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LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
use ieee.numeric_std.all;
entity alu is
port (
A, B: in std_logic_vector(31 downto 0);
ALUC: in std_logic_vector(3 downto 0);
S: out std_logic_vector(31 downto 0);
Z: out std_logic);
end entity;
architecture Behavioral of alu is
begin
S <= A + B when ALUC(2 downto 0) = B"000"
else A - B when ALUC(2 downto 0) ?= B"001"
else A and B when ALUC(2 downto 0) ?= B"100"
else A or B when ALUC(2 downto 0) ?= B"101"
else A xor B when ALUC(2 downto 0) ?= B"010"
else std_logic_vector(signed(A) sll 16) and H"FFFF0000" when ALUC(2 downto 0) ?= B"110"
else std_logic_vector(signed(A) sll to_integer(unsigned(B))) when ALUC ?= B"0011"
else std_logic_vector(signed(A) srl to_integer(unsigned(B))) when ALUC ?= B"0111"
else std_logic_vector(signed(A) sra to_integer(unsigned(B))) when ALUC ?= B"1111";
Z <= S ?= H"00000000";
end architecture;
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