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pjf |
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-- Company:
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-- Engineer: Peter Fall
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--
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-- Create Date: 16:20:42 06/01/2011
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-- Design Name:
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-- Module Name: IPv4_RX - Behavioral
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-- Project Name:
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-- Target Devices:
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-- Tool versions:
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-- Description:
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-- handle simple IP RX
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-- doesnt handle reassembly
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-- checks and filters for IP protocol
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-- checks and filters for IP addr
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-- Handle IPv4 protocol
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-- Dependencies:
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--
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-- Revision:
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-- Revision 0.01 - File Created
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-- Revision 0.02 - Improved error handling
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-- Revision 0.03 - Added handling of broadcast address
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-- Additional Comments:
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--
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----------------------------------------------------------------------------------
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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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use work.axi.all;
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use work.ipv4_types.all;
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use work.arp_types.all;
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entity IPv4_RX is
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Port (
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-- IP Layer signals
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ip_rx : out ipv4_rx_type;
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ip_rx_start : out std_logic; -- indicates receipt of ip frame.
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-- system signals
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clk : in STD_LOGIC; -- same clock used to clock mac data and ip data
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reset : in STD_LOGIC;
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our_ip_address : in STD_LOGIC_VECTOR (31 downto 0);
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rx_pkt_count : out STD_LOGIC_VECTOR(7 downto 0); -- number of IP pkts received for us
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-- MAC layer RX signals
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mac_data_in : in STD_LOGIC_VECTOR (7 downto 0); -- ethernet frame (from dst mac addr through to last byte of frame)
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mac_data_in_valid : in STD_LOGIC; -- indicates data_in valid on clock
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mac_data_in_last : in STD_LOGIC -- indicates last data in frame
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);
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end IPv4_RX;
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architecture Behavioral of IPv4_RX is
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type rx_state_type is (IDLE, ETH_HDR, IP_HDR, USER_DATA, WAIT_END, ERR);
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type rx_event_type is (NO_EVENT,DATA);
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type count_mode_type is (RST, INCR, HOLD);
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type settable_count_mode_type is (RST, INCR, SET_VAL, HOLD);
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type set_clr_type is (SET, CLR, HOLD);
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-- state variables
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signal rx_state : rx_state_type;
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signal rx_count : unsigned (15 downto 0);
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signal src_ip : std_logic_vector (31 downto 0); -- src IP captured from input
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signal dst_ip : std_logic_vector (23 downto 0); -- 1st 3 bytes of dst IP captured from input
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signal is_broadcast_reg : std_logic;
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signal protocol : std_logic_vector (7 downto 0); -- src protocol captured from input
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signal data_len : std_logic_vector (15 downto 0); -- src data length captured from input
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signal ip_rx_start_reg : std_logic; -- indicates start of user data
