Taking your requirements quite literally, "rotate from addr 20h to 2fh", means rotate as opposed to shift bits up (i.e., left) and the bit at bit address 7FH rotates around to bit address 00H.

        MOV     R0,#020H
        MOV     B,#16
        MOV     C,07FH
LOOP:   MOV     A,@R0
        RLC     A
        MOV     @R0,A
        INC     R0
        DJNZ    B,LOOP

NOTE: This code has not assembled or tested.