library IEEE;use IEEE.std_logic_1164.all;entity rightrotate isport (             A, B    : in std_logic_vector(31 downto 0);             O         : out std_logic_vector(31 downto 0));end rightrotate;architecture do_it of rightrotate issignal ab_xor : std_logic_vector(31 downto 0);  begin     ab_xor <= A xor B;     with B(4 downto 0) select          O<= ab_xor(0) & ab_xor(31 DOWNTO 1) WHEN "00001",              ab_xor(1 DOWNTO 0) & ab_xor(31 DOWNTO 2) WHEN "00010",              ab_xor(2 DOWNTO 0) & ab_xor(31 DOWNTO 3) WHEN "00011",              ab_xor(3 DOWNTO 0) & ab_xor(31 DOWNTO 4) WHEN "00100",              ab_xor(4 DOWNTO 0) & ab_xor(31 DOWNTO 5) WHEN "00101",              ab_xor(5 DOWNTO 0) & ab_xor(31 DOWNTO 6) WHEN "00110",              ab_xor(6 DOWNTO 0) & ab_xor(31 DOWNTO 7) WHEN "00111",	      ab_xor(7 DOWNTO 0) & ab_xor(31 DOWNTO 8) WHEN "01000",              ab_xor(8 DOWNTO 0) & ab_xor(31 DOWNTO 9) WHEN "01001",	      ab_xor(9 DOWNTO 0) & ab_xor(31 DOWNTO 10) WHEN "01010",              ab_xor(10 DOWNTO 0) & ab_xor(31 DOWNTO 11) WHEN "01011",	      ab_xor(11 DOWNTO 0) & ab_xor(31 DOWNTO 12) WHEN "01100",	      ab_xor(12 DOWNTO 0) & ab_xor(31 DOWNTO 13) WHEN "01101",	      ab_xor(13 DOWNTO 0) & ab_xor(31 DOWNTO 14) WHEN "01110",	      ab_xor(14 DOWNTO 0) & ab_xor(31 DOWNTO 15) WHEN "01111",	      ab_xor(15 DOWNTO 0) & ab_xor(31 DOWNTO 16) WHEN "10000",	      ab_xor(16 DOWNTO 0) & ab_xor(31 DOWNTO 17) WHEN "10001", 	      ab_xor(17 DOWNTO 0) & ab_xor(31 DOWNTO 18) WHEN "10010",              ab_xor(18 DOWNTO 0) & ab_xor(31 DOWNTO 19) WHEN "10011",              ab_xor(19 DOWNTO 0) & ab_xor(31 DOWNTO 20) WHEN "10100",              ab_xor(20 DOWNTO 0) & ab_xor(31 DOWNTO 21) WHEN "10101",              ab_xor(21 DOWNTO 0) & ab_xor(31 DOWNTO 22) WHEN "10110",              ab_xor(22 DOWNTO 0) & ab_xor(31 DOWNTO 23) WHEN "10111",	      ab_xor(23 DOWNTO 0) & ab_xor(31 DOWNTO 24) WHEN "11000",              ab_xor(24 DOWNTO 0) & ab_xor(31 DOWNTO 25) WHEN "11001",              ab_xor(25 DOWNTO 0) & ab_xor(31 DOWNTO 26) WHEN "11010",              ab_xor(26 DOWNTO 0) & ab_xor(31 DOWNTO 27) WHEN "11011",	      ab_xor(27 DOWNTO 0) & ab_xor(31 DOWNTO 28) WHEN "11100",              ab_xor(28 DOWNTO 0) & ab_xor(31 DOWNTO 29) WHEN "11101",              ab_xor(29 DOWNTO 0) & ab_xor(31 DOWNTO 30) WHEN "11110",              ab_xor(30 DOWNTO 0) & ab_xor(31) WHEN "11111",              ab_xor WHEN OTHERS;  end do_it;