JP2001100984A - Program link method of flash incorporated microcomputer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a load module which operates normally without any trouble even after self-writing is carried out in the operation of an application program. SOLUTION: A link-unsolved function call is regarded as a branch instruction to a function present in a load module 5 on the side of a rewritable part 1 and the branch destination of the branch instruction is corrected to a branch table 9 generated afterward in a load module 5 on the side of the rewritable part 1. After the link of the function call is solved, a list 11 of information on a function call at the corrected branch destination is automatically generated by a branch destination correcting routine 8 in a load module 6 on the side of a unrewritable part 2. The list 11 is referred to by a branch table generating routine when application program is linked at the time of the generation of the load module 5 on the side of the rewritable part 1 and the branch table 9 is automatically generated, so even after self-writing is performed, a load module can be generated which instantaneously automates the normal operation of the application program.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a program linking method for a microcomputer with a built-in flash, and more particularly, to a load module capable of automatically continuing its operation even when an application program in a rewritable portion is updated. The present invention relates to a program link method for a microcomputer with a built-in flash that can be generated.

[0002]

2. Description of the Related Art With the advent of a built-in flash EEPROM, self-rewriting of an application program is increasingly performed. By performing self-rewriting, it is easy to add / update the functions and information of the application program, and to deal with failures. However, when developing an application program, the application program can operate normally even after self-rewriting is performed. We have to prepare and manage various means.

[0003] In the prior art, a link method for fixing a branch destination of a function call to a certain address, arranging a branch instruction at that address, preparing a source file for performing two-stage branching, and generating a load module is known. Was used. In such a system using self-rewriting of an application program by a flash EEPROM, the scale of the application program becomes large, and it takes time to prepare a means for operating normally and manage it. The reason for the trouble is that the source file of the application program needs to be changed and the function must be modified every time the function is called so that the target function is not directly called but goes through the relay point.

[0004] Even after self-rewriting is performed during the operation of an application program of a microcomputer with a built-in flash, it is desired that normal operation be performed without any trouble.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a program linking method for a microcomputer with a built-in flash which can operate normally without any trouble even after self-rewriting is performed during the operation of an application program. is there.

[0006]

Means for solving the problem are described as follows. The technical items appearing in the expression are appended with numbers, symbols, and the like in parentheses (). The numbers, symbols, and the like are technical items that constitute at least one embodiment or a plurality of the embodiments of the present invention, in particular, the embodiments or the examples. Corresponds to the reference numerals, reference symbols, and the like assigned to the technical matters expressed in the drawings corresponding to the above. Such reference numbers and reference symbols clarify the correspondence and bridging between the technical matters described in the claims and the technical matters of the embodiments or examples. Such correspondence / bridge does not mean that the technical matters described in the claims are interpreted as being limited to the technical matters of the embodiments or the examples.

A program link method for a microcomputer with a built-in flash according to the present invention regards a function call whose link is unresolved as a branch instruction to a function existing in the load module (5) of the rewritable part (1). After the correction to the branch table and the link resolution of the function call are completed, a list (11) of the information of the function call at the branch destination by the correction is automatically generated, and the load module (6) of the non-rewritable part (2) is generated. And automatically generating the branch table (9) in the load module (5) of the rewritable part (1) based on the information. The application program operates normally without any trouble even after self-rewriting is performed during the operation.

When an undefined function is called at the time of linking the application program of the non-rewritable part (2), the list (11) is displayed when the load module (6) of the non-rewritable part (2) is generated. Is generated by the branch destination correction routine (8) when the application program is linked. If there is a list (11) at the time of linking the application program of the rewritable part (1), the branch table (9) stores the link of the application program at the time of generating the load module (5) on the side of the rewritable part (1). Sometimes, it is generated by the branch table generation routine (7).

The program linking method of the microcomputer with a built-in flash according to the present invention further includes a step of listing information in the application program of the non-rewritable part (2)
When the application program of the rewritable part (1) is updated, the branch table (9) is generated again with reference to the list (11) to link the application program of the rewritable part (1). To generate a load module (5) on the rewritable part (1) side, and to generate a load module that can automatically continue operation even when an application program is updated. be able to.

By performing self-rewriting during the operation of the application program, the size of the program code arranged in the flash changes, and the function address 1 fluctuates. However, as shown in FIG. 1, a two-stage branch table (9) is prepared in the flash at a fixed address, and relaying and branching is performed so that the function address can be changed. Become.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the program linking method for a microcomputer with a built-in flash according to the present invention, an application program is divided into a rewritable portion that can be rewritten and a non-rewritable portion that cannot be rewritten. It is provided. As shown in FIG. 2, the application program operating on the microcomputer with a built-in flash is divided into a rewritable part 1 and a non-rewritable part 2. The rewritable part 1 and the non-rewritable part 2 generate a rewritable part side load module 5 and a non-rewritable part side load module 6 by the first linker 3 and the second linker 4, respectively. First linker 3 and second linker 4
May be the same command. In this case, a mechanism for switching operations such as designating an option is prepared.

The first linker 3 is provided with a branch table generation routine 7 belonging thereto. The second linker 4 is provided with a branch destination correction routine 8 belonging thereto. The rewritable part load module 5 is provided with a branch table 9. Non-rewritable part load module 6
Is provided with a list 11.

The list 11 holds undefined function call information. The list 11 is generated by the branch destination correction routine 8 at the time of linking the application program in the generation process of the non-rewritable part side load module 6. If an undefined function is called when the non-rewritable part 2 is linked first, the branch destination correction routine 8 belonging to the second linker 4 calls the branch table 9 located at a fixed address. Non-rewritable part side load module 6
List of undefined function calls embedded in the file 11
Is referred to when the rewritable part 1 is linked, and the branch table generation routine 7 automatically generates a branch table 9 in which branch instructions are listed. The branch table 9 is embedded in the rewritable part side load module 5.

