Bit searching circuit and data processor including the same

摘要

A bit searching circuit includes an offset value designating circuit, a bit position detecting circuit, a count circuit, and a search-end detecting circuit. The offset value designating circuit outputs an offset value indicating a search-start position. The bit position detecting circuit searches for the first bit position which has a first binary value, in a search field between the bit position designated by the offset value and a last bit position in a bit string. The count circuit counts the number of bits in the search field having the first binary value. The search-end detecting circuit detects the end of search processing by subtracting the bit counts detected by the bit position detecting circuit from the count value counted by the count circuit until the result is zero. A data processor using such a bit searching circuit includes a control unit and an instruction execution unit. The control unit includes a decoding circuit, decoding an operation code field of an instruction for operating on plural data where the instruction includes a register list indicating the register numbers storing data to be operated on. The bit searching circuit searches the register list represented by a bit string field consisting of binary values, and controls execution of the instruction. The instruction executing unit executes the instruction.