raw-cpuid 8.1.2

A library to parse the x86 CPUID instruction, written in rust with no external dependencies. The implementation closely resembles the Intel CPUID manual description. The library does only depend on libcore.
Documentation 
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#include <stdint.h>

void cpuid(uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx) {
#ifdef _MSC_VER
  uint32_t regs[4];
  __cpuidex((int *)regs, *eax, *ecx);
  *eax = regs[0], *ebx = regs[1], *ecx = regs[2], *edx = regs[3];
#else
  asm volatile(
#if defined(__i386__) && defined(__PIC__)
      // The reason for this ebx juggling is the -fPIC rust compilation mode.
      // On 32-bit to locate variables it uses a global offset table whose
      // pointer is stored in ebx. Without temporary storing ebx in edi, the
      // compiler will complain about inconsistent operand constraints in an
      // 'asm'.
      // Also note that this is only an issue on older compiler versions.
      "mov %%ebx, %%edi;"
      "cpuid;"
      "xchgl %%ebx, %%edi;"
      :
      "+a" (*eax),
      "=D" (*ebx),
#else
      "cpuid"
      :
      "+a"(*eax),
      "=b"(*ebx),
#endif
      "+c"(*ecx),
      "=d"(*edx));
#endif
}