The information referred to when linking the non-rewritable part 2 is stored in the list 11, so that when the application program as the rewritable part 1 is updated, the branch table 9 is referred to again with reference to the list 11. Generate
The rewritable part 1 is linked to generate the rewritable part side load module 5. In this way, in the microcomputer with a built-in flash, even if the self-rewriting is performed during the operation of the application program, it is possible to automatically solve the mechanism that operates normally when the program is linked.

The branch table 9 holds a branch instruction for a two-stage branch, and is generated by the branch table generation routine 7 at the time of linking an application program in a step of generating a rewritable partial load module.

FIG. 3 shows the operation of the branch correction routine 8 in the embodiment described above. Branch destination correction routine 8
When there is a function call whose link is unresolved (step S1), the function call is regarded as a branch instruction to a function existing in the rewritable part side load module 5 (step S1), and the branch destination is set at the relay point. Correct to a certain branch table 9. As shown in FIG. 6, the internal address of the branch table 9 is calculated from the start address of the branch table + the serial number * the size of one element of the table. After link resolution of all function calls is completed, the corrected branch destination information list 11 is embedded in the non-rewritable part side load module 6 in the format shown in FIG. 5 (step S3).

FIG. 4 shows the operation of the branch table generation routine 7 in the embodiment described above. The branch table generation routine 7 reads the function call information list 11 whose branch destination has been corrected (step S4). Based on this information, a branch table 9 in which branch instructions are listed in the order of serial numbers is automatically generated inside the rewritable partial load module 5. At this time, information necessary for link resolution is also generated for each branch instruction (step S5). Thereafter, link resolution is performed (step S6), and it is determined whether an undefined function call exists (step S7). If an undefined function call exists, error processing is performed (step S8). When an undefined function call exists in the branch table 9, the linker cannot determine which load module should be included in the function. When the link resolution is completed normally, the generation of the load module that normally operates even after the self-rewriting is performed during the operation of the application program is completed.

The two-stage branch using the branch table shown in FIG. 6 can be replaced with a register indirect branch using the function address table shown in FIG. In the step of generating the non-rewritable partial load module, in step 9 (see FIG. 3) of the branch destination correction routine of the second linker 4, the N-th address stored in the function address table located at the fixed address is referred to. To resolve the link so as to branch.

Next, in the step of generating the rewritable part load module, the branch table generation routine 7 of the first linker 3 generates a function address table (FIG. 7) in which function addresses are listed in order of serial numbers in accordance with the information list 11. Automatically generated inside one linker 3. At this time, information necessary for link resolution is also generated for each function address. By performing such a change, alternative execution using register indirect branching using a function address table is possible. Which table to use is determined in consideration of the characteristics of the architecture for operating the application program to be generated.

[0020]

The program linking method for a microcomputer with a built-in flash according to the present invention has a branch table for arranging a branch instruction at a fixed address of a rewritable portion, and an application program which operates correctly by two-stage branching through the table is automatically executed by the linker. A user who is generated and develops an application program can use the self-rewriting function without being aware of it.

[Brief description of the drawings]

FIG. 1 is a conceptual block diagram of a program link method of a microcomputer with a built-in flash according to the present invention.

FIG. 2 is a circuit block diagram showing an embodiment of a program link method for a microcomputer with a built-in flash according to the present invention.

FIG. 3 is a flowchart showing an operation of a branch correction routine in the embodiment of the program link method of the microcomputer with a built-in flash according to the present invention.

FIG. 4 is a flowchart showing an operation of a branch table generation routine in the embodiment of the program link method of the microcomputer with a built-in flash according to the present invention.

FIG. 5 is a list of function call information.

FIG. 6 is a branch table.

FIG. 7 is a table showing function addresses;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rewriteable part (application program of) 2 ... Non-rewriteable part (application program of) 5 ... Reloadable part side load module 6 ... Rewriteable part side load module 7 ... Branch table generation routine 8 ... Branch destination correction routine 9 ... branch table 11 ... list

Claims (6)

[Claims] 1. A function call whose link has not been resolved is regarded as a branch instruction to a function existing in a load module of a rewritable part, a branch destination is corrected to a branch table to be described later, and link resolution of the function call has been completed. Later, automatically generate a list of function call information of the branch destination by the correction,
A program link method for a microcomputer with a built-in flash, comprising: storing in a load module of a non-rewritable part; and automatically generating a branch table in the load module of a rewritable part based on the information. 2. The program link method according to claim 1, wherein the list is generated by a branch destination correction routine when an application program is linked when the load module of the non-rewritable portion is generated. 3. The microcomputer with built-in flash according to claim 1, further comprising, when an undefined function is called at the time of linking the non-rewritable part of the application program, calling the branch table by a branch destination correction routine. Program link method. 4. A program linking method for a microcomputer with a built-in flash according to claim 3, further comprising referring to the list when linking an application program of a rewritable portion. 5. The method according to claim 4, wherein the automatic generation is performed by a branch table generation routine. 6. The information processing apparatus according to claim 1, further comprising: storing the information at the time of linking the non-rewritable portion of the application program in the list; and referring to the list when updating the rewritable portion of the application program. A program linking method for a microcomputer with a built-in flash, comprising: linking the application program in a rewritable portion to generate a load module in a rewritable portion by generating the branch table again.