Abstract: A data processor of an embodiment includes a memory, an instruction cache, a processing unit (CPU), and a fetch process control unit. The memory stores a program in which a plurality of instructions are written. The instruction cache operates only when a branch instruction included in the program is executed, and data of a greater capacity than a width of a bus of the memory is read from the memory and stored in the instruction cache in advance. The processing unit accesses both the memory and the instruction cache and executes, in a pipelined manner, instructions read from the memory or the instruction cache. The fetch process control unit generates, in response to a branch instruction executed by the processing unit, a stop signal for stopping a fetch process of reading an instruction from the memory, and outputs the stop signal to the memory.

Abstract: A data processor of an embodiment includes a memory, an instruction cache, a processing unit (CPU), and a fetch process control unit. The memory stores a program in which a plurality of instructions are written. The instruction cache operates only when a branch instruction included in the program is executed, and data of a greater capacity than a width of a bus of the memory is read from the memory and stored in the instruction cache in advance. The processing unit accesses both the memory and the instruction cache and executes, in a pipelined manner, instructions read from the memory or the instruction cache. The fetch process control unit generates, in response to a branch instruction executed by the processing unit, a stop signal for stopping a fetch process of reading an instruction from the memory, and outputs the stop signal to the memory.

Abstract: A dividing unit divides respective symbol sequences of input data applied with zigzag scan and a run-length process into a plurality of subsets having similar frequencies of occurrence, depending on a difference in frequencies of occurrence. A table creating unit scans each subset and creates a Huffman coding table for each subset. A coding unit executes a process for performing Huffman coding on each subset by using the Huffman coding table created for the subset, for all of the subsets in the plurality of subsets.

Abstract: A dividing unit divides respective symbol sequences of input data applied with zigzag scan and a run-length process into a plurality of subsets having similar frequencies of occurrence, depending on a difference in frequencies of occurrence. A table creating unit scans each subset and creates a Huffman coding table for each subset. A coding unit executes a process for performing Huffman coding on each subset by using the Huffman coding table created for the subset, for all of the subsets in the plurality of subsets.

Abstract: A semiconductor device includes a decoder receiving first multiplier data of 3 bits indicating a multiplier to output a shift flag, an inversion flag, and an operation flag in accordance with Booth's algorithm, and a first partial product calculation unit receiving first multiplicand data of 2 bits indicating a multiplicand, a shift flag, an inversion flag, and an operation flag to select one of the higher order bit and lower order bit of the first multiplicand data based on the shift flag, invert or non-invert the selected bit based on the inversion flag, select one of the inverted or non-inverted data and data of a predetermined logic level based on the operation flag, and output the selected data as partial product data indicating the partial product of the first multiplier data and the first multiplicand data.