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[/] [special_functions_unit/] [Open_source_SFU/] [cordic_vhdl/] [parts/] [cordic_ieee.vhd] - Blame information for rev 4

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1 4 divadnauj
-- Log2 IEEE754 case detect
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library ieee;
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        use ieee.std_logic_1164.all;
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        use ieee.numeric_std.all;
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entity cordic_ieee is
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        port      (     i_reset                                 : in std_logic;
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                                i_clk                                   : in std_logic;
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                                i_data                                  : in std_logic_vector(31 downto 0);
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                                i_en                                    : in std_logic;
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                                i_sel                                   : in std_logic;
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                                o_case_cos                              : out std_logic_vector(31 downto 0);
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                                o_case_sin                              : out std_logic_vector(31 downto 0);
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                                o_case_en                               : out std_logic);
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end entity;
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architecture rtl of cordic_ieee is
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        signal s_sgn    : std_logic;
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        signal s_exp    : std_logic_vector(7 downto 0);
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        signal s_mantis: std_logic_vector(22 downto 0);
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begin
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        s_sgn   <= i_data(i_data'left);
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        s_exp   <= i_data(i_data'left-1 downto 23);
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        s_mantis<= i_data(22 downto 0);
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        process(s_sgn, s_exp, s_mantis,i_en, i_clk, i_reset)
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        begin
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                if i_reset = '0' then
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                        o_case_sin      <= (others=>'0');
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                        o_case_cos      <= (others=>'0');
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                        o_case_en       <= '0';
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                elsif rising_edge(i_clk) then
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                        if i_en = '1' then
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                                if i_sel = '1' then
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                                        if s_exp = X"00" then --subnormal y 0
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                                                o_case_en       <= '1';
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                                                if s_sgn = '0' then
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                                                        o_case_cos <= X"3F800000";
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                                                        o_case_sin <= X"00000000";
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                                                else
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                                                        o_case_cos <= X"3F800000";
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                                                        o_case_sin <= X"80000000";
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                                                end if;
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                                        elsif  s_exp = X"FF" then -- +/- inf NaN
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                                                o_case_en <= '1';
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                                                o_case_cos <= X"FFFFFFFF";
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                                                o_case_sin <= X"FFFFFFFF";
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                                        else
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                                                o_case_en <= '0';
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                                                o_case_cos <= X"00000000";      -- (dont care)
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                                                o_case_sin <= X"00000000";
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                                        end if;
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                                else
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                                        o_case_sin      <= (others=>'0');
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                                        o_case_cos      <= (others=>'0');
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                                        o_case_en       <= '0';
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                                end if;
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                        end if;
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                end if;
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        end process;
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end rtl;
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