to
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entry Pending_Read (Where : Disk_Address; -- Wait for head to
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Data : out Disk_Buffer); -- move then read data.
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Data : out Disk_Buffer); -- move then read data.
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Current_Track : Disk_Track := Initial_Track; -- Current disk track.
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Current_Track : Disk_Track := Initial_Track; -- Current disk track.
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Operation_Pending : Boolean := False; -- Vis. entry barrier.
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Operation_Pending : Boolean := False; -- Vis. entry barrier.
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Disk_Interrupted : Boolean := False; -- Priv. entry barrier.
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Disk_Interrupted : Boolean := False; -- Priv. entry barrier.
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end Disk_Device;
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end Disk_Device;
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end C954001_0;
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end C954001_0;
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--==================================================================--
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--==================================================================--
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package body C954001_0 is -- Disk management abstraction.
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package body C954001_0 is -- Disk management abstraction.
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protected body Disk_Device is
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protected body Disk_Device is
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entry Read (Where : Disk_Address; Data : out Disk_Buffer)
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entry Read (Where : Disk_Address; Data : out Disk_Buffer)
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when not Operation_Pending is
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when not Operation_Pending is
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begin
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begin
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if (Where.Track = Current_Track) then -- If the head is over the
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if (Where.Track = Current_Track) then -- If the head is over the
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-- Read data from disk... -- requested track, read
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-- Read data from disk... -- requested track, read
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null; -- the data.
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null; -- the data.
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else -- Otherwise, defer read
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else -- Otherwise, defer read
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Operation_Pending := True; -- while head is moved to
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Operation_Pending := True; -- while head is moved to
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-- correct track (signaled
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-- correct track (signaled
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-- -- -- by a disk interrupt).
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-- -- -- by a disk interrupt).
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-- Requeue is tested here --
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-- Requeue is tested here --
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-- --
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-- --
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requeue Pending_Read;
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requeue Pending_Read;
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end if;
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end if;
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end Read;
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end Read;
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procedure Disk_Interrupt is -- Called when the disk
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procedure Disk_Interrupt is -- Called when the disk
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begin -- interrupts, indicating
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begin -- interrupts, indicating
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Disk_Interrupted := True; -- that the head is over
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Disk_Interrupted := True; -- that the head is over
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end Disk_Interrupt; -- the correct track.
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end Disk_Interrupt; -- the correct track.
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function TC_Track return Disk_Track is -- Artifice required for
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function TC_Track return Disk_Track is -- Artifice required for
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begin -- testing purposes.
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begin -- testing purposes.
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return (Current_Track);
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return (Current_Track);
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end TC_Track;
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end TC_Track;
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entry Pending_Read (Where : Disk_Address; Data : out Disk_Buffer)
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entry Pending_Read (Where : Disk_Address; Data : out Disk_Buffer)
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when Disk_Interrupted is
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when Disk_Interrupted is
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begin
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begin
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Current_Track := Where.Track; -- Head is now over the
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Current_Track := Where.Track; -- Head is now over the
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-- Read data from disk... -- correct track; read
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-- Read data from disk... -- correct track; read
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Operation_Pending := False; -- the data.
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Operation_Pending := False; -- the data.
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Disk_Interrupted := False;
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Disk_Interrupted := False;
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end Pending_Read;
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end Pending_Read;
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function TC_Pending_Queued return Boolean is
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function TC_Pending_Queued return Boolean is
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begin
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begin
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-- Return true when there is something on the Pending_Read queue
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-- Return true when there is something on the Pending_Read queue
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return (Pending_Read'Count /=0);
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return (Pending_Read'Count /=0);
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end TC_Pending_Queued;
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end TC_Pending_Queued;
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end Disk_Device;
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end Disk_Device;
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end C954001_0;
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end C954001_0;
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--==================================================================--
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--==================================================================--
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with Report;
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with Report;
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with ImpDef;
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with ImpDef;
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with C954001_0; -- Disk management abstraction.
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with C954001_0; -- Disk management abstraction.
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use C954001_0;
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use C954001_0;
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procedure C954001 is
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procedure C954001 is
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task type Read_Task is -- an unusual (but legal) declaration
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task type Read_Task is -- an unusual (but legal) declaration
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end Read_Task;
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end Read_Task;
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--
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--
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--
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--
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task body Read_Task is
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task body Read_Task is
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Location : constant Disk_Address := (Track => New_Track);
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Location : constant Disk_Address := (Track => New_Track);
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Data : Disk_Buffer := (others => ' ');
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Data : Disk_Buffer := (others => ' ');
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begin
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begin
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Disk_Device.Read (Location, Data); -- Invoke requeue statement.
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Disk_Device.Read (Location, Data); -- Invoke requeue statement.
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exception
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exception
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when others =>
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when others =>
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Report.Failed ("Exception raised in task");
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Report.Failed ("Exception raised in task");
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end Read_Task;
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end Read_Task;
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--==============================================--
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--==============================================--
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begin -- Main program.
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begin -- Main program.
