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190 lines
9.0 KiB
Verilog
190 lines
9.0 KiB
Verilog
// Copyright 2007 Altera Corporation. All rights reserved.
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// Altera products are protected under numerous U.S. and foreign patents,
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// maskwork rights, copyrights and other intellectual property laws.
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//
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// This reference design file, and your use thereof, is subject to and governed
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// by the terms and conditions of the applicable Altera Reference Design
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// License Agreement (either as signed by you or found at www.altera.com). By
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// using this reference design file, you indicate your acceptance of such terms
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// and conditions between you and Altera Corporation. In the event that you do
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// not agree with such terms and conditions, you may not use the reference
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// design file and please promptly destroy any copies you have made.
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//
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// This reference design file is being provided on an "as-is" basis and as an
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// accommodation and therefore all warranties, representations or guarantees of
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// any kind (whether express, implied or statutory) including, without
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// limitation, warranties of merchantability, non-infringement, or fitness for
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// a particular purpose, are specifically disclaimed. By making this reference
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// design file available, Altera expressly does not recommend, suggest or
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// require that this reference design file be used in combination with any
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// other product not provided by Altera.
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/////////////////////////////////////////////////////////////////////////////
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module mask_32 (in,mask);
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input [4:0] in;
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output [31:0] mask;
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reg [31:0] mask;
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parameter FROM_MSB = 1'b1;
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parameter DIAG_ONES = 1'b1;
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generate
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if (!FROM_MSB && !DIAG_ONES) begin
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always @(in) begin
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case (in)
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5'd0: mask=32'b00000000000000000000000000000000;
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5'd1: mask=32'b00000000000000000000000000000001;
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5'd2: mask=32'b00000000000000000000000000000011;
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5'd3: mask=32'b00000000000000000000000000000111;
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5'd4: mask=32'b00000000000000000000000000001111;
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5'd5: mask=32'b00000000000000000000000000011111;
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5'd6: mask=32'b00000000000000000000000000111111;
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5'd7: mask=32'b00000000000000000000000001111111;
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5'd8: mask=32'b00000000000000000000000011111111;
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5'd9: mask=32'b00000000000000000000000111111111;
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5'd10: mask=32'b00000000000000000000001111111111;
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5'd11: mask=32'b00000000000000000000011111111111;
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5'd12: mask=32'b00000000000000000000111111111111;
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5'd13: mask=32'b00000000000000000001111111111111;
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5'd14: mask=32'b00000000000000000011111111111111;
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5'd15: mask=32'b00000000000000000111111111111111;
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5'd16: mask=32'b00000000000000001111111111111111;
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5'd17: mask=32'b00000000000000011111111111111111;
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5'd18: mask=32'b00000000000000111111111111111111;
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5'd19: mask=32'b00000000000001111111111111111111;
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5'd20: mask=32'b00000000000011111111111111111111;
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5'd21: mask=32'b00000000000111111111111111111111;
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5'd22: mask=32'b00000000001111111111111111111111;
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5'd23: mask=32'b00000000011111111111111111111111;
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5'd24: mask=32'b00000000111111111111111111111111;
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5'd25: mask=32'b00000001111111111111111111111111;
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5'd26: mask=32'b00000011111111111111111111111111;
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5'd27: mask=32'b00000111111111111111111111111111;
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5'd28: mask=32'b00001111111111111111111111111111;
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5'd29: mask=32'b00011111111111111111111111111111;
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5'd30: mask=32'b00111111111111111111111111111111;
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5'd31: mask=32'b01111111111111111111111111111111;
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default: mask=0;
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endcase
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end
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end
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else if ( FROM_MSB && !DIAG_ONES) begin
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always @(in) begin
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case (in)
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5'd0: mask=32'b00000000000000000000000000000000;
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5'd1: mask=32'b10000000000000000000000000000000;
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5'd2: mask=32'b11000000000000000000000000000000;
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5'd3: mask=32'b11100000000000000000000000000000;
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5'd4: mask=32'b11110000000000000000000000000000;
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5'd5: mask=32'b11111000000000000000000000000000;
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5'd6: mask=32'b11111100000000000000000000000000;
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5'd7: mask=32'b11111110000000000000000000000000;
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5'd8: mask=32'b11111111000000000000000000000000;
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5'd9: mask=32'b11111111100000000000000000000000;
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5'd10: mask=32'b11111111110000000000000000000000;
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5'd11: mask=32'b11111111111000000000000000000000;
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5'd12: mask=32'b11111111111100000000000000000000;
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5'd13: mask=32'b11111111111110000000000000000000;
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5'd14: mask=32'b11111111111111000000000000000000;
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5'd15: mask=32'b11111111111111100000000000000000;
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5'd16: mask=32'b11111111111111110000000000000000;
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5'd17: mask=32'b11111111111111111000000000000000;
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5'd18: mask=32'b11111111111111111100000000000000;
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5'd19: mask=32'b11111111111111111110000000000000;
