STORAGE CONTROL APPARATUS

Abstract: A storage control apparatus for sequentially reading out each data element of vector data stored in a main storage unit (1-1-1) and for writing the readout data elements sequentially in the corresponding register elements of the vector register (VR1) disposed in a vector processor is disclosed. In the apparatus only the data element indicated as the write data by the mask information among the readout data elements are stored from the main storage unit (1-1-1) to the pertinent register elements of the vector register (VR1) in the vector processor based on the mask information which indicates whether or not the write operation is required (for example, "1" indicates that the write operation is necessary and "0" indicates that the write operation is unnecessary). When the mask information indicates that the write operation is not required, the storage control apparatus controls operations to prevent the memory bank of the main storage from being set to the busy state, thereby eliminating the memory bank con­ flict which should not take place in accordance with the intrinsic system characteristics.

Description: The present invention relates to a storage control apparatus for controlling operations to access a register or memory data in a vector processor or the like which is able to perform a high-speed vector operation. Figure 1 depicts an example of a FORTRAN program which contains a DO loop having a conditional statement and which is commonly utilized in a scientific calculation. The DO loop is processed in an ordinary vector processor as illustrated in Figure 2. First, each data element of a vector data A(l-n) comprising the vector data elements A(1), A(2), ..., A(n) stored in the main storage is sequentially read and is stored in a vector register VRØ(l-n), respectively. Then, each data element of VRØ(l-n) is compared with a constant data "0.0" by use of an arithmetic circuit associated with VRØ(l-n). If the compared data items are equal to each other, a bit "1" is stored as a mask information bit in the corresponding one of the register elements VMR0(1), VMR0(2), ..., VMR0(n) of the vector mask register VMRØ(l-n). If they are unequal, a bit "0" is stored in the corresponding register element in the same way. Next, each vector data element of the vector data C(l-n) and D(l-n) is sequentially read out in the similar manner and is stored in a corresponding one of the vector registers VR1(l-n) and VR2(l-n), respectively. Each register element of VR1(l-n), VR2(l-n), and VMRØ(l-n) is then sequentially read out. If the content of the register element of VMRØ(l-n) is "1", the content of the corresponding register element of vector register VR2(l-n) is stored in the corresponding register element of vector register VR3(l-n). If the content of the VMRØ(l-n) register element is "0", the content of the corresponding register element of vector register VR1(l-n) is stored in the corresponding register element of vector register VR3(l-n). Finally, the contents of vector register VR3(l-n) are written in the operand B(l-n) on the main storage. In the operation C ○ in Figure 2, the write operation is naturally unnecessary in the vector data C(l-n) read operation for the data element of which the corresponding mask information bit of the mask register MVRØ(l-n) is "1". Similarly, this is also the case in the vector data D(l-n) read operation d ○ for the data of which the corresponding mask information bit of the mask register MVRØ(l-n) is "0". In these operations, there has been problems that a plenty of registers are required because of the unnecessary data element read operations and that a loss time appears due to read operations of unrequired data elements from the main storage. From P. M. Kogge "The Architecture of Pipelined Computers", 1981, pages 150-155, Hemisphere Publishing Corporation, US, selective writing of vector elements provided by an operation unit into a memory is known. It is an object of the present invention to provide a storage control apparatus which executes the processing with a satisfactory performance by controlling the storage so that only the data elements necessary for the processing are selected from all the data elements sequentially read from the main storage and are written in the corresponding register elements of a register. The above object is achieved, according to the invention, by the features of claim 1. Claims 2 and 3 characterize advantageous developments thereof. The present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: Figure 1 is a program example commonly used in a computer system; Figure 2 depicts a flowchart of procedures for processing the program shown in Figure 1 by use of an ordinary vector processor; Figure 3 is a flowchart of procedures employed to process the program of Figure 1 with a vector processor to which the present invention is applied; Figure 4 illustrates a schematic block diagram of an embodiment of the present invention; Figure 5 depicts a conceptual diagram illustrating the procedure for transferring the vector data from the main storage to the vector register in the embodiment of Figure 4; Figure 6 is a simplified block diagram demonstrating an order pipeline configuration in the embodiment of Figure 