JPS62172457A - Bus connecting device - Google Patents

Abstract

PURPOSE:To prevent the transfer capacity of fundamental bus from being lowered by providing an expansion bus control means capable of changing the range of a channel number in an input/output control device under the control of an expansion bus by changing a mask value. CONSTITUTION:A fundamental bus control circuit 101 performs an interface control between a fundamental bus 107. An instruction from a central processor in a data processing system connected to the fundamental bus 107 is inputted to the fundamental bus control circuit 101 through the fundamental bus 107. In the channel number of the instruction, only the effective bit part represented by the content of a mask register 105 is compared with the content of a central value register 104, and as a compared result, when they are coincident a process control circuit 102 controls the fundamental bus control circuit 101, and returns a response to the central processor, and also, receives the instruction. The process control circuit 102 controls an expansion bus control circuit 103, and transmits the instruction to an expansion by 108. In this way, the lowering of the transfer capacity in the fundamental bus due to the connection of an expansion bus can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a bus connection device for a data processing system, and particularly to a bus connection device for a data processing system, in which a central processing unit, a storage device, and an input/output control device are connected to one common input/output bus. The present invention relates to a bus-connected VC device used in a data processing system and having a function of logically extending a common input/output bus.

(Prior Art) Conventionally, in this type of bus connection device, the channel number of the command from the central processing unit to the input/output control device is not determined. is transmitted to the input/output control device via the bus connection and the computer system, and the 5 answers from the input/output control device are again transmitted to the central processing unit via the bus connection device to complete. As a result, the bus usage time of the basic bus to which the central processing unit is connected becomes long, reducing the transfer capacity of the basic bus.

On the other hand, in order to eliminate the above-mentioned reduction in transfer capacity, a register is prepared in the bus connection device to store the representative value of the channel number of the input/output control device on the expansion bus. It is also possible to consider a system in which a part of the number is compared with the above-mentioned representative value, and only when they match, a response is sent to the central processing unit from the bus connection device itself, and at the same time a command is transmitted to the expansion bus. In this case, since the bus connection device once takes over the command, the bus use time of the basic bus is shortened, so that it is possible to prevent a reduction in the transfer capacity of the basic bus.

(Problems to be Solved by the Invention) In the conventional bus connection device described above, the representative value is located above the channel number of the input/output control device. Therefore, assuming that the channel number consists of 8 bits,
The range of channel numbers is from 00(H) to F'FI#■). Assuming that the bit width of the representative value is 4 pits and the representative value is 5 (6), the input/output control devices connected to the expansion bus under the bus connection device will have channel numbers from 5004 to 5Fθ0. However, in this case, since the number of input/output control devices connected to the expansion bus is limited by the bit length of the representative value, there is a drawback in that the system configuration of the data processing system is subject to limitations.

An object of the present invention is to store the representative value of the channel number of the input/output control device on the expansion bus, and to
Directly store the mask value for arbitrary masking, compare the channel number of the instruction from the central processing unit to the input/output control unit, the above representative value, and all the above masks according to the instructions of the valid bit indicated by the bus connection. The input/output control device connected to the expansion bus under the device accepts only the Kawacho 8 command once, transmits it to the expansion bus, and removes the above drawback by changing the mask value, and controls the input/output under the expansion bus. An object of the present invention is to provide a bus connection device configured so that the range of channel numbers of a control device can be changed.

(Means for Solving the Problems) A bus connection device according to the present invention is a bus connection device connected to a basic bus of a data processing system and an expansion bus formed by logically extending the basic bus. , a representative value register, a mask register, a comparison circuit, and an expansion bus control means.

The representative value register is for storing the representative value of the channel number in the input/output control device on the expansion bus.

The mask register is used to store a mask value for masking the entire contents of the representative value register.

The comparison circuit is for comparing the representative value using the channel number, value, and mask value of the command sent from the central processing unit on the basic bus to the input/output control unit.

The expansion bus control means accepts only instructions for the input/output control device on the expansion bus connected by the bus connection device,
By transmitting the information on the expansion bus and changing the mask value, it is possible to change the range of channel numbers of the input/output control device under the expansion bus.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a bus connection device according to the present invention. In FIG. 1, 101 is a basic bus control circuit, 102 is a processing control circuit, 103 is an expansion bus control circuit, 104 is a representative value register, 105 is a mask register, 106 is a comparison circuit, 107 is a basic bus, and 108 is an expansion bus. It is.

