How do I call "cpuid" in Linux?
Since you are compiling with GCC then you can include cpuid.h
which declares these functions:
/* Return highest supported input value for cpuid instruction. ext can
be either 0x0 or 0x8000000 to return highest supported value for
basic or extended cpuid information. Function returns 0 if cpuid
is not supported or whatever cpuid returns in eax register. If sig
pointer is non-null, then first four bytes of the signature
(as found in ebx register) are returned in location pointed by sig. */
unsigned int __get_cpuid_max (unsigned int __ext, unsigned int *__sig)
/* Return cpuid data for requested cpuid level, as found in returned
eax, ebx, ecx and edx registers. The function checks if cpuid is
supported and returns 1 for valid cpuid information or 0 for
unsupported cpuid level. All pointers are required to be non-null. */
int __get_cpuid (unsigned int __level,
unsigned int *__eax, unsigned int *__ebx,
unsigned int *__ecx, unsigned int *__edx)
You don't need to, and should not, re-implement this functionality.
for (a =0; a < 5; ++a;)
There should only be two semicolons there. You've got three.
This is basic C/C++ syntax; the CPUID is a red herring.