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Report.Test ("C954001", "Requeue from an entry within a P.O. " &
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Report.Test ("C954001", "Requeue from an entry within a P.O. " &
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"to a private entry within the same P.O.");
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"to a private entry within the same P.O.");
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declare
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declare
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IO_Request : Read_Task; -- Request a read from other
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IO_Request : Read_Task; -- Request a read from other
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-- than the current track.
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-- than the current track.
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-- IO_Request will be requeued
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-- IO_Request will be requeued
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-- from Read to Pending_Read.
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-- from Read to Pending_Read.
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begin
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begin
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-- To pass this test, the following must be true:
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-- To pass this test, the following must be true:
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--
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--
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-- (A) The Read entry call made by the task IO_Request must be
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-- (A) The Read entry call made by the task IO_Request must be
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-- completed by the requeue.
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-- completed by the requeue.
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-- (B) IO_Request must remain blocked following the requeue.
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-- (B) IO_Request must remain blocked following the requeue.
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-- (C) IO_Request must be queued on the Pending_Read entry queue.
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-- (C) IO_Request must be queued on the Pending_Read entry queue.
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-- (D) IO_Request must continue execution after the Pending_Read
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-- (D) IO_Request must continue execution after the Pending_Read
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-- entry completes.
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-- entry completes.
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--
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--
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-- First, verify (A): that the Read entry call is complete.
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-- First, verify (A): that the Read entry call is complete.
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--
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--
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-- Call a protected operation (Disk_Device.TC_Track). Since no two
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-- Call a protected operation (Disk_Device.TC_Track). Since no two
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-- protected actions may proceed concurrently unless both are protected
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-- protected actions may proceed concurrently unless both are protected
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-- function calls, a call to a protected operation at this point can
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-- function calls, a call to a protected operation at this point can
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-- proceed only if the Read entry call is already complete.
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-- proceed only if the Read entry call is already complete.
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--
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--
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-- Note that if Read is NOT complete, the test will likely hang here.
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-- Note that if Read is NOT complete, the test will likely hang here.
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--
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--
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-- Next, verify (B): that IO_Request remains blocked following the
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-- Next, verify (B): that IO_Request remains blocked following the
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-- requeue. Also verify that Pending_Read (the entry to which
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-- requeue. Also verify that Pending_Read (the entry to which
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-- IO_Request should have been queued) has not yet executed.
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-- IO_Request should have been queued) has not yet executed.
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-- Wait until the task had made the call and the requeue has been
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-- Wait until the task had made the call and the requeue has been
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-- effected.
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-- effected.
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while not Disk_Device.TC_Pending_Queued loop
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while not Disk_Device.TC_Pending_Queued loop
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delay ImpDef.Minimum_Task_Switch;
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delay ImpDef.Minimum_Task_Switch;
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end loop;
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end loop;
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if Disk_Device.TC_Track /= Initial_Track then
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if Disk_Device.TC_Track /= Initial_Track then
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Report.Failed ("Target entry of requeue executed prematurely");
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Report.Failed ("Target entry of requeue executed prematurely");
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elsif IO_Request'Terminated then
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elsif IO_Request'Terminated then
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Report.Failed ("Caller did not remain blocked after " &
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Report.Failed ("Caller did not remain blocked after " &
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"the requeue or was never requeued");
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"the requeue or was never requeued");
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else
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else
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-- Verify (C): that IO_Request is queued on the
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-- Verify (C): that IO_Request is queued on the
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-- Pending_Read entry queue.
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-- Pending_Read entry queue.
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--
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--
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-- Set the barrier for Pending_Read to true. Check that the
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-- Set the barrier for Pending_Read to true. Check that the
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-- current track is updated and that IO_Request terminates.
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-- current track is updated and that IO_Request terminates.
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Disk_Device.Disk_Interrupt; -- Simulate a disk interrupt,
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Disk_Device.Disk_Interrupt; -- Simulate a disk interrupt,
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-- signaling that the head is
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-- signaling that the head is
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-- over the correct track.
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-- over the correct track.
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-- The Pending_Read entry body will complete before the next
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-- The Pending_Read entry body will complete before the next
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-- protected action is called (Disk_Device.TC_Track).
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-- protected action is called (Disk_Device.TC_Track).
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if Disk_Device.TC_Track /= New_Track then
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if Disk_Device.TC_Track /= New_Track then
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Report.Failed ("Caller was not requeued on target entry");
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Report.Failed ("Caller was not requeued on target entry");
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end if;
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end if;
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-- Finally, verify (D): that Read_Task continues after Pending_Read
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-- Finally, verify (D): that Read_Task continues after Pending_Read
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-- completes.
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-- completes.
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--
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--
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-- Note that the test will hang here if Read_Task does not continue
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-- Note that the test will hang here if Read_Task does not continue
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-- executing following the completion of the requeued entry call.
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-- executing following the completion of the requeued entry call.
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end if;
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end if;
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end; -- We will not exit the declare block until the task completes
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end; -- We will not exit the declare block until the task completes
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Report.Result;
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Report.Result;
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end C954001;
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end C954001;
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