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• Rflag-specifications
• Register-readers-and-writers

Rflags-reads-and-writes

Reading from and writing to the rflags register in the x86 state

We define convenient macros flgi and !flgi to read a flag's value and to write a flag's value into the rflags field in the x86 state, respectively. Additionally, !flgi-undefined can be used to write an undefined value into a particular flag.

Definitions and Theorems

Function: undef-flg-logic

(defun undef-flg-logic (x86)
  (declare (xargs :stobjs (x86)))
  (declare (xargs :guard t))
  (let ((__function__ 'undef-flg-logic))
    (declare (ignorable __function__))
    (undef-read x86)))

Theorem: natp-of-undef-flg-logic.unknown

(defthm natp-of-undef-flg-logic.unknown
  (b* (((mv ?unknown ?x86)
        (undef-flg-logic x86)))
    (natp unknown))
  :rule-classes :type-prescription)

Theorem: x86p-of-undef-flg-logic.x86

(defthm x86p-of-undef-flg-logic.x86
  (implies (x86p x86)
           (b* (((mv ?unknown ?x86)
                 (undef-flg-logic x86)))
             (x86p x86)))
  :rule-classes :rewrite)

Function: undef-flg$notinline

(defun undef-flg$notinline (x86)
  (declare (xargs :stobjs (x86)))
  (declare (xargs :guard t))
  (let ((__function__ 'undef-flg))
    (declare (ignorable __function__))
    (b* (((mv val x86) (undef-flg-logic x86)))
      (mv (n01 val) x86))))

Theorem: bitp-of-undef-flg.unknown-bit

(defthm bitp-of-undef-flg.unknown-bit
  (b* (((mv ?unknown-bit ?x86)
        (undef-flg$notinline x86)))
    (bitp unknown-bit))
  :rule-classes :type-prescription)

Theorem: x86p-of-undef-flg.x86

(defthm x86p-of-undef-flg.x86
  (implies (x86p x86)
           (b* (((mv ?unknown-bit ?x86)
                 (undef-flg$notinline x86)))
             (x86p x86)))
  :rule-classes :rewrite)

