ceph/src/boost/libs/atomic/src/cpuid.hpp

   1 /*
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * Copyright (c) 2020 Andrey Semashev
   7  */
   8 /*!
   9  * \file   cpuid.hpp
  10  *
  11  * This file contains declaration of \c cpuid function
  12  */
  13
  14 #ifndef BOOST_ATOMIC_CPUID_HPP_INCLUDED_
  15 #define BOOST_ATOMIC_CPUID_HPP_INCLUDED_
  16
  17 #include <boost/predef/architecture/x86.h>
  18
  19 #if BOOST_ARCH_X86
  20
  21 #if defined(_MSC_VER)
  22 #include <intrin.h> // __cpuid
  23 #endif
  24 #include <boost/cstdint.hpp>
  25 #include <boost/atomic/detail/config.hpp>
  26
  27 #include <boost/atomic/detail/header.hpp>
  28
  29 namespace boost {
  30 namespace atomics {
  31 namespace detail {
  32
  33 //! The function invokes x86 cpuid instruction
  34 inline void cpuid(uint32_t& eax, uint32_t& ebx, uint32_t& ecx, uint32_t& edx)
  35 {
  36 #if defined(__GNUC__)
  37 #if (defined(__i386__) || defined(__VXWORKS__)) && (defined(__PIC__) || defined(__PIE__)) && !(defined(__clang__) || (defined(BOOST_GCC) && BOOST_GCC >= 50100))
  38     // Unless the compiler can do it automatically, we have to backup ebx in 32-bit PIC/PIE code because it is reserved by the ABI.
  39     // For VxWorks ebx is reserved on 64-bit as well.
  40 #if defined(__x86_64__)
  41     uint64_t rbx = ebx;
  42     __asm__ __volatile__
  43     (
  44         "xchgq %%rbx, %0\n\t"
  45         "cpuid\n\t"
  46         "xchgq %%rbx, %0\n\t"
  47             : "+DS" (rbx), "+a" (eax), "+c" (ecx), "+d" (edx)
  48     );
  49     ebx = static_cast< uint32_t >(rbx);
  50 #else // defined(__x86_64__)
  51     __asm__ __volatile__
  52     (
  53         "xchgl %%ebx, %0\n\t"
  54         "cpuid\n\t"
  55         "xchgl %%ebx, %0\n\t"
  56             : "+DS" (ebx), "+a" (eax), "+c" (ecx), "+d" (edx)
  57     );
  58 #endif // defined(__x86_64__)
  59 #else
  60     __asm__ __volatile__
  61     (
  62         "cpuid\n\t"
  63             : "+a" (eax), "+b" (ebx), "+c" (ecx), "+d" (edx)
  64     );
  65 #endif
  66 #elif defined(_MSC_VER)
  67     int regs[4] = {};
  68     __cpuid(regs, eax);
  69     eax = regs[0];
  70     ebx = regs[1];
  71     ecx = regs[2];
  72     edx = regs[3];
  73 #else
  74 #error "Boost.Atomic: Unsupported compiler, cpuid instruction cannot be generated"
  75 #endif
  76 }
  77
  78 } // namespace detail
  79 } // namespace atomics
  80 } // namespace boost
  81
  82 #include <boost/atomic/detail/footer.hpp>
  83
  84 #endif // BOOST_ARCH_X86
  85
  86 #endif // BOOST_ATOMIC_CPUID_HPP_INCLUDED_