Rotate operand1 right through Carry Flag. The number of rotates is set by
shift all bits right, the bit that goes off is set to
CF and previous value of CF is inserted to the left-most position.
STC ; set carry (CF=1).
MOV AL, 1Ch ; AL = 00011100b
RCR AL, 1 ; AL = 10001110b, CF=0.
OF=0 if first operand keeps original sign.