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78 lines
2.7 KiB
C++
78 lines
2.7 KiB
C++
// 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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//baeckler - 11-14-2006
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#include <stdio.h>
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int log2 (int n)
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{
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int bits = 0;
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while (n)
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{
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n >>= 1;
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bits++;
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}
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return (bits);
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}
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int main (void)
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{
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unsigned int num_ins = 6;
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unsigned int num_outs = log2(num_ins);
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unsigned int num_cases = (1<<num_ins);
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unsigned int n = 0, k = 0;
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unsigned int out_val = 0;
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fprintf (stdout,"//baeckler - 11-14-2006\n");
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fprintf (stdout,"// priority encoder\n");
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fprintf (stdout,"// no requests - output = 0\n");
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fprintf (stdout,"// request bit 0 (highest priority) - output = 1\n");
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fprintf (stdout,"// request bit %d (lowest priority) - output = %d\n",num_ins-1,num_ins);
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fprintf (stdout,"module prio_encode (reqs,out);\n");
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fprintf (stdout,"input [%d:0] reqs;\n",num_ins-1);
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fprintf (stdout,"output [%d:0] out;\n",num_outs-1);
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fprintf (stdout,"reg [%d:0] out;\n\n",num_outs-1);
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fprintf (stdout," always @(*) begin\n");
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fprintf (stdout," case(reqs)\n");
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fprintf (stdout," // 0 is special, no reqs\n");
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fprintf (stdout," %d'd%d: out = %d;\n\n",num_ins,0,0);
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for (n=1; n<num_cases; n++)
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{
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out_val = 1;
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k = n;
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while (k && !(k&1))
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{
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k >>=1;
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out_val += 1;
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}
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fprintf (stdout," %d'd%d: out = %d;\n",num_ins,n,out_val);
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}
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fprintf (stdout," endcase\n");
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fprintf (stdout," end\n");
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fprintf (stdout,"endmodule\n");
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return (0);
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} |