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  // +build 386 amd64 amd64p32
       6  // +build gccgo
       7  
       8  #include <cpuid.h>
       9  #include <stdint.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  // xgetbv reads the contents of an XCR (Extended Control Register)
      21  // specified in the ECX register into registers EDX:EAX.
      22  // Currently, the only supported value for XCR is 0.
      23  //
      24  // TODO: Replace with a better alternative:
      25  //
      26  //     #include <xsaveintrin.h>
      27  //
      28  //     #pragma GCC target("xsave")
      29  //
      30  //     void gccgoXgetbv(uint32_t *eax, uint32_t *edx) {
      31  //       unsigned long long x = _xgetbv(0);
      32  //       *eax = x & 0xffffffff;
      33  //       *edx = (x >> 32) & 0xffffffff;
      34  //     }
      35  //
      36  // Note that _xgetbv is defined starting with GCC 8.
      37  void
      38  gccgoXgetbv(uint32_t *eax, uint32_t *edx)
      39  {
      40  	__asm("  xorl %%ecx, %%ecx\n"
      41  	      "  xgetbv"
      42  	    : "=a"(*eax), "=d"(*edx));
      43  }