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// Copyright 2019 The libgav1 Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "src/utils/cpu.h"
#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
#include <cpuid.h>
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
#include <immintrin.h> // _xgetbv
#include <intrin.h>
#endif
namespace libgav1 {
#if defined(__i386__) || defined(__x86_64__) || defined(_M_IX86) || \
defined(_M_X64)
namespace {
#if defined(__GNUC__)
void CpuId(int leaf, uint32_t info[4]) {
__cpuid_count(leaf, 0 /*ecx=subleaf*/, info[0], info[1], info[2], info[3]);
}
uint64_t Xgetbv() {
const uint32_t ecx = 0; // ecx specifies the extended control register
uint32_t eax;
uint32_t edx;
__asm__ volatile("xgetbv" : "=a"(eax), "=d"(edx) : "c"(ecx));
return (static_cast<uint64_t>(edx) << 32) | eax;
}
#else // _MSC_VER
void CpuId(int leaf, uint32_t info[4]) {
__cpuidex(reinterpret_cast<int*>(info), leaf, 0 /*ecx=subleaf*/);
}
uint64_t Xgetbv() { return _xgetbv(0); }
#endif // __GNUC__
} // namespace
uint32_t GetCpuInfo() {
uint32_t info[4];
// Get the highest feature value cpuid supports
CpuId(0, info);
const int max_cpuid_value = info[0];
if (max_cpuid_value < 1) return 0;
CpuId(1, info);
uint32_t features = 0;
if ((info[3] & (1 << 26)) != 0) features |= kSSE2;
if ((info[2] & (1 << 9)) != 0) features |= kSSSE3;
if ((info[2] & (1 << 19)) != 0) features |= kSSE4_1;
// Bits 27 (OSXSAVE) & 28 (256-bit AVX)
if ((info[2] & (3 << 27)) == (3 << 27)) {
// XMM state and YMM state enabled by the OS
if ((Xgetbv() & 0x6) == 0x6) {
features |= kAVX;
if (max_cpuid_value >= 7) {
CpuId(7, info);
if ((info[1] & (1 << 5)) != 0) features |= kAVX2;
}
}
}
return features;
}
#else
uint32_t GetCpuInfo() { return 0; }
#endif // x86 || x86_64
} // namespace libgav1
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