[Libvisual-devel] VisCPU flags

[Duilio J. P. <dp...@fc...>]

Reading file lv_cpuid.c I see:

enum {
        CPU_FLAGS_TSC   = 1 << 4,
        CPU_FLAGS_MMX   = 1 << 23,
        CPU_FLAGS_SSE   = 1 << 25,
        CPU_FLAGS_SSE2  = 1 << 26,
        CPU_FLAGS_HT    = 1 << 28,
};
 
enum {
        CPU_FLAGS_EXT_3DNOWEXT  = 1 << 30,
        CPU_FLAGS_EXT_3DNOW     = 1 << 31
};

The problem with this code is that things like 3DNOW extension are
vendor specific, i.e. on Intel machines bit 30 says if current machine
is an IA64 or not.

One way to work around this would be to give the second enum a name, say
VisAMDFlagsExtended or something, and do that for every specific vendor
supported. The problem with this is that the user of the library must be
very carefull about seeing the flags accordingly with the current
machine.

A better approach would be to not expose the flags directly as returned
by the cpuid instruction, but instead make our own flags structure,
where the user can test against it with macros in a safe way.


Bye,
Duilio.