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
cpuid(uint32_t & eax,uint32_t & ebx,uint32_t & ecx,uint32_t & edx)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_
87