text: // Copyright 2011 Google Inc. All Rights Reserved.
  //
  // Use of this source code is governed by a BSD-style license
  // that can be found in the COPYING file in the root of the source
  // tree. An additional intellectual property rights grant can be found
  // in the file PATENTS. All contributing project authors may
  // be found in the AUTHORS file in the root of the source tree.
  // -----------------------------------------------------------------------------
  //
  // CPU detection
  //
  // Author: Christian Duvivier (cduvivier@google.com)
  
  #include "./dsp.h"
  
  #if defined(WEBP_ANDROID_NEON)
  #include <cpu-features.h>
  #endif
  
  //------------------------------------------------------------------------------
  // SSE2 detection.
  //
  
  // apple/darwin gcc-4.0.1 defines __PIC__, but not __pic__ with -fPIC.
  #if (defined(__pic__) || defined(__PIC__)) && defined(__i386__)
  static WEBP_INLINE void GetCPUInfo(int cpu_info[4], int info_type) {
    __asm__ volatile (
      "mov %%ebx, %%edi\n"
      "cpuid\n"
      "xchg %%edi, %%ebx\n"
      : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
      : "a"(info_type), "c"(0));
  }
  #elif defined(__i386__) || defined(__x86_64__)
  static WEBP_INLINE void GetCPUInfo(int cpu_info[4], int info_type) {
    __asm__ volatile (
      "cpuid\n"
      : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
      : "a"(info_type), "c"(0));
  }
  #elif (defined(_M_X64) || defined(_M_IX86)) && \
        defined(_MSC_FULL_VER) && _MSC_FULL_VER >= 150030729  // >= VS2008 SP1
  #include <intrin.h>
  #define GetCPUInfo(info, type) __cpuidex(info, type, 0)  // set ecx=0
  #elif defined(WEBP_MSC_SSE2)
  #define GetCPUInfo __cpuid
  #endif
  
  // NaCl has no support for xgetbv or the raw opcode.
  #if !defined(__native_client__) && (defined(__i386__) || defined(__x86_64__))
  static WEBP_INLINE uint64_t xgetbv(void) {
    const uint32_t ecx = 0;
    uint32_t eax, edx;
    // Use the raw opcode for xgetbv for compatibility with older toolchains.
    __asm__ volatile (
      ".byte 0x0f, 0x01, 0xd0\n"
      : "=a"(eax), "=d"(edx) : "c" (ecx));
    return ((uint64_t)edx << 32) | eax;
  }
  #elif (defined(_M_X64) || defined(_M_IX86)) && \
        defined(_MSC_FULL_VER) && _MSC_FULL_VER >= 160040219  // >= VS2010 SP1
  #include <immintrin.h>
  #define xgetbv() _xgetbv(0)
  #elif defined(_MSC_VER) && defined(_M_IX86)
  static WEBP_INLINE uint64_t xgetbv(void) {
    uint32_t eax_, edx_;
    __asm {
      xor ecx, ecx  // ecx = 0
      // Use the raw opcode for xgetbv for compatibility with older toolchains.
      __asm _emit 0x0f __asm _emit 0x01 __asm _emit 0xd0
      mov eax_, eax
      mov edx_, edx
    }
    return ((uint64_t)edx_ << 32) | eax_;
  }
  #else
  #define xgetbv() 0U  // no AVX for older x64 or unrecognized toolchains.
  #endif
  
  #if defined(__i386__) || defined(__x86_64__) || defined(WEBP_MSC_SSE2)
  static int x86CPUInfo(CPUFeature feature) {
    int max_cpuid_value;
    int cpu_info[4];
  
    // get the highest feature value cpuid supports
    GetCPUInfo(cpu_info, 0);
    max_cpuid_value = cpu_info[0];
    if (max_cpuid_value < 1) {
      return 0;
    }
  
    GetCPUInfo(cpu_info, 1);
    if (feature == kSSE2) {
      return 0 != (cpu_info[3] & 0x04000000);
    }
    if (feature == kSSE3) {
      return 0 != (cpu_info[2] & 0x00000001);
    }
    if (feature == kSSE4_1) {
      return 0 != (cpu_info[2] & 0x00080000);
    }
    if (feature == kAVX) {
      // bits 27 (OSXSAVE) & 28 (256-bit AVX)
      if ((cpu_info[2] & 0x18000000) == 0x18000000) {
        // XMM state and YMM state enabled by the OS.
        return (xgetbv() & 0x6) == 0x6;
      }
    }
    if (feature == kAVX2) {
      if (x86CPUInfo(kAVX) && max_cpuid_value >= 7) {
        GetCPUInfo(cpu_info, 7);
        return ((cpu_info[1] & 0x00000020) == 0x00000020);
      }
    }
    return 0;
  }
  VP8CPUInfo VP8GetCPUInfo = x86CPUInfo;
  #elif defined(WEBP_ANDROID_NEON)  // NB: needs to be before generic NEON test.
  static int AndroidCPUInfo(CPUFeature feature) {
    const AndroidCpuFamily cpu_family = android_getCpuFamily();
    const uint64_t cpu_features = android_getCpuFeatures();
    if (feature == kNEON) {
      return (cpu_family == ANDROID_CPU_FAMILY_ARM &&
              0 != (cpu_features & ANDROID_CPU_ARM_FEATURE_NEON));
    }
    return 0;
  }
  VP8CPUInfo VP8GetCPUInfo = AndroidCPUInfo;
  #elif defined(WEBP_USE_NEON)
  // define a dummy function to enable turning off NEON at runtime by setting
  // VP8DecGetCPUInfo = NULL
  static int armCPUInfo(CPUFeature feature) {
    (void)feature;
    return 1;
  }
  VP8CPUInfo VP8GetCPUInfo = armCPUInfo;
  #elif defined(WEBP_USE_MIPS32) || defined(WEBP_USE_MIPS_DSP_R2)
  static int mipsCPUInfo(CPUFeature feature) {
    if ((feature == kMIPS32) || (feature == kMIPSdspR2)) {
      return 1;
    } else {
      return 0;
    }
  
  }
  VP8CPUInfo VP8GetCPUInfo = mipsCPUInfo;
  #else
  VP8CPUInfo VP8GetCPUInfo = NULL;
  #endif
  
  