Use GCC Builtins for CPUID Checks

[Kfeavel]

See x86-Built-in-Functions for details.

__builtin_cpu_init();
if (__builtin_cpu_supports ("ssse3"))
    return ssse3_memcpy; // super fast memcpy with ssse3 instructions.
else
    return default_memcpy;

Other helpful functions:

int __builtin_cpu_is(const char* cpuname)

Not sure if these functions would be available during the bootloader to kernel bootstrap process, but if they are, then that will help a lot.

[micahswitzer]

They should be and it would make a lot of sense to use them