4; Figure 7 is a table outlining the correspondences between the memory addresses and banks in the embodiment of Figure 4; Figure 8 illustrates a timing chart depicting the sequential read operation of vector data elements from the main storage in accordance with the embodiment of Figure 4; Figure 9 is a timing chart illustrating procedures to sequentially read vector data elements from the main storage with memory bank conflict in the embodiment of Figure 4; Figure 10 depicts a schematic block diagram of the modified examples of the main storage and order pipeline in the embodiment of Figure 4; Figure 11 is a timing chart illustrating the procedure for sequentially read vector data elements from the main storage to which the configuration of Figure 10 is applied; Figure 12 depicts a simplified configuration of another embodiment in accordance with the present invention; Figure 13 is a schematic diagram showing the configuration of a request stack in accordance with the embodiment of Figure 12; Figures 14a, 14b, and 14c illustrate information for the memory request addresses in the embodiment of Figure 12; Figure 15 is a block diagram depicting the configuration of the memory port in the embodiment of Figure 12; Figure 16 illustrates a schematic diagram of the configuration of the request transmission determiner circuit in the embodiment of Figure 12; and Figure 17 is a diagram illustrating the configuration of the memory unit in accordance with the embodiment of Figure 12. Figure 3 is a flowchart of procedures for executing the program example of Figure 1 in the processing system in accordance with the present invention. Steps g ○, h ○, and k ○ are identical to steps a ○, b ○, and f ○ in Figure 2 excepting that VR3 in step f ○ of Figure 2 corresponds to VR1 in step k ○ of Figure 3. That is, the vector registers VR2 and VR3 utilized in Figure 2 may be omitted in the processing of Figure 3. Referring to Figure 3, when the vector data is read in step i ○, only the data elements of which the corresponding mask information bit of the vector mask register VMRØ(l-n) is "0", that is, only the valid data elements are stored in the corresponding register elements of the vector register VR1(l-n). In step j ○, when the vector data D(l-n) is read, only the data elements of which the corresponding mask information of VMRØ(l-n) is "1" are stored in the corresponding register elements of VR1(l-n). In step k ○ finally, the contents of VR1(l-n) are written in the operand B(l-n) on the main storage, thereby implementing the execution of the processing equivalent to that of Figure 1. Figure 4 illustrates a schematic diagram of the configuration of an embodiment in accordance with the present invention. This arrangement comprises a memory device 1-1, a main storage device 1-1-1 including eight different memory banks, an order pipeline 1-1-2, a selector 1-1-50, a mask register section 2, an inverter circuit 2-1, a selector 2-2, a vector register section 3, a decoder 3-1, a register address pointer 3-2, a plus-one circuit 3-3, a comparator circuit 3-4, a request stack or buffer 20, and a memory port 30. Figure 5 illustrates the operations corresponding to step i ○ of Figure 3 in which the vector data C(1-8) stored in the main storage 1-1-1 is sequentially read based on the mask information of each data element in the mask register VMRØ(1-8) (that is, only the data elements of which the corresponding mask information value VMRØ(1-8) is "0" are read) and is stored in the vector register VR1. Since the contents of the register elements of mask register VMRØ are "0s" for the data element Nos. 2, 4, and 5 of the vector C(1-8), the mask information inverted by the inverter circuit 2-1 becomes "1" only for these data elements while all data elements of the vector C are sequentially read. Therefore, only these data elements need be stored in the corresponding register elements of the vector register VR1, and the write operation need not be conducted for the other register elements. In the following paragraphs, explanations will be given in conjunction with the processing schematically illustrated in Figure 5. First of all, in the embodiment of Figure 4, the contents stored in the register elements VRØ(1), VRØ(2), ....., VRØ(n) of the vector register VRØ are sequentially read and are compared with the data constant "0.0" by use of the comparator circuit associated with the vector register VRØ. If the compare result indicates VRØ(i) = 0.0, a bit "0" is stored in the corresponding register element of the vector mask register VMRØ as the mask information bit, otherwise, "1" is stored as the mask information bit. The request information signals from the vector processor (not shown) comprising the data element read/write request signal with respect to the main storage 1-1-1, memory address, store data (unnecessary for reading data from the main storage), and request order (read/write identification information) are stored in the request stack 20, then they are sequentially transferred to the memory device 1-1 via the memory port 30 in the manner well known in the art. In this case, the mask information of the mask register VMRØ corresponding to the data element is read in synchronism with the request signal described above (if necessary, that