Invention Grant
- Patent Title: Multi-mode combined rotator
- Patent Title (中): 多模组合旋转器
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Application No.: US13174151Application Date: 2011-06-30
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Publication No.: US08972469B2Publication Date: 2015-03-03
- Inventor: Fang Liu , Honkai (John) Tam
- Applicant: Fang Liu , Honkai (John) Tam
- Applicant Address: US CA Cupertino
- Assignee: Apple Inc.
- Current Assignee: Apple Inc.
- Current Assignee Address: US CA Cupertino
- Agency: Meyertons, Hood, Kivlin, Kowert & Goetzel, P.C.
- Agent Rory D. Rankin
- Main IPC: G06F7/00
- IPC: G06F7/00 ; G06F5/01

Abstract:
A system and method for efficiently rotating data in a processor for multiple operand sizes. A processor comprises a rotator configured to support multiple operand sizes. The rotator receives a rotate amount and an input operand with a size less than a maximum operand size supported by the processor. The rotator generates a mask with a same size as the received input operand. The mask comprises a number of asserted most-significant bits equal to the rotate amount. The remaining bits in the mask are deasserted. For a given rotation result bit position with an associated asserted mask bit, the rotator selects a value in the input operand at a bit position with a distance from the given result bit position equal to the rotate amount plus a difference between the maximum operand size supported by the processor and the input operand size.
Public/Granted literature
- US20130007080A1 MULTI-MODE COMBINED ROTATOR Public/Granted day:2013-01-03
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