maria-developers team mailing list archive

[AugustQ <augustq@xxxxxxx>]

Hi,

couldn't do this earlier, please excuse for being so late.

I played with the test-pgm and modified it a bit. You can find my
version here:
https://drive.google.com/file/d/0B4h65dJSL95DXzdpaUNGYTQ5cVk/edit?usp=sharing

I also modified the definitions in myisampack.h and did some tests with
a table with 10 mio records in it (1 GB in size) to see the effect of
the modifications. You will find my results at the end of the
source-code.

At a first look the uintXkorr looks like a waste of time but the
modified versions do not have much effect on the whole process.

Regards
AugustQ


On So, 2014-01-26 at 19:28 +0400, Alexey Botchkov wrote:
> Thanks for the suggestions, Kristian.
> I for some reason didn't notice that __builtin_bswap things.
> 
> Best regards.
> HF
> 
> 
> 23.01.2014 19:51, Kristian Nielsen wrote:
> > Kristian Nielsen <knielsen@xxxxxxxxxxxxxxx> writes:
> >
> >> Do it like this:
> >> static inline ulonglong
> >> mi_uint6korr(const void *p)
> >> {
> >>    uint32 a= *(uint32 *)p;
> >>    uint16 b= *(uint16 *)(4+(char *)p);
> >>    ulonglong v= ((ulonglong)a | ((ulonglong)b << 32)) << 16;
> >>    asm ("bswapq %0" : "=r" (v) : "0" (v));
> >>    return v;
> >> }
> > Note that GCC also has __builtin_bswap64() (and __builtin_bswap32()). They
> > also generate bswap instruction, but would also work on other platforms...
> >
> >   - Kristian.
> 
> 
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