is, when the processing is equivalent to step i ○ of Figure 3, the read value is inverted by use of the inverter circuit 2-1), then the readout data is stored in the request stack 20 through the selection 2-2. As a result, the mask information thus read out is added as a portion of each request order and is transferred to the memory device 1-1 via the memory port 30. The memory port 30 identifies the relevant memory address contained in the request information signals read from the request stack 20 and checks the state (presence or absence of the bank busy output signal) of the bank in the memory device 1-1 corresponding to the memory address. If the bank is not in the busy state, the request signals are transmitted to the memory device 1-1 through the request line ℓ32-16; otherwise, the operation is controlled so as to delay the request signal transmission until the busy state is removed. On receiving the request signal transmitted from the memory port 30, the memory device 1-1 interprets the three low-order bits of the memory address simultaneously transferred and activates the necessary bank of the main storage 1-1-1; further, the memory device 1-1 outputs a read or write instruction signal on the line ℓ32-18 to indicate a read or write operation based on the read/write identification information of the request order. In this embodiment, a read operation is assumed to be indicated if the one-bit read/write identification information contains a value "0"; while a write operation is assumed if it contains a value "1". When the output signal from the memory port 30 indicates a read request, the control section of the memory device 1-1 transfers the read valid information indicating that there exists a read request for the required data element, the data valid information from the AND gate 1-1-202 indicating that the read valid information contains a value "1" (ON) and that the mask information passed through the selector 2-2 is "1", and the three low-order bits (bank address information) of the memory address on the line ℓ32-21 to the input of the order pipeline 1-1-2. In this embodiment, the order pipeline comprises a multiplicity of pipeline stages of which the number of stages is equal to the number of cycles which appear from the time when a read operation is initiated on a bank corresponding to the requested data element to the time when the requested data element is outputted as a read data from the bank. Based on the three-bit bank address information outputted from the last stage of the order pipeline 1-1-2 to the line ℓ1-1-50, the read data is selected via the selector 1-1-50 and is transferred to the vector register VR1. The read valid information is transferred as the write address update signal to the plus-one circuit 3-3 in the register section 3 through the line ℓ1-1-1 and is used to increment the register element address of the register address pointer 3-2 by one (register element updating for storing the subsequent read data). The data valid information is transferred as the write enable signal to the decoder 3-1 in the register section 3 through the line ℓ1-1-2. When the write enable signal is present, the data transferred from the memory device 1-1 is allowed to be stored as the valid data in the corresponding register element of the register VR1. In this manner, only the valid read data is stored in the relevant register element of the vector register VR1 specified by the register address pointer 3-2. Figure 6 concretely illustrates the configuration and input/output information of the order pipeline 1-1-2 described above. Referring to Figure 6, the circuit arrangement comprises a NOT circuit 1-1-200 and two AND circuits 1-1-201 and 1-1-202. It is assumed that the request information signals are sequentially transmitted from the vector processor (not shown) in the ascending order of the data element numbers assigned to the vector data and that each data element is read as the read data from the memory device 1-1 according to this order and only the valid data elements are stored in the corresponding register elements of the vector register VR1. Regardless of whether the data read from the memory device 1-1 is valid or invalid, the plus-one circuit 3-3 has been designed to access all the register elements ranging from the first register element address to the last register element address. That is, quite a simple configuration need only be used for the vector register section 3. In this case, since the read data of the data element of which the corresponding mask information which has passed the selector 2-2 of Figure 4 is "0" need not be written in the corresponding register element of the vector register VR1, the write enable signal is not required to be transferred to the decoder 3-1. However, the address update signal for writing the data of the next data element must be transferred to the plus-one circuit 3-3, hence the necessary information is required to be delivered to each stage of the order pipeline 1-1-2 even if the relevant mask information is "0". When the similar precessing is conducted on the vector D, all the desired data elements can be stored in the vector register VR1. For the write operation on the vector D, the selector 2-2 supplies the value of each register