A method of data transfer applicable to processing elements which are interconnected by a network to form a multiprocessor system, whereby when a datum is to be transferred from a processing element to the network, the datum is sent to a transfer controller of the processing element at the same time that it is being read out from memory to be used by the processor of the processing element, or as it is being generated from the processor and written into memory. Thus, the system performance can be substantially improved, since the time required to execute each data transfer can be "hidden" within the processor execution time.
A multiprocessor system includes first and second microcomputers, a address decoding mechanism, and a ready signalling device. The address decoder is coupled to an address bus, to decode address information transferred by the second microcomputer, and supplies a request signal to a request signal input terminal of the first microcomputer. A bus control unit of the first microcomputer responds to the request signal to detect whether an internal bus of the first microcomputer is free from being used by the CPU, and outputs an acknowledge signal to an acknowledge signal output terminal when the internal bus is free. The ready signaling device is coupled to the acknowledge signal output terminal to supply the ready signal to a ready signal input terminal of the second microcomputer in response to the acknowledge signal outputted at the acknowledge signal output terminal and the request signal. The bus control unit of the first microcomputer further responds to a strobe signal transferred to a strobe signal input terminal through a strobe signal line from the second microcomputer to access an address of the internal memory by using the address information transferred to a set of first address terminals through the address bus and performs a data read/write operation on the address of the internal memory through the internal bus.
In a digital processor having a plurality of memories and a plurality of ALUs, each of address ports of each of the memories is associated with an address generation circuit capable of executing a loop processing required for address generation. With this arrangement, it is possible to access a plurality of memories, and therefore, the processing efficiency is improved.
A multiprocessor system containing a networking apparatus and a plurality of processors for transferring data through the networking apparatus from one to another of the plurality of processors. At least one receiving-side processor transmits a transfer allowance signal to the networking apparatus when the processor is ready to receive data, and transmits an on-line/off-line signal to the networking apparatus, where the on-line/off-line signal indicates whether the second processor is in an on-line state or off-line state. The networking apparatus includes a data transfer control unit, provided on each route for transferring data, for receiving data transferred from one of transmitting-side processors, temporarily storing the data, and transferring the data to one of the receiving-side processor when the data transfer control unit receives the transfer allowance signal from the second processor; and an off-line state detecting unit for outputting a data discharge control signal to the data transfer control unit when the on-line/off-line signal indicates that the second processor is in the off-line state. The data transfer control unit further contains a data discharge unit for discharging the data temporarily stored in the data transfer control unit in response to the data discharge control signal, regardless of the transfer allowance signal.
A data transfer apparatus for providing efficient data transfer between one memory device and multiple devices by providing high speed switching of the multiple devices according to a count of the number of the data transfers performed between the one memory device and any of the multiple devices. The data transfer apparatus comprises a transferring unit for controlling a data transfer between the memory and a device; a counting unit for counting one each time data is transferred; and a selecting unit for selecting a device in accordance with a count value by decoding the count value output from the counting unit. The transferring unit controls the data transfer between the memory and the device selected by the selecting unit. The above data transfer apparatus may include the counting unit consisting of n-bits of a binary counter, 2.sup.n devices, and the selecting unit consisting of a decoder that inputs n-bits and outputs 2.sup.n -bits of data.
A data processing unit is adapted to exchange data with another data processing unit via a network. The data processing unit includes a main storage for storing programs and data, an instruction processor for issuing transfer requests by executing programs stored in the main storage, and a transfer processor for enqueuing the transfer requests from the instruction processor into a transfer request queue, and for carrying out a transfer process between the main storage and the network based on each transfer request which is obtained from the transfer request queue. The transfer processor includes a failure display for displaying a failure when the failure occurs during the transfer process of each transfer request, a reference to and an erasure of a content of the failure display are possible from the instruction processor. The transfer process of the transfer request enqueued in the transfer request queue is prohibited during a time in which the failure is displayed in the failure display.
