JP2001265620A - Program debugging system for rom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a software breakpoint in a ROM area. SOLUTION: In this system provided with a ROM storing a program, a RAM storing at least a memory management table and the program code of the ROM area, a memory management device provided with a logical/physical address conversion function for managing the storage data of the ROM and the RAM and a control means, by writing the change instruction of program control inside the RAM area corresponding to the ROM area storing the program by the control means and setting an execution address to the RAM by using the logical/physical address conversion function of the memory management device, the software breakpoint is set in the ROM area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a system for debugging a program without using an in-circuit emulator (ICE) or the like.

[0002]

2. Description of the Related Art As one of conventional program debugging methods, there is a software breakpoint debugging method. In this software breakpoint debugging method, program instructions for setting switch points are
A means for temporarily replacing an instruction for changing the program control, for example, an instruction for generating an interrupt (trap instruction) has been employed.

According to this method, the area for setting a breakpoint is limited to a program developed in the RAM area, so that setting a software breakpoint in the ROM area can be physically performed. Did not.

For example, according to the contents described in Japanese Patent Application Laid-Open No. 9-288598, a program is stored in a ROM as a target, and a manager refers to a switch table from a preset switch point of a process of the program. The program process is transferred to the debugger process, the program on the ROM is debugged, and the program to be debugged is switched by the table manager that manages the switch table, and the program is referred to by the corresponding switch table. Process is transferred to the debugger process,
It has been proposed that a plurality of different programs on the ROM can be debugged.

[0005]

However, according to this method, a large amount of time is required for the operation of comparing the reference tables each time the program is executed. Furthermore, since a switch point to be a predetermined break point is embedded in a program instruction in advance, it is difficult to set a switch point at an arbitrary position after the ROM is created. In addition, since it is assumed that the required number of switch points is embedded in the program instructions,
The capacity has increased significantly, resulting in an increase in the total program size, which has limited the freedom of design.

An object of the present invention is to propose a program debugging method which solves such a problem.

[0007]

In order to solve the above-mentioned problems, the present invention provides a ROM storing a program, a RAM storing at least a memory management table and a program code of the ROM area, the ROM and the RAM. In a system having a memory management device that manages the stored data and has a logical / physical address conversion function, and a control unit, the control unit stores the program by the control unit.
A program control change instruction is written in the RAM area corresponding to the OM area, and the logic
Using the physical address conversion function, the execution address is
By setting it to AM, it became possible to set a software breakpoint in the ROM area.

DETAILED DESCRIPTION OF THE INVENTION In a system having a memory management device, in a system having a memory management table control means, an instruction for changing program control is written in a RAM area corresponding to a ROM area.
By setting the execution address in the RAM using the logical / physical address conversion function of the memory management device, the RO
A program debugging method, wherein a software breakpoint can be set in the M area.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is an explanatory diagram showing an embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining the operation of the present embodiment.

In FIG. 1, reference numeral 1 denotes a read-only memory (hereinafter referred to as a ROM) in which a program to be debugged is stored. The program includes an instruction to be a point for starting a debugger.
Reference numeral 2 denotes a format in which program instructions in the ROM 1 are stored, and shows that programs corresponding to addresses are stored in the order of addresses. A random access memory (RAM) 3 stores a program and a memory management table used by a memory management unit (MMU).
It is. Reference numeral 4 denotes a memory management unit (MMU) which is an essential condition of the present embodiment.
It controls an address in the AM 3, and includes a program area copy unit 7, a break code control unit 8,
The address translation table control means 9 is constituted.

It is well known that the CPU 5 reads and executes the address of the program stored in the ROM 1 based on the address of the instruction to be executed, and the MMU 4 converts the address of the executed instruction to be taken into the CPU 5 to execute the instruction. It is a fact of.

In the ROM 1, program areas A, B, and C are stored, and it is necessary to debug a program to be debugged (a program area B including six debug points in FIG. 2). When an error occurs, an area including a program to be debugged in the ROM 1 area (a debug point inclusion area 6 in FIG. 2) in the ROM 1 area as shown in FIG. 7, the instruction for changing the program control is copied to the program area X in the RAM 3 area, and the unimplemented instruction (break code 8a) is copied in the copied program area X using the break code control means 8. The address translation table 10 is changed from 10a to 10
Rewrite as b.

When the CPU 5 of FIG. 1 executes an operation of reading a program to be debugged in the debug point inclusion area 6, the MMU 4 of FIG. 1 changes the address conversion table 10 and compares it with the address of the rewritten table 10b. By doing so, the address of the program area X8 in the RAM3 area is referred to, the instruction for changing the program control written in advance is read, and the control is transferred to a debugger program that supports debugging. Can operate as if a software breakpoint was set in the program.

[0015]

As described above, according to the configuration and method of the present invention, the instruction is read from a predetermined breakpoint of the program on the ROM by the transition control means by targeting the program on the ROM. Instead, the control of the program is transferred to the debugger by reading an instruction for changing the preset predetermined program control from the RAM.
The program on M can be debugged.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing the operation of the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Read-only memory (ROM) 2 Program instruction storage format 3 Random access memory (RAM) 4 Memory management unit (MMU) 5 Central processing unit (CPU) 6 Debug point inclusion area 7 Program area copy means 8 Break code control means 8a Break Code 9 Address conversion table control means 10 Address conversion table

Claims (1)

[Claims] 1. A ROM storing a program, a RAM storing at least a memory management table and a program code of the ROM area, and a memory having a logical / physical address conversion function for managing data stored in the ROM and the RAM. In a system having a management device and a control unit, an RO storing the program by the control unit
A program control change command is written in the RAM area corresponding to the M area, and the execution address is changed to the RA using the logical / physical address conversion function of the memory management device.
A program debugging method for a ROM, wherein a software breakpoint can be set in a ROM area by setting the value to M.