Abstract: A data processor for executing instructions using operand data stored in a main memory includes an instruction control unit having a first associative memory storing instructions read out from the main memory. The data processor also includes an instruction controller reading out an instruction from the first associative memory when the instruction is present in the first associative memory and reading an instruction from the main memory when the instruction is not present in the first associative memory. The controller also has as an output; and an instruction execution unit has a second associative memory storing operand data read out from the main memory. An instruction executioner executes the instruction by using operand data read out from the second associative memory when the operand data is present in the second associative memory and from the main memory when the operand data is not present in the second associative memory.

Abstract: A static logic circuit employs pull-down type logic gates having logic transistors forming a power supply current path and logic transistors forming a grounding current path and having current drive abilities higher than those of the logic transistors forming the power supply current path, and pull-up type logic gates having logic transistors forming a power supply current path and logic transistors forming a grounding current path and having current drive abilities lower than the logic transistors forming the power supply current path, and comprises logic series formed by alternately cascading the two types of the logic gates. The static logic circuit is provided with signal merged logic circuits each of which provides a signal having a high speed falling transient and a high speed rising transient by merging the output signals of the logic series.

Abstract: A pass transistor type selector circuit comprises a control signal supplying circuit for supplying a pair of control signals of opposite phases to the respective gate electrodes of a pair of nMOS transistors of a selecting circuit. The control signal supplying circuit includes a control signal interrupting means which operates in synchronism with a clock signal so as to selectively interrupt the supply of the control signals to the signal selecting circuit while the clock signal is low level. The control signal interrupting means is provided with a discharging means for discharging high-level one of the gate electrodes of the nMOS transistors of the signal selecting circuit while the clock signal is low level. The discharging means comprises two nMOS transistors, each connected between the respective gate electrodes of the nMOS transistors of the signal selecting circuit and a grounding terminal.

Abstract: A processor for use in a data processing system with a cache RAM and main memory has a control pin for deactivating the driving of the data bus without deactivating that of the address bus during a write cycle. This capability is useful during a cache storing operation following a miss for performing a write operation without the requirement of additional address storing circuitry. In particular, during a cache storing operation, the processor can drive the address bus while control of the data bus by the processor is floated. Then, the data in main memory can be put on the data bus and transferred into the cache memory. Once the data is transferred to the cache memory, the original write operation can be completed.

Abstract: The semiconductor device has more-significant global data lines and less-significant data lines hierarchically formed, and switches for controlling the more-significant global data lines and the less-significant data lines to be connected each other. In addition, the semiconductor device has the unit for precharging the global data lines independently of the data lines.

Abstract: An instruction fetch unit (640) of a data processor (610) capable of simultaneous execution of two instructions fetches a first and a second instruction from a memory (620) in one cycle. The first and the second instruction thus fetched are set in a first and a second register (641, 642) before being decoded in a first and a second instruction decoder (644, 645). Comparators (131, 132) compares data on the destination field of the first instruction with data on the source field of the second instruction. When both the data are inconsistent, a parallel operation control unit (646) permits the first and the second instruction execution unit (651, 652) under the first and the second instruction to execute the two instructions in response to the outputs of the comparators (131, 132). When both the data are consistent, the parallel operation control unit (646) inhibits the parallel execution.

Abstract: A multiprocessor system of the present invention has an address bus, a data bus, first and second processors, four access queues, and a shared memory divided into four banks. The four access queues are constituted by first-in first-out memories for buffering a plurality of access-request addresses transmitted through the address bus. Even if continuous access requests are addressed to one bank of the shared memory, a succeeding access request need not wait for a previous access request to be finished. Accordingly, the throughput of the system can be improved greatly.

Abstract: A data processor is used with a main memory that stores operand data and instructions. The data processor itself includes two cache memories, one of which stores logical instruction addresses and corresponding instructions while the other stores logical operand addresses and corresponding operand data. A selector chooses whether a logical operand address or logical instruction address should access the respective cache memory or the main memory to obtain an instruction or operand data. Furthermore, the processor includes the capability of invalidating all of the data in either the instruction cache memory or operand cache memory based on a software instruction signal received at a purge unit.

Abstract: A data processor is provided with a first register storing a first half word of one instruction; a second register storing a second half word of the instruction; a first decoder decoding the first half word and at the same time detecting whether there exists an addressing extension portion between the first half word and the second half word; a second decoder decoding the second half word; and, a decode result generating circuit, to which a detection signal of the first decoder indicates whether the addressing extension portion exists. A decode result of the first decoder and a decode result of the second decoder are supplied to the decode result generating circuit. An extension portion register is provided to store the addressing extension portion. When the first decoder detects the addressing extension portion, the decode result generating circuit invalidates the decode result of the second decoder.

Abstract: First and second instructions are simultaneously fetched from a memory to be respectively decoded by first and second instruction decoders. An instruction execution unit includes a register file, an arithmetic and logic unit, and a shifter. A first comparator compares a destination field of the first instruction with a first source field of the second instruction. The shifter produces an output in association with immediate data of the first instruction, the output being ordinarily stored in a register file. However, when both inputs of the comparator are identical to each other, the output from the shifter is supplied to an input of the arithmetic and logic unit via a bypass signal transmission path.

