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Implementation-environments

Ienv->uchar-max

The ACL2 integer value of UCHAR_MAX [C17:5.2.4.2.1/1].

Signature
(ienv->uchar-max ienv) → max
Arguments: ienv — Guard (ienvp ienv).
Returns: max — Type (posp max).

Although this currently does not depend on the implementation environment, we make that an input to this function for uniformity and extensibility.

Definitions and Theorems

Function: ienv->uchar-max

(defun ienv->uchar-max (ienv)
 (declare (xargs :guard (ienvp ienv)))
 (declare (ignore ienv))
 (declare
      (xargs :type-prescription (and (posp (ienv->uchar-max ienv))
                                     (> (ienv->uchar-max ienv) 1))))
 255)

Theorem: posp-of-ienv->uchar-max

(defthm posp-of-ienv->uchar-max
  (b* ((max (ienv->uchar-max ienv)))
    (posp max))
  :rule-classes :rewrite)

Theorem: ienv->uchar-max-correct

(defthm ienv->uchar-max-correct
  (equal (ienv->uchar-max ienv)
         (c::ienv->uchar-max (ldm-ienv ienv))))

Theorem: ienv->uchar-max-of-ienv-fix-ienv

(defthm ienv->uchar-max-of-ienv-fix-ienv
  (equal (ienv->uchar-max (ienv-fix ienv))
         (ienv->uchar-max ienv)))

Theorem: ienv->uchar-max-ienv-equiv-congruence-on-ienv

(defthm ienv->uchar-max-ienv-equiv-congruence-on-ienv
  (implies (ienv-equiv ienv ienv-equiv)
           (equal (ienv->uchar-max ienv)
                  (ienv->uchar-max ienv-equiv)))
  :rule-classes :congruence)