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Range-tools

Vl-range-size

The size of a range is one more than the difference between its msb and lsb. For example [3:0] has size 4.

Signature
(vl-range-size x) → size
Arguments: x — Guard (vl-range-p x).
Returns: size — Type (posp size).

Notice that this definition still works in the case of [1:1] and so on.

Definitions and Theorems

Function: vl-range-size

(defun vl-range-size (x)
       (declare (xargs :guard (vl-range-p x)))
       (declare (xargs :guard (vl-range-resolved-p x)))
       (let ((__function__ 'vl-range-size))
            (declare (ignorable __function__))
            (b* (((vl-range x) x)
                 (left (vl-resolved->val x.msb))
                 (right (vl-resolved->val x.lsb)))
                (+ 1 (abs (- left right))))))

Theorem: posp-of-vl-range-size

(defthm posp-of-vl-range-size
        (b* ((size (vl-range-size x)))
            (posp size))
        :rule-classes :type-prescription)

Theorem: vl-range-size-of-vl-range-fix-x

(defthm vl-range-size-of-vl-range-fix-x
        (equal (vl-range-size (vl-range-fix x))
               (vl-range-size x)))

Theorem: vl-range-size-vl-range-equiv-congruence-on-x

(defthm vl-range-size-vl-range-equiv-congruence-on-x
        (implies (vl-range-equiv x x-equiv)
                 (equal (vl-range-size x)
                        (vl-range-size x-equiv)))
        :rule-classes :congruence)