Arithmetic apparatus and control method of the same using cordic algorithm
AssigneeCanon Kabushiki Kaisha
InventorsTadayoshi Nakayama, Koki Mitsunami
Life of this patent
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Abstract
An arithmetic apparatus comprises a plurality of cascade-connected arithmetic units. Each of the plurality of arithmetic units comprises: a calculator configured to operate in one of a rotation mode of performing a rotation calculation, and a vectoring mode of calculating a rotation angle; and a holding unit configured to hold rotational direction information output from the calculator in the vectoring mode. In addition, when operating in the rotation mode, the calculator performs the rotation calculation on data input from an arithmetic unit in a preceding stage, based on the rotational direction information held in the holding unit.
Claims11
An arithmetic apparatus comprising a plurality of cascade-connected arithmetic units, each of the plurality of arithmetic units comprising:
- a calculator configured to operate in one of a rotation mode for performing a rotation calculation, and a vectoring mode for calculating a rotation angle;
- a register configured to hold a rotational direction in the rotation calculation by the calculator;
- and
- a selector configured to select a sign of specific input data to the calculator and output the selected sign to the calculator and register as the rotational direction in the vectoring mode, and select the rotational direction held in the register, output the selected rotational direction to the calculator, and maintain the rotational direction held in the register in the rotation mode,
- wherein when operating in the rotation mode, the calculator performs the rotation calculation on data input from a preceding arithmetic unit in the plurality of cascade-connected arithmetic units, with the rotational direction from the selector, and
- wherein operations of the calculator in the vectoring mode and the rotation mode are controlled by the selected rotational direction output from the selector.
A control method of an arithmetic apparatus comprising a plurality of cascade-connected arithmetic units each including a calculator configured to operate in one of a rotation mode for performing a rotation calculation and a vectoring mode for calculating a rotation angle, comprising:
- selecting a sign of specific input data to the calculator and outputting the selected sign to the calculator and a register as a rotational direction in the vectoring mode by a selector;
- calculating a rotation angle in the vectoring mode, by the calculator, which is controlled by the sign of the specific input data selected by the selector;
- selecting the rotational direction held in the register, outputting the selected rotational direction to the calculator, and maintaining the rotational direction held in the register in the rotation mode by the selector;
- and
- performing a rotation calculation on data input from a preceding arithmetic unit in the plurality of cascade-connected arithmetic units with the selected rotation direction output from the selector in the rotation mode, by the calculator,
- wherein operations of the calculator in the vectoring mode and the rotation mode are controlled by the selected rotational direction output from the selector.
Dependencies are inferred from the claim text.