core.EightStageQuarterRound: add

src/main/scala/uk/ac/soton/ecs/can/core/EightStageQuarterRound.scala

+// 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
+}