JPH04264930A - Microprogram control circuit - Google Patents

Abstract

PURPOSE:To improve the reliability of a data processing system by completing the collection of a state value at the time of the occurrence of an error so as to facilitate retrial. CONSTITUTION:A microprogram control circuit for ordinary operation consisting of a control memory 10, a microprogram address generation circuit 12, a microprogram register 14, and an error detection circuit 16 is provided with an error processing control memory 11 in which an error processing program is stored, an error processing microprogram address generation circuit 13, an error processing microprogram register 15, an error processing display register 18, and a selection circuit 17 to switch the output of the microprogram register for ordinary operation or for error processing by an error processing display signal 23, and at the time of the occurrence of the error, a system is switched by the selection circuit 17 so that the error processing control memory 11, the error processing microprogram address generation circuit 13, and the error processing microprogram register 15 are used, and error processing is executed without using a part in which a fault is caused.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microprogram control circuit, and more particularly to a control circuit for error processing by microprogram control when a failure occurs in a control memory or a microprogram register.

0002

2. Description of the Related Art Conventionally, in this type of microprogram control circuit, when a fault in a control memory or microprogram register is detected, error processing is performed using the faulty control memory or microprogram register. There is.

0003

As mentioned above, in the conventional microprogram control circuit, since the control memory and microprogram register that have once caused a failure are used, there is a high possibility that the failure will occur again when error handling is executed. This method has the disadvantage that it often fails to complete error processing or performs incorrect error processing.

An object of the present invention is to provide a microprogram control circuit for normal operation with an error processing control memory in which an error processing program is stored, an error processing microprogram address generation circuit, and an error processing microprogram register. and a selection circuit that switches the microprogram register output between normal operation and error processing using an error processing display register and an error processing display signal. When an error occurs, the selection circuit selects the error processing control memory and the error processing micro By switching to use the program address generation circuit and microprogram register for error handling, and performing error handling without using the part where the failure occurred, the above drawbacks can be resolved, and the status value can be collected easily when an error occurs. It is an object of the present invention to provide a microprogram control circuit that can be completed, facilitates retrying, and improves the reliability of a data processing system.

[0005]

[Means for Solving the Problems] A microprogram control circuit of the present invention includes a microprogram address generation circuit that generates a microprogram address, and a microprogram address that is stored in a microprogram address outputted by the microprogram address generation circuit. A control memory that outputs read data from the control memory, a microprogram register that inputs read data from the control memory and outputs a microprogram register output, and an error detection circuit that detects errors in the microprogram register output from the microprogram register. A microprogram control circuit having a microprogram control circuit, an error processing control memory that stores an error processing microprogram and outputs error processing read data, and stores error processing read data from the error processing control memory. an error processing microprogram register that generates an error processing microprogram register; an error processing microprogram address generation circuit that generates an address to an error processing control memory from the error processing microprogram register output of the error processing microprogram register; and a microprogram control circuit. An error processing display register that stores the error detection circuit output of the error detection circuit and indicates that error processing is in progress, and a microprogram register output of the microprogram control circuit and an error processing microprogram register output when the error processing display register indicates that error processing is in progress. and a selection circuit that selects the output of the microprogram register for error processing from the above, and performs error processing using the output of the selection circuit as a microprogram word.

[0006]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a microprogram control circuit according to an embodiment of the present invention.

In FIG. 1, the microprogram control circuit of this embodiment includes a control memory 10, a microprogram address generation circuit 12, and a microprogram register 14.
and an error detection circuit 16, an error processing microprogram control circuit consisting of an error processing control memory 11, an error processing microprogram address generation circuit 13, and an error processing microprogram register 15. It consists of a program control circuit, a selection circuit 17, and an error processing display register 18.

First, the normal operation will be explained.

