Access the |X86ISA|::|BASE31-24| field of a data-segment-descriptorbits bit structure.
(data-segment-descriptorbits->base31-24 x) → base31-24
Function:
(defun data-segment-descriptorbits->base31-24$inline (x) (declare (xargs :guard (data-segment-descriptorbits-p x))) (mbe :logic (let ((x (data-segment-descriptorbits-fix x))) (part-select x :low 56 :width 8)) :exec (the (unsigned-byte 8) (logand (the (unsigned-byte 8) 255) (the (unsigned-byte 8) (ash (the (unsigned-byte 64) x) -56))))))
Theorem:
(defthm 8bits-p-of-data-segment-descriptorbits->base31-24 (b* ((base31-24 (data-segment-descriptorbits->base31-24$inline x))) (8bits-p base31-24)) :rule-classes :rewrite)
Theorem:
(defthm data-segment-descriptorbits->base31-24$inline-of-data-segment-descriptorbits-fix-x (equal (data-segment-descriptorbits->base31-24$inline (data-segment-descriptorbits-fix x)) (data-segment-descriptorbits->base31-24$inline x)))
Theorem:
(defthm data-segment-descriptorbits->base31-24$inline-data-segment-descriptorbits-equiv-congruence-on-x (implies (data-segment-descriptorbits-equiv x x-equiv) (equal (data-segment-descriptorbits->base31-24$inline x) (data-segment-descriptorbits->base31-24$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm data-segment-descriptorbits->base31-24-of-data-segment-descriptorbits (equal (data-segment-descriptorbits->base31-24 (data-segment-descriptorbits limit15-0 base15-0 base23-16 a w e msb-of-type s dpl p limit19-16 avl l d/b g base31-24)) (8bits-fix base31-24)))
Theorem:
(defthm data-segment-descriptorbits->base31-24-of-write-with-mask (implies (and (fty::bitstruct-read-over-write-hyps x data-segment-descriptorbits-equiv-under-mask) (data-segment-descriptorbits-equiv-under-mask x y fty::mask) (equal (logand (lognot fty::mask) 18374686479671623680) 0)) (equal (data-segment-descriptorbits->base31-24 x) (data-segment-descriptorbits->base31-24 y))))