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Two-byte-opcodes

X86-bswap

Signature
(x86-bswap proc-mode start-rip temp-rip prefixes rex-byte opcode modr/m sib x86) → x86
Returns: x86 — Type (x86p x86), given (x86p x86).

Definitions and Theorems

Function: x86-bswap

(defun x86-bswap (proc-mode start-rip temp-rip
                            prefixes rex-byte opcode modr/m sib x86)
 (declare (xargs :stobjs (x86)))
 (declare (type (integer 0 4) proc-mode)
          (type (signed-byte 48) start-rip)
          (type (signed-byte 48) temp-rip)
          (type (unsigned-byte 52) prefixes)
          (type (unsigned-byte 8) rex-byte)
          (type (unsigned-byte 8) opcode)
          (type (unsigned-byte 8) modr/m)
          (type (unsigned-byte 8) sib))
 (declare (ignorable proc-mode start-rip temp-rip
                     prefixes rex-byte opcode modr/m sib))
 (declare (xargs :guard (and (prefixes-p prefixes)
                             (modr/m-p modr/m)
                             (sib-p sib)
                             (rip-guard-okp proc-mode temp-rip))))
 (let ((__function__ 'x86-bswap))
  (declare (ignorable __function__))
  (b* ((?ctx 'x86-bswap))
    (b*
      (((the (integer 2 8) operand-size)
        (select-operand-size proc-mode nil
                             rex-byte nil prefixes nil nil nil x86))
       (badlength? (check-instruction-length start-rip temp-rip 0))
       ((when badlength?)
        (!!fault-fresh :gp 0
                       :instruction-length badlength?))
       (reg-index (reg-index (logand 7 opcode)
                             rex-byte 0))
       (operand (rgfi-size operand-size reg-index rex-byte x86))
       ((mv result x86)
        (case operand-size
          (2 (b* (((mv undef-val x86) (undef-read x86)))
               (mv (n16 undef-val) x86)))
          (4 (mv (bswap 4 operand) x86))
          (8 (mv (bswap 8 operand) x86))
          (t (mv 0 x86))))
       (x86 (!rgfi-size operand-size
                        reg-index result rex-byte x86))
       (x86 (write-*ip proc-mode temp-rip x86)))
      x86))))

Theorem: x86p-of-x86-bswap

(defthm x86p-of-x86-bswap
 (implies (x86p x86)
          (b* ((x86 (x86-bswap proc-mode start-rip temp-rip prefixes
                               rex-byte opcode modr/m sib x86)))
            (x86p x86)))
 :rule-classes :rewrite)