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Logops-definitions

Logsquash

Squashes to 0 the lowest n bits of i.

Signature
(logsquash n i) → val
Arguments: n — Guard (natp n).; i — Guard (integerp i).
Returns: val — Type (integerp val).

Definitions and Theorems

Function: logsquash$inline

(defun logsquash$inline (n i)
  (declare (xargs :guard (and (natp n) (integerp i))))
  (let ((__function__ 'logsquash))
    (declare (ignorable __function__))
    (logand i (ash -1 (nfix n)))))

Theorem: integerp-of-logsquash

(defthm integerp-of-logsquash
  (b* ((val (logsquash$inline n i)))
    (integerp val))
  :rule-classes :type-prescription)