rohd-hcl: find

lib/rohd_hcl.dart

@@ -4,6 +4,7 @@
 export 'src/arbiter.dart';
 export 'src/exceptions.dart';
 export 'src/fifo.dart';
+export 'src/find.dart';
 export 'src/interfaces/interfaces.dart';
 export 'src/memory.dart';
 export 'src/one_hot.dart';

lib/src/find.dart

@@ -0,0 +1,154 @@
+// Copyright (C) 2023 Intel Corporation
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// fifo.dart
+// Implementation of FIFOs.
+//
+// 2023 March 13
+// Author: Rahul Gautham Putcha <[email protected]>
+//
+
+import 'dart:math';
+
+import 'package:rohd/rohd.dart';
+import 'package:rohd_hcl/rohd_hcl.dart';
+import 'package:rohd_hcl/src/utils.dart';
+
+/// Doc coming soon...
+class FindFirstOne extends Module {
+  /// Doc coming soon...
+  late Logic _output;
+
+  /// Doc coming soon...
+  Logic get index => _output;
+
+  /// Doc coming soon...  First 1 from the least significan (right)
+  FindFirstOne(Logic bus) {
+    final oneHotList = <Logic>[];
+    for (var i = 0; i < bus.width; i++) {
+      oneHotList.add(bus[i] & ~bus.getRange(0, i).or());
+    }
+
+    final bin = OneHotToBinary(oneHotList.rswizzle()).binary;
+    _output = addOutput('findFirstOne', width: bin.width);
+    _output <= bin;
+  }
+}
+
+/// Doc coming soon...
+class FindFirstZero extends Module {
+  /// Doc coming soon...
+  late Logic _output;
+
+  /// Doc coming soon...
+  Logic get index => _output;
+
+  /// Doc coming soon...  First 1 from the least significan (right)
+  FindFirstZero(Logic bus) {
+    final oneHotList = <Logic>[];
+    for (var i = 0; i < bus.width; i++) {
+      if (i == 0)
+        oneHotList.add(~bus[i]);
+      else
+        oneHotList.add(~bus[i] & bus.getRange(0, i).and());
+    }
+
+    final bin = OneHotToBinary(oneHotList.rswizzle()).binary;
+    _output = addOutput('findFirstZero', width: bin.width);
+    _output <= bin;
+  }
+}
+
+/// Doc coming soon...
+class FindNthOne extends Module {
+  /// Doc coming soon...
+  late Logic _output;
+
+  /// Doc coming soon...
+  Logic get index => _output;
+
+  /// Doc coming soon...  First 1 from the least significan (right)
+  FindNthOne(Logic bus, Logic n) {
+    final oneHotList = <Logic>[];
+    for (var i = 0; i < bus.width; i++) {
+      final oneCount = Count(bus.getRange(0, i + 1));
+
+      var paddedNValue = n;
+      var paddedCountValue = oneCount.index;
+      if (n.width < oneCount.index.width) {
+        paddedNValue = n.zeroExtend(oneCount.index.width);
+      } else {
+        paddedCountValue = oneCount.index.zeroExtend(n.width);
+      }
+
+      // If `bus[i]` is a `1` and the number of `1`'s from index 0 to `i` is `n`
+      oneHotList.add(bus[i] & paddedCountValue.eq(paddedNValue));
+    }
+
+    final bin = OneHotToBinary(oneHotList.rswizzle()).binary;
+    _output = addOutput('findNthOne', width: bin.width);
+    _output <= bin;
+  }
+}
+
+/// Doc coming soon...
+class FindNthZero extends Module {
+  /// Doc coming soon...
+  late Logic _output;
+
+  /// Doc coming soon...
+  Logic get index => _output;
+
+  /// Doc coming soon...  First 1 from the least significan (right)
+  FindNthZero(Logic bus, Logic n) {
+    final oneHotList = <Logic>[];
+    for (var i = 0; i < bus.width; i++) {
+      if (i == 0) {
+        oneHotList.add(~bus[i] & n.eq(0));
+      } else {
+        final zeroCount = Count(bus.getRange(0, i), countOne: false);
+
+        var paddedNValue = n;
+        var paddedZeroCountValue = zeroCount.index;
+        if (n.width < zeroCount.index.width) {
+          paddedNValue = n.zeroExtend(zeroCount.index.width);
+        } else {
+          paddedZeroCountValue = zeroCount.index.zeroExtend(n.width);
+        }
+
+        // If `bus[i]` is a `0` and the number of `0`'s from index 0 to `i` is `n`
+        oneHotList.add(~bus[i] & paddedZeroCountValue.eq(paddedNValue));
+      }
+    }
+
+    final bin = OneHotToBinary(oneHotList.rswizzle()).binary;
+    _output = addOutput('findNthOne', width: bin.width);
+    _output <= bin;
+  }
+}
+
+/// Doc coming soon...
+class Count extends Module {
+  /// Doc coming soon...
+  late Logic _output;
+
+  /// Doc coming soon...
+  Logic get index => _output;
+
+  /// Doc coming soon...  First 1 from the least significan (right)
+  Count(Logic bus, {bool countOne = true}) {
+    Logic count = Const(0, width: max(1, log2Ceil(bus.width)));
+    for (var i = 0; i < bus.width; i++) {
+      count += bus[i].zeroExtend(count.width);
+    }
+    _output =
+        addOutput('count${countOne ? "One" : "Zero"}', width: count.width);
+
+    _output <=
+        (countOne
+            // count one
+            ? count
+            // Count zero by removing one's from bus width
+            : Const(bus.width, width: count.width) - count);
+  }
+}

test/find_test.dart

@@ -0,0 +1,52 @@
+// Copyright (C) 2023 Intel Corporation
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// find_test.dart
+// Tests for Find
+//
+// 2023 June 8
+// Author: Max Korbel <[email protected]>
+//
+
+import 'package:rohd/rohd.dart';
+import 'package:rohd_hcl/rohd_hcl.dart';
+import 'package:rohd_hcl/src/utils.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('count all 1s', () {
+    final bus = Const(bin('01101'), width: 5);
+    final mod = Count(bus);
+    expect(mod.index.value.toInt(), 3);
+  });
+
+  test('count all 0s', () {
+    final bus = Const(bin('001101'), width: 6);
+    final mod = Count(bus, countOne: false);
+    expect(mod.index.value.toInt(), 3);
+  });
+
+  test('find first one', () {
+    final bus = Const(bin('0111000100'), width: 10);
+    final mod = FindFirstOne(bus);
+    expect(mod.index.value.toInt(), 2);
+  });
+
+  test('find nth one', () {
+    final bus = Const(bin('10110'), width: 5);
+    final mod = FindNthOne(bus, Const(3, width: log2Ceil(5)));
+    expect(mod.index.value.toInt(), 4);
+  });
+
+  test('find first zero', () {
+    final bus = Const(bin('0111011111'), width: 10);
+    final mod = FindFirstZero(bus);
+    expect(mod.index.value.toInt(), 5);
+  });
+
+  test('find nth zero', () {
+    final bus = Const(bin('0111001010'), width: 10);
+    final mod = FindNthZero(bus, Const(3, width: log2Ceil(10)));
+    expect(mod.index.value.toInt(), 5);
+  });
+}