| // 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 |