| Date | Fri, 20 Feb 2015 10:11:55 -0800 | From | Richard Henderson <> | Subject | Re: [RFC PATCH v2 10/15] cpu-model/s390: Add cpu class initialization routines |
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On 02/17/2015 06:24 AM, Michael Mueller wrote: > +static inline uint64_t big_endian_bit(unsigned long nr) > +{ > + return 1ul << (BITS_PER_LONG - (nr % BITS_PER_LONG)); > +};
This is buggy. NR=0 should map to 63, not 64.
> + return !!(*ptr & big_endian_bit(nr));
Personally I dislike !! as an idiom. Given that big_endian_bit isn't used anywhere else, can we integrate it and change this to
static inline int test_facility(unsigned long nr, uint64_t *fac_list) { unsigned long word = nr / BITS_PER_LONG; unsigned long be_bit = 63 - (nr % BITS_PER_LONG); return (fac_list[word] >> be_bit) & 1; }
r~
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