diff options
Diffstat (limited to 'fpga/usrp2/simple_gemac/crc.v')
| -rw-r--r-- | fpga/usrp2/simple_gemac/crc.v | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/fpga/usrp2/simple_gemac/crc.v b/fpga/usrp2/simple_gemac/crc.v new file mode 100644 index 000000000..ac019083a --- /dev/null +++ b/fpga/usrp2/simple_gemac/crc.v @@ -0,0 +1,66 @@ +
+module crc
+ (input clk,
+ input reset,
+ input clear,
+ input [7:0] data,
+ input calc,
+ output [31:0] crc_out,
+ output match);
+
+ function[31:0] NextCRC;
+ input[7:0] D;
+ input[31:0] C;
+ reg[31:0] NewCRC;
+ begin
+ NewCRC[0] = C[24]^C[30]^D[1]^D[7];
+ NewCRC[1] = C[25]^C[31]^D[0]^D[6]^C[24]^C[30]^D[1]^D[7];
+ NewCRC[2] = C[26]^D[5]^C[25]^C[31]^D[0]^D[6]^C[24]^C[30]^D[1]^D[7];
+ NewCRC[3] = C[27]^D[4]^C[26]^D[5]^C[25]^C[31]^D[0]^D[6];
+ NewCRC[4] = C[28]^D[3]^C[27]^D[4]^C[26]^D[5]^C[24]^C[30]^D[1]^D[7];
+ NewCRC[5] = C[29]^D[2]^C[28]^D[3]^C[27]^D[4]^C[25]^C[31]^D[0]^D[6]^C[24]^C[30]^D[1]^D[7];
+ NewCRC[6] = C[30]^D[1]^C[29]^D[2]^C[28]^D[3]^C[26]^D[5]^C[25]^C[31]^D[0]^D[6];
+ NewCRC[7] = C[31]^D[0]^C[29]^D[2]^C[27]^D[4]^C[26]^D[5]^C[24]^D[7];
+ NewCRC[8] = C[0]^C[28]^D[3]^C[27]^D[4]^C[25]^D[6]^C[24]^D[7];
+ NewCRC[9] = C[1]^C[29]^D[2]^C[28]^D[3]^C[26]^D[5]^C[25]^D[6];
+ NewCRC[10] = C[2]^C[29]^D[2]^C[27]^D[4]^C[26]^D[5]^C[24]^D[7];
+ NewCRC[11] = C[3]^C[28]^D[3]^C[27]^D[4]^C[25]^D[6]^C[24]^D[7];
+ NewCRC[12] = C[4]^C[29]^D[2]^C[28]^D[3]^C[26]^D[5]^C[25]^D[6]^C[24]^C[30]^D[1]^D[7];
+ NewCRC[13] = C[5]^C[30]^D[1]^C[29]^D[2]^C[27]^D[4]^C[26]^D[5]^C[25]^C[31]^D[0]^D[6];
+ NewCRC[14] = C[6]^C[31]^D[0]^C[30]^D[1]^C[28]^D[3]^C[27]^D[4]^C[26]^D[5];
+ NewCRC[15] = C[7]^C[31]^D[0]^C[29]^D[2]^C[28]^D[3]^C[27]^D[4];
+ NewCRC[16] = C[8]^C[29]^D[2]^C[28]^D[3]^C[24]^D[7];
+ NewCRC[17] = C[9]^C[30]^D[1]^C[29]^D[2]^C[25]^D[6];
+ NewCRC[18] = C[10]^C[31]^D[0]^C[30]^D[1]^C[26]^D[5];
+ NewCRC[19] = C[11]^C[31]^D[0]^C[27]^D[4];
+ NewCRC[20] = C[12]^C[28]^D[3];
+ NewCRC[21] = C[13]^C[29]^D[2];
+ NewCRC[22] = C[14]^C[24]^D[7];
+ NewCRC[23] = C[15]^C[25]^D[6]^C[24]^C[30]^D[1]^D[7];
+ NewCRC[24] = C[16]^C[26]^D[5]^C[25]^C[31]^D[0]^D[6];
+ NewCRC[25] = C[17]^C[27]^D[4]^C[26]^D[5];
+ NewCRC[26] = C[18]^C[28]^D[3]^C[27]^D[4]^C[24]^C[30]^D[1]^D[7];
+ NewCRC[27] = C[19]^C[29]^D[2]^C[28]^D[3]^C[25]^C[31]^D[0]^D[6];
+ NewCRC[28] = C[20]^C[30]^D[1]^C[29]^D[2]^C[26]^D[5];
+ NewCRC[29] = C[21]^C[31]^D[0]^C[30]^D[1]^C[27]^D[4];
+ NewCRC[30] = C[22]^C[31]^D[0]^C[28]^D[3];
+ NewCRC[31] = C[23]^C[29]^D[2];
+ NextCRC = NewCRC;
+ end
+ endfunction
+
+ reg [31:0] crc_reg;
+ always @ (posedge clk)
+ if (reset | clear)
+ crc_reg <= 32'hffffffff;
+ else if (calc)
+ crc_reg <= NextCRC(data,crc_reg);
+
+ assign crc_out = ~{crc_reg[24],crc_reg[25],crc_reg[26],crc_reg[27],crc_reg[28],crc_reg[29],crc_reg[30],crc_reg[31],
+ crc_reg[16],crc_reg[17],crc_reg[18],crc_reg[19],crc_reg[20],crc_reg[21],crc_reg[22],crc_reg[23],
+ crc_reg[8],crc_reg[9],crc_reg[10],crc_reg[11],crc_reg[12],crc_reg[13],crc_reg[14],crc_reg[15],
+ crc_reg[0],crc_reg[1],crc_reg[2],crc_reg[3],crc_reg[4],crc_reg[5],crc_reg[6],crc_reg[7] };
+
+ assign match = (crc_reg == 32'hc704_dd7b);
+
+endmodule // crc
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