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signal hdr_valid_reg : std_logic; -- indicates that hdr data is valid
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signal frame_err_cnt : unsigned (7 downto 0); -- number of frame errors
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signal error_code_reg : std_logic_vector (3 downto 0);
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signal rx_pkt_counter : unsigned (7 downto 0); -- number of rx frames received for us
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-- rx control signals
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signal next_rx_state : rx_state_type;
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signal set_rx_state : std_logic;
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signal rx_event : rx_event_type;
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signal rx_count_mode : settable_count_mode_type;
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signal set_dst_ip3 : std_logic;
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signal set_dst_ip2 : std_logic;
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signal set_dst_ip1 : std_logic;
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signal set_ip3 : std_logic;
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signal set_ip2 : std_logic;
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signal set_ip1 : std_logic;
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signal set_ip0 : std_logic;
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signal set_protocol : std_logic;
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signal set_len_H : std_logic;
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signal set_len_L : std_logic;
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signal set_ip_rx_start : set_clr_type;
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signal set_hdr_valid : set_clr_type;
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signal set_frame_err_cnt: count_mode_type;
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signal dataval : std_logic_vector (7 downto 0);
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signal rx_count_val : unsigned (15 downto 0);
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signal set_error_code : std_logic;
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signal error_code_val : std_logic_vector (3 downto 0);
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signal set_pkt_cnt : count_mode_type;
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signal set_data_last : std_logic;
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signal dst_ip_rx : std_logic_vector (31 downto 0);
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signal set_is_broadcast : set_clr_type;
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-- IP datagram header format
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--
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-- 0 4 8 16 19 24 31
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-- --------------------------------------------------------------------------------------------
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-- | Version | *Header | Service Type | Total Length including header |
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-- | (4) | Length | (ignored) | (in bytes) |
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-- --------------------------------------------------------------------------------------------
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-- | Identification | Flags | Fragment Offset |
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-- | | | (in 32 bit words) |
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-- --------------------------------------------------------------------------------------------
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-- | Time To Live | Protocol | Header Checksum |
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-- | (ignored) | | |
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-- --------------------------------------------------------------------------------------------
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-- | Source IP Address |
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-- | |
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-- --------------------------------------------------------------------------------------------
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-- | Destination IP Address |
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-- | |
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-- --------------------------------------------------------------------------------------------
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-- | Options (if any - ignored) | Padding |
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-- | | (if needed) |
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-- --------------------------------------------------------------------------------------------
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-- | Data |
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-- | |
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-- --------------------------------------------------------------------------------------------
