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### 16.6 sb-rotate-byte

The `sb-rotate-byte` module offers an interface to bitwise rotation, with an efficient implementation for operations which can be performed directly using the platform's arithmetic routines. It implements the specification at http://www.cliki.net/ROTATE-BYTE.

Bitwise rotation is a component of various cryptographic or hashing algorithms: MD5, SHA-1, etc.; often these algorithms are specified on 32-bit rings. [FIXME cite cite cite].

— Function: sb-rotate-byte:rotate-byte count bytespec integer

> Rotates a field of bits within `integer`; specifically, returns an integer that contains the bits of `integer` rotated `count` times leftwards within the byte specified by `bytespec`, and elsewhere contains the bits of `integer`.