Abstract: In a first embodiment of a CAM (Content Addressable Memory) or cache memory of the present invention disclosed herein, comparing information stored in a memory cell with comparison input information is accomplished in a comparison circuit without first converting a readout current from the memory cell into voltage information. In another embodiment, a matching detection between first stored information outputted from a first memory cell array and second stored information outputted from a second memory cell array is accomplished by an integrally formed sensing and matching detection circuit which is characterized as having both sensing and matching detection capabilities. That is, the sensing and matching detection circuit senses both stored information and thereafter detects matching based on a sensing result.

Abstract: A data processor for executing instructions using operand data stored in a main memory includes an instruction control unit having a first associative memory storing instructions read out from the main memory, and an instruction controller reading out an instruction from the first associative memory when the instruction is present in the first associative memory and from the main memory when the instruction is not present in the first associative memory the instruction control unit produces an output to be executed. An instruction execution unit has a second associative memory that stores operand data read out from the main memory, and an instruction executioner executing the instruction by using operand data read out from the second associative memory when the operand data is present in the second associative memory and from the main memory when the operand data is not present in the second associative memory.

Abstract: In a pipeline processing microprocessor, an instruction fetch unit is keyed to the formation or nonformation of a conditional branch micro-instruction result to determine the subsequent macro-instruction to be fetched from an external memory or cache. A macro-instruction is first decoded in an instruction decoder to generate micro-addresses which address is a micro-ROM. The first micro-instruction retrieved from the micro-ROM contains information for executing a conditional discrimination, a signal requesting branch ready, and a subsequent micro-address for the actual execution of the branch request in accordance with the result of the conditional discrimination. When the branch condition is satisfied, a micro-address generating circuit feeds the subsequent micro-instruction to a micro-ROM address decoder and the least significant bit of the subsequent micro-address to a micro-address analyzing circuit.

Abstract: A data processor for executing instructions using operand data stored in a main memory includes an instruction control unit having a first associative memory storing instructions read out from the main memory, and the instruction control unit also includes an instruction controller reading out an instruction from the first associative memory when the instruction is present in the first associative memory and from the main memory when the instruction is not present in the first associative memory. The instruction controller provides the instruction to be executed as an output. The data processor further includes an instruction execution unit having a second associative memory storing operand data read out from the main memory, and an instruction execution unit that executes the instruction.

Abstract: A microcomputer system has a microprocessor and a number of independent coprocessors for executing individual instructions according to instruction data sent from the microprocessor. An address bus and a data bus interconnect the coprocessors with the microprocessor. The microprocessor sends instruction data to the coprocessors via the data bus and concurrently sends coprocessor designation data to the coprocessors via the address bus. The coprocessor designated by the designation data reads and reacts to the instruction data while the other coprocessors within the system disregard the instruction data.

Abstract: A data processor for executing instructions using operand data stored in a main memory includes an instruction control unit having a first associative memory storing instruction read out from the main memory, and an instruction controller reading out an instruction from the first associative memory when the instruction is present in the first associative memory and from the main memory when the instruction is not present in the first associative memory the instruction control unit produces an output the instruction to be executed. An instruction execution unit has a second associative memory that stores operand data read out from the main memory, and an instruction executioner executing the instruction by using operand data read out from the second associative memory when the operand data is present in the second associative memory and from the main memory when the operand data is not present in the second associative memory.

Abstract: When the access is effected sequentially such as the prefetching of an instruction or the restoration of a register in the stack region, the retrieval is effected simultaneously for the consecutive addresses and the result is stored. When the consecutive addresses are to be accessed, the hit is determined relying upon the result that is stored without effecting the cache memory reference. In the case of mishit, the external memory is readily accessed to shorten the overhead time required for the cache memory reference. Therefore, the access time can be shortened in average.

Abstract: A content-addressable memory which has a storage bit cell (121, 122), signal supplying circuits (380, 390, 400) and comparison circuits (125, 126, 127, 128). The storage bit cell (121, 122) holds a first data (D) and a second data (D) of opposite phases. The signal supplying circuits (380, 390, 400) supply a first signal (a1) and a second signal (a1), respectively, to a first data line (180) and a second data line (190) of the storage bit cell (121, 122) in response to an input signal (A1) and a control signal (510). The first and second signals (a1, a1) are in opposite phases.

Abstract: A microprocessor and a peripheral equipment communicate data through a bus. If an error occurs during communication, the microprocessor starts the next bus cycle and commands retry of the data communication. If a predetermined number of times of retry fail, and if an address signal corresponds to an unmounted area of an address space, wherein the unmounted area is an area of the address space not occupied by peripheral equipment including an I/O device, the microprocessor inhibits the retry.

Abstract: An asynchronous signal synchronizing circuit for sampling and external asynchronous signal in a quarter of the period of a clock. A first latch circuit latches asynchronous input signal in accordance with a first clock, and a second latch circuit latches the output of the first latch circuit in accordance with a second clock having a phase shift 180.degree. out of phase with the first clock. A third latch circuit latches the output signal of the second latch signal in accordance with a clock signal that represents the inverse of the first clock. A fourth latch circuit latches the output signal of the third latch circuit under the control of a clock that corresponds to the inverse of the second clock. The asynchronous input signal is sampled at the tailing edge of the first clock signal and validated by the tailing edge of the second clock signal. The synchronization of the asynchronous signal can thus be performed in a quarter of a clock cycle.