element of VMRØ directly to the request stack 20 without passing the value to the inverter circuit 2-1. Moreover, the configuration of Figure 6 demonstrating the masked data read operation in accordance with the present invention can be easily modified to be applicable to the ordinary data read operation. That is, to achieve an ordinary data read operation by use of the arrangement depicted in Figure 6, the mask information from the memory port 30, the AND circuit, and the data valid information selected from various information to be inserted into the order pipeline 1-1-2 becomes unnecessary. In this case, the write address update signal need only be utilized in place of the write enable signal. As described before, the main storage 1-1-1 of this embodiment comprises eight memory banks. Since each bank requires a plurality of cycles in general from the initiation of activation to the termination thereof, a read operation cannot be initiated for the different data elements in the same bank for each cycle. Therefore, the memory port 30 must issue such a request by checking the bank (busy) state in any cases. For the different banks, it becomes possible to issue a request for each cycle. Figure 7 shows an example of the correspondence between the memory addresses and banks in the main storage 1-1-1. In this table, each data element comprises eight bytes (64 bits) and the addresses are indicated in the hexadecimal notation. Figure 8 illustrates the operation timing and the write operation timing of the read data element in the vector register VR1 for the memory device 1-1, where the memory addresses for the data element request of the vector data C(1-8) are allocated to the banks in she ascending bank number order (bank 1 to bank 8) and the number of stage cycles of the order pipeline 1-1-2 is eight. It is assumed in this diagram that the write control signal represents the before-stated address update signal and write enable signal. Since the specified banks are different from each other in this situation, the request can be transmitted from the memory port 30 to the memory device 1-1 for each cycle unless there exist any requests from the other requester. Consequently, all the data read operations are completed through 17 cycles. Figure 9 is a schematic diagram depicting the similar operation timing as illustrated in Figure 8, where the banks are allocated in the order of banks 1, 5, 1, 5, 1, 5, 1, and 5 to the memory addresses for the data element request of vector data C(1-8). Such a bank allocation often occurs in the actual vector processing. Since four requests are issued to the banks 1 and 5, respectively in this case, the request to the memory device 1-1 cannot be transmitted for each cycle, and a loss time of 18 cycles (=35-17) may take place in some cases. The embodiment of Figure 4 allows to store only the valid data in the vector register as described before, and the step e ○ of Figure 2 can be eliminated, thus the number of vector registers to be used is reduced. As explained above, the unused cycle may appear due to the difference between memory addresses; furthermore, when there exist several requests from a plurality of requesters, the number of unused cycles is likely to increase due to the conflict among these requests. However, if the time elapsed by the unused cycles is minimized, the memory throughput can be reduced. When the mask information (which has passed the selector 2-2) corresponding to the data element for which a read request is accepted is "0", the relevant read data need not be written in the vector register VR1; therefore, the busy information of the bank is not required to be outputted. The write address update signal, however, is required to be transmitted to update the address of the register element to be written. In Figure 4, since the memory port 30 transmits the request signal for this purpose regardless of whether the mask information is "0" or "1" (by assuming that each mask information is "1"), the bank in which the unnecessary data element is stored becomes busy in some cases, and there exists a bank conflict, hence an unused cycle takes place because the subsequent request cannot be issued. Figure 10 is an example of a memory device configured not to cause the unnecessary unused cycle, wherein the same reference numerals as those of Figure 6 indicate the same parts or those having the equivalent functions. As compared with Figure 6, the memory banks 1-8 and the bank selector 1-1-3 are additionally illustrated in Figure 10. Referring to Figure 10, it is characteristic that the request signal on the line ℓ32-16 and the mask information on the line ℓ32-17 are logically processed by the AND gate 1-1-5 and that the resultant signal is supplied to an input of each of 16 AND gates 1-1-7, 1-1-8, ..., 1-1-22. Consequently, even when a request signal appears, all the AND gates 1-1-7, 1-1-8, ..., 1-1-22 are closed if the mask information is "0". That is, even when a bank is selected by the decoder 1-1-3, the bank is not activated. The bank activation for an unnecessary data element is thus prevented and the undesirable unused cycle does not take place. Figure 11 is the timing chart of the processing conducted by the memory device 1-1 of Figure 10, where any banks