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-- | .... |
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-- | |
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-- --------------------------------------------------------------------------------------------
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--
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-- * - in 32 bit words
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begin
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-----------------------------------------------------------------------
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-- combinatorial process to implement FSM and determine control signals
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-----------------------------------------------------------------------
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rx_combinatorial : process (
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-- input signals
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mac_data_in, mac_data_in_valid, mac_data_in_last, our_ip_address,
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-- state variables
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rx_state, rx_count, src_ip, dst_ip, protocol, data_len, ip_rx_start_reg, hdr_valid_reg,
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frame_err_cnt, error_code_reg, rx_pkt_counter, is_broadcast_reg,
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-- control signals
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next_rx_state, set_rx_state, rx_event, rx_count_mode,
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set_ip3, set_ip2, set_ip1, set_ip0, set_protocol, set_len_H, set_len_L,
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set_dst_ip3, set_dst_ip2, set_dst_ip1,
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set_ip_rx_start, set_hdr_valid, set_frame_err_cnt, dataval, rx_count_val,
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set_error_code, error_code_val, set_pkt_cnt, set_data_last, dst_ip_rx, set_is_broadcast
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)
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begin
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-- set output followers
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ip_rx_start <= ip_rx_start_reg;
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ip_rx.hdr.is_valid <= hdr_valid_reg;
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ip_rx.hdr.protocol <= protocol;
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ip_rx.hdr.data_length <= data_len;
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ip_rx.hdr.src_ip_addr <= src_ip;
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ip_rx.hdr.num_frame_errors <= std_logic_vector(frame_err_cnt);
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ip_rx.hdr.last_error_code <= error_code_reg;
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ip_rx.hdr.is_broadcast <= is_broadcast_reg;
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rx_pkt_count <= STD_LOGIC_VECTOR(rx_pkt_counter);
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-- transfer data upstream if in user data phase
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if rx_state = USER_DATA then
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ip_rx.data.data_in <= mac_data_in;
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ip_rx.data.data_in_valid <= mac_data_in_valid;
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ip_rx.data.data_in_last <= set_data_last;
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else
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ip_rx.data.data_in <= (others => '0');
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ip_rx.data.data_in_valid <= '0';
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ip_rx.data.data_in_last <= '0';
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end if;
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-- set signal defaults
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next_rx_state <= IDLE;
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set_rx_state <= '0';
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rx_event <= NO_EVENT;
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rx_count_mode <= HOLD;
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set_ip3 <= '0';
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set_ip2 <= '0';
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set_ip1 <= '0';
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set_ip0 <= '0';
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set_dst_ip3 <= '0';
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set_dst_ip2 <= '0';
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set_dst_ip1 <= '0';
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set_protocol <= '0';
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set_len_H <= '0';
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set_len_L <= '0';
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set_ip_rx_start <= HOLD;
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set_hdr_valid <= HOLD;
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set_frame_err_cnt <= HOLD;
