GCC/MSVC inline assembly porting

I have one small program. It is supposed to determine the width of VMA (Virtual Memory Address). It works fine with gcc/mingw, but for now i need equivalent to work with msvc. Here is the code

#include <stdio.h>

int main(int argc, char *argv[])

{
  unsigned long ret = 0x80000000;

  __asm __volatile("cpuid\n" : "+a" (ret));
  if (ret >= 0x80000008) {
    ret = 0x80000008;
    __asm __volatile("cpuid\n" : "+a" (ret));
    printf("%lu", (ret >> 8) & 0xff);
  } else {
    return (1);
  }
return (0);
}

Visual Studio 2008 prints:

.\main.c(7) : error C2400: inline assembler syntax error in 'opcode'; found '('
.\main.c(8) : error C2143: syntax error : missing ';' before ':'
.\main.c(11) : error C2400: inline assembler syntax error in 'opcode'; found '('
.\main.c(12) : error C2143: syntax error : missing ';' before ':'

Could someone give a hint how to port this code?