Verified Commit 522b32e0 authored by Minyong Li's avatar Minyong Li 💬
Browse files

core.BaseRound: fix reversed casts

Chisel UInt conversion from/to aggregates involves reversal. This
causes problem for the Quarter Rounds, since they receive wrong
bits, leading to completely different results (which are wrong).
parent 8d984e3e
......@@ -10,6 +10,8 @@ class Adder extends MultiIOModule {
val rhs = IO(Input(UInt(512.W)))
val out = IO(Output(UInt(512.W)))
// NOTE: Unlike what's done in `BaseRound`, here no reversal is applied, since
// the additions are done on the basis of words and do not spread bits.
private val _lhs = lhs.asTypeOf(Vec(16, UInt(32.W)))
private val _rhs = rhs.asTypeOf(Vec(16, UInt(32.W)))
private val _out = Wire(Vec(16, UInt(32.W)))
......
......@@ -4,6 +4,7 @@
package uk.ac.soton.ecs.can.core
import chisel3._
import chisel3.util.Cat
import uk.ac.soton.ecs.can.config.CanCoreConfiguration
abstract class BaseRound(implicit cfg: CanCoreConfiguration)
......@@ -11,9 +12,19 @@ abstract class BaseRound(implicit cfg: CanCoreConfiguration)
val in = IO(Input(UInt(512.W)))
val out = IO(Output(UInt(512.W)))
protected val _in = in.asTypeOf(Vec(16, UInt(32.W)))
// NOTE: A conversion between an UInt and an aggregate type reverses the
// sequence of elements. The `_in` cast below reverses such reversal by
// manually creating a `Vec` with the elements in the casted `Vec` reversed.
// Same for the `out` connection, where `Cat`, which concatenates elements
// from the most significant element to the least significant element, is used
// instead of `_out.asUInt()`, which puts the first element in the `Vec` to
// the least significant position of `UInt`.
//
// See also:
// - https://github.com/chipsalliance/chisel3/blob/master/core/src/main/scala/chisel3/Data.scala#L695-L696
protected val _in = VecInit(in.asTypeOf(Vec(16, UInt(32.W))).reverse)
protected val _out = Wire(Vec(16, UInt(32.W)))
out := _out.asUInt()
out := Cat(_out)
protected def wire(wireBox: Seq[Seq[Int]]): Unit = wireBox.foreach {
wireSeq =>
......
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