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rx_count_val <= x"0000";
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set_error_code <= '0';
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error_code_val <= RX_EC_NONE;
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set_pkt_cnt <= HOLD;
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dataval <= (others => '0');
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set_data_last <= '0';
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dst_ip_rx <= (others => '0');
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set_is_broadcast <= HOLD;
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-- determine event (if any)
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if mac_data_in_valid = '1' then
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rx_event <= DATA;
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dataval <= mac_data_in;
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end if;
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-- RX FSM
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case rx_state is
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when IDLE =>
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rx_count_mode <= RST;
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case rx_event is
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when NO_EVENT => -- (nothing to do)
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when DATA =>
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rx_count_mode <= INCR;
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set_hdr_valid <= CLR;
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next_rx_state <= ETH_HDR;
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set_rx_state <= '1';
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end case;
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when ETH_HDR =>
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case rx_event is
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when NO_EVENT => -- (nothing to do)
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when DATA =>
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if rx_count = x"000d" then
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rx_count_mode <= RST;
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next_rx_state <= IP_HDR;
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set_rx_state <= '1';
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else
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rx_count_mode <= INCR;
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end if;
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-- handle early frame termination
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if mac_data_in_last = '1' then
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error_code_val <= RX_EC_ET_ETH;
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set_error_code <= '1';
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set_frame_err_cnt <= INCR;
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set_ip_rx_start <= CLR;
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set_data_last <= '1';
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next_rx_state <= IDLE;
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set_rx_state <= '1';
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else
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case rx_count is
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when x"000c" =>
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if mac_data_in /= x"08" then -- ignore pkts that are not type=IP
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next_rx_state <= WAIT_END;
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set_rx_state <= '1';
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end if;
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when x"000d" =>
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if mac_data_in /= x"00" then -- ignore pkts that are not type=IP
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next_rx_state <= WAIT_END;
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set_rx_state <= '1';
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end if;
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when others => -- ignore other bytes in eth header
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end case;
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end if;
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end case;
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when IP_HDR =>
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case rx_event is
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when NO_EVENT => -- (nothing to do)
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when DATA =>
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if rx_count = x"0013" then
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rx_count_val <= x"0001"; -- start counter at 1
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rx_count_mode <= SET_VAL;
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else
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rx_count_mode <= INCR;
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end if;
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-- handle early frame termination
