JPS60204044A - Fault searching circuit - Google Patents

Abstract

PURPOSE:To detect automatically a stall state without requiring a manual operation or an inference, and to display a stall address of a microprogram by comparing a micro-address and a comparing address. CONSTITUTION:An address setting circuit 20 inputs an executing address of that time point by an external input signal line 102, informs it to a comparing address circuit 40, and also indicates a start of a time monitor to a timer circuit 30. The address comparing circuit 40 compares a value of a micro-address of a signal line 101, and a comparing address of a signal line 201, and in case they coincide with each other, the coincidence is informed to a counter circuit 50. When the contents of the counter circuit 50 reach a prescribed value, a display is indicated to a displaying circuit 60, a suspension of the operation is indicated to the address setting circuit 20, and also the operation of the timer circuit 30 is suspended. The displaying circuit 60 displays a stall and also displays a stall address.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fault detection circuit in a microprogram evaluation device, and more particularly to a system for automatically detecting a stall in a microprogram.

(Prior Art) Conventionally, in microprogram evaluation and fault investigation, maintenance equipment such as a maintenance panel, reed or analyzer that is provided for the device that executes the microprogram, or a maintenance adapter that can be connected to the installed device has been used. The tools were used to evaluate software and search for faults.

Generally, during the execution of a microprogram, a loop with no exit exit may occur.

In other words, a so-called stall may occur.

Conventionally, in order to investigate such a stall phenomenon, if there is no change in the operation of the processing unit after a certain period of time, a stop switch is used as a precautionary measure to check the microprogram. Alternatively, the stall address has been estimated by reading the display of the microbuzigram address display circuit, which is usually installed in the above-mentioned maintenance means, as an approximate value based on experience. For this reason, the conventional method has the disadvantage that the stall address cannot be determined.

(Object of the invention) The object of the present invention is to generate a comparison address by capturing the microaddress being executed on the microaddress bus, and to compare the microaddress on the microaddress signal line with the above comparison address, and to compare the microaddress on the microaddress signal line with the above comparison address. The address is incremented each time a match is reported, and a stall report is sent out while monitoring the time starting from the time when the instruction to start execution is sent out, thereby simultaneously displaying the occurrence of a stall and the stall address. This method eliminates the above disadvantages by automatically detecting the stall condition without requiring any manual operation or guesswork, and the above mentioned stall address without stopping the execution of the microprogram.

It is configured as an evaluation tool that can display the

The object of the present invention is to provide a fault search circuit with improved performance.

(The fault search circuit according to the present invention includes an address setting circuit, an address comparison circuit, a counter circuit, a timer circuit, and a 2-display circuit.) Address setting circuit heating, micro address This is to generate a comparison address by taking in the microaddress being executed from the bus.

The address comparison circuit compares the microaddress on the microaddress bus with the comparison address output from the address setting circuit and detects whether the two addresses match.

The counter circuit increments its contents each time the address comparison circuit reports a match between the two addresses.

The timer circuit monitors the elapsed time starting from the execution start instruction from the address setting circuit, stops the operation when a stall occurs, and reports all occurrences of the stall.

The display circuit is for simultaneously displaying the occurrence of a stall and the stall address at the time when the counter circuit reports the occurrence of a stall.

(Actual example) Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a fault search circuit according to the present invention. In FIG. 1, 20 is an address setting circuit, 60 is a timer circuit, 40 is an address comparison circuit,
50 is a counter circuit, and 60 is a display circuit. In FIG. 1, the address setting circuit 20, which has received an instruction to start an operation via the external input signal line 102, takes in the current execution address from the micro address signal fIJ101 and transfers it to the signal line 20. .

The address comparison circuit 40 compares the value of the microaddress on the signal line 101 and the comparison address on the signal line 201, and if the two match, it reports the match to the counter circuit 50 via the instruction signal line 401.

The counter circuit 50 increments the count value for each match report, and when the contents of the counter circuit 50 reach a specified value, the instruction on the signal line 501 instructs the LED display circuit 60 to display, and the instruction on the signal line 502 At the same time, it instructs the driver address setting circuit 20 to stop its operation, and also instructs the timer circuit 60 to stop its operation via the instruction signal line 506.

The display circuit 60 operates according to instructions from the counter circuit 50.
It is determined that the microprogram has stalled, the stall is displayed, and the comparison address on the signal line 201 is displayed as the stall address. Further, the address setting circuit 20 stops operating according to the instruction on the signal line 502.

On the other hand, the timer circuit 30 starts monitoring the execution time according to the instruction on the signal line 202, and when this time reaches the specified value VC, it instructs the counter circuit 50 to stop counting according to the instruction on the signal line 602, and In accordance with the instruction on line 601, the address setting circuit 20 is instructed to correct the address setting.

According to the above, the address setting circuit 20 re-captures the microprogram in the same manner as when the instruction arrives again through the external input signal line 102. Thereafter, the above operation is repeated in the same manner.

(Effects of the Invention) As explained above, in the present invention, the microaddress being executed is taken from the microaddress bus to generate a comparison address, and the microaddress on the i microaddress signal line is compared with the comparison address, By incrementing the address value each time a match between the above two addresses is reported and sending a stall report while monitoring the time as the starting point when the instruction to start execution is sent, it is possible to detect the occurrence of a stall. By displaying the stall address at the same time, it automatically detects the stall state and provides an evaluation tool to display the stall address without stopping the execution of the microprogram. This has the effect that it is possible to effectively search for obstacles without having to do so.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a fault search circuit according to the present invention. 20...Address setting circuit 60...Timer circuit 40...Address comparison circuit 50...Counter circuit 60...Display circuit 101.102,201,202,301゜502*4
01-501-S503...Φ...Signal line patent applicant NEC Corporation representative Patent attorney Hisashi I) Ro

Claims (1)

[Claims] an address setting circuit for taking in a microaddress being executed from a microaddress bus and generating a comparison address; and comparing the microaddress on the microaddress bus with the comparison address output from the address setting circuit. an address comparison circuit for detecting an address match; a counter circuit for incrementing contents each time the address match is reported from the address comparison circuit; and a counter circuit for incrementing the contents each time the address match is reported from the address comparison circuit; a timer circuit for monitoring, stopping operation when a stall occurs and reporting the occurrence of the stall; and displaying the stall and displaying the stall address when the counter circuit reports the occurrence of the stall. It is characterized by being configured with a display circuit for performing