first commit after restructuring

adi_library/common/ad_perfect_shuffle.v

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