are not set to the busy state if the mask information is "0". To compare the operations between Figures 9 and 11, the banks 1, 5, 1, 5, 1, 5, 1 and 5 are assigned in this order, respectively to the memory addresses for the request of data elements C(1), C(2), ..., C(8). Since the mask information passed through the selector 2-2 is "0" for the request of data element C(1), the bank 1 is not set to the busy state in the first cycle (the banks enclosed with the broken lines will not become busy), the necessary information is transferred to the stage 1 of the order pipeline 1-1-2. The mask information passed through the selector 2-2 is "1" for the C(2) request in the second cycle, hence the bank 5 is made to be busy and the necessary information is delivered to the stage 1 at the same time. Moreover, the relevant information of the data element C(1) is shifted from the stage 1 to the stage 2. The mask information is "0" for the data element C(3) request, thus the necessary information is transferred to the stage 1 in the third cycle subsequent to the C(2) request irrespective of the bank utilization stage. (It is noted that the bank 1 is not set to the busy state in this situation.) At the same time, the necessary information items on the stages 1 and 2 are shifted to the stages 2 and 3, respectively. On the other hand, even when the mask information outputted from the selector 2-1 is "0", the corresponding bank is set to the busy state in Figure 9, so the C(3) request processing is delayed until the bank 1 which has been made busy with the C(1) request is freed. In accordance with above-mentioned processing, the number of unused cycles is reduced from 18 (Figure 9) to 6 (Figure 11). Figure 12 is a simplified configuration illustrating another embodiment in accordance with the present invention, where a plurality of requesters for requesting the vector data read/write operations and a plurality of memory devices are provided. Referring to Figure 12, the simplified configuration comprises memory devices 1-1 to 1-4, main storage units 1-1-1 to 1-4-1, each consisting of eight banks, order pipelines 1-1-2 to 1-4-2, a mask register section 2 comprising mask registers, NOT circuits 2-1 to 2-3, selectors 2-2 and 2-4, a vector register section 3 comprising vector registers, a data pass select circuit 3-100 for writing the read data in the specified vector register, a vector processing unit (VU)4 for processing the vector instructions, a scalar processing unit (SU)5 for processing the scalar instructions, a channel processor (CHP)6 for processing input/output operations, a memory control unit (MCU)7, and memory requesters 10 and 11. The memory request source is VU4, SU5, or CHP6. Request stacks 20 and 21 are used to stack the memory requests from the VU; request stacks 22 and 23 are used to buffer the memory requests from the CHP and SU, respectively; memory ports 30-33 are provided for the memory devices 1-3, 1-4, 1-1, and 1-2, respectively; selector circuits 40 and 41 are used to select from the memory devices 1-1 to 1-4 the read data corresponding to the read request transmitted from the memory requester 10 or 11 of the VU and to transfer the read data to the vector register group 3, and selector circuits 42 and 43 are provided for the CHP and SU, respectively. Figure 13 illustrates the configuration of the request stack 20 (the same configuration is also used for the request stacks 21-23). The reference numerals 20-1 to 20-8 indicate a stack register group comprising a plurality of stack registers for stacking the request information transferred from the memory requesters through the signal lines ℓ20-1, ℓ20-3, and ℓ20-4 and the mask information transferred from the selector 2-2 via the signal line ℓ20-2; the reference numeral 20-1 indicates a request signal (one bit), the reference numeral 20-2 indicates the mask information (one bit), the reference numeral 20-3 represents the read/write identification information (one bit; "0" for a read operation and "1" for a write operation), the reference numeral 20-4 indicates the access request source information (two bits; for example, "00" for the VU memory requester 10, "01" for the VU memory requester 11, "10" for the SU, and "11" for the (CHP); the reference numeral 20-5 represents the high-order address for specifying a memory position in the specified bank, the reference numeral 20-6 indicates a bank address (three bits), the reference numeral 20-7 represents a port address (two bits), and the reference numeral 20-8 indicates a register group for storing therein the store data (only for a write request). From the mask register group 2, the corresponding mask data element is sequentially read as the mask information in synchronism with the request signal 20-1. In this case, with the instruction which specifies the processing i ○ of Figure 3, the register element No. 1 of the VMR is selected and the mask information bit stored therein is read out from the mask register group 2. Since the signal obtained by inverting the value of the mask information bit in the register element No. 1 of VMR is used as the mask information in the processing i ○, the read data is inputted to the memory stack 20 through the NOT (inverter) circuit 2-1 and the selector 2-2. Although the