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One-byte-opcodes

X86-lahf

Signature
(x86-lahf 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-lahf

(defun x86-lahf (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-lahf))
  (declare (ignorable __function__))
  (b* ((?ctx 'x86-lahf))
   (b*
    (((the (unsigned-byte 32) rflags)
      (rflags x86))
     (cf (rflagsbits->cf rflags))
     (pf (rflagsbits->pf rflags))
     (af (rflagsbits->af rflags))
     (zf (rflagsbits->zf rflags))
     (sf (rflagsbits->sf rflags))
     ((the (unsigned-byte 8) new-ah)
      (!rflagsbits->cf
       cf
       (!rflagsbits->res1
        1
        (!rflagsbits->pf
         pf
         (!rflagsbits->res2
          0
          (!rflagsbits->af
             af
             (!rflagsbits->res3
                  0
                  (!rflagsbits->zf zf (!rflagsbits->sf sf 0)))))))))
     ((the (unsigned-byte 16) ax)
      (rr16 0 x86))
     ((the (unsigned-byte 16) new-ax)
      (logior (logand 255 ax) (ash new-ah 8)))
     (x86 (wr16 0 new-ax x86))
     (x86 (write-*ip proc-mode temp-rip x86)))
    x86))))

Theorem: x86p-of-x86-lahf

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