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Fp-statusbits

Fp-statusbits->sf

Access the |X86ISA|::|SF| field of a fp-statusbits bit structure.

Signature
(fp-statusbits->sf x) → sf
Arguments: x — Guard (fp-statusbits-p x).
Returns: sf — Type (bitp sf).

Definitions and Theorems

Function: fp-statusbits->sf$inline

(defun fp-statusbits->sf$inline (x)
 (declare (xargs :guard (fp-statusbits-p x)))
 (mbe
    :logic
    (let ((x (fp-statusbits-fix x)))
      (part-select x :low 6 :width 1))
    :exec (the (unsigned-byte 1)
               (logand (the (unsigned-byte 1) 1)
                       (the (unsigned-byte 10)
                            (ash (the (unsigned-byte 16) x) -6))))))

Theorem: bitp-of-fp-statusbits->sf

(defthm bitp-of-fp-statusbits->sf
  (b* ((sf (fp-statusbits->sf$inline x)))
    (bitp sf))
  :rule-classes :rewrite)

Theorem: fp-statusbits->sf$inline-of-fp-statusbits-fix-x

(defthm fp-statusbits->sf$inline-of-fp-statusbits-fix-x
  (equal (fp-statusbits->sf$inline (fp-statusbits-fix x))
         (fp-statusbits->sf$inline x)))

Theorem: fp-statusbits->sf$inline-fp-statusbits-equiv-congruence-on-x

(defthm fp-statusbits->sf$inline-fp-statusbits-equiv-congruence-on-x
  (implies (fp-statusbits-equiv x x-equiv)
           (equal (fp-statusbits->sf$inline x)
                  (fp-statusbits->sf$inline x-equiv)))
  :rule-classes :congruence)

Theorem: fp-statusbits->sf-of-fp-statusbits

(defthm fp-statusbits->sf-of-fp-statusbits
 (equal (fp-statusbits->sf
             (fp-statusbits ie
                            de ze oe ue pe sf es c0 c1 c2 top c3 b))
        (bfix sf)))

Theorem: fp-statusbits->sf-of-write-with-mask

(defthm fp-statusbits->sf-of-write-with-mask
  (implies (and (fty::bitstruct-read-over-write-hyps
                     x fp-statusbits-equiv-under-mask)
                (fp-statusbits-equiv-under-mask x y fty::mask)
                (equal (logand (lognot fty::mask) 64)
                       0))
           (equal (fp-statusbits->sf x)
                  (fp-statusbits->sf y))))