JPH01229346A - Program automatic recovery system - Google Patents

Abstract

PURPOSE:To continue the operation of a system without stopping the execution of a program if it is small-scale destruction by reading an abnormal instruction which has been erroneously destroyed from above an external storage and substituting only a read abnormal instruction so as to resume execution. CONSTITUTION:When the instruction on the main storage 1 is detected, a program reading means 24 reads the program in which the abnormal instruction is included from the external storage 3. An instruction comparison means 25 compares the instruction which has come to the abnormal instruction in a comparison part and the instruction corresponding to the address of the instruction. When they coincide, an interruption processing at the time of detecting the abnormal instruction is started. When they do not coincide, an instruction substitution means 26 is started. The means 26 substitutes the instruction which has come to the abnormal instruction on the main storage 1 for the corresponding instruction which has been read from the external storage, and starts an execution resume means 27. The means 27 returns the state of the system to a state immediately before the abnormal instruction is detected by a stage reset part, and starts an execution control means 21. The means 21 starts the execution again from the address of the command being the abnormal instruction and continues normal processing.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic program repair method for a computer system, and particularly relates to an automatic repair method for program corruption in main memory. The computer systems included are:
Comparatively small-scale systems are mentioned.

Since these systems do not have a memory ring protection function, the code area of the program can be easily destroyed due to a programming error or the like.

[Problem to be solved by the invention]

In the conventional computer system described above, when a program in main memory is accidentally destroyed by another program,
If an attempt is made to execute this destroyed part, it will become an invalid command, and the program execution will stop, waiting for operator intervention, or the system will go down, resulting in the entire system stopping.

[Means to solve the problem]

The automatic program repair method of the present invention is an automatic program repair method for a computer system that does not have a memory protection function for the main storage device. a program reading means for reading from the device; an instruction comparison means for comparing the instruction on the main storage device that is the illegal instruction with an instruction corresponding to the illegal instruction in the program read from the external storage device; and the instruction comparison device. instruction replacement means for replacing the instruction on the main storage device with an instruction read from the external storage device if the comparison result by the means does not match;
and an execution resuming means for restarting execution from the instruction replaced by the instruction replacing means.

〔Example〕

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

Referring to FIG. 1, one embodiment of the present invention has a main storage device 1.
, a central processing unit 2 , and an external storage device 3 . Further, the central processing unit 2 includes an execution control means 21, an instruction decoding means 22, an instruction execution means 23, a program reading means 24, an instruction comparison means 25, an instruction replacement means 26, and an execution resuming means 27. has been done.

Referring to FIG. 2, the program reading means 24 includes a program determining section 241, a program searching section 242,
Program loading section 243 and instruction comparison means starting section 24
It is composed of 4.

Referring to FIG. 3, the instruction comparing means 25 includes an illegal instruction corresponding instruction searching section 251, an instruction comparing section 252, an instruction replacing means starting section 253, and an illegal instruction interrupt processing starting section 254. Referring to FIG. 4, instruction replacement means 2
6 is a main memory changing unit 261 and an execution resuming means starting unit 26
It is composed of 2. Referring to FIG. 5, the execution resuming means 27 includes an instruction counter changing section 271 and a state B f!
1 part 272 and an execution control means starting part 273.

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

If the instruction on the main memory is normal, the execution control means 21 takes out one instruction from the main memory indicated by the instruction counter and activates the instruction decoding means 22.

The instruction decoding means 22 analyzes the instruction read from the main memory 1 and activates the instruction execution means 23. After executing various instructions, the instruction execution means 23 updates the instruction counter and starts the execution control means 21.

When an instruction on the main storage device is destroyed, the instruction decoding means 22 analyzes the read instruction and finds that it is an invalid instruction, and activates the program reading means 24.

The program reading unit 24 includes a program determining unit 24
1, the program searching unit 242 searches for the program from the external storage device, and the program loading unit 243
reads the program from the external storage device W3,
The instruction comparison means 25 is activated.

The instruction comparing means 25 searches the external storage device 3 for an instruction corresponding to the address of the instruction that becomes an illegal instruction on the read program by using the illegal instruction corresponding instruction search unit 251.
The instruction comparison unit 252 compares the invalid instruction with the instruction corresponding to the address of the instruction, and if they do not match, the instruction replacement unit activation unit 253 activates the instruction replacement unit 26. In the case of a match, since the program stored in the external storage device 3 has already become an illegal instruction, the illegal instruction interrupt processing activation section 254 activates the conventional interrupt processing when an illegal instruction is detected.

The instruction replacing unit 26 causes the main memory changing unit 261 to replace the illegal instruction in the main memory with the corresponding instruction read from the external memory, and causes the execution restarting unit activating unit 262 to activate the execution resuming unit 27. The execution resuming means 27 is
The instruction counter changing unit 271 replaces the instruction counter with the address of the illegal instruction, the state restoring unit 272 returns the state of the computer system to the state immediately before detecting the illegal instruction, and the execution control means starting unit 273 changes the execution control means. Start 21.

The execution control means 21 resumes execution from the address pointed to by the instruction counter, that is, the address where the invalid instruction is located, and normal processing continues.

〔Effect of the invention〕

As explained above, the present invention is capable of reading out an instruction that has become an illegal instruction due to a program error in the main storage device from an external storage device, replacing only the instruction that has become an illegal instruction, and restarting execution. This has the effect that, in the case of small-scale program destruction, the computer system can continue operating without stopping program execution.

[Brief explanation of the drawing]

1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the program reading means 24 shown in FIG. 1, and FIG. 3 is a block diagram showing the configuration of the instruction comparing means 25 shown in FIG. 1. 4 is a block diagram showing the instruction replacement means 2 of FIG. 1.
6 is a block diagram showing the configuration of the execution resuming means 27 of FIG. 1. FIG. 1... Main storage device, 2... Central processing unit, 3...
External storage device, 21... Execution control means, 22... Instruction decoding means, 23... Instruction execution means, 24...
Program reading means, 25...Instruction comparison means, 2
6... Instruction replacement means, 27... Execution resuming means.

Claims (1)

[Claims] In a program automatic correction method for a computer system that does not have a memory protection function for a main storage device, an instruction decoding means generates an interrupt when an illegal instruction is detected, a program reading means reads out a program including the illegal instruction from an external storage device, and the program reading means reads a program including the illegal instruction from an external storage device; An instruction comparison means that compares an instruction on the main storage device that is an illegal instruction with an instruction corresponding to the illegal instruction in the program read from the external storage device, and if the comparison result by the instruction comparison means does not match, the instruction is determined to be invalid. An automated program comprising: instruction replacement means for replacing an instruction on a main storage device with an instruction read from the external storage device; and execution restart means for restarting execution from the instruction replaced by the instruction replacement means. Repair method.