JPH0497435A - Control system for exceptional treatment - Google Patents

Abstract

PURPOSE:To eliminate relation between modules and to easily generate an exceptional treatment routine(ETR) by making it possible execute the temporary switching of the ETR. CONSTITUTION:When an exception is executed in a self-task, the ETR started by an exception interruption mechanism 16 is set up as a routine inherent in the task, and when the ETR has already been set up, the old ETR is saved and a new ETR is newly reset by an ETR setting means 13. When the application range of the ETR set up by the means 13 is completed, the ETR is released and the saved old ETR is restored by an ETR releasing means 14. Consequently, the ETR can be temporarily switched, relation between modules can be eliminated and the ETR can easily be generated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an exception handling control method, and particularly to a control method for an exception handling routine that is started when an exception occurs in a task in a computer system. [Technology] Conventionally, only one exception handling routine could be set for each task, and even when multiple settings were made, the exception handling routine would be used after determining the exception within the one exception handling routine that was set. Each exception handling routine was dispatched.

[Problem to be solved by the invention]

In the conventional exception handling method described above, the processing of the exception handling routine must be created with consideration to all the processing to be executed by the task within the applicable scope of the exception handling routine.

Also, in the upper module, it was necessary to be aware that the exception handling routine was set in the lower module, and to reset the exception handling routine after returning from the lower module.

[Means to solve the problem]

The exception handling method of the present invention sets an exception handling routine that is activated by the exception interrupt generation mechanism when an exception occurs in a self-task as unique to that task, and when an exception handling routine has already been set. is an exception handling routine setting means for saving the old exception handling routine and resetting a new exception handling routine, and when the application range of the exception handling routine set by the exception handling routine setting means ends, the exception handling routine is and exception handling routine release means for releasing the routine and restoring the saved old exception handling routine.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of the present invention.

In FIG. 1, main routine 11 is subroutine 1.
2, and each routine sets its own exception handling routine. The main routine 11 activates the exception handling routine setting means 13 in order to set an exception handling routine to be activated when an exception occurs within the main routine.

The exception handling routine setting means 13 checks whether an exception handling routine has already been set. Since the exception handling routine has not been set, the exception handling routine setting means 13 stores the entry address of the exception handling routine designated by the main routine 11 and sets the exception handling routine to the main routine 11. Return control to. When the subroutine 12 is called from the main routine 11, it activates the exception handling routine setting means 13 to set an exception handling routine to be used in the subroutine 12. The exception handling routine setting means 13 checks whether an exception handling routine has been set.Since it has already been set in the main routine 11, the exception handling routine setting means 13 saves the entry address of the set exception handling routine, and then executes the exception handling specified by the subroutine 12. The entry address of the routine is stored and control is returned to the subroutine 12. The subroutine 12 activates the exception handling routine release means 14 to release the exception handling routine when the scope of application of the exception handling routine ends.

After releasing the currently set exception handling routine, the exception handling routine release means 14 checks whether the entry address of the exception handling routine has been saved by the exception handling routine setting means 13, and saves the exception handling routine entry address. has not been saved, the process returns to the main routine 11 as is.

Exception handling routine application range 15 When an exception occurs during processing, an exception interrupt mechanism 16 operates to check whether an exception handling routine has been set. In this case, since a corresponding exception handling routine has been set, control is passed to the exception handling routine.

FIG. 2 is a diagram showing the structure of a program using an exception handling routine in one embodiment of the present invention. In FIG. 2, main routine 21 calls subroutine 22, and subroutine 22 calls subroutine 23. Subroutine 23 further calls subroutine 24, and each subroutine returns to its respective caller.

FIGS. 3 to 5 are diagrams showing the transition of the relationship between control structures in relation to FIG. 2. The control structure 31 stores a pointer 32 to an exception handling routine entry address storage area (hereinafter referred to as an exception handling pointer) and a pointer 33 to a task 34 that uses the exception handling routine.

The exception handling pointer 32 points to the highest address of the exception handling routine entry address storage area 35 when no exception handling routine is set. The main routine 21 and subroutines 22 to 24 each have a corresponding exception handling routine set only within each routine.

FIG. 4 is a diagram showing the state after setting the exception handling routine 41 corresponding to the main routine 2.

When the main routine 21 is activated, it activates the exception handling routine setting means 13 in order to set the corresponding exception handling routine 41 within its own routine. The exception handling routine setting means 13 shifts the pointer 32 in the lower direction and stores the entry address of the exception handling routine 41 corresponding to the main routine 21 in the area 42 indicated by the pointer 32'. If an exception occurs during the processing of the main routine 21 at this point, the exception generating mechanism 16 transfers control to the exception handling routine 41 whose address is stored in the area 42 indicated by the pointer 32'.

FIG. 5 shows a subroutine 21 similar to the main routine 21.
・23 and 24 are called and the entry addresses of exception handling routines 5153 and 55 corresponding to each routine are set. If an exception occurs during the processing of the subroutine 24 at this point, the exception generating mechanism 16 transfers control to the exception handling routine 55 whose entry address is stored in the area 56 indicated by the pointer 32''.

When the application range of the exception handling routine of the subroutine 24 ends, the subroutine 24 activates the exception handling routine release means 14. The exception handling routine releasing means 14 checks whether the entry address of the exception handling routine is stored in the area indicated by the pointer 32'', and since the entry address of the exception handling routine 56 is currently stored, the same exception handling routine is executed. To release routine 56, pointer 32'' is shifted upward.

Similar to the subroutine 24, the subroutines 23 and 22 and the main routine 21 correspond to each other in an exception handling routine 5.
When 3, 51, and 41 are released, the state returns to the initial state shown in FIG.

At this point, if an exception occurs before the processing of the main routine 21 ends, the exception generation mechanism 17 determines that no exception handling routine has been set because the pointer 32 indicates the lowest address of the exception handling routine entry storage area. Make a decision and end the process.

〔Effect of the invention〕

As described above, the exception handling method of the present invention enables temporary switching of exception handling routines, eliminates the relationship between modules, and facilitates the creation of exception handling routines.

[Brief explanation of drawings]

Figure 1 is a diagram showing the overall configuration of the present invention, Figure 2 is a diagram showing the configuration of a program that uses an exception handling routine in one embodiment of the present invention, and Figures 3 to 5 are as shown in Figure 2. FIG. 4 is a diagram illustrating the transition of the relationship between control structures; 11...Main routine, 12...Subroutine,
13...Exception handling routine setting means, 14...Exception handling routine setting means, 15...Exception handling routine application range, 16...Exception interrupt generation mechanism, 21...
Main routine, 22-24...subroutine, 31
... Control structure, 32, 32', 32°'... Pointer to exception handling routine entry, 33... Task pointer, 34... Task, 35... Exception handling routine entry storage area, 41 ...Main routine 2
], 42... entry address of exception handling routine 41, 51... exception handling routine corresponding to subroutine 22, 52... entry address of exception handling routine 51, 53... subroutine Exception handling routine corresponding to 23, 54... Nitori address of exception handling routine 53, 55... Exception handling routine corresponding to subroutine 24, 56...
Entry address of exception handling routine 55.

Claims (1)

[Claims] In a computer system having an exception interrupt generation mechanism, an exception handling routine that is activated by the exception interrupt generation mechanism when an exception occurs in a self-task is set as unique to that task, and an exception handling routine is already set. If the exception handling routine is set by the exception handling routine setting means, the old exception handling routine is saved and a new exception handling routine is newly set. 1. An exception handling control method, comprising: exception handling routine release means for releasing the exception handling routine and restoring a saved old exception handling routine, and temporarily switching the exception handling routine.