JPH0293730A - Information processor - Google Patents

Abstract

PURPOSE:To execute a prescribed program up to the end of the program without fail by providing a detecting means to detect whether over-flow is generated in a prescribed stack area or not and an allocating means to allocate the new stack area. CONSTITUTION:When the generation of the over-flow in a stack area 21 of a main memory 2 is detected by a stack over-flow detecting part 4 during the execution of the program, the detecting part 4 houses the value of a pointer, which shows a present control frame, to a partway progress keeping area 22. Next, the detecting part 4 houses a program counted value, which shows the position of an object code to be presently executed, to the area 22 and further delivers control to a stack over-flow processing routine 12. The routine 12 investigates whether there is an extending area in the area 21 or not. When there is an idle storing area, a new stack area for one page is allocated to the idle area and the area 21 is extended for one page. When there is no idle area, the stack area for one page is allocated to a usable area 23. Thus, the prescribed program, especially, a large scale program can be executed up to the end.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information processing device that executes a predetermined program.

[Conventional technology]

As is well known, in conventional information processing devices, during execution of a predetermined program, each time a procedure (or function) is called, data related to the procedure (or function), such as data indicating a calculation result, etc. It is common to set a stack area in advance to store the .

[Problem to be solved by the invention]

By the way, in the conventional information processing device described above, if the preset stack area overflows during program execution, it is impossible to continue the program execution.
Execution of the program will be interrupted.

In particular, when executing a large-scale program, there is a high probability that the stack area will overflow, so there is a drawback that the execution of the program is likely to be interrupted.

SUMMARY OF THE INVENTION An object of the present invention is to provide an information processing apparatus that can eliminate the above-mentioned drawbacks and reliably execute a predetermined program to the end.

[Means to solve the problem]

In the present invention, a storage means for storing data in a storage area including a predetermined stack area, a detection means for detecting whether an overflow occurs in the predetermined stack area, and a detecting means for detecting whether or not an overflow occurs in the predetermined stack area; and allocation means for allocating a new stack area related to the predetermined stack area to an empty storage area in the storage means.

[Effect]

In the information processing apparatus of the present invention, when a predetermined stack area set in advance overflows during execution of a program, an empty storage area in the storage means, for example, an empty storage area contiguous to the predetermined stack area, is used. If there is, a new stack area is allocated to the free storage area (in other words, the specified stack area is expanded), and conversely, if there is no continuous free storage area, a new stack area is allocated to the other free storage area in the storage means. allocate stack space. Data after the predetermined stack area overflows is stored in a new allocated stack area.

〔Example〕

Embodiments of an information processing apparatus according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of an information processing apparatus according to the present invention. In the figure, the information processing device includes a memory section 1, a main memory 2, a program execution control section 3,
It has a stack overflow detection section 4. The memory unit 1 has a real memory consisting of RAM and a disk device, and this disk device stores a predetermined program 1.
1. Stack overflow processing routine 12 and programs based on flowchart 1 showing the operation of stack overflow processing described later are stored, while the real memory stores predetermined programs 11 etc. read from the disk device. The main memory 2 that partially stores a predetermined stack area 21, a program execution progress holding area (hereinafter referred to as an interim progress holding area) 22 that holds the progress of the execution of the program 11, and a Available area 2 indicating a part of the storage area of the free storage W4 area
3. The program execution control section 3 controls the execution of a predetermined program 11, and the stack overflow detection section 4 detects whether an overflow occurs in the stack area 21.

Figure 2 shows the structure of the stack according to the present invention. In the figure, the stack is data in a format called a frame that is piled up on the stack when a function, which is a structural unit of a program, is called. A control frame 30 in which certain control information is stored, and the control frame 3
Intermediate result of calculation 31 placed on the stack following 0
, a register 32 that holds a pointer indicating the current control frame, an object code 33 of a function corresponding to the current control frame, and a program counter that indicates the position of the object code currently being executed within the object code 33. It is composed of a register 34 that holds an offset from the beginning of the object code 33, called the object code 33.

The control frame 30 stores a pointer 35 to the control frame 30a corresponding to the function that was executed immediately before, and a pointer 36 to the object code 33.

Next, the stack overflow processing operation of the information processing apparatus will be explained based on the flowchart of FIG. 3.

First, each time a function, which is a processing unit of a program, is called, a control frame 30 storing control information regarding that function is configured in the stack area 21, and following the control frame 30, the control frame 30 stores control information regarding that function. Intermediate results 31 in the execution of the function are stacked on the stack area 21 .

