Static information storage and retrieval – Floating gate – Particular connection
Reexamination Certificate
2000-10-20
2001-11-06
Dinh, Son T. (Department: 2824)
Static information storage and retrieval
Floating gate
Particular connection
C714S002000, C714S006130
Reexamination Certificate
active
06314024
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data processing apparatus, and, more particularly, to a data processing apparatus executing a program, which is formed by modifying an program having an error and stored in a read-only memory.
2. Description of the Related Art
A basic control program for controlling a data processing apparatus is written in a ROM (Read-Only Memory) installed in the apparatus. After the ROM is installed in the apparatus, patching (correction) of data written in the ROM can not be realized.
When to correct the control program, the ROM itself needs to be exchanged for another ROM. However, exchanging the ROM for another ROM requires extra time and is very time consuming.
Unexamined Japanese Patent Application KOKAI Publication Nos. H1-124041, H8- 305556, H4-259046 and H7-64784 disclose a technique for overcoming the above problems.
A data processing apparatus disclosed in the Unexamined Japanese Patent Application KOKAI Publication No. H1-124041 loads a program stored in a ROM into a RAM, corrects the program in the RAM based on patch data stored in a non-volatile memory, and executes the program. When there is not stored patch data in the non-volatile memory, this data processing apparatus loads the program into the RAM. In this structure, the program needs to be loaded into the RAM before executing the program, thus it is very time consuming. There is only little disclosure of this publication, i.e., there is no specific explanations of how the program is corrected and executed.
According to a technique disclosed in Unexamined Japanese Patent Application KOKAI Publication No. H8-305556, when transferring a program from a ROM into a RAM, correction data is loaded from a non-volatile memory instead of loading the program from the ROM into the RAM, if an address of target program to be read coincides with a registered address. A data processing apparatus disclosed in this publication stores a program in the RAM, even the program has no error, thus it is very time consuming before executing the program.
Unexamined Japanese Patent Application KOKAI Publication No. H4-259046 discloses a data processing apparatus. This apparatus copies a page having a bug within a program stored in a ROM, then corrects the page with the bug and executes the program. According to this technique, the program stored in the ROM is copied into a RAM in the unit of pages. Hence, a program for realizing one particular function may be divided into a plurality of pages. In this case, in order to realize one particular function, both the program stored in the ROM and the program stored in the RAM need to be executed, thus addresses of such programs are complicatedly controlled.
Unexamined Japanese Patent Application KOKAI Publication No. H7-64784 discloses a data processing apparatus. When executing a program stored in a mask ROM, a CPU included in this data processing apparatus skips a portion having a bug within the program, and executes a corrected program stored in a RAM. The data processing apparatus disclosed in this publication needs to refer to addresses of the program stored in different storage mediums one after the other, so that a portion having a bug within the program is not executed. This data processing apparatus needs to carry out a complicated process for controlling the addresses.
The entire disclosures of Unexamined Japanese Patent Application KOKAI Publication Nos. H1-124041, H8- 305556, H4-259046 and H7-64784 are incorporated herein by reference.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above facts. It is accordingly an object of the present invention to provide a data processing apparatus which can easily correct a program with a bug and execute the program, when the program stored in a read-only memory needs to be corrected.
Another object thereof is to provide a data processing apparatus which does not need to refer to both an address of a program stored in a read-only memory and an address of a copied program stored in a random access memory, in which the program stored in the read-only memory is copied and corrected.
Still another object thereof is to provide a data processing apparatus in which a random access memory storing a target program to be corrected, of programs stored in a read-only memory, has a small storage capacity.
In order to achieve the above objects, according to the first aspect of the present invention, there is provided a data processing apparatus comprising:
a read-only memory which stores a program composed of a plurality of modules each having a function;
a writable non-volatile memory storing a replacing module in which an deficiency included in one of the plurality of modules is corrected;
a random access memory which is readable and writable; and
a controller which transfers the replacing module from the non-volatile memory into the random access memory, executes the program written in the read-only memory, reads and executes the replacing module stored in the random access memory without reading and executing the module with the deficiency.
According to the above structure, the plurality of modules are included in the program, thus the correction or modification of the program can be performed in the unit of modules. Hence, in this structure, while correcting the bug included in the program, the correction of the program can be achieved.
Each of the non-volatile memory and the random access memory may include a RAM (Random Access Memory) wherein the replacing module may be written.
In order to achieve the above objects, according to the second aspect of the present invention, there is provided a data processing apparatus,
a read-only memory wherein a program to be executed is written;
a writable non-volatile memory which stores correction data for correcting a deficiency which is included in the program;
a random access memory which is readable and writable;
a controller which copies the program stored in the read-only memory into the random access memory, corrects the deficiency included in the copied program in the random access memory using the correction data stored in the non-volatile memory, reads and executes the program which has been corrected and stored in the random access memory, and
wherein the data processing apparatus executes the copied program while referring to an address thereof without referring to an address of the program stored in the read-only memory.
According to the above structure, the deficiency of the program can easily be corrected. Besides, the target program to be executed is copied in the random access memory. Hence, it is not necessary to refer to both of the address of the program stored in the ROM and the address of the program stored in the RAM, one after another. Therefore, the program can be executed while referring only one of the address of the program.
The read-only memory may include a mask ROM (read-only memory).
Each of the non-volatile memory and the random access memory may include a RAM, in one area of which correction data is stored and in other area of which the program to be executed is copied by the controller; and
the controller may correct the deficiency included in the copied program using the correction data stored in the one area of the random access memory.
In order to achieve the above objects, according to the third aspect of the present invention, there is provided a data processing apparatus comprising:
a read-only memory which stores a program composed of a plurality of modules each having a function;
a writable non-volatile memory which stores correction data for correcting a deficiency included in the program;
a ramdom access memory which is readable and writable; and
a controller which copies one of the plurality of module with the deficiency stored in the read-only memory into the random access memory, corrects the deficiency in the copied module using the correction data stored in the non-volatile memory, executes the program stored in the read-only memory, reads and executes
Dinh Son T.
NEC Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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