JP2001318802A - In-circuit emulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the operability or efficiency of a delugging for a large- scaled program. SOLUTION: An emulation memory 11 is provided with a memory part for storing a user program or data and a memory part for storing set information corresponding to the storage address of the user program. Then, the user program and set information are read in parallel in an emulation mode from each memory part, and outputted to a data bus and a break signal generating circuit 13 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-circuit emulator, and more particularly to an in-circuit emulator that is controlled by a host computer to switch to an emulation mode and substitute for a CPU in a user system.

[0002]

2. Description of the Related Art Conventionally, this kind of in-circuit emulator is connected between a host computer and a user system, is controlled by the host computer, switches to an emulation mode, and executes a user program on behalf of a CPU in the user system. It is used to execute in time, break in response to setting information, and debug a user program mounted on a user system. For example, source debugging is performed in which execution of a user program is broken in units of source code or function, and data being executed is collected and debugged.

FIG. 2 is a block diagram showing a program / debug device disclosed in Japanese Patent Laid-Open No. 9-44374, which is shown as an example of a conventional in-circuit emulator.

The conventional in-circuit emulator includes a memory 51 for storing and executing a user program, a CPU 52, and a detector 53 for detecting a break condition for stopping program execution and outputting a break signal. 53 further includes a register 53
1, a register 532 and a comparator 533.

Register 531 stores address, status, data and pre-execution / post-execution break information as break conditions for stopping program execution, and register 532 stores address bus, status and data bus signals for CPU 52 to access memory. Is latched in response to the bus strobe signal, and the comparator 533 compares the contents of the register 531 and the contents of the register 532 and outputs a break signal when they match.

In this conventional in-circuit emulator, an address value, a status value, a data value and break information before / after execution, which are break conditions, are stored in advance in a register 531 of the detector 53, and the CPU 52 executes the emulation when the emulation is executed. Internal prefetch buffer 52
The pre-execution break bit or the post-execution break bit in the prefetch buffer 521 is valid when the instruction is prefetched together with the instruction by enabling the pre-execution break bit or the post-execution break bit corresponding to the contents of the register 531. Is checked, and if valid, the contents of the register 532 and the register 531 of the detector 53 are compared. If they match, a break signal is output and the program execution is stopped.

After the execution of the program is stopped, data collection is performed, and source debugging of a sequence having complicated conditions is easily performed.

[0008]

The above-mentioned conventional in-circuit emulator has problems that when debugging or analyzing a large-scale program, the cost increases and the time for providing the program to the user is delayed.

The reason is that a detector for detecting a break condition is provided exclusively by hardware, the number of break condition settings is limited, and operability or debugging efficiency at the time of debugging is low.

Therefore, an object of the present invention is to improve operability or debugging efficiency at the time of debugging a large-scale program.

[0011]

SUMMARY OF THE INVENTION Therefore, the present invention is directed to a computer system which is connected between a host computer and a user system, is controlled by the host computer, switches to an emulation mode, and executes a user program on behalf of a CPU in the user system. In an in-circuit emulator that executes in real time and breaks in response to setting information, the in-circuit emulator stores the setting information corresponding to a storage address of the user program under the control of the host computer, and stores the setting information in the emulation mode. The setting information is read out in parallel.

[0012] The setting information may include a break setting bit set at an address where a break occurs with respect to execution of the user program, and an access guard setting set within an address range accessible in the emulation mode based on memory mapping information. And a bit.

An emulation memory is provided for storing the user program and the setting information under the control of the host computer and reading out the user program and the setting information in parallel in the emulation mode.

An emulation CPU that substitutes a CPU in the user system in the emulation mode and executes the user program in the emulation memory in real time;
A break signal generation circuit that generates a break signal in response to the setting information read out together with the user program from the emulation memory; and causing the emulation CPU to execute a break processing program in response to the break signal. A break control circuit for stopping execution of the user program and switching from the emulation mode.

Further, the emulation memory includes a memory unit for storing the user program, and a memory unit for storing the setting information corresponding to a storage address of the user program under the control of the host computer. .

In the emulation mode, the user program and the setting information are read from the respective memory units in parallel.

[0017]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an in-circuit emulator according to the present invention. Referring to FIG. 1, an in-circuit emulator 1 of the present embodiment
Are emulation memory 11, emulation C
It includes a PU 12, a break signal generation circuit 13, and a break control circuit 14, and switches to the emulation mode under the control of the host computer 2, executes a user program in real time on behalf of the CPU in the user system 3, and responds to setting information. And break.

The emulation memory 11 stores a user program and setting information under the control of the host computer 2. The emulation memory 11 reads out the user program and setting information in parallel in the emulation mode. Respectively.

In this embodiment, the emulation memory 11 includes a memory unit for storing a user program or data, and a memory unit for storing setting information corresponding to a storage address of the user program.
From each of these memory sections, the user program and setting information are read out in parallel in the emulation mode. Further, the setting information includes a break setting bit set at an address where a break occurs for execution of the user program, and an access guard setting bit set at an address range accessible in the emulation mode based on the memory mapping information.

