Access the |ACL2|::|W| field of a data-segment-descriptor-attributesbits bit structure.
(data-segment-descriptor-attributesbits->w x) → w
Function:
(defun data-segment-descriptor-attributesbits->w$inline (x) (declare (xargs :guard (data-segment-descriptor-attributesbits-p x))) (mbe :logic (let ((x (data-segment-descriptor-attributesbits-fix x))) (part-select x :low 1 :width 1)) :exec (the (unsigned-byte 1) (logand (the (unsigned-byte 1) 1) (the (unsigned-byte 15) (ash (the (unsigned-byte 16) x) -1))))))
Theorem:
(defthm bitp-of-data-segment-descriptor-attributesbits->w (b* ((w (data-segment-descriptor-attributesbits->w$inline x))) (bitp w)) :rule-classes :rewrite)
Theorem:
(defthm data-segment-descriptor-attributesbits->w$inline-of-data-segment-descriptor-attributesbits-fix-x (equal (data-segment-descriptor-attributesbits->w$inline (data-segment-descriptor-attributesbits-fix x)) (data-segment-descriptor-attributesbits->w$inline x)))
Theorem:
(defthm data-segment-descriptor-attributesbits->w$inline-data-segment-descriptor-attributesbits-equiv-congruence-on-x (implies (data-segment-descriptor-attributesbits-equiv x x-equiv) (equal (data-segment-descriptor-attributesbits->w$inline x) (data-segment-descriptor-attributesbits->w$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm data-segment-descriptor-attributesbits->w-of-data-segment-descriptor-attributesbits (equal (data-segment-descriptor-attributesbits->w (data-segment-descriptor-attributesbits a w e msb-of-type s dpl p avl l d/b g unknownbits)) (bfix w)))
Theorem:
(defthm data-segment-descriptor-attributesbits->w-of-write-with-mask (implies (and (fty::bitstruct-read-over-write-hyps x data-segment-descriptor-attributesbits-equiv-under-mask) (data-segment-descriptor-attributesbits-equiv-under-mask x y fty::mask) (equal (logand (lognot fty::mask) 2) 0)) (equal (data-segment-descriptor-attributesbits->w x) (data-segment-descriptor-attributesbits->w y))))