Abstract: A multiprocessor system includes a plurality of processors, each including a task scheduler that determines a task execution order of tasks in a task set to be executed by the processors within a task period which is defined as a period in repeated execution of the task sets; and a scheduler management device having a command unit configured to issue a command for at least one of the task schedulers to change the task execution order, wherein each of the at least one of the task schedulers, when receiving the command from the command unit, changes the task execution order of the corresponding processor.

Abstract: A cache memory and method for controlling the cache memory. The cache memory selects, from an access address, a unique set from among a plurality of sets, each access set including a plurality of cache entries. Each cache entry holds unit data for caching. The cache memory holds, for each of the cache entries, order data that indicates an access order of the cache entries in each set, and replaces a cache entry that is oldest in the access order. The cache memory modifies the order data regardless of an actual access order, and selects, based on the modified order data, a cache entry to be replaced.

Abstract: A cache memory of the present invention includes a second cache memory that is operated in parallel with a first cache memory, a judgment unit which, when a cache miss occurs in both of the first cache memory and the second cache memory, makes a true or false judgment relating to an attribute of data for which memory access resulted in the cache miss, and a controlling unit which stores memory data in the second cache memory when a judgment of true is made, and stores the memory data in the first cache memory when a judgment of false is made.

Abstract: A cache memory system which readily accepts software control for processing includes: a cache memory provided between a processor and memory; and a TAC (Transfer and Attribute Controller) for controlling the cache memory. The TAC receives a command which indicates a transfer and an attribute operation of cache data and a target for the operation, resulting from the execution of a predetermined instruction by the processor, so as to request the operation indicated by the command against the address to the cache memory.

Abstract: A processor according to the present invention includes a decoding unit 20, an operation unit 40 and others. When the decoding unit 20 decodes Instruction vcchk, the operation unit 40 and the like judges whether vector condition flags VC0˜VC3 (110) of a condition flag register (CFR) 32 are all zero or not, and (i) sets condition flags C4 and C5 of the condition flag register (CFR) 32 to 1 and 0, respectively, when all of the vector condition flags VC0˜VC3 are zero, and (ii) sets the condition flags C4 and C5 to 0 and 1, respectively, when not all the vector condition flags are zero. Then, the vector condition flags VC0˜VC3 are stored in the condition flags C0˜C3.

Abstract: The cache memory in the present invention includes a C flag setting unit 40 which adds, to each cache entry holding line data, a cleaning flag C indicating whether or not a write operation will be performed hereafter, and a cleaning unit 39 which writes back, to the memory, line data of a cache entry that has been added with a cleaning flag C indicating that a write operation will not be performed, and has been set with a dirty flag D indicating that the cache entry has been written into.

Abstract: A cache memory system which readily accepts software control for processing includes: a cache memory provided between a processor and memory; and a TAC (Transfer and Attribute Controller) for controlling the cache memory. The TAC receives a command which indicates a transfer and an attribute operation of cache data and a target for the operation, resulting from the execution of a predetermined instruction by the processor, so as to request the operation indicated by the command against the address to the cache memory.

Abstract: A cache memory of the present invention includes a second cache memory that is operated in parallel with a first cache memory, a judgment unit which, when a cache miss occurs in both of the first cache memory and the second cache memory, makes a true or false judgment relating to an attribute of data for which memory access resulted in the cache miss, and a controlling unit which stores memory data in the second cache memory when a judgment of true is made, and stores the memory data in the first cache memory when a judgment of false is made.

Abstract: The cache memory in the present invention is an N-way set-associative cache memory including a control register which indicates one or more ways among N ways, a control unit which activates the way indicated by said control register, and an updating unit which updates contents of said control register. The control unit restricts at least replacement, for a way other than the active way indicated by the control register.

Abstract: The cache memory in the present invention is a cache entry having, in a correspondence with a cache entry which holds a data unit of caching, a valid flag indicating whether or not the cache entry is valid, and a dirty flag indicating whether or not the cache entry has been written into. The cache memory in the present invention includes an altering unit which, based on an instruction from a processor, sets, in the cache entry, an address serving as a tag and sets the valid flag, without loading data from a memory, or resets the dirty flag in a state in which the cache entry holds rewritten data that has not been written back.

Abstract: The present invention provides a processor which has a small-scale circuit and is capable of executing loop processing at a high speed while consuming a small amount of power. When the processor decodes an instruction “jloop C6,C1:C4,TAR,Ra”, the processor (i) sets a conditional flag C4 to 0 when the value of a register Ra is smaller than 0, (ii) moves the value of a conditional flag C2 to a conditional flag C1, moves the value of a conditional flag C3 to the conditional flag C2, and moves the value of the conditional flag C4 to the conditional flags C3 and C6, (iii) adds ?1 to the register Ra and stores the result into the register Ra, and (iv) branches to an address specified by a branch register (TAR). When not filled with a branch target instruction, the jump buffer will be filled with a branch target instruction.

