Messages in this thread | | | From | Denys Vlasenko <> | Subject | Re: [PATCH 2/3] lib: vsprintf: optimised put_dec() for 32-bit machines | Date | Fri, 6 Aug 2010 07:18:38 +0200 |
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On Friday 06 August 2010 00:38, Michal Nazarewicz wrote: > The disadvantage is that the proposed function is 2.5-3.5 bigger. > Those are not big functions though -- we are talking here about > proposed function being below 512.
It's a slippery slope. Here's where it ends: glibc has memcpy() function which is "only" 8k of code or so. I'm not joking.
> +#if BITS_PER_LONG == 64 > + ... > +#else ... > +/* > + * Based on code by Douglas W. Jones found at > + * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>. This > + * performs no 64-bit division and hence should be faster on 32-bit > + * machines then the version of the function above. > + */ > +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?
-- vda
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