Rotate-right-8
- Signature
(rotate-right-8 x places) → *
- Arguments
- x — The bit vector to be rotated right.
- places — The number of places to rotate right.
Definitions and Theorems
Function: rotate-right-8$inline
(defun rotate-right-8$inline (x places)
(declare (type (unsigned-byte 8) x)
(type (unsigned-byte 8) places))
(let ((__function__ 'rotate-right-8))
(declare (ignorable __function__))
(mbe
:logic (rotate-right x 8 places)
:exec
(let* ((x (mbe :logic (loghead 8 x) :exec x))
(places (mbe :logic (lnfix places)
:exec places))
(places (if (< places 8)
(the (integer 0 7) places)
(the (integer 0 7) (rem places 8))))
(mask (the (unsigned-byte 8)
(1- (the (unsigned-byte 8)
(ash 1 places)))))
(xl (the (unsigned-byte 8) (logand x mask)))
(xh-shift (the (unsigned-byte 8)
(ash x (the (integer -8 0) (- places)))))
(high-num (the (integer 0 8) (- 8 places)))
(xl-shift (the (unsigned-byte 8)
(ash xl high-num)))
(ans (the (unsigned-byte 8)
(logior xl-shift xh-shift))))
ans))))