Abstract: A cache memory according to the present invention includes: a W flag setting unit (40) that modifies order data indicating an access order per cache entry that holds a data unit of a cache so as to reflect an actual access order; and a replace unit (39) that selects a cache entry for replacement based on the modified order data and replaces the cache entry.

Abstract: The present invention provides a processor which has a small-scale circuit and is capable of executing loop processing at a high speed while consuming a small amount of power. When the processor decodes an instruction “jloop C6,C1:C4,TAR,Ra”, the processor (i) sets a conditional flag C4 to 0 when the value of a register Ra is smaller than 0, (ii) moves the value of a conditional flag C2 to a conditional flag C1, moves the value of a conditional flag C3 to the conditional flag C2, and moves the value of the conditional flag C4 to the conditional flags C3 and C6, (iii) adds ?1 to the register Ra and stores the result into the register Ra, and (iv) branches to an address specified by a branch register (TAR). When not filled with a branch target instruction, the jump buffer will be filled with a branch target instruction.

Abstract: A processor according to the present invention includes a decoding unit 20, an operation unit 40 and others. When the decoding unit 20 decodes Instruction vcchk, the operation unit 40 and the like judges whether vector condition flags VC0˜VC3 (110) of a condition flag register (CFR) 32 are all zero or not, and (i) sets condition flags C4 and C5 of the condition flag register (CFR) 32 to 1 and 0, respectively, when all of the vector condition flags VC0˜VC3 are zero, and (ii) sets the condition flags C4 and C5 to 0 and 1, respectively, when not all the vector condition flags are zero. Then, the vector condition flags VC0˜VC3 are stored in the condition flags C0˜C3.

Abstract: A processor according to the present invention includes a decoding unit 20, an operation unit 40 and others. When the decoding unit 20 decodes Instruction vcchk, the operation unit 40 and the like judges whether vector condition flags VC0˜VC3 (110) of a condition flag register (CFR) 32 are all zero or not, and (i) sets condition flags C4 and C5 of the condition flag register (CFR) 32 to 1 and 0, respectively, when all of the vector condition flags VC0˜VC3 are zero, and (ii) sets the condition flags C4 and C5 to 0 and 1, respectively, when not all the vector condition flags are zero. Then, the vector condition flags VC0˜VC3 are stored in the condition flags C0˜C3.

Abstract: A processor according to the present invention includes a decoding unit 20, an operation unit 40 and others. When the decoding unit 20 decodes Instruction vcchk, the operation unit 40 and the like judges whether vector condition flags VC0˜VC3 (110) of a condition flag register (CFR) 32 are all zero or not, and (i) sets condition flags C4 and C5 of the condition flag register (CFR) 32 to 1 and 0, respectively, when all of the vector condition flags VC0˜VC3 are zero, and (ii) sets the condition flags C4 and C5 to 0 and 1, respectively, when not all the vector condition flags are zero. Then, the vector condition flags VC0˜VC3 are stored in the condition flags C0˜C3.

Abstract: A processor according to the present invention includes a decoding unit 20, an operation unit 40 and others. When the decoding unit 20 decodes Instruction vcchk, the operation unit 40 and the like judges whether vector condition flags VC0˜VC3 (110) of a condition flag register (CFR) 32 are all zero or not, and (i) sets condition flags C4 and C5 of the condition flag register (CFR) 32 to 1 and 0, respectively, when all of the vector condition flags VC0˜VC3 are zero, and (ii) sets the condition flags C4 and C5 to 0 and 1, respectively, when not all the vector condition flags are zero. Then, the vector condition flags VC0˜VC3 are stored in the condition flags C0˜C3.

Abstract: A processor according to the present invention includes a decoding unit 20, an operation unit 40 and others. When the decoding unit 20 decodes Instruction vcchk, the operation unit 40 and the like judges whether vector condition flags VC0˜VC3 (110) of a condition flag register (CFR) 32 are all zero or not, and (i) sets condition flags C4 and C5 of the condition flag register (CFR) 32 to 1 and 0, respectively, when all of the vector condition flags VC0˜VC3 are zero, and (ii) sets the condition flags C4 and C5 to 0 and 1, respectively, when not all the vector condition flags are zero. Then, the vector condition flags VC0˜VC3 are stored in the condition flags C0˜C3.

Abstract: The cache memory in the present invention includes a prediction unit 39 which predicts, based on the progress of the memory access outputted from the memory, a line address which should be prefetched next.

Abstract: The cache memory in the present invention is a cache entry having, in a correspondence with a cache entry which holds a data unit of caching, a valid flag indicating whether or not the cache entry is valid, and a dirty flag indicating whether or not the cache entry has been written into. The cache memory in the present invention includes an altering unit which, based on an instruction from a processor, sets, in the cache entry, an address serving as a tag and sets the valid flag, without loading data from a memory, or resets the dirty flag in a state in which the cache entry holds rewritten data that has not been written back.