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

                     +---------------------.---+
                     |  +---------------+   +----+
                     +-.|  destination  |--.| CF |
                        +---------------+   +----+

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

    The shift is repeated the number of times indicated by the second
    operand, which is either an immediate 8-bit value (max. 1 on the
    8086 processor) or the contents of the CL register. To reduce the
    maximum execution time, the 80186+ uses only the lower 5 bits of
    the count, limiting the count value to 31; the 8086 uses all 8
    bits of count.

    If the count operand is not an immediate 1, the overflow flag (OF)
    is undefined; otherwise RCR sets OF to 0 if destination's sign bit
    was not changed by the operation, to 1 if the sign bit was changed.


    Opcode      Format
    C0 /3 ib    RCR  r/m8,imm8
    C1 /3 ib    RCR  r/m16,imm8
    C1 /3 ib    RCR  r/m32,imm8
    D0 /3       RCR  r/m8,1
    D1 /3       RCR  r/m16,1
    D1 /3       RCR  r/m32,1
    D2 /3       RCR  r/m8,CL
    D3 /3       RCR  r/m16,CL
    D3 /3       RCR  r/m32,CL


    Length and timing
    Operands    Bytes   8088    186     286     386     486     Pentium
    reg, 1       2       2       2       2       9       3       1   PU
    mem, 1    2+d(0,2)  23+EA   15       7      10       4       3   PU
    reg, cl      2       8+4n    5+n    5+n      9      8-30    7-24 NP
    mem, cl   2+d(0,2) 28+EA+4n 17+n    8+n     10      9-31    9-26 NP
    reg, imm     3       -       5+n    5+n      9      8-30    8-25 NP
    mem, imm  3+d(0,2)   -      17+n    8+n     10      9-31   10-27 NP