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Evex-byte2

Evex-byte2->w

Access the |ACL2|::|W| field of a evex-byte2 bit structure.

Signature
(evex-byte2->w x) → w
Arguments: x — Guard (evex-byte2-p x).
Returns: w — Type (bitp w).

Definitions and Theorems

Function: evex-byte2->w$inline

(defun evex-byte2->w$inline (x)
 (declare (xargs :guard (evex-byte2-p x)))
 (mbe
     :logic
     (let ((x (evex-byte2-fix x)))
       (part-select x :low 7 :width 1))
     :exec (the (unsigned-byte 1)
                (logand (the (unsigned-byte 1) 1)
                        (the (unsigned-byte 1)
                             (ash (the (unsigned-byte 8) x) -7))))))

Theorem: bitp-of-evex-byte2->w

(defthm bitp-of-evex-byte2->w
  (b* ((w (evex-byte2->w$inline x)))
    (bitp w))
  :rule-classes :rewrite)

Theorem: evex-byte2->w$inline-of-evex-byte2-fix-x

(defthm evex-byte2->w$inline-of-evex-byte2-fix-x
  (equal (evex-byte2->w$inline (evex-byte2-fix x))
         (evex-byte2->w$inline x)))

Theorem: evex-byte2->w$inline-evex-byte2-equiv-congruence-on-x

(defthm evex-byte2->w$inline-evex-byte2-equiv-congruence-on-x
  (implies (evex-byte2-equiv x x-equiv)
           (equal (evex-byte2->w$inline x)
                  (evex-byte2->w$inline x-equiv)))
  :rule-classes :congruence)

Theorem: evex-byte2->w-of-evex-byte2

(defthm evex-byte2->w-of-evex-byte2
  (equal (evex-byte2->w (evex-byte2 pp res vvvv w))
         (bfix w)))

Theorem: evex-byte2->w-of-write-with-mask

(defthm evex-byte2->w-of-write-with-mask
  (implies (and (fty::bitstruct-read-over-write-hyps
                     x evex-byte2-equiv-under-mask)
                (evex-byte2-equiv-under-mask x y fty::mask)
                (equal (logand (lognot fty::mask) 128)
                       0))
           (equal (evex-byte2->w x)
                  (evex-byte2->w y))))