`timescale 1ns / 1ps
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`timescale 1ns / 1ps
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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// Company:
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// Company:
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// Engineer:
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// Engineer:
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//
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//
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// Create Date: 21:23:10 11/21/05
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// Create Date: 21:23:10 11/21/05
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// Design Name:
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// Design Name:
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// Module Name: rxLenTypChecker
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// Module Name: rxLenTypChecker
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// Project Name:
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// Project Name:
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// Target Device:
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// Target Device:
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// Tool versions:
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// Tool versions:
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// Description:
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// Description:
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//
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//
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// Dependencies:
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// Dependencies:
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//
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//
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// Revision:
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// Revision:
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// Revision 0.01 - File Created
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// Revision 0.01 - File Created
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// Additional Comments: Length/Type:
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// Additional Comments: Length/Type:
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// 1. <64: Length, we should remove PAD
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// 1. <64: Length, we should remove PAD
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// 2. >=64, <= 1518: Length, valid frame, we don't need remove PAD(0x2E, 0x5DC)
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// 2. >=64, <= 1518: Length, valid frame, we don't need remove PAD(0x2E, 0x5DC)
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// 3. >=1518: <9k+18: Length, jumbo frame, if supported (0x5DC, 0x2400)
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// 3. >=1518: <9k+18: Length, jumbo frame, if supported (0x5DC, 0x2400)
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// 4. >9k+18, = 0x8100: Type, Tagged frame
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// 4. >9k+18, = 0x8100: Type, Tagged frame
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// 5. >9k+18, = 0x8808: Type, pause frame
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// 5. >9k+18, = 0x8808: Type, pause frame
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// |<------------------------------ Data Field ---------------------------->|
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// |<------------------------------ Data Field ---------------------------->|
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// |<------------- True Data Field --------------> <-----Padded bits------->|
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// |<------------- True Data Field --------------> <-----Padded bits------->|
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// |____________________________|_________________|
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// |____________________________|_________________|
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// | | |
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// | | |
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// | small_integer_cnt * 64 | small_bits_more |
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// | small_integer_cnt * 64 | small_bits_more |
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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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// | integer_cnt * 64 | bits_more |
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// | integer_cnt * 64 | bits_more |
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// |___________________________________________________|____________________|
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// |___________________________________________________|____________________|
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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module rxLenTypChecker(lt_data, tagged_len, jumbo_enable, tagged_frame, pause_frame, small_frame,
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module rxLenTypChecker(lt_data, tagged_len, jumbo_enable, tagged_frame, pause_frame, small_frame,
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len_invalid, integer_cnt, small_integer_cnt, bits_more, inband_fcs,
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len_invalid, integer_cnt, small_integer_cnt, bits_more, inband_fcs,
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small_bits_more, vlan_enable );
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small_bits_more, vlan_enable );
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input[15:0] lt_data; //Length or Type field of a frame
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input[15:0] lt_data; //Length or Type field of a frame
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input[15:0] tagged_len; //Actual length carried with tagged frame
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input[15:0] tagged_len; //Actual length carried with tagged frame
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input jumbo_enable; //Enable jumbo frame recieving
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input jumbo_enable; //Enable jumbo frame recieving
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input inband_fcs; //In-band FCS
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input inband_fcs; //In-band FCS
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input vlan_enable; //VLAN mode enable bit
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input vlan_enable; //VLAN mode enable bit
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output pause_frame; //Indicate that current frame is a pause frame (a kind of control frame)
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output pause_frame; //Indicate that current frame is a pause frame (a kind of control frame)
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output small_frame;
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output small_frame;
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output len_invalid; //Indicate that current frame is not an valid frame
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output len_invalid; //Indicate that current frame is not an valid frame
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output[12:0] integer_cnt; //number of 64bits DATA field contains
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output[12:0] integer_cnt; //number of 64bits DATA field contains
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output[12:0] small_integer_cnt; //number of 64bits real DATA field contains(without pad part)
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output[12:0] small_integer_cnt; //number of 64bits real DATA field contains(without pad part)
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output tagged_frame; //number of 64bits DATA field of tagged frame contains
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output tagged_frame; //number of 64bits DATA field of tagged frame contains
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output[2:0] bits_more; //number that is less than 64bits(whole data field)
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output[2:0] bits_more; //number that is less than 64bits(whole data field)
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output[2:0] small_bits_more; //number that is less than 64bits(unpadded data field)
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output[2:0] small_bits_more; //number that is less than 64bits(unpadded data field)
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wire[15:0] current_len;
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wire[15:0] current_len;
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wire[15:0] current_cnt;
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wire[15:0] current_cnt;
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wire small_frame;
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wire small_frame;
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wire tagged_frame;
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wire tagged_frame;
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parameter TP =1 ;
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parameter TP =1 ;
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assign current_len = tagged_frame?(tagged_len+2):(lt_data-2); //Data field length
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assign current_len = tagged_frame?(tagged_len+2):(lt_data-2); //Data field length
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assign current_cnt = current_len >> 3; //the number of 64bits data field has
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assign current_cnt = current_len >> 3; //the number of 64bits data field has
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assign padded_frame = (current_len[15:6]==0) & (~current_len[5] | (current_len[5] & ~current_len[4]));
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assign padded_frame = (current_len[15:6]==0) & (~current_len[5] | (current_len[5] & ~current_len[4]));
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assign small_frame = padded_frame & ~inband_fcs; //padded frame
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assign small_frame = padded_frame & ~inband_fcs; //padded frame
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assign bits_more = padded_frame? 4 :current_len[2:0]; // bits that is not 64bits enough
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assign bits_more = padded_frame? 4 :current_len[2:0]; // bits that is not 64bits enough
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assign small_bits_more = current_len[2:0];// for situation smaller than 64
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assign small_bits_more = current_len[2:0];// for situation smaller than 64
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assign integer_cnt = padded_frame? 5 :current_cnt[12:0];
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assign integer_cnt = padded_frame? 5 :current_cnt[12:0];
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assign small_integer_cnt = current_cnt[12:0];
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assign small_integer_cnt = current_cnt[12:0];
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assign tagged_frame = (lt_data==16'h8100) & vlan_enable;
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assign tagged_frame = (lt_data==16'h8100) & vlan_enable;
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assign pause_frame = (lt_data==16'h8808);
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assign pause_frame = (lt_data==16'h8808);
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assign len_invalid = ((~jumbo_enable & (lt_data > 1500)) & ~(tagged_frame|pause_frame)) | (~vlan_enable & tagged_frame);
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assign len_invalid = ((~jumbo_enable & (lt_data > 1500)) & ~(tagged_frame|pause_frame)) | (~vlan_enable & tagged_frame);
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//not a large frame(except LT is type interpretion) when jumbo is not enabled, not a tagged frame when vlan is not enbaled
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//not a large frame(except LT is type interpretion) when jumbo is not enabled, not a tagged frame when vlan is not enbaled
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endmodule
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endmodule
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