Function: write-user-rflags$inline

(defun write-user-rflags$inline
       (user-flags-vector undefined-mask x86)
  (declare (xargs :stobjs (x86)))
  (declare (type (unsigned-byte 32)
                 user-flags-vector)
           (type (unsigned-byte 32)
                 undefined-mask))
  (b* ((user-flags-vector (mbe :logic (n32 user-flags-vector)
                               :exec user-flags-vector))
       (undefined-mask (mbe :logic (n32 undefined-mask)
                            :exec undefined-mask))
       ((the (unsigned-byte 32) input-rflags)
        (mbe :logic (n32 (rflags x86))
             :exec (rflags x86))))
    (mbe :logic
         (b* ((x86 (if (equal (rflagsbits->cf undefined-mask)
                              1)
                       (!flgi-undefined :cf x86)
                     (!flgi :cf (rflagsbits->cf user-flags-vector)
                            x86)))
              (x86 (if (equal (rflagsbits->pf undefined-mask)
                              1)
                       (!flgi-undefined :pf x86)
                     (!flgi :pf (rflagsbits->pf user-flags-vector)
                            x86)))
              (x86 (if (equal (rflagsbits->af undefined-mask)
                              1)
                       (!flgi-undefined :af x86)
                     (!flgi :af (rflagsbits->af user-flags-vector)
                            x86)))
              (x86 (if (equal (rflagsbits->zf undefined-mask)
                              1)
                       (!flgi-undefined :zf x86)
                     (!flgi :zf (rflagsbits->zf user-flags-vector)
                            x86)))
              (x86 (if (equal (rflagsbits->sf undefined-mask)
                              1)
                       (!flgi-undefined :sf x86)
                     (!flgi :sf (rflagsbits->sf user-flags-vector)
                            x86)))
              (x86 (if (equal (rflagsbits->of undefined-mask)
                              1)
                       (!flgi-undefined :of x86)
                     (!flgi :of (rflagsbits->of user-flags-vector)
                            x86))))
           x86)
         :exec
         (if (eql undefined-mask 0)
             (b* ((x86 (!flgi :cf (rflagsbits->cf user-flags-vector)
                              x86))
                  (x86 (!flgi :pf (rflagsbits->pf user-flags-vector)
                              x86))
                  (x86 (!flgi :af (rflagsbits->af user-flags-vector)
                              x86))
                  (x86 (!flgi :zf (rflagsbits->zf user-flags-vector)
                              x86))
                  (x86 (!flgi :sf (rflagsbits->sf user-flags-vector)
                              x86))
                  (x86 (!flgi :of (rflagsbits->of user-flags-vector)
                              x86)))
               x86)
           (b* ((x86 (if (equal (rflagsbits->cf undefined-mask)
                                1)
                         (!flgi-undefined :cf x86)
                       (!flgi :cf (rflagsbits->cf user-flags-vector)
                              x86)))
                (x86 (if (equal (rflagsbits->pf undefined-mask)
                                1)
                         (!flgi-undefined :pf x86)
                       (!flgi :pf (rflagsbits->pf user-flags-vector)
                              x86)))
                (x86 (if (equal (rflagsbits->af undefined-mask)
                                1)
                         (!flgi-undefined :af x86)
                       (!flgi :af (rflagsbits->af user-flags-vector)
                              x86)))
                (x86 (if (equal (rflagsbits->zf undefined-mask)
                                1)
                         (!flgi-undefined :zf x86)
                       (!flgi :zf (rflagsbits->zf user-flags-vector)
                              x86)))
                (x86 (if (equal (rflagsbits->sf undefined-mask)
                                1)
                         (!flgi-undefined :sf x86)
                       (!flgi :sf (rflagsbits->sf user-flags-vector)
                              x86)))
                (x86 (if (equal (rflagsbits->of undefined-mask)
                                1)
                         (!flgi-undefined :of x86)
                       (!flgi :of (rflagsbits->of user-flags-vector)
                              x86))))
             x86)))))

Theorem: x86p-of-write-user-rflags

(defthm x86p-of-write-user-rflags
  (implies (x86p x86)
           (b* ((x86 (write-user-rflags$inline
                          user-flags-vector undefined-mask x86)))
             (x86p x86)))
  :rule-classes :rewrite)

Theorem: xr-write-user-rflags

(defthm xr-write-user-rflags
  (implies (and (not (equal fld :rflags))
                (not (equal fld :undef)))
           (equal (xr fld index
                      (write-user-rflags flags mask x86))
                  (xr fld index x86))))

Theorem: xr-write-user-rflags-no-mask

(defthm xr-write-user-rflags-no-mask
  (implies (not (equal fld :rflags))
           (equal (xr fld
                      index (write-user-rflags flags 0 x86))
                  (xr fld index x86))))

Theorem: rflags-and-write-user-rflags-no-mask

(defthm rflags-and-write-user-rflags-no-mask
  (equal (write-user-rflags user-flags-vector 0 x86)
         (b* ((x86 (!flgi :cf (rflagsbits->cf user-flags-vector)
                          x86))
              (x86 (!flgi :pf (rflagsbits->pf user-flags-vector)
                          x86))
              (x86 (!flgi :af (rflagsbits->af user-flags-vector)
                          x86))
              (x86 (!flgi :zf (rflagsbits->zf user-flags-vector)
                          x86))
              (x86 (!flgi :sf (rflagsbits->sf user-flags-vector)
                          x86))
              (x86 (!flgi :of (rflagsbits->of user-flags-vector)
                          x86)))
           x86)))

Subtopics

Write-user-rflags

Writing user rflags (CF, PF, AF, ZF, SF, and OF), including undefined ones, to the x86 state

Undef-flg-logic

Undef-flg