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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)