/*

   +----------------------------------------------------------------------+

   | Zend Engine                                                          |

   +----------------------------------------------------------------------+

   | Copyright (c) Zend Technologies Ltd. (http://www.zend.com)           |

   +----------------------------------------------------------------------+

   | This source file is subject to version 2.00 of the Zend license,     |

   | that is bundled with this package in the file LICENSE, and is        |

   | available through the world-wide-web at the following url:           |

   | http://www.zend.com/license/2_00.txt.                                |

   | If you did not receive a copy of the Zend license and are unable to  |

   | obtain it through the world-wide-web, please send a note to          |

   | license@zend.com so we can mail you a copy immediately.              |

   +----------------------------------------------------------------------+

   | Authors: Xinchen Hui <xinchen.h@zend.com>                            |

   +----------------------------------------------------------------------+

*/

#include "zend_cpuinfo.h"

typedef struct _zend_cpu_info {

  uint32_t eax;

  uint32_t ebx;

  uint32_t ecx;

  uint32_t edx;

  uint32_t initialized;

} zend_cpu_info;

static zend_cpu_info cpuinfo = {0};

#if (defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__))

# if defined(HAVE_CPUID_H) && defined(HAVE_CPUID_COUNT) /* use cpuid.h functions */

#  include <cpuid.h>

static void __zend_cpuid(uint32_t func, uint32_t subfunc, zend_cpu_info *cpuinfo) {

  __cpuid_count(func, subfunc, cpuinfo->eax, cpuinfo->ebx, cpuinfo->ecx, cpuinfo->edx);

}

# else /* use inline asm */

static void __zend_cpuid(uint32_t func, uint32_t subfunc, zend_cpu_info *cpuinfo) {

#  if defined(__i386__) && (defined(__pic__) || defined(__PIC__))

  /* PIC on i386 uses %ebx, so preserve it. */

  __asm__ __volatile__ (

    "pushl  %%ebx\n"

    "cpuid\n"

    "mov    %%ebx,%1\n"

    "popl   %%ebx"

    : "=a"(cpuinfo->eax), "=r"(cpuinfo->ebx), "=c"(cpuinfo->ecx), "=d"(cpuinfo->edx)

    : "a"(func), "c"(subfunc)

  );

#  else

  __asm__ __volatile__ (

    "cpuid"

    : "=a"(cpuinfo->eax), "=b"(cpuinfo->ebx), "=c"(cpuinfo->ecx), "=d"(cpuinfo->edx)

    : "a"(func), "c"(subfunc)

  );

#  endif

}

# endif

#elif defined(_MSC_VER) && !defined(__clang__) && (defined(_M_X64) || defined(_M_IX86)) /* use MSVC __cpuidex intrin */

# include <intrin.h>

static void __zend_cpuid(uint32_t func, uint32_t subfunc, zend_cpu_info *cpuinfo) {

  int regs[4];

  __cpuidex(regs, func, subfunc);

  cpuinfo->eax = regs[0];

  cpuinfo->ebx = regs[1];

  cpuinfo->ecx = regs[2];

  cpuinfo->edx = regs[3];

}

#else /* fall back to zero */

static void __zend_cpuid(uint32_t func, uint32_t subfunc, zend_cpu_info *cpuinfo) {

  cpuinfo->eax = 0;

}

#endif

#if defined(__i386__) || defined(__x86_64__) || defined(_M_X64) || defined(_M_IX86)

/* Function based on compiler-rt implementation. */

static unsigned get_xcr0_eax(void) {

# if defined(__GNUC__) || defined(__clang__)

  // Check xgetbv; this uses a .byte sequence instead of the instruction

  // directly because older assemblers do not include support for xgetbv and

  // there is no easy way to conditionally compile based on the assembler used.

  unsigned eax, edx;

  __asm__(".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c"(0));

  return eax;

# elif defined(ZEND_WIN32) && defined(_XCR_XFEATURE_ENABLED_MASK)

  return _xgetbv(_XCR_XFEATURE_ENABLED_MASK);

# else

  return 0;

# endif

}

static bool is_avx_supported(void) {

  if (!(cpuinfo.ecx & ZEND_CPU_FEATURE_AVX)) {

    /* No support for AVX */

    return 0;

  }

  if (!(cpuinfo.ecx & ZEND_CPU_FEATURE_OSXSAVE)) {

    /* The operating system does not support XSAVE. */

    return 0;

  }

  if ((get_xcr0_eax() & 0x6) != 0x6) {

    /* XCR0 SSE and AVX bits must be set. */

    return 0;

  }

  return 1;

}

#else

static bool is_avx_supported(void) {

  return 0;

}

#endif

void zend_cpu_startup(void)

{

  if (!cpuinfo.initialized) {

    zend_cpu_info ebx;

    int max_feature;

    cpuinfo.initialized = 1;

    __zend_cpuid(0, 0, &cpuinfo);

    max_feature = cpuinfo.eax;

    if (max_feature == 0) {

      return;

    }

    __zend_cpuid(1, 0, &cpuinfo);

    /* for avx2 */

    if (max_feature >= 7) {

      __zend_cpuid(7, 0, &ebx);

      cpuinfo.ebx = ebx.ebx;

    } else {

      cpuinfo.ebx = 0;

    }

    if (!is_avx_supported()) {

      cpuinfo.edx &= ~ZEND_CPU_FEATURE_AVX;

      cpuinfo.ebx &= ~(ZEND_CPU_FEATURE_AVX2 & ~ZEND_CPU_EBX_MASK);

    }

  }

}

ZEND_API int zend_cpu_supports(zend_cpu_feature feature) {

  ZEND_ASSERT(cpuinfo.initialized);

  if (feature & ZEND_CPU_EDX_MASK) {

    return (cpuinfo.edx & (feature & ~ZEND_CPU_EDX_MASK));

  } else if (feature & ZEND_CPU_EBX_MASK) {

    return (cpuinfo.ebx & (feature & ~ZEND_CPU_EBX_MASK));

  } else {

    return (cpuinfo.ecx & feature);

  }

}