2016-03-03 17:29+0100, Paolo Bonzini: > On 03/03/2016 17:03, Radim Krčmář wrote: >>> > diff --git a/powerpc/rtas.c b/powerpc/rtas.c >>> > +#define DAYS(y,m,d) (365UL * (y) + ((y) / 4) - ((y) / 100) + ((y) / 400) + \ >>> > + 367UL * (m) / 12 + \ >>> > + (d)) >> This function is hard to (re)use. >> What about putting the "month -= 2" block together with DAYS to give a >> better estimate of the amount of days in the gregorian calendar? > > Even the Gregorian calendar only starts in 1583 though. :) > > This is just a utility function for mktime. I think it's okay. We > should aim at making libcflat a minimal libc, and in that case we would > move mktime to lib/. Putting stuff directly in tests is good enough > (worse is better), but let's remember that duplicated code is not. I agree that there is no need to move stuff into lib/. I just wouldn't expose DAYS in this shape even to mktime, because DAYS makes little sense without the "month -= 2" fixup. >>> > + /* Put February at end of the year to avoid leap day this year */ Leap day is not the only reason. '367UL * (m) / 12' equation needs to have shifted months to report the correct numbers of days throughout any year. >>> > + /* compute epoch: substract DAYS(since_March(1-1-1970)) */ >>> > + epoch = DAYS(year, month, day) - DAYS(1969, 11, 1); And this comment points out that the API is bad. :) (Btw. am I going overboard?) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