The emulation CPU 12 executes the user program in the emulation memory 11 in real time in the emulation mode on behalf of the CPU in the user system.

The break signal generating circuit 13 generates a break signal corresponding to the setting information read out together with the user program from the emulation memory 11 by the emulation CPU 12 and the bus control signal.

In response to the break signal, the break control circuit 14 causes the emulation CPU 12 to execute the break processing program, stops the execution of the user program, and switches from the emulation mode.

Next, the operation of the in-circuit emulator of this embodiment will be described.

First, a user program or data is stored in the emulation memory 11 under the control of the host computer 2, and setting information is stored corresponding to the storage address of the user program. At this time, as setting information, for example, a break setting bit is stored at an address where a break occurs with respect to the execution of the user program, and an access guard setting bit is stored in an address range accessible in the emulation mode based on the memory mapping information.

Next, the emulation mode is switched to the emulation mode under the control of the host computer 2, and the emulation CPU 12 reads the user program stored in the emulation memory 11 and executes it in real time on behalf of the CPU in the user system 3. I do. at the same time,
The setting information stored in the emulation memory 11 is read out in parallel and output to the break signal generation circuit 13.

Next, in the break signal generation circuit 13, a break signal is output to the break control circuit 14 in accordance with the setting information read from the emulation memory 11 and the bus control signal from the emulation CPU 12. In this embodiment, a break signal is output in response to a logical product output of a break setting bit and an access guard setting bit stored as setting information and a bus control signal.

Next, in the break control circuit 14, in response to the break signal from the break signal generation circuit 13, the emulation CPU 12 executes the break processing program to stop the execution of the user program.
The mode is switched from the emulation mode and returns to the control of the host computer 2.

The execution and break of the user program in the emulation mode and the data collection under the control of the host computer 2 are repeated for each address where the setting information is stored, and the user program is debugged. At this time, the source information of the user program can be easily debugged by storing the setting information in source code or function units.

[0029]

As described above, in the in-circuit emulator according to the present invention, the operability during debugging of a large-scale program or the debugging efficiency is significantly improved.

Further, the memory section for storing the setting information can be realized by a memory having a small bit width, the hardware configuration required for break setting and detection is simplified, and the number of break settings is not restricted by hardware resources. .

Further, there is an effect that the in-circuit emulator for a large-scale program does not affect the hardware cost and the time of providing the user.

The reason is that, under the control of the host computer, the setting information can be stored for each storage address of the user program, and the user program and the setting information are read out in parallel in the emulation mode, and the setting information is stored. This is because a break signal can be output for each address.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an in-circuit emulator according to the present invention.

FIG. 2 is a block diagram showing an example of a conventional in-circuit emulator.

[Explanation of symbols]

 Reference Signs List 1 in-circuit emulator 2 host computer 3 user system 11 emulation memory 12 emulation CPU 13 break signal generation circuit 14 break control circuit 51 memory 52 CPU 53 detector 521 prefetch buffer 531 532 register 533 comparator

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiji Iwasaki 1-403, Kosugi-cho, Nakahara-ku, Kawasaki-shi, Kanagawa 53 F-term within NEC Ic Microcomputer System Co., Ltd. 5B042 HH03 HH05 HH11 HH25 LA05 5B048 AA13 BB02 FF01

Claims (6)

[Claims] 1. An emulation mode, which is connected between a host computer and a user system, is controlled by the host computer, switches to an emulation mode, executes a user program on behalf of a CPU in the user system, and responds to setting information. In the in-circuit emulator that breaks, the setting information is respectively stored corresponding to the storage address of the user program under the control of the host computer, and the user program and the setting information are read out in parallel in the emulation mode. And an in-circuit emulator. 2. The method according to claim 1, wherein the setting information is a break setting bit set at an address at which a break occurs for execution of the user program, and an access guard setting is set at an address range accessible in the emulation mode based on memory mapping information. 2. The in-circuit emulator according to claim 1, comprising a bit. 3. An emulation memory according to claim 1, wherein said user program and said setting information are respectively stored under control of said host computer, and said user program and said setting information are read out in parallel in said emulation mode. In-circuit emulator. 4. An emulation CPU which substitutes a CPU in the user system in the emulation mode to execute the user program in the emulation memory in real time, and is read together with the user program from the emulation memory by the emulation CPU. A break signal generating circuit for generating a break signal in response to the setting information; and causing the emulation CPU to execute a break processing program in response to the break signal to stop execution of the user program and switch from the emulation mode. The in-circuit emulator according to claim 3, further comprising a break control circuit. 5. The emulation memory includes a memory unit for storing the user program and a memory unit for storing the setting information corresponding to a storage address of the user program under the control of the host computer. Item 3. An in-circuit emulator according to item 3. 6. The in-circuit emulator according to claim 5, wherein in the emulation mode, the user program and the setting information are read from the respective memory units in parallel.