Joseph Heled <[email protected]> writes:
> I fully appreciate your plight as a package maintainer, but I think that
> users which use rollouts, a quite important GNUBG feature, care a *lot*
> about speed.
> Perhaps the GNUBG code can be structured in a way that it can be
> compiled with all those "advance features", yet they are used *only* in
> rollouts and so everything else works on older systems?
> Is that possible or am I just showing my ignorance?
I don't see an obvious reason why it wouldn't be possible, although this
is currently not what gnubg does.
#if defined(USE_SIMD_INSTRUCTIONS)
result = SIMD_Supported();
switch (result) {
case -1:
outputerrf(_("Can't check for SIMD support\n"));
break;
case -2:
outputerrf(_("No cpuid check available\n"));
break;
case 0:
/* No SIMD support */
break;
case 1:
/* SIMD support */
simderror = FALSE;
break;
default:
outputerrf(_("Unknown error while doing SIMD support test\n"));
}
if (simderror) {
#if defined(USE_AVX)
outputerrf(_
("\nThis version of GNU Backgammon is compiled with AVX
support but this machine does not support AVX\n"));
#else
outputerrf(_
("\nThis version of GNU Backgammon is compiled with SSE
support but this machine does not support SSE\n"));
#endif
exit(EXIT_FAILURE);
}
#endif
In other words, it checks at runtime if built with AVX to confirm that AVX
is supported and, if not, it terminates the program. I could define
DISABLE_SIMD_TEST; then, I'm not sure what behavior it would have.
--
Russ Allbery ([email protected]) <https://www.eyrie.org/~eagle/>
