Rotate-right-9
- Signature
(rotate-right-9 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-9$inline
(defun rotate-right-9$inline (x places)
(declare (type (unsigned-byte 9) x)
(type (unsigned-byte 9) places))
(let ((__function__ 'rotate-right-9))
(declare (ignorable __function__))
(mbe
:logic (rotate-right x 9 places)
:exec
(let* ((x (mbe :logic (loghead 9 x) :exec x))
(places (mbe :logic (lnfix places)
:exec places))
(places (if (< places 9)
(the (integer 0 8) places)
(the (integer 0 8) (rem places 9))))
(mask (the (unsigned-byte 9)
(1- (the (unsigned-byte 9)
(ash 1 places)))))
(xl (the (unsigned-byte 9) (logand x mask)))
(xh-shift (the (unsigned-byte 9)
(ash x (the (integer -9 0) (- places)))))
(high-num (the (integer 0 9) (- 9 places)))
(xl-shift (the (unsigned-byte 9)
(ash xl high-num)))
(ans (the (unsigned-byte 9)
(logior xl-shift xh-shift))))
ans))))
