Fujitsu Corporation

Kenichi Nabeya

Takumi Takeno

Junya Matsushima

Daisuke Ban

Tatsumi Nakada

An apparatus for aiding a design of a semiconductor device including a plurality of wirings, the apparatus has a display, a memory that stores information corresponding to the wirings, and a processor that obtains a power consumption value of each wiring in reference to the information about the wirings stored in the memory, and displays each of the wirings on the display in a manner that each wiring is distinguishable as to the obtained power consumption value of the each wiring.

Apparatus for aiding design of semiconductor device and method

In order to efficiently create a library of characteristic values of a low hierarchical circuit, which library is used in operation verification of circuitry including low hierarchical circuitry and high hierarchical circuitry, so that the time period necessary to create a library is considerably reduced, the present apparatus includes a recognizing unit which recognizes a simulation object circuit in circuitry; a simulation unit which simulates the simulation object circuit; and a creating unit which creates a library of characteristic values of the simulation object circuit based on the simulation result obtained by said simulation unit.

Library creating apparatus and method, and recording medium recording library creating program thereon

The present invention prevents, at high speed, a malfunction from occurring at the time of changing a mode in a processor, in which information to be decoded varies with modes. The processor is provided with a circuit for referring to a result of decoding information or issuing an instruction when a write operation is performed on a register for storing data containing a bit that indicates a current mode, and for outputting a purge signal if the result of decoding information or issuing an instruction is information represented by a mode switching signal. Thus, when a mode switching signal is written to the register, a purge signal is outputted to a cache memory. Consequently, the valid bit of prefetched cache data is turned off. This prevents prefetched data from being decoded in a different mode. As a result, operations are normally performed after the switching of the mode. Alternatively, the purge signal is outputted by detecting a change in the value of the bit indicating the current mode.

Processor having cache purge controller

A processor is adapted to support a complex instruction set without making major modifications to the existing hardware but by adding just a few controls and thereby emulating instructions in hardware. The processor is implemented by adding, to the existing processor, a second instruction decoder for decoding an expanded instruction code not capable of issuing an instruction per cycle, and for issuing one instruction per cycle by translating the expanded instruction code into a sequence of basic instructions; a counter for counting the number of instructions to be issued by the second instruction decoder, and for outputting a signal indicating that the expanded instruction code is being executed; and an instruction selection unit for selecting the instruction issued from the first instruction decoder when executing a basic instruction code and the instruction issued from the second instruction decoder when executing the expanded instruction code.

Processor

In a computer system having a coprocessor dedicated to arithmetic operations, one of the coprocessor and CPU is equipped with an abnormality decision section and the other is equipped with a transmission section which transmits to the abnormality decision section signals by which the abnormality decision section is permitted to decide whether abnormality has occurred. In a first arrangement, upon detecting that an instruction transferred from the CPU is abnormal, the coprocessor turns off a flag indicating that it is active. In the CPU, its internal storage state indicates that the coprocessor is active and the flag is received which indicates that the coprocessor is inactive. Thereby, the CPU is permitted to decide that abnormality has occurred. In a second arrangement, upon detecting abnormality, the coprocessor turns off that flag indicating that it is active and turns on a flag indicating that the buffer is full. By receiving this signal state which cannot usually exist, the CPU is permitted to decide that abnormality has occurred.

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Kawasaki, Japan

Kenichi Nabeya