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Pointer-operations

Lognot-pointer-value

Apply ! to a pointer value [C:6.5.3.3/5].

Signature
(lognot-pointer-value val) → resval
Arguments: val — Guard (valuep val).
Returns: resval — Type (valuep resval).

This always returns an int (never an error), either 0 or 1. It is equivalent to comparing the pointer for equality to 0, i.e. to check whether the pointer is null or not.

Definitions and Theorems

Function: lognot-pointer-value

(defun lognot-pointer-value (val)
  (declare (xargs :guard (valuep val)))
  (declare (xargs :guard (value-case val :pointer)))
  (let ((__function__ 'lognot-pointer-value))
    (declare (ignorable __function__))
    (if (value-pointer-nullp val)
        (value-sint 1)
      (value-sint 0))))

Theorem: valuep-of-lognot-pointer-value

(defthm valuep-of-lognot-pointer-value
  (b* ((resval (lognot-pointer-value val)))
    (valuep resval))
  :rule-classes :rewrite)

Theorem: lognot-pointer-value-of-value-fix-val

(defthm lognot-pointer-value-of-value-fix-val
  (equal (lognot-pointer-value (value-fix val))
         (lognot-pointer-value val)))

Theorem: lognot-pointer-value-value-equiv-congruence-on-val

(defthm lognot-pointer-value-value-equiv-congruence-on-val
  (implies (value-equiv val val-equiv)
           (equal (lognot-pointer-value val)
                  (lognot-pointer-value val-equiv)))
  :rule-classes :congruence)