On Fri, 9 Feb 2001, Jun Sun wrote: > a) an explicit config option, CONFIG_HAS_FPU, (which is not associated with > PrID), plus "#ifdef CONFIG_HAS_FPU ..." code. Or > > b) have run-time detection and many "if .. then .." code. > > I listed some pro's and con's for both of them in my first email. Right now, > I found myself not having a strong preference but still biased towards config > option approach ( - as if that really matters. :-0) Well, the number of places a run-time condition exist is small and they are not performance-critical. > I actually don't understand your IDT quote. It requires one to call mfc1 to > get FCR0. On many CPUs without a FPU, this will generate an exception. Are > you suggesting that we should catch the exception and from that we conclude > there is no FPU present? I don't have an FPU-less system and I can't check such code. I need to depend on others (I couldn't test all possible configurations anyway). If we have a chance to get an exception we have to catch it, of course (that's trivial to handle in Linux). -- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available +
