Hitachi, Ltd.

Hitachi Microcomputer System, Ltd.

Tooru Hiraoka

Tohru Shonai

Kouji Nakamura

A method and apparatus for controlling a conditional branch instruction in a pipeline type data processing apparatus which are adapted to judge whether or not a conditional branch instruction is valid, judge whether or not a condition code necessary for a taken/not-taken judgement made for the conditional branch instruction is valid, and selectively make a taken/not-taken judgement for the conditional branch instruction in accordance with the results of the judgements made to the conditional branch instruction and the condition code.

Method and apparatus for controlling conditional branch instructions for

An information processing method and apparatus for applying pipeline control and an advanced control to a sequence of instructions to be executed. The instruction sequence contains a plurality of conditional branch instructions. The apparatus includes a section for sequentially holding therein each instruction of the sequence of instructions to be input in a manner like a pipeline operation; an arithmetic section for obtaining a result of an operation of an instruction associated with each of the plural conditional branch instructions of the instruction sequence and selecting, from the associated instruction, instructions for which an advanced operation is possible so as to attain an operation result for each of the instructions thus selected; a holding section for holding therein either one of the operation result attained for each of the associated instructions and the operation result obtained in advance and outputting, at an execution of an objective conditional branch instruction selected from the plural conditional branch instruction; the operation result of a particular instruction corresponding to the objective conditional branch instruction, and a judge section for comparing branch control information of the objective conditional branch instruction with the operation result outputted from the holding means to judge a branch success or failure for the objective conditional branch instruction so as to decide a next instruction to be executed in accordance with the objective conditional branch instruction.

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Hadano, Japan

Tooru Hiraoka