EightStageQuarterRound.scala 732 Bytes
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// SPDX-FileCopyrightText: 2021 Minyong Li <ml10g20@soton.ac.uk>
// SPDX-License-Identifier: CERN-OHL-W-2.0

package uk.ac.soton.ecs.can.core

import chisel3._

class EightStageQuarterRound extends BaseQuarterRound {
  private val a0 = in(0)
  private val b0 = in(1)
  private val c0 = in(2)
  private val d0 = in(3)

  private val a1 = RegNext(a0 + b0)
  private val d1 = RegNext(rotateLeft(d0 ^ a1, 16))
  private val c1 = RegNext(c0 + d1)
  private val b1 = RegNext(rotateLeft(b0 ^ c1, 12))

  private val a2 = RegNext(a1 + b1)
  private val d2 = RegNext(rotateLeft(d1 ^ a2, 8))
  private val c2 = RegNext(c1 + d2)
  private val b2 = RegNext(rotateLeft(b1 ^ c2, 7))

  out(0) := a2
  out(1) := b2
  out(2) := c2
  out(3) := d2
}