RCR              Rotate through Carry Right          Flags: O D I T S Z A P C
                                                            *               *
RCR destination,count

                     +--------------------.----+
                     |  +---------------+  +---+--+
                     +-.|  Destination  |-.|  CF  |
                        +---------------+  +------+

    RCR shifts the word or byte at the destination to the right by the
    number of bit positions specified in the second operand, COUNT. A bit
    shifted out of the right (low-order) end of the destination enters the
    carry flag, and the displaced carry flag rotates around to enter the
    vacated left-most bit position of the destination. This "bit rotation"
    continues the number of times specified in COUNT. (Another way of
    looking at this is to consider the carry flag as the lowest order bit
    of the word being rotated.)

    If COUNT is not equal to 1, the Overflow flag is undefined. If COUNT
    is equal to 1, the Overflow Flag is set to the XOR of the top 2 bits
    of the result.

  --------------------------------------------------------------------------
   Operands                  Clocks   Transfers  Bytes   Example
                           byte(word)
   register, 1                 2          -        1     RCR CX,1
   register, CL            8 + 4/bit      -        2     RCR DL,CL
   memory, 1              15(23) + EA     2       2-4    RCR DIVIDE_BY_2,1
   memory, CL           20(28)+EA+4/bit   2       2-4    RCR AROUND_MOVE,CL
  --------------------------------------------------------------------------

       Notes:         COUNT is normally taken as the value in CL. If,
                      however, you wish to rotate only one position,
                      replace the second operand, CL, with the value 1, as
                      shown in the first example above.

                      The 80286 and 80386 microprocessors limit the COUNT
                      value to 31.  If COUNT is greater than 31, these
                      microprocessors use COUNT MOD 32 to produce a new
                      COUNT between 0 and 31.  This upper bound exists to
                      limit the amount of time an interrupt response will
                      be delayed waiting for the instruction to complete.

                      Multiple RCRs that use 1 as the COUNT may be faster
                      and require less memory than a single RCR that uses
                      CL for COUNT.

                      The overflow flag is undefined if the rotate count
                      is greater than 1.