golang.org/x/sys@v0.20.1-0.20240517151509-673e0f94c16d/cpu/cpu_gccgo_x86.c (about)

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build (386 || amd64 || amd64p32) && gccgo
     6  
     7  #include <cpuid.h>
     8  #include <stdint.h>
     9  #include <x86intrin.h>
    10  
    11  // Need to wrap __get_cpuid_count because it's declared as static.
    12  int
    13  gccgoGetCpuidCount(uint32_t leaf, uint32_t subleaf,
    14                     uint32_t *eax, uint32_t *ebx,
    15                     uint32_t *ecx, uint32_t *edx)
    16  {
    17  	return __get_cpuid_count(leaf, subleaf, eax, ebx, ecx, edx);
    18  }
    19  
    20  #pragma GCC diagnostic ignored "-Wunknown-pragmas"
    21  #pragma GCC push_options
    22  #pragma GCC target("xsave")
    23  #pragma clang attribute push (__attribute__((target("xsave"))), apply_to=function)
    24  
    25  // xgetbv reads the contents of an XCR (Extended Control Register)
    26  // specified in the ECX register into registers EDX:EAX.
    27  // Currently, the only supported value for XCR is 0.
    28  void
    29  gccgoXgetbv(uint32_t *eax, uint32_t *edx)
    30  {
    31  	uint64_t v = _xgetbv(0);
    32  	*eax = v & 0xffffffff;
    33  	*edx = v >> 32;
    34  }
    35  
    36  #pragma clang attribute pop
    37  #pragma GCC pop_options