JPH0962502A - Information processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information processor with which an additionally unwritable program stored in a mask ROM or the like and integrated in an integral system can be exchanged. SOLUTION: This information processor in which a program is stored in a read only memory and the function of program is executed by an executing means by reading out this program, is provided with a first storage means for storing the calling address of program made into a table, changing means for changing the calling address of the program, and second storage means for storing the program corresponding to the calling address changed by the changing means. Thus, when performing the defective correction or function addition of program, a program to be exchanged relating to the program to be a correcting object can be exchanged without affecting the relevant program to be exchanged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus, and more particularly, to an apparatus for replacing a software program installed in advance in a small portable information processing apparatus.

[0002]

2. Description of the Related Art Conventionally, in the case where a program stored in a read-only memory is hindered or the function of the program is desired to be expanded, in order to replace the program of the information processing device, the read-in program is incorporated. I replaced all the dedicated memory.

Alternatively, instead of a read-only memory,
The program was stored in a rewritable memory.

[0004]

When a program is incorporated in the read-only memory, a device capable of freely mounting the memory is required to replace the memory. For this reason, (1) an increase in the mounting cost of the hardware memory replacement mechanism (2) an increase in the cost due to the re-creation of the mask ROM memory (3) a problem that the device cannot be downsized due to the hardware memory replacement mechanism Occurs.

If the memory itself is not a read-only memory but a rewritable memory, the mask ROM
Compared with the read-only memory represented by (1), there is a problem that (1) the cost is increased due to the use of the flash memory or SRAM, and (2) the power consumption is increased due to the flash memory or SRAM.

An object of the present invention is to provide an information processing apparatus which solves the above problems with a simple and inexpensive structure.

[0007]

In order to achieve the above object, the present invention has an information processing apparatus in which a program is stored in a read-only memory, and the execution unit reads the program to execute the function of the program. In a first storage means for storing a calling address of the program tabulated, a changing means for changing the calling address of the program, and a program for storing a program corresponding to the calling address changed by the changing means. When the calling address is changed by the changing unit, the function of the program stored in the second storing unit is not the program stored in the read-only memory. Provided is an information processing device characterized by being executed by an executing means.

[0008]

With the above-mentioned structure, the mask RO is used in the present invention.
When a software program is stored in an additional write-disabled device (hereinafter referred to as an embedded system) stored in M or the like, the change of the additional write-disabled program (program to be programmed) is performed separately without affecting other programs. Since the program can be replaced with the above program, the program to be corrected can be replaced without affecting the program related to the program to be corrected when the defect of the program is corrected or the function is added.

Further, since the program to be executed can be replaced with a program having another function for the software system integrated in the embedded system device, the embedded system having several functions can be executed in one book. You can make multiple types with the device.

Further, since the program to be executed can be executed while being replaced by the program having some other function in the embedded system device at any time, a plurality of functions can be executed at any time in one device.

As a result, even if the software program is incorporated into the read-only memory in advance in the information processing apparatus, the program can be replaced with another arbitrary program at a relatively low cost.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an information processing apparatus according to the present invention, in which 1 is a microprocessor, 2 is a read-only memory (mask ROM) containing a program integrated with the microprocessor 1, and 3 is writable. Memory (DRA
M), 4 and 5 are a flash EEPROM and an SRAM containing programs to be replaced. The storage device containing the program is not only directly connected to this device, but also by using the communication function, the Modem
It is also possible to record in another device (server host or the like) 6 via the Unit 7. In addition, there is an ASIC 8 that controls the microprocessor and peripherals.

In order to exchange programs, there is one large unit which constitutes a program group called a task / process and the minimum unit which constitutes a program called a function / subroutine. Here, the programs are exchanged for a minimum unit that constitutes a program such as a function / subroutine. This reduces the capacity of the rewritable memory occupied by the program to be replaced.

To replace the programs, an address table showing the pointers of the functions required to jump to the program to be replaced is created as shown in FIG. This is called a stub table.

High-level language (C language is used in this embodiment)
Is a set of functions. By registering the actual address when calling this function and the actual address of the function in the stub table, the address of the actual function can be made different. For this reason, all function calls should be made using function pointers.

In order to embed the stub in the function call portion, it is necessary to modify the existing program and reduce the modification amount as much as possible. Therefore, in order to make the case of embedding a stub and the case of not embedding it as similar as possible, macro expansion by a C preprocessor is used. Macro is M
When AKE_STUB is defined, the stub is embedded in the function call. That is, when MAKE_STUB is defined and compiled, a function declared / defined using a macro is called via the stub table.

There are three macro definitions as follows.

(1) #ifdef MAKE_STUB #define DEC (x) x #### _ DEF #else #define DEC (x) x #endif (2) #ifdef MAKE_STUB #define PROX # * define (*) PROTO (x) x #endif (3) #ifdef MAKE_STUB #define PROTOTYPE extern #else #define PROTOTYPE #endif All programs with embedded stubs are called when the address of the program called by that program is resolved (linkage) All can be solved by knowing the address of the program pointer.

The function to be called can be replaced with another program by loading the program from the storage device into a rewritable memory at any time and rewriting it to the address loaded in the stub table.

A replacement program is loaded in the stub table by the following method.

(1) Storage devices 1 and 2 at the start of the system
The program is loaded into the fixed address of the rewritable area by the system from the storage device at (replacement program A).

(2) At an arbitrary time point, a fixed address in the rewritable area is loaded from the storage device 3 using a communication device or the like (replacement program B).

(3) The program written in the storage device 2 or 3 is directly used (replacement program C).

Further, the replacement program can also call the function registered in the stub table from the replacement program by resolving the address using this stub table.

[0025]

According to the present invention, when a defect of a program is corrected or a function is added, the program can be replaced without affecting the program to be associated with the program to be corrected.

Further, since the embedded system of the present invention uses an inexpensive mask ROM and is directly mounted on the device, a low-cost and downsized system device can be realized. Furthermore, since the call destination of the program can be changed at any time, it becomes possible to replace the test of the program or the function-enhanced program.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an information processing apparatus according to the present invention.

FIG. 2 is a structure of a stub table according to the present invention.

[Explanation of symbols]

1 ... Microprocessor, 2 ... Read-only memory, 3 ...
Writable memory, 4 ... Flash EEPROM,
5 ... SRAM, 6 ... Server host, 7 ... ModemUn
it, 8 ... ASIC.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Shima, 81-chome, Onoue-cho, Naka-ku, Yokohama-shi, Kanagawa, Hitachi Software Engineering Co., Ltd. (72) Kenji Saito Inoue-cho, Naka-ku, Yokohama, Kanagawa Address 81 Nitchi Software Engineering Co., Ltd.

Claims (2)

[Claims] 1. An information processing apparatus in which a program is stored in a read-only memory, and the execution means reads the program to execute the functions of the program, and stores a table-calling address of the program. Storage means, changing means for changing the calling address of the program, and second storage means for storing the program corresponding to the calling address changed by the changing means, and the calling address is changed by the changing means. An information processing apparatus, wherein when changed, the execution means executes the function of the program stored in the second storage means instead of the program stored in the read-only memory. 2. The information processing apparatus according to claim 1, wherein the second storage means is provided in another device via a communication network.