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Re: [PATCH] config.gcc: improve description of need_64bit_hwint
On Fri, 20 Mar 2009, Dave Korn wrote:
> Bingfeng Mei wrote:
>
> > +# for this target. This is true if this target
> > +# supports "long" or "wchar_t" wider than 32 bits,
> > +# or BITS_PER_WORD is wider than 32 bits.
>
> Need to tweak the alignment there before you check it in :)
>
> (BTW, isn't this logically the same anyway, since if BITS_PER_WORD (=
> SImode) is > 32 bits, then int must be > 32 bits, and long is necessarily at
> least >= int? Or can SImode be < BITS_PER_WORD sometimes? Not that I
> disagree with making the implications explicit for clarity in either case.)
int is nothing to do with SImode, and SImode is nothing to do with
BITS_PER_WORD. SImode (if it exists - I don't think it did on c4x) is
always four times QImode, and QImode's width is BITS_PER_UNIT. int's
width is INT_TYPE_SIZE which may be more or less than four times
BITS_PER_UNIT. BITS_PER_WORD is a comparatively arbitrary and poorly
defined value that need have no relation to the C type sizes.
--
Joseph S. Myers
joseph@codesourcery.com