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One-byte-opcodes

X86-iret

Signature
(x86-iret 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-iret

(defun x86-iret (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-iret))
  (declare (ignorable __function__))
  (b* ((?ctx 'x86-iret))
    (b*
      (((unless (equal proc-mode *64-bit-mode*))
        (!!ms-fresh :iret-not-supported))
       ((the (integer 2 8) operand-size)
        (select-operand-size proc-mode
                             nil rex-byte nil prefixes t t nil x86))
       ((unless (equal operand-size 8))
        (!!ms-fresh :iret-unsupported-operand-size operand-size))
       (rsp (read-*sp proc-mode x86))
       ((mv flg new-cs-addr)
        (add-to-*sp proc-mode rsp 8 x86))
       ((when flg)
        (!!fault-fresh :ss 0 :call flg))
       ((mv flg new-rflags-addr)
        (add-to-*sp proc-mode rsp 16 x86))
       ((when flg)
        (!!fault-fresh :ss 0 :call flg))
       ((mv flg new-rsp-addr)
        (add-to-*sp proc-mode rsp 24 x86))
       ((when flg)
        (!!fault-fresh :ss 0 :call flg))
       ((mv flg new-ss-addr)
        (add-to-*sp proc-mode rsp 32 x86))
       ((when flg)
        (!!fault-fresh :ss 0 :call flg))
       (check-alignment? (alignment-checking-enabled-p x86))
       ((mv flg new-rip x86)
        (rime64 proc-mode
                rsp 2 :r check-alignment? x86))
       ((when flg) (!!ms-fresh :rme64 flg))
       ((mv flg new-cs x86)
        (rme16 proc-mode
               new-cs-addr 2 :r check-alignment? x86))
       ((when flg) (!!ms-fresh :rme16 flg))
       ((mv flg new-rflags x86)
        (rme64 proc-mode new-rflags-addr
               2 :r check-alignment? x86))
       (new-rflags (loghead 32 new-rflags))
       ((when flg) (!!ms-fresh :rme64 flg))
       ((mv flg new-rsp x86)
        (rime64 proc-mode
                new-rsp-addr 2 :r check-alignment? x86))
       ((when flg) (!!ms-fresh :rime64 flg))
       ((mv flg new-ss x86)
        (rme16 proc-mode
               new-ss-addr 2 :r check-alignment? x86))
       ((when flg) (!!ms-fresh :rme16 flg))
       ((unless (canonical-address-p new-rip))
        (!!fault-fresh :gp 0
                       :non-canonical-iret-rip new-rip))
       ((when (equal new-cs 0))
        (!!fault-fresh :gp new-cs
                       :null-iret-cs new-cs))
       ((mv flg cs-descriptor x86)
        (get-segment-descriptor 1 new-cs x86))
       ((when flg)
        (if (equal flg t)
            (!!ms-fresh :get-system-segment-descriptor)
          (!!fault-fresh (car flg)
                         (cadr flg)
                         (caddr flg))))
       ((mv flg ss-descriptor x86)
        (get-segment-descriptor 2 new-ss x86))
       ((when flg)
        (if (equal flg t)
            (!!ms-fresh :get-system-segment-descriptor)
          (!!fault-fresh (car flg)
                         (cadr flg)
                         (caddr flg))))
       (x86 (!rflags new-rflags x86))
       (x86 (load-segment-reg *ss* new-ss ss-descriptor x86))
       (x86 (load-segment-reg *cs* new-cs cs-descriptor x86))
       (x86 (write-*ip proc-mode new-rip x86))
       (x86 (write-*sp proc-mode new-rsp x86)))
      x86))))

Theorem: x86p-of-x86-iret

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