Re: [kvm-unit-tests PATCH] powerpc: Add tests for RTAS

[Paolo Bonzini <pbonzini@redhat.com>]

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.

Paolo

>   static inline unsigned long days(int year, int month, int day) {
>   	month -= 2;
>   	if (month <= 0) {
>   		month += 12;
>   		year -= 1;
>   	}
>   	return DAYS(year, month, day);
>   }
> 
> (Or replacing it with an obvious, but slower/bigger implementation? :])
> 
>> > +	/* Put February at end of the year to avoid leap day this year */
>> > +
>> > +	month -= 2;
>> > +	if (month <= 0) {
>> > +		month += 12;
>> > +		year -= 1;
>> > +	}
>> > +
>> > +	/* compute epoch: substract DAYS(since_March(1-1-1970)) */
>> > +
>> > +	epoch = DAYS(year, month, day) - DAYS(1969, 11, 1);