Re: [PATCH 2/3] lib: vsprintf: optimised put_dec() for 32-bit machines

[MichaÅ Nazarewicz]

On Fri, 06 Aug 2010 09:35:26 +0200, Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx> wrote:

> On Friday 06 August 2010 09:08, Michal Nazarewicz wrote:
> > >> +static noinline_for_stack
> > >> +char *put_dec(char *buf, unsigned long long n)
> > >> +{
> > >> +	uint32_t d3, d2, d1, q;
> > >> +
> > >> +	if (!n) {
> > >> +		*buf++ = '0';
> > >> +		return buf;
> > >> +	}
> > >> +
> > >> +	d1  = (n >> 16) & 0xFFFF;
> > >> +	d2  = (n >> 32) & 0xFFFF;
> > >> +	d3  = (n >> 48) & 0xFFFF;
> > >
> > > Are you assuming that sizeof(long long) == 8, always?
> >
> > Well...  yes.  C requires long long to be at least 64-bit and I don't
> > see it being larger in any foreseeable feature.
>
> "640k will be enough for everybody"?
>
> > Wouldn't it be enough to put a static assert here?
>
> I'd prefer the code which works with arbitrarily wide long long.
> If needed, use
>
> if (sizeof(long long) == 8)
> 	64-bit code
> else
> 	generic code

Thanks.  That seems like a perfect solution.  I rearrange the code
and try to post updated version after the weekend.

--
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| Humble Liege of Serenely Enlightened Majesty of  o' \,=./ `o
| Computer Science,  MichaÅ "mina86" Nazarewicz       (o o)
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