Access the |X86ISA|::|D/B| field of a data-segment-descriptor-attributesbits bit structure.
(data-segment-descriptor-attributesbits->d/b x) → d/b
Function:
(defun data-segment-descriptor-attributesbits->d/b$inline (x) (declare (xargs :guard (data-segment-descriptor-attributesbits-p x))) (mbe :logic (let ((x (data-segment-descriptor-attributesbits-fix x))) (part-select x :low 10 :width 1)) :exec (the (unsigned-byte 1) (logand (the (unsigned-byte 1) 1) (the (unsigned-byte 6) (ash (the (unsigned-byte 16) x) -10))))))
Theorem:
(defthm bitp-of-data-segment-descriptor-attributesbits->d/b (b* ((d/b (data-segment-descriptor-attributesbits->d/b$inline x))) (bitp d/b)) :rule-classes :rewrite)
Theorem:
(defthm data-segment-descriptor-attributesbits->d/b$inline-of-data-segment-descriptor-attributesbits-fix-x (equal (data-segment-descriptor-attributesbits->d/b$inline (data-segment-descriptor-attributesbits-fix x)) (data-segment-descriptor-attributesbits->d/b$inline x)))
Theorem:
(defthm data-segment-descriptor-attributesbits->d/b$inline-data-segment-descriptor-attributesbits-equiv-congruence-on-x (implies (data-segment-descriptor-attributesbits-equiv x x-equiv) (equal (data-segment-descriptor-attributesbits->d/b$inline x) (data-segment-descriptor-attributesbits->d/b$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm data-segment-descriptor-attributesbits->d/b-of-data-segment-descriptor-attributesbits (equal (data-segment-descriptor-attributesbits->d/b (data-segment-descriptor-attributesbits a w e msb-of-type s dpl p avl l d/b g unknownbits)) (bfix d/b)))
Theorem:
(defthm data-segment-descriptor-attributesbits->d/b-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) 1024) 0)) (equal (data-segment-descriptor-attributesbits->d/b x) (data-segment-descriptor-attributesbits->d/b y))))