Xenia-Canary/src/xenia/apu/conversion.h

/**
 ******************************************************************************
 * Xenia : Xbox 360 Emulator Research Project                                 *
 ******************************************************************************
 * Copyright 2021 Ben Vanik. All rights reserved.                             *
 * Released under the BSD license - see LICENSE in the root for more details. *
 ******************************************************************************
 */

#ifndef XENIA_APU_CONVERSION_H_
#define XENIA_APU_CONVERSION_H_

#include <cstdint>

#include "xenia/base/byte_order.h"
#include "xenia/base/platform.h"

namespace xe {
namespace apu {
namespace conversion {

#if XE_ARCH_AMD64

XE_NOINLINE
static void _generic_sequential_6_BE_to_interleaved_6_LE(
    float* XE_RESTRICT output, const float* XE_RESTRICT input,
    unsigned ch_sample_count) {
  for (unsigned sample = 0; sample < ch_sample_count; sample++) {
    for (unsigned channel = 0; channel < 6; channel++) {
      unsigned int value = *reinterpret_cast<const unsigned int*>(
          &input[channel * ch_sample_count + sample]);

      *reinterpret_cast<unsigned int*>(&output[sample * 6 + channel]) =
          xe::byte_swap(value);
    }
  }
}
#if XE_COMPILER_CLANG_CL != 1 && !XE_PLATFORM_LINUX
// load_be_u32 unavailable on clang-cl
XE_NOINLINE
static void _movbe_sequential_6_BE_to_interleaved_6_LE(
    float* XE_RESTRICT output, const float* XE_RESTRICT input,
    unsigned ch_sample_count) {
  for (unsigned sample = 0; sample < ch_sample_count; sample++) {
    for (unsigned channel = 0; channel < 6; channel++) {
      *reinterpret_cast<unsigned int*>(&output[sample * 6 + channel]) =
          _load_be_u32(reinterpret_cast<const unsigned int*>(
              &input[channel * ch_sample_count + sample]));
    }
  }
}

inline static void sequential_6_BE_to_interleaved_6_LE(
    float* output, const float* input, unsigned ch_sample_count) {
  if (amd64::GetFeatureFlags() & amd64::kX64EmitMovbe) {
    _movbe_sequential_6_BE_to_interleaved_6_LE(output, input, ch_sample_count);
  } else {
    _generic_sequential_6_BE_to_interleaved_6_LE(output, input,
                                                 ch_sample_count);
  }
}
#else
inline static void sequential_6_BE_to_interleaved_6_LE(
    float* output, const float* input, unsigned ch_sample_count) {
  _generic_sequential_6_BE_to_interleaved_6_LE(output, input, ch_sample_count);
}
#endif

inline void sequential_6_BE_to_interleaved_2_LE(float* output,
                                                const float* input,
                                                size_t ch_sample_count) {
  assert_true(ch_sample_count % 4 == 0);
  const __m128i byte_swap_shuffle =
      _mm_set_epi8(12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3);
  const __m128 half = _mm_set1_ps(0.5f);
  const __m128 two_fifths = _mm_set1_ps(1.0f / 2.5f);

  // put center on left and right, discard low frequency
  for (size_t sample = 0; sample < ch_sample_count; sample += 4) {
    // load 4 samples from 6 channels each
    __m128 fl = _mm_loadu_ps(&input[0 * ch_sample_count + sample]);
    __m128 fr = _mm_loadu_ps(&input[1 * ch_sample_count + sample]);
    __m128 fc = _mm_loadu_ps(&input[2 * ch_sample_count + sample]);
    __m128 bl = _mm_loadu_ps(&input[4 * ch_sample_count + sample]);
    __m128 br = _mm_loadu_ps(&input[5 * ch_sample_count + sample]);
    // byte swap
    fl = _mm_castsi128_ps(
        _mm_shuffle_epi8(_mm_castps_si128(fl), byte_swap_shuffle));
    fr = _mm_castsi128_ps(
        _mm_shuffle_epi8(_mm_castps_si128(fr), byte_swap_shuffle));
    fc = _mm_castsi128_ps(
        _mm_shuffle_epi8(_mm_castps_si128(fc), byte_swap_shuffle));
    bl = _mm_castsi128_ps(
        _mm_shuffle_epi8(_mm_castps_si128(bl), byte_swap_shuffle));
    br = _mm_castsi128_ps(
        _mm_shuffle_epi8(_mm_castps_si128(br), byte_swap_shuffle));

    __m128 center_halved = _mm_mul_ps(fc, half);
    __m128 left = _mm_add_ps(_mm_add_ps(fl, bl), center_halved);
    __m128 right = _mm_add_ps(_mm_add_ps(fr, br), center_halved);
    left = _mm_mul_ps(left, two_fifths);
    right = _mm_mul_ps(right, two_fifths);
    _mm_storeu_ps(&output[sample * 2], _mm_unpacklo_ps(left, right));
    _mm_storeu_ps(&output[(sample + 2) * 2], _mm_unpackhi_ps(left, right));
  }
}
#else
inline void sequential_6_BE_to_interleaved_6_LE(float* output,
                                                const float* input,
                                                size_t ch_sample_count) {
  for (size_t sample = 0; sample < ch_sample_count; sample++) {
    for (size_t channel = 0; channel < 6; channel++) {
      output[sample * 6 + channel] =
          xe::byte_swap(input[channel * ch_sample_count + sample]);
    }
  }
}
inline void sequential_6_BE_to_interleaved_2_LE(float* output,
                                                const float* input,
                                                size_t ch_sample_count) {
  // Default 5.1 channel mapping is fl, fr, fc, lf, bl, br
  // https://docs.microsoft.com/en-us/windows/win32/xaudio2/xaudio2-default-channel-mapping
  for (size_t sample = 0; sample < ch_sample_count; sample++) {
    // put center on left and right, discard low frequency
    float fl = xe::byte_swap(input[0 * ch_sample_count + sample]);
    float fr = xe::byte_swap(input[1 * ch_sample_count + sample]);
    float fc = xe::byte_swap(input[2 * ch_sample_count + sample]);
    float br = xe::byte_swap(input[4 * ch_sample_count + sample]);
    float bl = xe::byte_swap(input[5 * ch_sample_count + sample]);
    float center_halved = fc * 0.5f;
    output[sample * 2] = (fl + bl + center_halved) * (1.0f / 2.5f);
    output[sample * 2 + 1] = (fr + br + center_halved) * (1.0f / 2.5f);
  }
}
#endif

}  // namespace conversion
}  // namespace apu
}  // namespace xe

#endif