mask information bit stored in the register element No. 1 of VMR is similarly read out with the instruction which specifies the processing j ○ of Figure 3, the mask information need not be inverted, thus the read data is not transferred to the NOT circuit 2-1, that is, it is directly inputted to the memory stack 20 through the selector 2-2. The reference numeral 20-10 indicates a write pointer, the reference numeral 20-14 represents a read pointer, the reference numerals 20-11 and 20-15 indicate plus-one circuits, the reference numerals 20-16, 20-13, and 20-17 represent decoders, the reference numeral 20-16 indicates an OR circuit, the reference numerals 20-18 to 20-21 represent AND circuits, and the reference numerals ℓ20-1 to ℓ20-4, ℓ20-10 to ℓ20-21, ℓ30-6, ℓ31-6, ℓ32-6, and ℓ33-6 indicate signal lines. When a request signal is transmitted via the signal line ℓ20-1, the value of the write pointer 20-10 is interpreted by the decoder 20-12 and the request information is stacked in the stack register having the specified register number; furthermore, the value of the write pointer 20-10 is incremented by one in the plus-one circuit 20-11 to prepare the stack register number for the next request. The value of the read pointer 20-14 is decoded by the decoder 20-13, then the request information is read from the stack register having the specified register number. In this case, the request signal outputted from the register group 20-1 is inputted to the AND circuits 20-18 to 20-21, and the port address transmitted from the register group 20-7 is decoded by the decoder 20-17 and is delivered to the AND circuits 20-18 to 20-21 as depicted in Figure 13, then these two signals are ANDed. That is, if the request signal is "1", a two-bit port address is obtained by the decode operation, and "1" is outputted from one of the AND circuits 20-18 to 20-21. When the port address is indicated with "00", "01", "10", or "11", only one of the corresponding outputs on the signal lines ℓ20-16 to ℓ20-19 becomes "1", respectively; and the output is transmitted as a port request signal to the port 32, 33, 30, or 31, respectively. At the same time, the mask information, read/write identification information, access request source information, high-order address, bank address, and store data are transmitted to all of the ports 30-33 through the signal lines ℓ20-11, ℓ20-12, ℓ20-13, ℓ20-14, ℓ20-15, and ℓ20-20, respectively. The port requests transmitted to the ports 30-33 are checked to determine their priority with respect to the port requests from the other request stacks and transmitted to the corresponding memory devices. Then the accept signal indicating that the memory request has been transmitted to the corresponding memory device is returned from the ports 32, 33, 30, and 31, respectively via the signal lines ℓ32-6, ℓ33-6, ℓ30-6, and ℓ31-6 to the corresponding request stack. These signals are ORed in the OR circuit 20-16 and the resultant signal is inputted to the plus-one circuit 20-15 through the signal line 20-21 to be used to increment the value of the read pointer 20-14 by one. The signal ine ℓ20-21 also transfers the signal to the corresponding requester to notify that the transmitted request has been processed (enabling to transmit another request if necessary). Figures 14a, 14b, and 14c depict examples in detail of the high-order address, bank address, and the port address, respectively. If it is assumed that the memory capacity is 4 GB and the memory address is indicated in byte units, an address information must comprise 32 bits in this case. Furthermore, the data processing unit (for instance, the vector data element) for the memory access is eight bytes and the three low-order bits of the memory address is to be ignored (or is assumed to be all "0"). Figure 15 illustrates the configuration of the port 32. The same function is also provided for the ports 30, 31, and 33. Referring to Figure 15, the reference numerals 32-1 to 32-4 indicate the request transmission determiner circuits which determines the condition for transmitting a request to the memory device 1-1 by inputting the port request signal, mask information, and bank address transmitted from the request stacks 20-23, respectively and the bank busy signals outputted from the bank busy circuit 32-9 through the signal lines ℓ32-5-1 to ℓ32-5-8; the reference numerals 32-5 to 32-10 indicate a priority circuit, an OR circuit, a selector, an AND circuit, a bank busy circuit, and a register; and the reference numerals ℓ32-1 to ℓ32-4, ℓ32-5-1 to ℓ32-5-8, and ℓ32-6 to ℓ32-22 represents the signal lines. Figure 16 illustrates the configuration of the request transmission determiner circuit 32-1 (as well as the request transmission determiner circuits 32-2 to 32-4) comprising NOT circuits 32-50 to 32-58, AND circuits 32-59 to 32-67, an OR circuit 32-68, and a decoder 32-69. The three-bit bank address transferred via the signal line ℓ20-15 is decoded by the decoder 32-69. When the decoded value is "000", "001", ..., or "111"; the bank 1, 2, ..., or 8 is specified, respectively; and the resultant signal is inputted to one of the AND circuits 32-60 to 32-67, accordingly. Furthermore, bank busy signals for the banks 1 to 8 outputted from the bank busy circuit 32-9 are