69 lines
2.6 KiB
Verilog
69 lines
2.6 KiB
Verilog
// ***************************************************************************
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// ***************************************************************************
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// Copyright 2018 (c) Analog Devices, Inc. All rights reserved.
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//
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// Each core or library found in this collection may have its own licensing terms.
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// The user should keep this in in mind while exploring these cores.
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//
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// Redistribution and use in source and binary forms,
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// with or without modification of this file, are permitted under the terms of either
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// (at the option of the user):
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//
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// 1. The GNU General Public License version 2 as published by the
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// Free Software Foundation, which can be found in the top level directory, or at:
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// https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html
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//
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// OR
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//
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// 2. An ADI specific BSD license as noted in the top level directory, or on-line at:
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// https://github.com/analogdevicesinc/hdl/blob/dev/LICENSE
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//
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// ***************************************************************************
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// ***************************************************************************
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`timescale 1ns/100ps
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module ad_perfect_shuffle #(
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parameter NUM_GROUPS = 2,
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parameter WORDS_PER_GROUP = 2,
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parameter WORD_WIDTH = 8
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) (
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input [NUM_GROUPS*WORDS_PER_GROUP*WORD_WIDTH-1:0] data_in,
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output [NUM_GROUPS*WORDS_PER_GROUP*WORD_WIDTH-1:0] data_out
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);
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/*
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* Performs the perfect shuffle operation.
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*
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* The perfect shuffle splits the input vector into NUM_GROUPS groups and then
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* each group in WORDS_PER_GROUP. The output vector consists of WORDS_PER_GROUP
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* groups and each group has NUM_GROUPS words. The data is remapped, so that
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* the i-th word of the j-th word in the output vector is the j-th word of the
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* i-th group of the input vector.
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* The inverse operation of the perfect shuffle is the perfect shuffle with
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* both parameters swapped.
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* I.e. [perfect_suffle B A [perfect_shuffle A B data]] == data
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*
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* Examples:
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* NUM_GROUPS = 2, WORDS_PER_GROUP = 4
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* [A B C D a b c d] => [A a B b C c D d]
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* NUM_GROUPS = 4, WORDS_PER_GROUP = 2
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* [A a B b C c D d] => [A B C D a b c d]
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* NUM_GROUPS = 3, WORDS_PER_GROUP = 2
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* [A B a b 1 2] => [A a 1 B b 2]
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*/
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generate
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genvar i;
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genvar j;
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for (i = 0; i < NUM_GROUPS; i = i + 1) begin: shuffle_outer
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for (j = 0; j < WORDS_PER_GROUP; j = j + 1) begin: shuffle_inner
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localparam src_lsb = (j + i * WORDS_PER_GROUP) * WORD_WIDTH;
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localparam dst_lsb = (i + j * NUM_GROUPS) * WORD_WIDTH;
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assign data_out[dst_lsb+:WORD_WIDTH] = data_in[src_lsb+:WORD_WIDTH];
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end
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end
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endgenerate
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endmodule
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