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5'd20: mask=32'b11111111111111111111000000000000;
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5'd21: mask=32'b11111111111111111111100000000000;
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5'd22: mask=32'b11111111111111111111110000000000;
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5'd23: mask=32'b11111111111111111111111000000000;
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5'd24: mask=32'b11111111111111111111111100000000;
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5'd25: mask=32'b11111111111111111111111110000000;
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5'd26: mask=32'b11111111111111111111111111000000;
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5'd27: mask=32'b11111111111111111111111111100000;
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5'd28: mask=32'b11111111111111111111111111110000;
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5'd29: mask=32'b11111111111111111111111111111000;
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5'd30: mask=32'b11111111111111111111111111111100;
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5'd31: mask=32'b11111111111111111111111111111110;
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default: mask=0;
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endcase
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end
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end
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else if (!FROM_MSB && DIAG_ONES) begin
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always @(in) begin
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case (in)
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5'd0: mask=32'b00000000000000000000000000000001;
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5'd1: mask=32'b00000000000000000000000000000011;
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5'd2: mask=32'b00000000000000000000000000000111;
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5'd3: mask=32'b00000000000000000000000000001111;
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5'd4: mask=32'b00000000000000000000000000011111;
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5'd5: mask=32'b00000000000000000000000000111111;
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5'd6: mask=32'b00000000000000000000000001111111;
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5'd7: mask=32'b00000000000000000000000011111111;
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5'd8: mask=32'b00000000000000000000000111111111;
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5'd9: mask=32'b00000000000000000000001111111111;
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5'd10: mask=32'b00000000000000000000011111111111;
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5'd11: mask=32'b00000000000000000000111111111111;
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5'd12: mask=32'b00000000000000000001111111111111;
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5'd13: mask=32'b00000000000000000011111111111111;
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5'd14: mask=32'b00000000000000000111111111111111;
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5'd15: mask=32'b00000000000000001111111111111111;
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5'd16: mask=32'b00000000000000011111111111111111;
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5'd17: mask=32'b00000000000000111111111111111111;
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5'd18: mask=32'b00000000000001111111111111111111;
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5'd19: mask=32'b00000000000011111111111111111111;
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5'd20: mask=32'b00000000000111111111111111111111;
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5'd21: mask=32'b00000000001111111111111111111111;
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5'd22: mask=32'b00000000011111111111111111111111;
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5'd23: mask=32'b00000000111111111111111111111111;
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5'd24: mask=32'b00000001111111111111111111111111;
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5'd25: mask=32'b00000011111111111111111111111111;
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5'd26: mask=32'b00000111111111111111111111111111;
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5'd27: mask=32'b00001111111111111111111111111111;
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5'd28: mask=32'b00011111111111111111111111111111;
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5'd29: mask=32'b00111111111111111111111111111111;
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5'd30: mask=32'b01111111111111111111111111111111;
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5'd31: mask=32'b11111111111111111111111111111111;
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default: mask=0;
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endcase
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end
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end
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else if ( FROM_MSB && DIAG_ONES) begin
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always @(in) begin
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case (in)
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5'd0: mask=32'b10000000000000000000000000000000;
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5'd1: mask=32'b11000000000000000000000000000000;
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5'd2: mask=32'b11100000000000000000000000000000;
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5'd3: mask=32'b11110000000000000000000000000000;
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5'd4: mask=32'b11111000000000000000000000000000;
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5'd5: mask=32'b11111100000000000000000000000000;
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5'd6: mask=32'b11111110000000000000000000000000;
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5'd7: mask=32'b11111111000000000000000000000000;
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5'd8: mask=32'b11111111100000000000000000000000;
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5'd9: mask=32'b11111111110000000000000000000000;
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5'd10: mask=32'b11111111111000000000000000000000;
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5'd11: mask=32'b11111111111100000000000000000000;
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5'd12: mask=32'b11111111111110000000000000000000;
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5'd13: mask=32'b11111111111111000000000000000000;
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5'd14: mask=32'b11111111111111100000000000000000;
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5'd15: mask=32'b11111111111111110000000000000000;
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5'd16: mask=32'b11111111111111111000000000000000;
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5'd17: mask=32'b11111111111111111100000000000000;
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5'd18: mask=32'b11111111111111111110000000000000;
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5'd19: mask=32'b11111111111111111111000000000000;
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5'd20: mask=32'b11111111111111111111100000000000;
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5'd21: mask=32'b11111111111111111111110000000000;
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5'd22: mask=32'b11111111111111111111111000000000;
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5'd23: mask=32'b11111111111111111111111100000000;
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5'd24: mask=32'b11111111111111111111111110000000;
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5'd25: mask=32'b11111111111111111111111111000000;
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5'd26: mask=32'b11111111111111111111111111100000;
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5'd27: mask=32'b11111111111111111111111111110000;
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5'd28: mask=32'b11111111111111111111111111111000;
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5'd29: mask=32'b11111111111111111111111111111100;
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5'd30: mask=32'b11111111111111111111111111111110;
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5'd31: mask=32'b11111111111111111111111111111111;
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default: mask=0;
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endcase
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end
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end
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endgenerate
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endmodule
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