Here, before stacking the intermediate result 31 in the stack area 21, the stack overflow detection unit 4
Step 100) calculates the data amount of 1, compares the data amount with the free space of the stack area 21, and stacks the data of the intermediate result 31 in the free space of the stack area 21, thereby preventing the stack area 21 from overflowing. (Step ioi>) If there is an overflow, the stack overflow detection unit 4 stores the value of the pointer indicating the current control frame in the intermediate progress holding area 22 (Step 102), and Step 103: Store the value of the program counter indicating the position of the object code currently being executed in the holding area 22.
), further controls the stack overflow handling routine 1
Pass it to 2.

The stack overflow processing routine 12 is executed in the main memory 2.
In step 104), it is determined whether there is a continuous empty storage area in the stack area 21, that is, whether there is an expansion area of the stack area 21. If there is an empty storage area, the empty storage area is A new stack area corresponding to one page is allocated to the area, and the stack area 21 is expanded by one page (step 105).

On the other hand, if there is no continuous free storage area, the stutter overflow processing routine 12 allocates a new stack area for one page in the available area 23 in the main memory 2, and Based on the value of the pointer to the control frame 30 stored in the intermediate progress holding area 22, the content of the control frame 30 and the stack area 21 are overflowed. Intermediate results 31 that are not stored in the stack area 21 are stored in the available area 23.
(step 107).

Here, the contents of the control frame 30 that are moved to the new stack area allocated to the available area 23 include the function executed immediately before the function corresponding to the intermediate result 31 that is not stored in the stack area 21. Corresponding control frame 30
A pointer 35 to a and a pointer 36 to the object code 33 are included.

Note that in the free storage area contiguous to the stack area 21,
If a new stack area for one page is allocated,
The contents of the control frame 30 are not moved, and only the intermediate results 31 that are not stored in the stack area 21 are stored in the new stack area.

By the way, the stack overflow processing routine 12 that has completed the above input step 105 stores the value of the pointer to the control frame 30 stored in the intermediate progress storage area 22 as
The stack overflow processing routine 12 that has completed step 107 returns the pointer to the control frame 30 that has been moved to the new stack area (step 108). The value is stored in a register 32 that holds a pointer to the current control frame (step 108).

After the value of the pointer to the control frame 30 is stored in the register 32, the stack overflow handling routine 12
returns the value of the program counter stored in the intermediate progress holding area 22 to the register 34 (step 1
09).

Then, by executing the control frame and object code corresponding to the values of the pointers held in the registers 32 and 34, execution of the program can be continued.

Note that if there is no overflow in step 101, there is still a free storage area in the stack area 21, and the intermediate result 31 is 8! following the control frame 30 stored in the stack area 21. It will stop.

Furthermore, if there is no overflow in step 101, or if step 108 is completed, the stack overflow process ends.

In the above embodiment, when the stack area overflows, a new stack area of one page is allocated, but the present invention is not limited to this, and a new stack area is allocated. Any storage area unit may be used.

According to the above embodiment, even if the stack overflows during execution of a program, it is possible to continue processing without interrupting the execution of the program,
It becomes possible to execute a large-scale program to the end.

〔Effect of the invention〕

As explained above, according to the present invention, when a predetermined stack area overflows during program execution, a new stack area is allocated to an empty storage area in the storage means, and the overflow is stored in the new stack area. Since the data after the execution is stored, the interruption of program execution due to overflow of the predetermined stack area is extremely rare, and the program execution process can be performed reliably, especially when executing a large-scale program. There is an advantage.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an information processing device according to the present invention, FIG. 2 is a block diagram showing an example of the structure of a stack according to the present invention, and FIG. 3 is a block diagram showing an example of the stack structure of the information processing device. It is a flowchart showing the operation. DESCRIPTION OF SYMBOLS 1...Memory unit, 2...Main memory, 3...Program execution control unit, 4...Stack overflow detection unit, 11...Program, 12...Stack overflow processing routine, 21...・Stack area, 22...
・Program execution progress storage area, 23... Available area, 30... Control frame, 31... Intermediate calculation result, 32. 34... Register, 33... Object code, 35. 36. ...pointer.

Claims (1)

[Scope of Claims] An information processing apparatus having a storage means for storing data in a storage area including a predetermined stack area, further comprising: a detection means for detecting whether an overflow occurs in the predetermined stack area; and the overflow. 2. An information processing apparatus comprising: allocation means for allocating a new stack area related to the predetermined stack area to an empty storage area in the storage means when this occurs.