1 files changed, 70 insertions, 0 deletions
diff --git a/src/audio_core/renderer/command/mix/mix.cpp b/src/audio_core/renderer/command/mix/mix.cpp
new file mode 100644
index 000000000..8ecf9b05a
--- /dev/null
+++ b/src/audio_core/renderer/command/mix/mix.cpp
@@ -0,0 +1,70 @@
+// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <limits>
+#include <span>
+
+#include "audio_core/renderer/adsp/command_list_processor.h"
+#include "audio_core/renderer/command/mix/mix.h"
+#include "common/fixed_point.h"
+
+namespace AudioCore::AudioRenderer {
+/**
+ * Mix input mix buffer into output mix buffer, with volume applied to the input.
+ *
+ * @tparam Q           - Number of bits for fixed point operations.
+ * @param output       - Output mix buffer.
+ * @param input        - Input mix buffer.
+ * @param volume       - Volume applied to the input.
+ * @param sample_count - Number of samples to process.
+ */
+template <size_t Q>
+static void ApplyMix(std::span<s32> output, std::span<const s32> input, const f32 volume_,
+                     const u32 sample_count) {
+    const Common::FixedPoint<64 - Q, Q> volume{volume_};
+    for (u32 i = 0; i < sample_count; i++) {
+        output[i] = (output[i] + input[i] * volume).to_int();
+    }
+}
+
+void MixCommand::Dump([[maybe_unused]] const ADSP::CommandListProcessor& processor,
+                      std::string& string) {
+    string += fmt::format("MixCommand");
+    string += fmt::format("\n\tinput {:02X}", input_index);
+    string += fmt::format("\n\toutput {:02X}", output_index);
+    string += fmt::format("\n\tvolume {:.8f}", volume);
+    string += "\n";
+}
+
+void MixCommand::Process(const ADSP::CommandListProcessor& processor) {
+    auto output{processor.mix_buffers.subspan(output_index * processor.sample_count,
+                                              processor.sample_count)};
+    auto input{processor.mix_buffers.subspan(input_index * processor.sample_count,
+                                             processor.sample_count)};
+
+    // If volume is 0, nothing will be added to the output, so just skip.
+    if (volume == 0.0f) {
+        return;
+    }
+
+    switch (precision) {
+    case 15:
+        ApplyMix<15>(output, input, volume, processor.sample_count);
+        break;
+
+    case 23:
+        ApplyMix<23>(output, input, volume, processor.sample_count);
+        break;
+
+    default:
+        LOG_ERROR(Service_Audio, "Invalid precision {}", precision);
+        break;
+    }
+}
+
+bool MixCommand::Verify(const ADSP::CommandListProcessor& processor) {
+    return true;
+}
+
+} // namespace AudioCore::AudioRenderer