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