JPH0325552A - Bus connector - Google Patents

Abstract

PURPOSE:To prevent processing capability from lowering when changing a processing according to the extension of an input/output device by processing an interruption processing request for a central processing unit in the inside of a bus connector. CONSTITUTION:When the input/output device 3 or 6 issues the interruption processing request, an interruption level is bus-transferred, however, the central processing unit 1 returns an interruption processing acceptable response to a transfer origin when the level is higher than that of a processing under execution. When it is equivalent to or less than the level under execution, an interruption processing unacceptable response is returned to the transfer origin, then an interruption awaiting state is set. The bus connector 4 sets the processing level after change on a change level register 10, and compares the processing level after change with the one before change with a comparator 11, and when the value of the change level register 10 is less than that of the processing level register 9, the value is transmitted to the input/output device 6 on an extension bus 5 with a change level transmission circuit 12. Thereby, it is possible to prevent the processing capability front lowering when the processing level of the central processing unit 1 is changed according to the extension of the input/ output device.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention disseminates a processing level change notification updated from a data processing device, more specifically, a central processing unit, to input/output devices. It relates to a bus connection device.

(Prior art) Conventionally, in this type of data processing device, the central processing unit determines whether or not the interrupt is capable of accepting an interrupt based on the processing level of the central processing unit in response to an interrupt processing request Wh9 from each input/output device. Otherwise, if the interrupt could not be accepted, a response indicating that the interrupt could not be accepted was returned to the requesting input/output device.

When receiving a response indicating that interrupts cannot be accepted, the input/output device waits for notification of a change in the processing level from the central processing unit (pending state).

Then, upon receiving a processing level change notification from the central processing unit, the input/output device that was in the pending state requests interrupt processing activation again.

Therefore, when processing to increase the number of buses by installing a bus connection device and using multiple input/output devices connected to the bus, interrupt processing requests for pending input/output devices are generated each time the level is changed. It was occurring.

(Problem to be Solved by the Invention) In conventional information processing devices, an interrupt I8'fjjA request is generated to the central processing unit every time a processing level change notification is received from the central processing unit. There is a problem in that the processing capacity of the device and the transfer processing capacity of the common bus and the extension bus are reduced.

An object of the present invention is to solve the above-mentioned drawbacks, and the purpose of the present invention is to prevent the processing capacity from decreasing when changing the processing level of the central processing unit even when an input/output device is added, and to prevent the transfer processing capacity from decreasing between the common bus and the expansion bus. The object of the present invention is to provide a bus connection device fIt that does not require a bus connection fIt.

(Means for Solving the Problems) In order to achieve the above object, a bus connection device according to the present invention connects a common bus to which a central processing unit is connected and an extension bus to which added input/output devices are connected. connected to,
When the input/output device issues an interrupt processing start request, the interrupt processing start request is transmitted to the central processing unit, the central processing unit determines whether or not the interrupt can be accepted, and outputs a response indicating that the interrupt cannot be accepted. If the central processing unit issues a processing level change notification, the response is not accepted to the input/output device that issued the interrupt processing start request, and the input/output device goes into a waiting state. Concerning a bus connection device in a data processing device that transmits a notification to an input/output device that is waiting for an interrupt processing start request. a processing level register that holds the highest processing level of instructions output by the central processing unit to each input/output device connected to the expansion bus;
a change level register that stores the changed processing level from the central processing unit; a level comparison circuit that compares the contents of the changed level register; A change level transmission circuit that notifies the input/output device on the expansion bus when the processing level is lower, but does not notify the change when the processing level is 1 or higher. be.

(Example) Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a bus connection device according to the present invention.

The central processing unit l is connected to the input/output device 3 or the input/output device t6.
Outputs instructions at a certain processing level.

A command for the input/output device 6 is set in a command reception register 8 in the bus connection device 4 and transmitted to the expansion bus 5. At the same time, the processing level of the instruction is determined by the level comparison circuit l1.
This is compared with the value of the processing level register 9. As a result of the comparison, if the processing level of the instruction is higher than the value in the processing level register 9, the processing level register 9 is updated. On the other hand, if the level is the same or a lower value, no update is performed.

After that, the input/output device 3 or the
When the input/output device 6 executes an interrupt processing request, the interrupt level is transmitted to the central processing unit 1 by bus transfer.

If the level of the central processing unit ml is higher than that of the processing being executed, the central processing unit ml returns an interrupt processing acceptance response to the input/output device [31 or 6] that is the transfer source.

If the level is the same as or lower than the level of the process being executed, a response indicating that the interrupt process cannot be accepted is returned to the transfer source input/output device 3 or input/output device t6, and the input/output device t6 is placed in an interrupt waiting state.

The processing level reporting circuit 7 of the central processing unit #l reports the processing level of the processing program after the history has changed to the input/output device 3 connected to the common bus 2 and the bus connection device 4.

The bus connection device 4 sets the changed processing level in the changed level register 10, and compares it with the level comparison circuit 11. As a result of the comparison, the value of change level register 10 is
If the processing level register 9 is higher than or equal to 1, it is not transmitted to the extension bus 5, and if it is lower, it is transmitted to the input/output device 6 on the extension bus 5 by the change level transmission circuit l2. .

The input/output device t6 in the interrupt waiting state activates a re-interrupt request in response to the processing level change notification from the central processing unit l.

(Effects of the Invention) As described above, the present invention provides a bus connection device for the purpose of adding input/output devices, which is configured to process interrupt processing requests to the central processing unit within the bus connection device. Therefore, it is possible to prevent a decrease in the processing capacity when changing the processing level of the central processing unit due to the addition of input/output devices, and also to prevent a decrease in the transfer processing capacity of the common bus and the expansion bus.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a bus connection device according to the present invention. l... Central processing unit 2... Common bus 3... Input/output control device A 4... Bus connection device 5... Extension bus 6... Input/output control device b7... Processing level report Circuit 8...Instruction reception register 9...Processing level register 10...Change level register 11...Level comparison circuit l2...Change level transmission circuit

Claims (1)

[Claims] Connected between the common bus to which the central processing unit is connected and the expansion bus to which the added input/output devices are connected,
When the input/output device issues an interrupt processing start request, the interrupt processing start request is transmitted to the central processing unit, the central processing unit determines whether or not the interrupt can be accepted, and issues a response indicating that the interrupt cannot be accepted. In this case, the unacceptable response is transmitted to the input/output device that issued the interrupt processing start request, and the input/output device enters the waiting state.Afterwards, if the central processing unit issues a processing level change notification, the change notification is sent as an interrupt. A bus connection device in a data processing device that transmits a processing start request to an input/output device in a waiting state, transmits the highest processing level of an instruction that the central processing unit outputs to each input/output device connected to an expansion bus. a processing level register to hold;
a change level register that stores a changed processing level from the central processing unit; a level comparison circuit that compares the contents of the changed level register and the processed level register; A change level transmission circuit is provided, which notifies the input/output device on the expansion bus of a change when the processing level is lower, but does not notify the change when the processing level is the same or higher. bus connection device.