-- The Potato Processor - A simple processor for FPGAs
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-- The Potato Processor - A simple processor for FPGAs
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-- (c) Kristian Klomsten Skordal 2014 <kristian.skordal@wafflemail.net>
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-- (c) Kristian Klomsten Skordal 2014 <kristian.skordal@wafflemail.net>
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-- Report bugs and issues on <https://github.com/skordal/potato/issues>
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-- Report bugs and issues on <http://opencores.org/project,potato,bugtracker>
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library ieee;
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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use ieee.numeric_std.all;
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use work.pp_utilities.all;
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use work.pp_utilities.all;
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--! @brief Component for comparing two registers in the ID stage whens branching.
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--! @brief Component for comparing two registers in the ID stage whens branching.
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entity pp_comparator is
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entity pp_comparator is
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port(
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port(
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funct3 : in std_logic_vector(14 downto 12);
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funct3 : in std_logic_vector(14 downto 12);
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rs1, rs2 : in std_logic_vector(31 downto 0);
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rs1, rs2 : in std_logic_vector(31 downto 0);
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result : out std_logic --! Result of the comparison.
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result : out std_logic --! Result of the comparison.
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);
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);
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end entity pp_comparator;
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end entity pp_comparator;
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architecture behaviour of pp_comparator is
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architecture behaviour of pp_comparator is
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begin
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begin
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compare: process(funct3, rs1, rs2)
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compare: process(funct3, rs1, rs2)
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begin
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begin
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case funct3 is
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case funct3 is
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when b"000" => -- EQ
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when b"000" => -- EQ
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result <= to_std_logic(rs1 = rs2);
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result <= to_std_logic(rs1 = rs2);
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when b"001" => -- NE
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when b"001" => -- NE
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result <= to_std_logic(rs1 /= rs2);
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result <= to_std_logic(rs1 /= rs2);
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when b"100" => -- LT
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when b"100" => -- LT
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result <= to_std_logic(signed(rs1) < signed(rs2));
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result <= to_std_logic(signed(rs1) < signed(rs2));
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when b"101" => -- GE
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when b"101" => -- GE
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result <= to_std_logic(signed(rs1) >= signed(rs2));
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result <= to_std_logic(signed(rs1) >= signed(rs2));
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when b"110" => -- LTU
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when b"110" => -- LTU
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result <= to_std_logic(unsigned(rs1) < unsigned(rs2));
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result <= to_std_logic(unsigned(rs1) < unsigned(rs2));
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when b"111" => -- GEU
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when b"111" => -- GEU
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result <= to_std_logic(unsigned(rs1) >= unsigned(rs2));
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result <= to_std_logic(unsigned(rs1) >= unsigned(rs2));
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when others =>
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when others =>
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result <= '0';
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result <= '0';
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end case;
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end case;
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end process compare;
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end process compare;
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end architecture behaviour;
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end architecture behaviour;
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