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      • Ubyte2

      Ubyte2-fix

      Fixer for ubyte2.

      Signature
      (ubyte2-fix x) → fixed-x
      Arguments
      x — Guard (ubyte2p x).
      Returns
      fixed-x — Type (ubyte2p fixed-x).

      Definitions and Theorems

      Function: ubyte2-fix

      (defun ubyte2-fix (x)
        (declare (xargs :guard (ubyte2p x)))
        (mbe :logic (if (ubyte2p x) x 0)
             :exec x))

      Theorem: ubyte2p-of-ubyte2-fix

      (defthm ubyte2p-of-ubyte2-fix
        (b* ((fixed-x (ubyte2-fix x)))
          (ubyte2p fixed-x))
        :rule-classes :rewrite)

      Theorem: ubyte2-fix-when-ubyte2p

      (defthm ubyte2-fix-when-ubyte2p
        (implies (ubyte2p x)
                 (equal (ubyte2-fix x) x)))