In FIG. 1, a basic bus control circuit 101 is a basic bus 1
This is done for interface control with 07.

Commands from a central processing unit of a data processing system connected to basic bus 107 are input to basic bus control circuit 101 via basic bus 107 .

The channel number of the instruction is stored in the mask register by the comparator circuit 106! Only the valid bit portion indicated by the contents of 05 is compared with the contents of the representative value register 104. As a result of the comparison, if the two match, the processing control circuit 102 controls the basic bus control circuit 101, sends a response to the central processing unit, and takes over the command. The processing control circuit 102 controls the expansion bus control circuit 103g and transmits the above instructions to the expansion bus 108.

FIG. 2 is a block diagram showing an embodiment of a data processing system using a bus connection device according to the present invention. In FIG. 2, 201 is a basic bus, 202 is a central processing unit,
203 is a memory fCt1. 2041205 are bus connection devices, 206, 211, 212.221 to 2, respectively.
28 are input/output control devices, and 210 and 220 are expansion buses.

In FIG. 2, the central processing unit 202 is a storage device R2O3.
, bus-connected gi devices 204 and 205, and input/output control device fIL 206 via a basic bus 201, respectively. The bus-connecting FFC device 204 connects the basic bus 201 and the expansion bus 210, and the expansion bus 210 is connected to other input/output side #devices 211 and 212.

The bus connection device 205 includes a basic bus 201 and an expansion bus 220.
The expansion bus 220 is connected to other input/output control devices 221 to 228.

In the data processing system shown in FIG. 2, the channel number of the input/output control device is assumed to be 8 bits. At this time, the range of channel numbers is oo(H) to FF64). The representative value register 104 of the bus connection device 204 has a value of 10 (b).
is set, and FO■ is set in the mask register 105. At this time, the channel number range of the input/output control devices 211 and 212 connected to the expansion bus 210 is 100) to 13-. Further, the representative value register 104 of the bus connection device 205 is set to 20 (b), and the mask register 105 is set to dF8-. At this time, 2 in the channel number range of the input/output control devices 221 to 22B connected to the expansion bus 220.
0 (b) to 28 (g).

In this way, according to the configuration of the expansion bus, the mask register 10
By changing the contents of 5, it is possible to change the channel number range of the input/output control device on the expansion bus. The configuration can be varied.

(Effects of the Invention) As explained above, the present invention stores the representative value of the channel number of the input/output control device of the expansion bus in the bus connection device, and also stores the mask value indicating the valid bit of the representative value. , the representative value is compared with the channel number of the instruction from the central processing unit to the input/output side (Ill device), and only the valid bit part of the above mask value is compared, and the command from the central processing unit is output to the above bus connection device. receiving the instruction, transmitting it to the expansion bus, and changing the channel number range on the expansion bus by changing the mask value, only for the input/output control device connected to the expansion bus of Prevents a decline in the transfer capacity of the basic bus due to connection to an expansion bus,
This has the effect that the system configuration limitations can be relaxed compared to the case where no chemask register is provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of a bus connection IT according to the present invention. FIG. 2 is a block diagram showing an embodiment of a data processing system using a bus connection device according to the present invention. 101... Basic bus control circuit 102... Processing control circuit 103... Expansion bus control circuit 104... Representative value register 105... Mask register 106... Comparison circuit 107, 201... Basic bus 108, 210, 22tl...Expansion bus 202.
...Central processing unit is 203...Storage devices 204, 205...Bus g:, connection device 206.211
．． 212, 221-228... Input/output control device Figure 1 L16 A'2[4 zu01

Claims (1)

[Claims] A bus connection device connected to a basic bus of a data processing system and an expansion bus formed by logically extending the basic bus, the bus connection device having a representative value of a channel number in an input/output control device on the expansion bus. a representative value register for storing, a mask register for storing a mask value for masking the contents of the representative value register, and input/outputs sent from the representative value and the central processing unit on the basic bus. a comparison circuit for comparing a channel number of an instruction to a control device using the mask value; and a comparison circuit for accepting only instructions for an input/output control device on the expansion bus connected by the bus connection device; and an expansion bus control means capable of transmitting information on the bus and changing the range of channel numbers of input/output control devices under the expansion bus by changing the mask value. bus connection device.