| 摘要 |
A method and apparatus for determining a byte select vector for a crossbar shifter include processing that begins by storing data in a first set of byte locations and in a second set of byte locations. Typically, a data operand is written into the first and a shift value is written into the second set of byte locations. The processing continues by obtaining a shift amount value for the data. The processing then continues by determining, for each byte multiplexor of a set of byte multiplexors associated with a corresponding output byte, whether a wrapped condition will occur based on the shift amount for the data. When the wrap condition occurs, a wrap shift amount is determined based on a mode of shifting. The processing then continues by generating a byte select vector for the set of byte multiplexors based on the wrap shift amount and the shift amount. The byte select vector includes a first nibble that is associated with a first one of the byte multiplexors and a second nipple that is associated with a second one of the byte multiplexors.
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