inputted to the AND circuits 32-60 to 32-67, respectively through the signal lines ℓ32-5-1 to ℓ32-5-8 and the NOT circuits 32-51 to 32-58, respectively. These input signals and the bank address signal transferred through the signal line ℓ20-15 are ANDed, then the resultant output signals are inputted to the OR circuit 32-68. The mask information transferred via the signal line ℓ20-11 is inverted by the NOT circuit 32-50, and the inverted signal is ANDed with the port request signal by the AND circuit 32-59, then the ANDed output is transferred to the input of the OR circuit 32-68. That is, a signal "1" is outputted from the OR circuit 32-68 via the signal line ℓ32-1 if the port request signal is "1" and the bank busy signal is "0" (indicating that the relevant bank is not busy) for the bank number specified with the bank address, or if the port request signal is "1" and the mask information is "0". The latter condition indicates that the request can be transmitted regardless of the bank utilization state because the mask information is "0". The request transmission enable signals for each request stack outputted from the request transmission determiner circuits 32-1 to 32-4 via the signal lines 32-1 to ℓ32-4, respectively are accepted by the priority circuit 32-5 in accordance with a predetermined priority. The priority circuit will not be described in detail; however, in a situation in which a priority number is assigned to each equest transmission enable signal inputted to the priority circuit and there exists a plurality of request transmission enable signals to be input thereto, it can be considered to control the signal acceptance in the descending priority number order. The signal lines ℓ32-6 to ℓ32-9 are set to "1" when accepted for the port request signals from the request stacks 20-23, respectively, and these signals are transmitted as before-stated accept signals to the corresponding request stacks, respectively. Moreover, these signals are inputted to the selector 32-7 and are used to select the request information from the corresponding request stack and the selected information is set to the register 32-10, then the mask information, read/write identification information, access request source information, high-order address, bank address, and store data are transmitted to the memory device 1-1 through the signal lines ℓ32-17 to ℓ32-22, respectively. The request transmission enable signals outputted via the signal lines ℓ32-1 to ℓ32-4 are ORed by the OR circuit 32-6, and the ORed output signal is transmitted to the memory device 1-1 as the memory request signal via the signal line ℓ32-16. The signal line ℓ32-10 is further connected to the AND circuit 32-8 and is ANDed with the signal line ℓ32-11 from which the mask information is outputted, then the ANDed output signal inputted to the bank busy circuit 32-9 through the signal line ℓ32-15. At the same time, the bank address is inputted to the bank busy circuit 32-9 via the signal line 32-13. That is, only when any one of the request transmission enable signals is "1" and the mask information is "1", the signal line ℓ32-15 is set to "1" and the bank having the bank number specified by the bank address inputted from the signal line ℓ32-13 is made busy for a time period comprising the necessary number of cycles. If the mask information is "0", the bank is not set to the busy state. Figure 17 depicts the configuration of the memory device 1-1 (the other memory devices are also configured in the same manner) comprising an order pipeline 1-1-2, a decoder 1-1-3 for decoding the three-bit bank address, a NOT circuit 1-1-4, AND circuits 1-1-5 to 1-1-23 (AND circuits 1-1-11 to 1-1-20 are not shown), a selector 1-1-24, memory banks 1-1-25 to 1-1-32 (memory banks 1-1-27 to 1-1-31 are omitted), and signal lines ℓ1-1-1 to ℓ1-1-4. A three-bit bank address transferred via the signal line ℓ32-21 is decoded by the decoder 1-1-3, and the decoded signal is inputted to the AND circuits 1-1-7 to 1-1-22; while the memory request signal transferred through the signal line ℓ32-16 is ANDed with the mask information transferred through the signal line ℓ32-17 by the AND circuit 1-1-5, then the obtained output signal is supplied to the AND circuits 1-1-7 to 1-1-22. Furthermore, the read/write identification information transmitted via the signal line ℓ32-18 is inverted by the NOT circuit 1-1-4 and the resultant inverted signal is inputted to the AND circuits 1-1-7, 1-1-9, 1-1-11, ..., 1-1-21. Then, these input signals are ANDed therein and the output signals are delivered as the read initiate signals to the memory banks 1-1-25 to 1-1-32, respectively. The identification information described above is directly inputted to the AND circuits 1-1-8, 1-1-10, ..., 1-1-22, and the resultant output signals are used as the write initiate signals to the memory banks, respectively. At the same time, the high-order address and the store data (only for a write request) transferred through the signal lines ℓ32-20 and ℓ32-22 are also inputted to each memory bank. The read valid information ("1" indicates that there exists a read request) outputted from the AND circuit 1-1-6, the data valid information (outputted from the AND circuit 1-1-23) which is set to "1" when the read valid