JPH0540613A - Link system with sum checking data - Google Patents

Abstract

PURPOSE:To confirm the invariability and the propriety of the program code data by confirming the sum checking data with the padding calculation when the program code data is finally decided and the practicable program code data is produced. CONSTITUTION:An absolute value production means 10 secures the connection among plural program code data codes 5a-5c that can be rearranged and replaces the data and command codes with the unique relative value code data. Then, an initial value production means 20 replaces the initial value secured with an area securing instruction with the fixed value (f). Furthermore a sum checking data calculation means 30 produces the correction value data so that the computing result obtained by adding successively the program code data decided by both means 10 and 20 from the first through the end of the data is equal to (x). Then, a sum checking data padding means 40 adds the sum checking data to the end of the program code data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sum check data-attached link system, and in particular, a plurality of relocatable program code data are combined and converted into unique relative value code data, and executable program code data is converted. The program link method to be created.

[0002]

2. Description of the Related Art Conventionally, this kind of program link is a combination of individual relocatable programs, a unique relative value address is given to form one executable program data code, and the program is placed anywhere in the main memory. Based on the information whether to do, so that the program can be executed consistently,
It can be said that this is the work of creating the final form of the program code data. Generally, it is performed at the final stage of the program creation process, and the program code data does not change after linking. In other words, it can be said that the program code data is decided at this stage.

[0003]

Generally, unless the code data is intended to secure an area having no initial value and the code data is rewritten even by one byte, the original correct operation is performed. It will be gone. For example, if the program code data is rewritten due to data destruction in the memory device that stores the program code data, or if the main memory is faulty and the program is transferred from the storage medium to the main memory. If the code data cannot be expanded correctly, the original program function cannot be achieved even if this program is executed. Therefore, it can be said that the code data of a program is required to be invariant.

However, there is a problem that there is no means for confirming that the program code data expanded in the main memory has not been rewritten from the original program code data.

[0005]

In the link method with sum check data of the present invention, a relative value code data creating means for replacing a plurality of relocatable program code data with unique relative value code data and an area are secured. The indefinite value area in which the initial value is not determined, which is secured by the instruction, is replaced by the fixed value'f ', the initial value creating means, the absolute value code data creating means, and the program code data determined by the initial value creating means. To generate correction value data such that the operation result is x from the beginning to the end of the code data, sum check data calculation means, and add the sum check data to the end of the program code data, embed the sum check data Have means.

[0006]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, one embodiment of the present invention is a sum check for adding relative value code data creating means 10, initial value creating means 20, sum check data calculating means 30 and sum check data to the end of the code data of a program. The data embedding unit 40 is used.

Relocatable program code data 5a,
5b and 5c are separate program code data including an operand code whose relative value code is not fixed until linked and a portion where an initial value is not given and only an area is secured. On the other hand, the relative value program code data 50 is the program code after all the code data is uniquely determined by linking the relocatable program code data 5a, 5b, 5c. Is.

The relative value code data creating means 10 determines the operand code which cannot be determined until the relocatable program code data 5a, 5b, 5c are linked, based on the given address information, and the area The operand code excluding the reserved instruction is uniquely determined.

Next, the initial value creating means 20 searches the area reserved by the area reserving instruction of the relocatable program code data 5a, 5b, 5c, and the secured data length is a fixed value '. Replace with f '. In this embodiment, it is assumed that the data is "0".

The absolute value code data creating means 10 described above.
Then, the initial value creating means 20 converts all the program code data into absolute value code data having a unique value as one program, and the relative value program code data 50 is generated.

Next, the sum check data calculation means 30
Then, add the code data of the absolute value program code data 30 sequentially from the beginning to the end, and calculate the total value d thereof.

[0013]

A correction value d-bar for d such that

In this embodiment, x is assumed to be "0",

[0016]

The sum check data thus obtained is added to the end of the code data by the sum check data embedding means 40.

The code data to which the correction value data is added as described above is expanded in the main memory by the loader as it is. Therefore, at the end of loading, the correction data is added sequentially from the beginning of the code data, and by confirming that the calculation result becomes 0, the program was correctly stored in the secondary storage medium. And that the program is correctly expanded in the main memory.

Generally, the code data written in the ROM is embedded with the sum check data in the ROM by the same method as the sum check data calculation method 30, and this is used to confirm the invariance of the data in the ROM. Is being done.

[0020]

As described above, according to the present invention, the sum check data of the program code data is embedded at the time of linking when the program code data is finally determined and the executable program code data is created. By confirming the data by calculation, there is an effect that the invariance and correctness of the program code data can be confirmed when the main memory is expanded during the execution of the program.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 10 Absolute value code data creating means 20 Initial value creating means 30 Sum check data calculating means 40 Sum check data embedding means 5a Relocatable program data code 5b Relocatable program data code 5c Relocatable program data code 50 Absolute value program code Data 100 Processing flow 200 Action flow

Claims (1)

[Claims] 1. Relative value code data creating means for combining a plurality of relocatable program code data and replacing the data and command code with unique relative value code data, and an initial value secured by an instruction to secure an area. Initial value creating means for replacing an undefined indeterminate value area with a fixed value'f ', and program code data determined by the absolute value code data creating means and the initial value creating means are sequentially added from the beginning to the end of the data. Sum check data including a sum check data calculation unit for creating correction value data so that the calculation result is x, and a sum check data embedding unit for adding the sum check data to the end of the program code data. Link system.