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@ -11,157 +11,157 @@ use work.wishbone_types.all;
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-- In this cycle we read or write any data and do sign extension and update if required.
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-- In this cycle we read or write any data and do sign extension and update if required.
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entity loadstore2 is
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entity loadstore2 is
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port (
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port (
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clk : in std_ulogic;
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clk : in std_ulogic;
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l_in : in Loadstore1ToLoadstore2Type;
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l_in : in Loadstore1ToLoadstore2Type;
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w_out : out Loadstore2ToWritebackType;
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w_out : out Loadstore2ToWritebackType;
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m_in : in wishbone_slave_out;
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m_in : in wishbone_slave_out;
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m_out : out wishbone_master_out
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m_out : out wishbone_master_out
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);
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);
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end loadstore2;
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end loadstore2;
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architecture behave of loadstore2 is
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architecture behave of loadstore2 is
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signal l_saved : Loadstore1ToLoadstore2Type;
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signal l_saved : Loadstore1ToLoadstore2Type;
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signal w_tmp : Loadstore2ToWritebackType;
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signal w_tmp : Loadstore2ToWritebackType;
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signal m_tmp : wishbone_master_out;
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signal m_tmp : wishbone_master_out;
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type state_t is (IDLE, WAITING_FOR_READ_ACK, WAITING_FOR_WRITE_ACK);
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type state_t is (IDLE, WAITING_FOR_READ_ACK, WAITING_FOR_WRITE_ACK);
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signal state : state_t := IDLE;
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signal state : state_t := IDLE;
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function length_to_sel(length : in std_logic_vector(3 downto 0)) return std_ulogic_vector is
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function length_to_sel(length : in std_logic_vector(3 downto 0)) return std_ulogic_vector is
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begin
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begin
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case length is
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case length is
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when "0001" =>
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when "0001" =>
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return "00000001";
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return "00000001";
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when "0010" =>
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when "0010" =>
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return "00000011";
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return "00000011";
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when "0100" =>
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when "0100" =>
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return "00001111";
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return "00001111";
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when "1000" =>
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when "1000" =>
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return "11111111";
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return "11111111";
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when others =>
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when others =>
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return "00000000";
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return "00000000";
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end case;
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end case;
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end function length_to_sel;
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end function length_to_sel;
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function wishbone_data_shift(address : in std_ulogic_vector(63 downto 0)) return natural is
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function wishbone_data_shift(address : in std_ulogic_vector(63 downto 0)) return natural is
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begin
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begin
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return to_integer(unsigned(address(2 downto 0))) * 8;
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return to_integer(unsigned(address(2 downto 0))) * 8;
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end function wishbone_data_shift;
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end function wishbone_data_shift;
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function wishbone_data_sel(size : in std_logic_vector(3 downto 0); address : in std_logic_vector(63 downto 0)) return std_ulogic_vector is
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function wishbone_data_sel(size : in std_logic_vector(3 downto 0); address : in std_logic_vector(63 downto 0)) return std_ulogic_vector is
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begin
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begin
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return std_ulogic_vector(shift_left(unsigned(length_to_sel(size)), to_integer(unsigned(address(2 downto 0)))));
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return std_ulogic_vector(shift_left(unsigned(length_to_sel(size)), to_integer(unsigned(address(2 downto 0)))));
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end function wishbone_data_sel;
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end function wishbone_data_sel;
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begin
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begin
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w_out <= w_tmp;
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w_out <= w_tmp;
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m_out <= m_tmp;
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m_out <= m_tmp;
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loadstore2_0: process(clk)
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loadstore2_0: process(clk)
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variable tmp : std_ulogic_vector(63 downto 0);
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variable tmp : std_ulogic_vector(63 downto 0);
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variable data : std_ulogic_vector(63 downto 0);
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variable data : std_ulogic_vector(63 downto 0);
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variable sign_extend_byte_reverse : std_ulogic_vector(1 downto 0);
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variable sign_extend_byte_reverse : std_ulogic_vector(1 downto 0);
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begin
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begin
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if rising_edge(clk) then
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if rising_edge(clk) then
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tmp := (others => '0');
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tmp := (others => '0');
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data := (others => '0');
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data := (others => '0');
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w_tmp <= Loadstore2ToWritebackInit;
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w_tmp <= Loadstore2ToWritebackInit;
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l_saved <= l_saved;
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l_saved <= l_saved;
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case_0: case state is
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case_0: case state is
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when IDLE =>
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when IDLE =>
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if l_in.valid = '1' then
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if l_in.valid = '1' then
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m_tmp <= wishbone_master_out_init;
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m_tmp <= wishbone_master_out_init;
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m_tmp.sel <= wishbone_data_sel(l_in.length, l_in.addr);
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m_tmp.sel <= wishbone_data_sel(l_in.length, l_in.addr);
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m_tmp.adr <= l_in.addr(63 downto 3) & "000";
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m_tmp.adr <= l_in.addr(63 downto 3) & "000";
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m_tmp.cyc <= '1';
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m_tmp.cyc <= '1';
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m_tmp.stb <= '1';
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m_tmp.stb <= '1';
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l_saved <= l_in;
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l_saved <= l_in;
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if l_in.load = '1' then
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if l_in.load = '1' then
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m_tmp.we <= '0';
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m_tmp.we <= '0';
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-- Load with update instructions write two GPR destinations.