According to the microprogram register output 21 which is the output of the microprogram register 14, the microprogram address generation circuit 12 generates a microprogram address 27, and the next microprogram reads data from the control memory 10 using this microprogram address 27. 25 and stored in the microprogram register 14. This operation is basically repeated. The microprogram register output 21 is constantly checked by the error detection circuit 16. If no error is detected by the error detection circuit 16, the error processing display register 18 is not set, and the microprogram register output 21 is selected by the selection circuit 17 as the microprogram word 20 to control the data processing device.

Next, a case where a failure occurs in the control memory 10, the read data 25, the microprogram register 14, or the microprogram register output 21 will be described.

The error detection circuit 16 outputs an error signal 24 when detecting a failure. The error signal 24 is stored in the error processing display register 18, indicating that error processing is in progress, and is simultaneously input to the error processing microprogram address generation circuit 13. The error processing microprogram address generation circuit 13 generates an error processing start address and outputs it as an error processing microprogram address 28. The first microprogram for error processing is read out as error processing read data 26 from the error processing control memory 11 according to the error processing microprogram address 28 and stored in the error processing microprogram register 15 .

In the next cycle, the error processing display signal 23 which is the output of the error processing display register 18 is output. When the error processing display signal 23 is output, the error processing microprogram address generation circuit 13 generates a microprogram address according to the error processing microprogram register output 22 and outputs the error processing microprogram address 28. . Further, the selection circuit 17 selects the error processing microprogram register output 22 as the microprogram word 20 from the microprogram register output 21 used during normal operation and the error processing microprogram register output 22 used during error processing, Output.

As described above, when a fault is detected in the control memory and microprogram register used during normal operation, the control memory and microprogram register used for error processing are switched to the error processing without using the faulty part. Perform processing.

[0015]

As explained above, the microprogram control circuit of the present invention includes a microprogram control circuit for normal operation, an error processing control memory storing an error processing program, and an error processing microprogram control circuit for normal operation. It has an address generation circuit, a microprogram register for error processing, and a selection circuit that switches the microprogram register output between normal operation and error processing using an error processing display register and an error processing display signal, and when an error occurs, the selection circuit By switching to use the control memory for error handling, the microprogram address generation circuit for error handling, and the microprogram register for error handling, and performing error handling without using the part where the failure occurred, the state at the time of error occurrence can be changed. This has the effect that value collection can be completed, retrying becomes easy, and reliability of the data processing system can be improved.

[0016] Particularly in microprocessor systems, the ability to transfer processing to another processor can be easily performed, and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a microprogram control circuit according to an embodiment of the present invention.

[Explanation of symbols]

10 Control memory 11 Error processing control memory 12 Microprogram address generation circuit 13
Error processing microprogram address generation circuit 14 Microprogram register 15
Error processing microprogram register 16
Error detection circuit 17 Selection circuit 18 Error processing display register 20 Micro program word 21 Micro program register output 22
Error processing microprogram register output 23
Error processing display signal 24 Error signal 25 Read data

Claims (1)

[Claims] 1. A microprogram address generation circuit that generates a microprogram address; a control memory that outputs read data from a stored microprogram according to a microprogram address output by the microprogram address generation circuit;
In the microprogram control circuit, the microprogram control circuit includes a microprogram register that inputs read data from the control memory and outputs a microprogram register output, and an error detection circuit that detects an error in the microprogram register output from the microprogram register. a microprogram control circuit; an error processing control memory that stores an error processing microprogram and outputs error processing read data; and an error processing microprogram that stores error processing read data from the error processing control memory. a register, an error processing microprogram address generation circuit that generates an address from the error processing microprogram register output of the error processing microprogram register to the error processing control memory, and an error detection circuit of the microprogram control circuit. an error processing display register that stores the output of the error detection circuit and indicates that error processing is in progress, and a microprogram register output of the microprogram control circuit and an output of the error processing microprogram register when the error processing display register indicates that error processing is in progress. and a selection circuit that selects the output of the error processing microprogram register from the above, and performs error processing using the output of the selection circuit as a microprogram word.