Panasonic Corporation

Noboru Asai

Manabu Kuroda

Yoshihiro Koga

Kazutoshi Funahashi

Akira Kitamura

A general-purpose OS (operating system) is used as a host OS and a real-time OS operating as one or more tasks on the host OS is used as a guest OS. An interrupt handler and a task on the host OS and an interrupt handler and a task on the guest OS issue APIs (application program interfaces) for requesting task state change to a start, stop or like state. An API processor is provided in each OS and outputs an instruction for task state change. An instruction storage for storing instructions output from an API processor of the guest OS in order and outputting the instructions is provided. When interrupt handlers are not in execution, an instruction synchronization timing controller preferentially selects from instructions output from the API processor of the host OS and from the instruction storage the latter and outputs the selected instruction to a scheduler.

Computer system

A semiconductor device has a processor, a first memory unit accessed by the processor, a plurality of page memory units obtained by partitioning a second memory unit which is accessible by the processor at a speed higher than the speed at which the first memory unit is accessible such that each of the page memory units has a storage capacity larger than the memory capacity of a line composing a cache memory, a tag adding, to each of the page memory units, tag information indicative of an address value in the first memory unit and priority information indicative of a replacement priority, a tag comparator for comparing, upon receipt of an access request from the processor, the address value in the first memory unit with the tag information held by the tag, and a replacement control unit for replacing the respective contents of the page memory units.

Growing community of inventors

Osaka, Japan

Noboru Asai