From a389dd59bd881cf2cff09a1f67f5c30de61123e6 Mon Sep 17 00:00:00 2001
From: Mary <me@thog.eu>
Date: Tue, 18 Aug 2020 03:49:37 +0200
Subject: Amadeus: Final Act (#1481)

* Amadeus: Final Act

This is my requiem, I present to you Amadeus, a complete reimplementation of the Audio Renderer!

This reimplementation is based on my reversing of every version of the audio system module that I carried for the past 10 months.
This supports every revision (at the time of writing REV1 to REV8 included) and all features proposed by the Audio Renderer on real hardware.

Because this component could be used outside an emulation context, and to avoid possible "inspirations" not crediting the project, I decided to license the Ryujinx.Audio.Renderer project under LGPLv3.

- FE3H voices in videos and chapter intro are not present.
- Games that use two audio renderer **at the same time** are probably going to have issues right now **until we rewrite the audio output interface** (Crash Team Racing is the only known game to use two renderer at the same time).

- Persona 5 Scrambler now goes ingame but audio is garbage. This is caused by the fact that the game engine is syncing audio and video in a really aggressive way. This will disappears the day this game run at full speed.

* Make timing more precise when sleeping on Windows

Improve precision to a 1ms resolution on Windows NT based OS.
This is used to avoid having totally erratic timings and unify all
Windows users to the same resolution.

NOTE: This is only active when emulation is running.
---
 Ryujinx.Audio.Renderer/Utils/BitArray.cs | 120 +++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 Ryujinx.Audio.Renderer/Utils/BitArray.cs

(limited to 'Ryujinx.Audio.Renderer/Utils/BitArray.cs')

diff --git a/Ryujinx.Audio.Renderer/Utils/BitArray.cs b/Ryujinx.Audio.Renderer/Utils/BitArray.cs
new file mode 100644
index 00000000..743ece24
--- /dev/null
+++ b/Ryujinx.Audio.Renderer/Utils/BitArray.cs
@@ -0,0 +1,120 @@
+//
+// Copyright (c) 2019-2020 Ryujinx
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+using System;
+using System.Runtime.CompilerServices;
+
+namespace Ryujinx.Audio.Renderer.Utils
+{
+    /// <summary>
+    /// A simple bit array implementation backed by a <see cref="Memory{T}"/>.
+    /// </summary>
+    public class BitArray
+    {
+        /// <summary>
+        /// The backing storage of the <see cref="BitArray"/>.
+        /// </summary>
+        private Memory<byte> _storage;
+
+        /// <summary>
+        /// Create a new <see cref="BitArray"/> from <see cref="Memory{T}"/>.
+        /// </summary>
+        /// <param name="storage">The backing storage of the <see cref="BitArray"/>.</param>
+        public BitArray(Memory<byte> storage)
+        {
+            _storage = storage;
+        }
+
+        /// <summary>
+        /// Get the byte position of a given bit index.
+        /// </summary>
+        /// <param name="index">A bit index.</param>
+        /// <returns>The byte position of a given bit index.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static int ToPosition(int index) => index / 8;
+
+        /// <summary>
+        /// Get the bit position of a given bit index inside a byte.
+        /// </summary>
+        /// <param name="index">A bit index.</param>
+        /// <returns>The bit position of a given bit index inside a byte.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static int ToBitPosition(int index) => index % 8;
+
+        /// <summary>
+        /// Test if the bit at the given index is set.
+        /// </summary>
+        /// <param name="index">A bit index.</param>
+        /// <returns>Return true if the bit at the given index is set</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public bool Test(int index)
+        {
+            ulong mask = 1ul << ToBitPosition(index);
+
+            return (_storage.Span[ToPosition(index)] & mask) == mask;
+        }
+
+        /// <summary>
+        /// Set the bit at the given index.
+        /// </summary>
+        /// <param name="index">A bit index.</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void Set(int index)
+        {
+            Set(index, true);
+        }
+
+        /// <summary>
+        /// Reset the bit at the given index.
+        /// </summary>
+        /// <param name="index">A bit index.</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void Reset(int index)
+        {
+            Set(index, false);
+        }
+
+        /// <summary>
+        /// Set a bit value at the given index.
+        /// </summary>
+        /// <param name="index">A bit index.</param>
+        /// <param name="value">The new bit value.</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private void Set(int index, bool value)
+        {
+            byte mask = (byte)(1 << ToBitPosition(index));
+
+            if (value)
+            {
+                _storage.Span[ToPosition(index)] |= mask;
+            }
+            else
+            {
+                _storage.Span[ToPosition(index)] &= (byte)~mask;
+            }
+        }
+
+        /// <summary>
+        /// Reset all bits in the storage.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void Reset()
+        {
+            _storage.Span.Fill(0);
+        }
+    }
+}
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