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if mac_data_in_last = '1' then
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error_code_val <= RX_EC_ET_IP;
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set_error_code <= '1';
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set_frame_err_cnt <= INCR;
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set_ip_rx_start <= CLR;
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set_data_last <= '1';
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next_rx_state <= IDLE;
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set_rx_state <= '1';
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else
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case rx_count is
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when x"0000" =>
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if mac_data_in /= x"45" then -- ignore pkts that are not v4 with 5 header words
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next_rx_state <= WAIT_END;
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set_rx_state <= '1';
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end if;
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when x"0002" => set_len_H <= '1';
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when x"0003" => set_len_L <= '1';
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when x"0006" =>
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if (mac_data_in(7) = '1') or (mac_data_in (4 downto 0) /= "00000") then
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-- ignore pkts that require reassembly (MF=1 or frag offst /= 0)
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next_rx_state <= WAIT_END;
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set_rx_state <= '1';
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end if;
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when x"0007" =>
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if mac_data_in /= x"00" then -- ignore pkts that require reassembly (frag offst /= 0)
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next_rx_state <= WAIT_END;
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set_rx_state <= '1';
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end if;
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when x"0009" => set_protocol <= '1';
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when x"000c" => set_ip3 <= '1';
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when x"000d" => set_ip2 <= '1';
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when x"000e" => set_ip1 <= '1';
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when x"000f" => set_ip0 <= '1';
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when x"0010" => set_dst_ip3 <= '1';
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when x"0011" => set_dst_ip2 <= '1';
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when x"0012" => set_dst_ip1 <= '1';
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when x"0013" =>
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-- now have the dst IP addr
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dst_ip_rx <= dst_ip & mac_data_in;
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if dst_ip_rx = IP_BC_ADDR then
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set_is_broadcast <= SET;
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else
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set_is_broadcast <= CLR;
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end if;
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set_hdr_valid <= SET; -- header values are now valid, although the pkt may not be for us
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|
| 324 |
|
|
if dst_ip_rx = our_ip_address or dst_ip_rx = IP_BC_ADDR then
|
| 325 |
|
|
next_rx_state <= USER_DATA;
|
| 326 |
|
|
set_pkt_cnt <= INCR; -- count another pkt received
|
| 327 |
|
|
set_rx_state <= '1';
|
| 328 |
|
|
set_ip_rx_start <= SET;
|
| 329 |
|
|
else
|
| 330 |
|
|
next_rx_state <= WAIT_END;
|
| 331 |
|
|
set_rx_state <= '1';
|
| 332 |
|
|
end if;
|
| 333 |
|
|
|
| 334 |
|
|
when others => -- ignore other bytes in ip header
|
| 335 |
|
|
end case;
|
| 336 |
|
|
end if;
|
| 337 |
|
|
end case;
|
| 338 |
|
|
|
| 339 |
|
|
when USER_DATA =>
|
| 340 |
|
|
case rx_event is
|
| 341 |
|
|
when NO_EVENT => -- (nothing to do)
|
| 342 |
|
|
when DATA =>
|
| 343 |
|
|
-- note: data gets transfered upstream as part of "output followers" processing
|
| 344 |
|
|
if rx_count = unsigned(data_len) then
|
| 345 |
|
|
set_ip_rx_start <= CLR;
|
| 346 |
|
|
rx_count_mode <= RST;
|
| 347 |
|
|
set_data_last <= '1';
|
| 348 |
|
|
if mac_data_in_last = '1' then
|
| 349 |
|
|
next_rx_state <= IDLE;
|
| 350 |
|
|
set_ip_rx_start <= CLR;
|
| 351 |
|
|
else
|
| 352 |
|
|
next_rx_state <= WAIT_END;
|
| 353 |
|
|
end if;
|
| 354 |
|
|
set_rx_state <= '1';
|
| 355 |
|
|
else
|
| 356 |
|
|
rx_count_mode <= INCR;
|
| 357 |
|
|
-- check for early frame termination
|
| 358 |
|
|
if mac_data_in_last = '1' then
|
| 359 |
|
|
error_code_val <= RX_EC_ET_USER;
|
| 360 |
|
|
set_error_code <= '1';
|
| 361 |
|
|
set_frame_err_cnt <= INCR;
|
| 362 |
|
|
set_ip_rx_start <= CLR;
|
| 363 |
|
|
next_rx_state <= IDLE;
|
| 364 |
|
|
set_rx_state <= '1';
|
| 365 |
|
|
end if;
