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Claude e49ec771c3 Add NEON forms of the AX mix kernels
On arm64 the AXWii mix (ramped mix-add, volume envelope, aux returns
and the big-endian bus marshalling) ran the scalar loops, since only an
AVX2 form existed. The Neon forms do eight 16-bit samples per step as
two int32x4 halves and keep the scalar loops for the tail.

The header part of rooklz's 43463622; its other changes are left out.
A new test checks every vector form against the scalar loops at every
tail length and at the ramp and clamp extremes; it passes under
qemu-aarch64 (NEON), with -mavx2 and with neither.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018NKSMYZU43wUfYtm1sxGsC
2026-10-05 15:18:43 +00:00

124 lines
4.8 KiB
C++

// The AX mix kernels' vector forms (AVX2 on x86-64, NEON on arm64) must be bit-exact with the
// scalar reference loops they replace. Random blocks at every tail length, plus the ramp and
// clamp extremes; on a build with neither vector form this compares the scalar loops with
// themselves.
#include "../src/hle/audio/ax_mix_kernels.h"
#include <cstdint>
#include <cstring>
#include <iostream>
#include <random>
#include <vector>
namespace {
int g_failures = 0;
void Fail(const char* kernel, uint32_t count, uint32_t volume, uint32_t delta) {
if (++g_failures <= 10) {
std::cerr << kernel << " differs from the scalar loop: count " << count << ", volume "
<< volume << ", delta " << delta << '\n';
}
}
template <typename T>
std::vector<T> RandomBlock(std::mt19937& rng, uint32_t count, int64_t low, int64_t high) {
std::uniform_int_distribution<int64_t> dist(low, high);
std::vector<T> block(count);
for (auto& value : block) {
value = static_cast<T>(dist(rng));
}
return block;
}
void CheckRamps(std::mt19937& rng, uint32_t count, uint16_t volume, uint16_t delta) {
const auto input = RandomBlock<int16_t>(rng, count, INT16_MIN, INT16_MAX);
const auto bus = RandomBlock<int32_t>(rng, count, -(1 << 24), 1 << 24);
auto expectedOut = bus;
auto actualOut = bus;
int16_t expectedDpop = 1234;
int16_t actualDpop = 1234;
const uint16_t expectedVolume =
AxMixKernels::MixAddRampScalar(expectedOut.data(), input.data(), count, volume, delta, expectedDpop);
const uint16_t actualVolume =
AxMixKernels::MixAddRamp(actualOut.data(), input.data(), count, volume, delta, actualDpop);
if (expectedOut != actualOut || expectedDpop != actualDpop || expectedVolume != actualVolume) {
Fail("MixAddRamp", count, volume, delta);
}
auto expectedSamples = input;
auto actualSamples = input;
const uint16_t expectedScaled = AxMixKernels::ScaleRampScalar(expectedSamples.data(), count, volume, delta);
const uint16_t actualScaled = AxMixKernels::ScaleRamp(actualSamples.data(), count, volume, delta);
if (expectedSamples != actualSamples || expectedScaled != actualScaled) {
Fail("ScaleRamp", count, volume, delta);
}
}
void CheckAccumAndMarshal(std::mt19937& rng, uint32_t count) {
const auto src = RandomBlock<int32_t>(rng, count, INT32_MIN, INT32_MAX);
const auto ramp = RandomBlock<uint16_t>(rng, count, 0, UINT16_MAX);
const auto bus = RandomBlock<int32_t>(rng, count, -(1 << 24), 1 << 24);
auto expected = bus;
auto actual = bus;
AxMixKernels::MixAccumRamp32Scalar(expected.data(), src.data(), ramp.data(), count);
AxMixKernels::MixAccumRamp32(actual.data(), src.data(), ramp.data(), count);
if (expected != actual) {
Fail("MixAccumRamp32", count, 0, 0);
}
std::vector<uint8_t> expectedBytes(count * 4);
std::vector<uint8_t> actualBytes(count * 4);
AxMixKernels::StoreBigEndian32Scalar(expectedBytes.data(), src.data(), count);
AxMixKernels::StoreBigEndian32(actualBytes.data(), src.data(), count);
if (expectedBytes != actualBytes) {
Fail("StoreBigEndian32", count, 0, 0);
}
std::vector<int32_t> expectedWords(count);
std::vector<int32_t> actualWords(count);
AxMixKernels::LoadBigEndian32Scalar(expectedWords.data(), expectedBytes.data(), count);
AxMixKernels::LoadBigEndian32(actualWords.data(), expectedBytes.data(), count);
if (expectedWords != actualWords || expectedWords != src) {
Fail("LoadBigEndian32", count, 0, 0);
}
}
} // namespace
int main() {
std::mt19937 rng(0x41584D58u);
std::uniform_int_distribution<uint32_t> any16(0, UINT16_MAX);
const uint16_t edges[] = {0, 1, 0x7FFF, 0x8000, 0x8001, 0xFFFE, 0xFFFF};
// Every tail length around the vector widths, and the AX frame sizes (96 per 3 ms frame,
// 160 at the 5 ms subframe the AXWii list can use).
for (uint32_t count = 0; count <= 40; ++count) {
for (uint16_t volume : edges) {
for (uint16_t delta : edges) {
CheckRamps(rng, count, volume, delta);
}
}
for (int trial = 0; trial < 64; ++trial) {
CheckRamps(rng, count, static_cast<uint16_t>(any16(rng)), static_cast<uint16_t>(any16(rng)));
}
CheckAccumAndMarshal(rng, count);
}
for (uint32_t count : {96u, 160u, 255u}) {
for (int trial = 0; trial < 256; ++trial) {
CheckRamps(rng, count, static_cast<uint16_t>(any16(rng)), static_cast<uint16_t>(any16(rng)));
CheckAccumAndMarshal(rng, count);
}
}
if (g_failures != 0) {
std::cerr << g_failures << " mismatches\n";
return 1;
}
std::cout << "ax mix kernels match the scalar loops (avx2 " << MKW_AX_MIX_AVX2 << ", neon "
<< MKW_AX_MIX_NEON << ")\n";
return 0;
}