JPS62119642A - Trace system - Google Patents

Abstract

PURPOSE:To relieve the load of the hardware and to trace of a required part only by using a trace stop instruction included in a program so as to release the storage condition into a trace memory thereby stopping the trace means. CONSTITUTION:After the start of execution, the condition to store the execution result of a program after the trace start instruction into the trace memory is set by the said instruction to start the trace means and the trace stop instruction releases the storage condition into the trace memory to stop the trace means and until the program end reaches, the start/stop of the storage are repeated for a prescribed number of times as required. Thus, the hardware is reduced and the trace only the required part is attained.

Description

[Detailed Description of the Invention] [Summary] This is a tracing method for testing or testing a device including a CPU and memory, in which storage in the trace memory is controlled by a trace start or end command included in a program to be executed. This allows you to reduce hardware and trace only the necessary parts.

[Industrial application field]

The present invention relates to a tracing method for tracing the state of program execution by storing program execution results in a trace memory and outputting the stored results.

In order to check whether a program is executing as expected, it is possible to store addresses and data during execution in a trace memory separate from the program memory, and output this content after program execution. It is done.

FIG. 2 is a flowchart model of program execution, and includes a plurality of steps or branches. In this Unapu l”l gram, A
In order to perform loosing of the range not shown by B, addresses and data corresponding to steps A to B may be stored in the trace memory. However, as mentioned above, the amount of tracing increases more than necessary due to multiple conditional decision branches or subroutine calls included in the program, and as shown in FIG.
Also, as shown in (al), it takes a lot of effort to search for the required area 8 in the written area 7.

For this reason, there is a demand for a method that allows writing only the required trace portion.

[Conventional technology]

Conventionally, in order to debug a device in which a CPU and a program are stored, for example, as shown in FIG.
After the address signals and data in the device under test 11 including the memory IJ 14 and the memory IJ 14 in which the program is stored are stored in the trace memory 15 in the test device 12, the contents are read out. The test device 12 includes registers 20.21 in which storage start and storage end addresses are set by external inputs 22.23, and a comparator 18.21 that compares the contents of these registers 20.21 with the address value of the device under test. 19 is included. Furthermore, the address in the device under test 11 is stored in the register 20.21.
It includes a Fritsopf 11 knob 17 that is inverted when it matches the content set in , and a trace pointer 16 that controls the trace memory 15. 1. Stored in the race memory 15.

[Problem that the invention seeks to solve]

In this conventional method, it is necessary to input the settings of the storage start and end addresses from the outside, and at least two registers and two comparators are required to hold the set addresses. If an attempt is made to increase the storage start and end points for tracing, it has the disadvantage that the burden on the hardware becomes extremely large.

The present invention was created in view of these points, and an object of the present invention is to provide a tracing method that can reduce the burden on hardware and trace only necessary parts.

[Means for solving problems]

FIG. 1 shows a principle diagram of the tracing method of the present invention.

In the figure, l is an execution start step, and after the start of execution in this step, a trace start instruction sets conditions for storing the execution results of the program after the instruction in the trace memory. The storage condition for the trace memory is canceled by the trace stop command, and (4) the trace means 3 is stopped, and the storage is started and stopped as necessary until the program ends. is repeated a predetermined number of times.

[Effect]

If there is a trace start instruction included in the program and the trace start instruction is generated in step 2,
When the trace means 3 starts storing the program execution result in the trace memory and a command to stop tracing is issued in step 4, the trace means 3 stops storing the program execution result in the trace memory. Even after the trace is stopped, the trace can be started due to the presence of the trace start command, and this sequence is repeated until the trace is ended at the end of the program (step 6).

〔Example〕

FIG. 5 shows an embodiment of the present invention, in which components having similar functions to those shown in the fourth WJ are given the same reference numerals for easy understanding.

In the same figure, the device under test! 11 has CPUI 3 and
The test word N12 includes a trace memory 15 . flip flop 1
7 and a trace pointer 16 for controlling the trace memory 15, and a register 24. Furthermore, LSB 26 of the register 24 is used to set the flip-flop 17, and bit 25, which is one bit higher than L5B26, is used to reset the flip-flop 17. The format of the trace instruction stored in the memory 14 is structured as shown in FIG. 6, and consists of an operation code 27 indicating writing, an address 28, and immediate data 29.30. Here, the flip-flop 17 is configured to start storing data in the I/race memory 15 when the lower two bits of the immediate data 29 are 01.
is set, and the flip-flop 17 is reset to stop storing when the lower two bits are 10.

Therefore, by writing a trace start instruction at the position of the program where you want to start tracing, the lower two bits 25 and 26 of register 24 are set to 01, and the trace is placed at the position of the program where you want to stop (end) tracing. By writing the stop command, the lower two bits 24 and 26 of the register 24 are set to 10. In this way, the flip-flop 17 is set and reset, and storage in the trace memory 15 is controlled. Therefore, a register for setting addresses and a comparator for comparing addresses are not required, and the amount of hardware is reduced.

〔Effect of the invention〕

As described above, according to the present invention, the amount of hardware is reduced and it is possible to trace only the necessary portions, which is extremely useful in practice.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the principle of the tracing method of the present invention, Fig. 2 is an explanatory diagram of the trace range, Fig. 3 is an explanatory diagram showing the storage state of the memory in the conventional example, and Fig. 4
5 is a block circuit diagram of a conventional example, FIG. 5 is a block circuit diagram of an embodiment of the present invention, and FIG. 6 is an explanatory diagram of a trace instruction. 4 and 5, 11 is a device under test, 12 is a test device, and 13 is a CPU. 14 is a memory in which a program is stored, I5 is a trace memory, 17 is a flip-flop, 18.19 is a comparator, and 20.21.24 is a register. , Book, Eyebrows of Aman Day, Ori Map Figure 1

Claims (1)

[Claims] In a system capable of tracing program execution results, a trace start instruction included in the program sets conditions for storing program execution results after the instruction in a trace memory (2). Tracing means (3
) is started, the storage condition in the trace memory is canceled by a trace stop command included in the program, and (4) the tracing means (3) is stopped.