cvw/src/ieu/aes/aes64ks1i.sv
2024-03-16 07:26:40 -07:00

51 lines
2.1 KiB
Systemverilog

///////////////////////////////////////////
// aes64ks1i.sv
//
// Written: ryan.swann@okstate.edu, james.stine@okstate.edu
// Created: 20 February 2024
//
// Purpose: aes64ks1i instruction: part of AES keyschedule with involving sbox
//
// A component of the CORE-V-WALLY configurable RISC-V project.
// https://github.com/openhwgroup/cvw
//
// Copyright (C) 2021-24 Harvey Mudd College & Oklahoma State University
//
// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
//
// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file
// except in compliance with the License, or, at your option, the Apache License version 2.0. You
// may obtain a copy of the License at
//
// https://solderpad.org/licenses/SHL-2.1/
//
// Unless required by applicable law or agreed to in writing, any work distributed under the
// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
// either express or implied. See the License for the specific language governing permissions
// and limitations under the License.
////////////////////////////////////////////////////////////////////////////////////////////////
module aes64ks1i(
input logic [3:0] round,
input logic [63:0] rs1,
input logic [31:0] Sbox0Out,
output logic [31:0] SboxKIn,
output logic [63:0] result
);
logic finalround;
logic [31:0] rcon, rs1Rotate;
rconlut32 rc(round, rcon); // Get rcon value from lookup table
assign rs1Rotate = {rs1[39:32], rs1[63:40]}; // Get rotated value fo ruse in tmp2
assign finalround = (round == 4'b1010); // round 10 is the last one
assign SboxKIn = finalround ? rs1[63:32] : rs1Rotate; // Don't rotate on the last round
// Share sbox with encryption in zknde64. This module just sends value to shared sbox and gets result back
// send out value as SboxKIn, get back subsittuted result as Sbox0Out
assign result[31:0] = Sbox0Out ^ rcon;
assign result[63:32] = Sbox0Out ^ rcon;
endmodule