information delivered from the AND circuit 1-1-16 is "1" and the mask information via the signal line ℓ32-17 is "1", the access request source information from the signal line ℓ32-19, and the bank address from the signal line ℓ32-21 are inputted to the order pipeline 1-1-2. Through the pipeline stage operations of which the time period is equal to the number of cycles enough to access a memory bank, the selector circuits 40-43 are supplied with the read valid information as the write address update signal via the signal line ℓ1-1-1, the data valid information as the write enable signal via the signal line ℓ1-1-2, the access request source information via the signal line ℓ1-1-3, and one of the data signals outputted from memory banks and selected as the read data based on the bank address by the selector 1-1-24 via the signal line ℓ1-1-4. Each selector circuit 40-43 interprets the two bits of the access request source information to determine whether or not the information is to be obtained. If this is the case, the write address update signal, write enable signal, and the read data are obtained, then they are transferred to the access request source, respectively. With an execution of an instruction for specifying the processing i ○ of Figure 3, for instance, the read data corresponding to the request signal issued from the memory requester 10 is fetched into the relevant selector circuit 40. The fetched read data is transferred via the data pass select circuit 3-100 and is stored in the first vector register (VR1) of the vector register group 3. At the same time, in synchronism with the read data, the write address update signal and the write enable signal are also transferred to the first vector register. The write address update signal indicates to increment (by one) the content of the pointer which specifies the vector register element number for storing data in the vector register, thereby setting the element number for storing the next read data to be transferred. The write enable signal indicates whether or not the transferred read data is to be stored in the register element specified by the content of the store register element numer pointer before it is incremented by one with the write address update signal. The vector data read out from the memory in the order of the ascending register element numbers are, in this manner, stored sequentially in the vector registers under control of the write address update signal and the write enable signal. Although the information which generates the write enable signal, write address update signal, request issue source information, and the like is supplied to the order pipeline in the memory device, this provision need not be necessarly disposed in the memory device, that is, the provision can be also disposed in any device that assures the identical functions thereof. As can be clear from the foregoing description, the present invention allows to read only the vector elements necessary for the processing, thereby realizing an efficient processing.

Claims: A storage control apparatus, comprising: a memory (1-1) comprised of a plurality of memory banks for storing therein at least one vector data block comprising a plurality of vector elements; a vector register (VR1) having a plurality of storage locations in which each of the plurality of vector elements can be stored; a memory requester (10) for sequentially generating memory addresses for the vector elements and related read requests; mask register means (2) for providing mask information corresponding to each of the vector elements, which indicates a corresponding vector element to be written into the vector register; a memory port (32) for supplying a memory address and a related read request generated by the memory requester for a vector element to be read next, to the memory, under a condition that one of the memory banks which holds the vector element is available for access; and characterized by an order control pipeline circuit (1-1-2) for delaying the read request supplied from the memory port to the memory and corresponding mask information provided by the mask register means (2) by a time period which is dependent upon a time period required for read out of the vector element; and write control means (3-1 to 3-3) for writing the vector element read out from the memory in a corresponding location of the vector register in response to the delayed read request if the delayed mask information indicates that the vector element is to be written. A storage control apparatus according to claim 1, wherein the memory does not perform a read operation when mask information for a vector element to be read next indicates that the vector element should not be written into the vector register. A storage control apparatus according to claim 1 or 2, further comprising a request stack for holding request groups each comprising a memory address and a related read request generated by the memory requester for a vector element and corresponding mask information provided by the mask means, wherein the memory port sequentially supplies the request groups to the memory.

Inventors: NAGASHIMA, SHIGEO, OMODA, KOICHIRO
Applicants: HITACHI, LTD.
Application year: 1984
Main classification: G06F15
IPC codes: G06F15, G06F17