|
| 366 |
|
|
end if;
|
| 367 |
|
|
end case;
|
| 368 |
|
|
|
| 369 |
|
|
when ERR =>
|
| 370 |
|
|
set_frame_err_cnt <= INCR;
|
| 371 |
|
|
set_ip_rx_start <= CLR;
|
| 372 |
|
|
if mac_data_in_last = '0' then
|
| 373 |
|
|
set_data_last <= '1';
|
| 374 |
|
|
next_rx_state <= WAIT_END;
|
| 375 |
|
|
set_rx_state <= '1';
|
| 376 |
|
|
else
|
| 377 |
|
|
next_rx_state <= IDLE;
|
| 378 |
|
|
set_rx_state <= '1';
|
| 379 |
|
|
end if;
|
| 380 |
|
|
|
| 381 |
|
|
|
| 382 |
|
|
when WAIT_END =>
|
| 383 |
|
|
case rx_event is
|
| 384 |
|
|
when NO_EVENT => -- (nothing to do)
|
| 385 |
|
|
when DATA =>
|
| 386 |
|
|
if mac_data_in_last = '1' then
|
| 387 |
|
|
set_data_last <= '1';
|
| 388 |
|
|
next_rx_state <= IDLE;
|
| 389 |
|
|
set_rx_state <= '1';
|
| 390 |
|
|
set_ip_rx_start <= CLR;
|
| 391 |
|
|
end if;
|
| 392 |
|
|
end case;
|
| 393 |
|
|
|
| 394 |
|
|
end case;
|
| 395 |
|
|
|
| 396 |
|
|
end process;
|
| 397 |
|
|
|
| 398 |
|
|
|
| 399 |
|
|
-----------------------------------------------------------------------------
|
| 400 |
|
|
-- sequential process to action control signals and change states and outputs
|
| 401 |
|
|
-----------------------------------------------------------------------------
|
| 402 |
|
|
|
| 403 |
|
|
rx_sequential : process (clk,reset)
|
| 404 |
|
|
begin
|
| 405 |
|
|
if rising_edge(clk) then
|
| 406 |
|
|
if reset = '1' then
|
| 407 |
|
|
-- reset state variables
|
| 408 |
|
|
rx_state <= IDLE;
|
| 409 |
|
|
rx_count <= x"0000";
|
| 410 |
|
|
src_ip <= (others => '0');
|
| 411 |
|
|
dst_ip <= (others => '0');
|
| 412 |
|
|
protocol <= (others => '0');
|
| 413 |
|
|
data_len <= (others => '0');
|
| 414 |
|
|
ip_rx_start_reg <= '0';
|
| 415 |
|
|
hdr_valid_reg <= '0';
|
| 416 |
|
|
is_broadcast_reg <= '0';
|
| 417 |
|
|
frame_err_cnt <= (others => '0');
|
| 418 |
|
|
error_code_reg <= RX_EC_NONE;
|
| 419 |
|
|
rx_pkt_counter <= x"00";
|
| 420 |
|
|
|
| 421 |
|
|
else
|
| 422 |
|
|
-- Next rx_state processing
|
| 423 |
|
|
if set_rx_state = '1' then
|
| 424 |
|
|
rx_state <= next_rx_state;
|
| 425 |
|
|
else
|
| 426 |
|
|
rx_state <= rx_state;
|
| 427 |
|
|
end if;
|
| 428 |
|
|
|
| 429 |
|
|
-- rx_count processing
|
| 430 |
|
|
case rx_count_mode is
|
| 431 |
|
|
when RST => rx_count <= x"0000";
|
| 432 |
|
|
when INCR => rx_count <= rx_count + 1;
|
| 433 |
|
|
when SET_VAL => rx_count <= rx_count_val;
|
| 434 |
|
|
when HOLD => rx_count <= rx_count;
|
| 435 |
|
|
end case;
|
| 436 |
|
|
|
| 437 |
|
|
-- frame error count processing
|
| 438 |
|
|
case set_frame_err_cnt is
|
| 439 |
|
|
when RST => frame_err_cnt <= x"00";
|
| 440 |
|
|
when INCR => frame_err_cnt <= frame_err_cnt + 1;
|
| 441 |
|
|
when HOLD => frame_err_cnt <= frame_err_cnt;
|
| 442 |
|
|
end case;
|
| 443 |
|
|
|
| 444 |
|
|
-- ip pkt processing
|
| 445 |
|
|
case set_pkt_cnt is
|
| 446 |
|
|
when RST => rx_pkt_counter <= x"00";
|
| 447 |
|
|
when INCR => rx_pkt_counter <= rx_pkt_counter + 1;
|
| 448 |
|
|
when HOLD => rx_pkt_counter <= rx_pkt_counter;
|
| 449 |
|
|
end case;
|
| 450 |
|
|
|
| 451 |
|
|
-- source ip capture
|
| 452 |
|
|
if (set_ip3 = '1') then src_ip(31 downto 24) <= dataval; end if;
|
| 453 |
|
|
if (set_ip2 = '1') then src_ip(23 downto 16) <= dataval; end if;
|
| 454 |
|
|
if (set_ip1 = '1') then src_ip(15 downto 8) <= dataval; end if;
|
| 455 |
|
|
if (set_ip0 = '1') then src_ip(7 downto 0) <= dataval; end if;
|
| 456 |
|
|
|
| 457 |
|
|
-- dst ip capture
|
| 458 |
|
|
if (set_dst_ip3 = '1') then dst_ip(23 downto 16) <= dataval; end if;
|
| 459 |
|
|
if (set_dst_ip2 = '1') then dst_ip(15 downto 8) <= dataval; end if;
|
| 460 |
|
|
if (set_dst_ip1 = '1') then dst_ip(7 downto 0) <= dataval; end if;
|
| 461 |
|
|
|
| 462 |
|
|
if (set_protocol = '1') then
|
| 463 |
|
|
protocol <= dataval;
|
| 464 |
|
|
else
|
| 465 |
|
|
protocol <= protocol;
|
| 466 |
|
|
end if;
|
| 467 |
|
|
|
| 468 |
|
|
if (set_len_H = '1') then
|
| 469 |
|
|
data_len (15 downto 8) <= dataval;
|
| 470 |
|
|
data_len (7 downto 0) <= x"00";
|
| 471 |
|
|
elsif (set_len_L = '1') then
|
| 472 |
|
|
-- compute data length, taking into account that we need to subtract the header length
|
| 473 |
|
|
data_len <= std_logic_vector(unsigned(data_len(15 downto 8) & dataval) - 20);
|
| 474 |
|
|
else
|
| 475 |
|
|
data_len <= data_len;
|
| 476 |
|
|
end if;
|
| 477 |
|
|
|
| 478 |
|
|
case set_ip_rx_start is
|
| 479 |
|
|
when SET => ip_rx_start_reg <= '1';
|
| 480 |
|
|
when CLR => ip_rx_start_reg <= '0';
|
| 481 |
|
|
when HOLD => ip_rx_start_reg <= ip_rx_start_reg;
|
| 482 |
|
|
end case;
|
| 483 |
|
|
|
| 484 |
|
|
case set_is_broadcast is
|
| 485 |
|
|
when SET => is_broadcast_reg <= '1';
|
| 486 |
|
|
when CLR => is_broadcast_reg <= '0';
|
| 487 |
|
|
when HOLD => is_broadcast_reg <= is_broadcast_reg;
|
| 488 |
|
|
end case;
|
| 489 |
|
|
|
| 490 |
|
|
case set_hdr_valid is
|
| 491 |
|
|
when SET => hdr_valid_reg <= '1';
|
| 492 |
|
|
when CLR => hdr_valid_reg <= '0';
|
| 493 |
|
|
when HOLD => hdr_valid_reg <= hdr_valid_reg;
|
| 494 |
|
|
end case;
|
| 495 |
|
|
|
| 496 |
|
|
-- set error code
|
| 497 |
|
|
if set_error_code = '1' then
|
| 498 |
|
|
error_code_reg <= error_code_val;
|
| 499 |
|
|
else
|
| 500 |
|
|
error_code_reg <= error_code_reg;
|
| 501 |
|
|
end if;
|
| 502 |
|
|
end if;
|
| 503 |
|
|
end if;
|
| 504 |
|
|
end process;
|
| 505 |
|
|
|
| 506 |
|
|
end Behavioral;
|
| 507 |
|
|
|
