RecursiveModulePriorityEncoderNode constructor

Implementation

RecursiveModulePriorityEncoderNode(List<Logic> seq,
    {super.name, int depth = 0})
    : super(definitionName: 'PriorityEncodeNode_W${seq.length}') {
  seq = [
    for (var i = 0; i < seq.length; i++)
      addInput('seq$i', seq[i], width: seq[i].width)
  ];
  if (seq.length == 1) {
    addOutput('ret') <= ~seq[0];
  } else if (seq.length == 2) {
    final l = seq[0].named('leftLeafLead_d$depth');
    final r = seq[1].named('rightLeafLead_d$depth');
    addOutput('ret', width: 2);
    Combinational([
      If.block([
        Iff(l, [
          ret < Const(0, width: 2),
        ]),
        ElseIf(r, [
          ret < [Const(0), Const(1)].swizzle(),
        ]),
        Else([
          ret < [Const(1), Const(0)].swizzle(),
        ]),
      ]),
    ]);
  } else {
    final divisor = (log(seq.length - 1) / log(2)).floor();
    final split = pow(2.0, divisor).toInt();

    final left = RecursiveModulePriorityEncoderNode(
            seq.getRange(0, split).toList(),
            name: 'left_d$depth',
            depth: depth + 1)
        .ret;
    var right = RecursiveModulePriorityEncoderNode(
            seq.getRange(split, seq.length).toList(),
            name: 'right_d$depth',
            depth: depth + 1)
        .ret;
    if (right.width < left.width) {
      right = right.zeroExtend(left.width);
    }
    final l = left[-1].named('leftLead_d$depth');
    final r = right[-1].named('rightLead_d$depth');
    addOutput('ret', width: right.width + 1);
    final rhs = ((right.width > 1)
            ? [Const(0), Const(1), right.slice(-2, 0)]
                .swizzle()
                .named('zo_right_d$depth')
            : [Const(0), Const(1)].swizzle().named('zo_d$depth'))
        .named('right_d$depth');
    Combinational([
      If.block([
        Iff(l & r, [
          ret <
              [Const(1), Const(0, width: right.width)]
                  .swizzle()
                  .named('lr_d$depth'),
        ]),
        ElseIf(~l, [
          ret < [Const(0), left.slice(-1, 0)].swizzle().named('zl_d$depth'),
        ]),
        ElseIf(l, [
          ret < rhs,
        ]),
      ]),
    ]);
  }
}