cvw/pipelined/src/generic/priorityonehot.sv

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///////////////////////////////////////////
// priorityonehot.sv
//
// Written: tfleming@hmc.edu & jtorrey@hmc.edu 7 April 2021
// Modified: Teo Ene 15 Apr 2021:
// Temporarily removed paramterized priority encoder for non-parameterized one
// To get synthesis working quickly
// Kmacsaigoren@hmc.edu 28 May 2021:
// Added working version of parameterized priority encoder.
// David_Harris@Hmc.edu switched to one-hot output
//
// Purpose: Priority circuit producing a 1 in the output in the column where
// the least significant 1 appears in the input.
//
// Example: msb lsb
// in 01011101010100000
// out 00000000000100000
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy,
// modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
// OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
///////////////////////////////////////////
`include "wally-config.vh"
module priorityonehot #(parameter N = 8) (
input logic [N-1:0] a,
output logic [N-1:0] y
);
logic [N-1:0] nolower;
// create thermometer code mask
prioritythermometer #(N) maskgen(.a({a[N-2:0], 1'b0}), .y(nolower));
assign y = a & nolower;
endmodule