Abstract: The invention provides a multichannel drive circuit by which, even when there occurs a variation between channels in circuit characteristics of each channel including current source due to the semiconductor manufacturing process and the like, loads of each channel constituting a load array can be driven under conditions uniform between all the channels. The invention includes; an interchannel common connection line (5) for making conduction between respective current paths of each channel for connecting the respective current sources of each channel constituting a current source array (11) with respective input switches of each channel constituting an input switch array (13); and current blocking means (12) for blocking output current of the current source of that channel of the plurality of channels in which the input switch is in an OFF state from flowing into the interchannel common connection line.

Abstract: The invention provides a multichannel drive circuit by which, even when there occurs a variation between channels in circuit characteristics of each channel including current source due to the semiconductor manufacturing process and the like, loads of each channel constituting a load array can be driven under conditions uniform between all the channels. The invention includes; an interchannel common connection line (5) for making conduction between respective current paths of each channel for connecting the respective current sources of each channel constituting a current source array (11) with respective input switches of each channel constituting an input switch array (13); and current blocking means (12) for blocking output current of the current source of that channel of the plurality of channels in which the input switch is in an OFF state from flowing into the interchannel common connection line.

Abstract: An apparatus that changes text data into a voice signal based on the position of a vehicle is disclosed. A main gazetteer is subdivided into multiple area gazetteers, wherein each area gazetteer contains information corresponding to the mapping area that the vehicle is located. When the vehicle's position moves to a different mapping area, an analysis controller detects the change in mapping area and selects the new corresponding area gazetteer. The information of the new area gazetteer is then outputted as speech. This technique of subdividing the main gazetteer into area gazetteers increases the retrieval speed of information to the operator of the vehicle.

Abstract: A accordance determining circuit (113) that determines whether or not a cache address CA required in updating a cache data memory (111) and a cache tag memory (112) accords with the address of data read from an external memory (130) is provided. When the accordance determining circuit (150) has determined an accordance state, a register (115) is enabled so that cache data read from the external memory (130) is stored in a register (115) and supplied to a cache requester (101). Alternatively, a means for generating an address corresponding to the next data of data to be updated in updating the cache data memory (111) and (112) is provided so as to determine the cache status of an address being generated. Thus, if the determined result represents that the cache data has not been stored, a plurality of data are updated at a time. Consequently, the mis-hit penalty time can be reduced and the hit ratio can be improved.

Abstract: In an instruction prefetch circuit, even when a branch instruction is prefetched, the circuit continues a prefetch operation until branching is actually executed. Accordingly, when the branch instruction is a conditional branch instruction and not actually executed, the circuit continues the prefetch operation so that the prefetched instructions are efficiently supplied to a processor. It may be arranged that, when the branch instruction is an unconditional branch instruction, a branch destination address is extracted from the unconditional branch instruction and used as a prefetch address. Accordingly, the circuit continues the prefetch operation even when branching is executed. It may further be arranged that, when the branch instruction is a conditional branch instruction, a branch destination address is extracted from the conditional branch instruction and further a branch prediction is performed.

Abstract: A accordance determining circuit (113) that determines whether or not a cache address CA required in updating a cache data memory (111) and a cache tag memory (112) accords with the address of data read from an external memory (130) is provided. When the accordance determining circuit (150) has determined an accordance state, a register (115) is enabled so that cache data read from the external memory (130) is stored in a register (115) and supplied to a cache requester (101). Alternatively, a means for generating an address corresponding to the next data of data to be updated in updating the cache data memory (111) and (112) is provided so as to determine the cache status of an address being generated. Thus, if the determined result represents that the cache data has not been stored, a plurality of data are updated at a time. Consequently, the mis-hit penalty time can be reduced and the hit ratio can be improved.

Abstract: A cache memory device stores image data which are arranged corresponding to address data having first and second two-dimensional coordinate data. The image data are divided into a plurality of first groups in accordance with the first two-dimensional coordinate data, with the first groups further divided into a plurality of second groups in accordance with the second two-dimensional coordinate data. The cache memory device includes an image data memory for storing a given image data therein, which is divided into a plurality of block areas arranged in two dimensions. The reading and writing of image data from and to the image data memory is controlled by a central processing unit. A cache storage, comprising a cache memory, an address data decoding circuit, an address matching circuit and a control circuit, is coupled between the image data memory and the central processing unit by way of buses.

Abstract: A processing unit has a first data bus and a second data bus that receive first and second data from, respectively, first and second registers in a register file. An arithmetic-logic unit performs arithmetic and logic operations on the first and second data to produce third data, which it places on a third data bus. A selection circuit coupled to the first and third data buses selects either the first or third data for input to a third register in the register file, and either the first or third data for input to a fourth register in the register file. The first, second, third, and fourth registers are selected by a control circuit.