Access the |ACL2|::|E| field of a data-segment-descriptor-attributesbits bit structure.
(data-segment-descriptor-attributesbits->e x) → e
Function:
(defun data-segment-descriptor-attributesbits->e$inline (x) (declare (xargs :guard (data-segment-descriptor-attributesbits-p x))) (mbe :logic (let ((x (data-segment-descriptor-attributesbits-fix x))) (part-select x :low 2 :width 1)) :exec (the (unsigned-byte 1) (logand (the (unsigned-byte 1) 1) (the (unsigned-byte 14) (ash (the (unsigned-byte 16) x) -2))))))
Theorem:
(defthm bitp-of-data-segment-descriptor-attributesbits->e (b* ((e (data-segment-descriptor-attributesbits->e$inline x))) (bitp e)) :rule-classes :rewrite)
Theorem:
(defthm data-segment-descriptor-attributesbits->e$inline-of-data-segment-descriptor-attributesbits-fix-x (equal (data-segment-descriptor-attributesbits->e$inline (data-segment-descriptor-attributesbits-fix x)) (data-segment-descriptor-attributesbits->e$inline x)))
Theorem:
(defthm data-segment-descriptor-attributesbits->e$inline-data-segment-descriptor-attributesbits-equiv-congruence-on-x (implies (data-segment-descriptor-attributesbits-equiv x x-equiv) (equal (data-segment-descriptor-attributesbits->e$inline x) (data-segment-descriptor-attributesbits->e$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm data-segment-descriptor-attributesbits->e-of-data-segment-descriptor-attributesbits (equal (data-segment-descriptor-attributesbits->e (data-segment-descriptor-attributesbits a w e msb-of-type s dpl p avl l d/b g unknownbits)) (bfix e)))
Theorem:
(defthm data-segment-descriptor-attributesbits->e-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) 4) 0)) (equal (data-segment-descriptor-attributesbits->e x) (data-segment-descriptor-attributesbits->e y))))