Re: [Libvisual-devel] VisCPU flags

[Dennis S. <sy...@yo...>]

On Tue, 2004-11-09 at 23:25 -0300, Duilio Javier Protti wrote:
> 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.

Ai never knew...

> 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.

We don't, we have the VISUAL_CPU macros containing the final result in 
simply TRUE/FALSE.