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-- Load with update instructions write two GPR destinations.
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-- We don't want the expense of two write ports, so make it
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-- We don't want the expense of two write ports, so make it
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-- single in the pipeline and write back the update GPR now
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-- single in the pipeline and write back the update GPR now
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-- and the load once we get the data back. We'll have to
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-- and the load once we get the data back. We'll have to
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-- revisit this when loads can take exceptions.
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-- revisit this when loads can take exceptions.
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if l_in.update = '1' then
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if l_in.update = '1' then
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w_tmp.write_enable <= '1';
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w_tmp.write_enable <= '1';
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w_tmp.write_reg <= l_in.update_reg;
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w_tmp.write_reg <= l_in.update_reg;
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w_tmp.write_data <= l_in.addr;
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w_tmp.write_data <= l_in.addr;
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end if;
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end if;
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state <= WAITING_FOR_READ_ACK;
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state <= WAITING_FOR_READ_ACK;
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else
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else
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m_tmp.we <= '1';
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m_tmp.we <= '1';
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data := l_in.data;
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data := l_in.data;
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m_tmp.dat <= std_logic_vector(shift_left(unsigned(data), wishbone_data_shift(l_in.addr)));
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m_tmp.dat <= std_logic_vector(shift_left(unsigned(data), wishbone_data_shift(l_in.addr)));
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assert l_in.sign_extend = '0' report "sign extension doesn't make sense for stores" severity failure;
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assert l_in.sign_extend = '0' report "sign extension doesn't make sense for stores" severity failure;
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state <= WAITING_FOR_WRITE_ACK;
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state <= WAITING_FOR_WRITE_ACK;
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end if;
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end if;
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end if;
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end if;
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when WAITING_FOR_READ_ACK =>
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when WAITING_FOR_READ_ACK =>
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if m_in.ack = '1' then
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if m_in.ack = '1' then
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tmp := std_logic_vector(shift_right(unsigned(m_in.dat), wishbone_data_shift(l_saved.addr)));
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tmp := std_logic_vector(shift_right(unsigned(m_in.dat), wishbone_data_shift(l_saved.addr)));
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case to_integer(unsigned(l_saved.length)) is
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case to_integer(unsigned(l_saved.length)) is
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when 0 =>
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when 0 =>
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when 1 =>
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when 1 =>
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data(7 downto 0) := tmp(7 downto 0);
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data(7 downto 0) := tmp(7 downto 0);
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when 2 =>
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when 2 =>
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data(15 downto 0) := tmp(15 downto 0);
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data(15 downto 0) := tmp(15 downto 0);
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when 4 =>
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when 4 =>
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data(31 downto 0) := tmp(31 downto 0);
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data(31 downto 0) := tmp(31 downto 0);
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when 8 =>
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when 8 =>
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data(63 downto 0) := tmp(63 downto 0);
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data(63 downto 0) := tmp(63 downto 0);
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when others =>
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when others =>
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assert false report "invalid length" severity failure;
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assert false report "invalid length" severity failure;
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end case;
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end case;
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sign_extend_byte_reverse := l_saved.sign_extend & l_saved.byte_reverse;
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sign_extend_byte_reverse := l_saved.sign_extend & l_saved.byte_reverse;
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case sign_extend_byte_reverse is
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case sign_extend_byte_reverse is
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when "10" =>
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when "10" =>
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data := sign_extend(data, to_integer(unsigned(l_saved.length)));
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data := sign_extend(data, to_integer(unsigned(l_saved.length)));
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when "01" =>
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when "01" =>
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data := byte_reverse(data, to_integer(unsigned(l_saved.length)));
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data := byte_reverse(data, to_integer(unsigned(l_saved.length)));
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when others =>
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when others =>
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end case;
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end case;
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w_tmp.write_data <= data;
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w_tmp.write_data <= data;
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-- write data to register file
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-- write data to register file
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w_tmp.valid <= '1';
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w_tmp.valid <= '1';
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w_tmp.write_enable <= '1';
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w_tmp.write_enable <= '1';
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w_tmp.write_reg <= l_saved.write_reg;
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w_tmp.write_reg <= l_saved.write_reg;
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m_tmp <= wishbone_master_out_init;
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m_tmp <= wishbone_master_out_init;
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state <= IDLE;
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state <= IDLE;
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end if;
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end if;
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when WAITING_FOR_WRITE_ACK =>
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when WAITING_FOR_WRITE_ACK =>
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if m_in.ack = '1' then
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if m_in.ack = '1' then
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w_tmp.valid <= '1';
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w_tmp.valid <= '1';
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if l_saved.update = '1' then
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if l_saved.update = '1' then
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w_tmp.write_enable <= '1';
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w_tmp.write_enable <= '1';
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w_tmp.write_reg <= l_saved.update_reg;
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w_tmp.write_reg <= l_saved.update_reg;
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w_tmp.write_data <= l_saved.addr;
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w_tmp.write_data <= l_saved.addr;
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end if;
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end if;
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m_tmp <= wishbone_master_out_init;
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m_tmp <= wishbone_master_out_init;
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state <= IDLE;
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state <= IDLE;
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end if;
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end if;
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end case;
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end case;
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end if;
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end if;
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end process;
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end process;
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end;
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end;
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