On Tue, 1 Jul 2003, Andrew Morton wrote:
>
> By requiring an explicit do_div we are made aware of all those 64-bit
> divides and are made to think about them.
do_div() is NOT a 64-bit divide.
It's a 64/32->64+32 div/mod operation, which is a totally different thing
than a full 64/64 divide, and is usually much faster to compute on most
32-bit architectures.
> Why 64-bit divides in particular were victimised in this manner is a matter
> for speculation ;)
Because gcc historically _cannot_ generate an efficient 64/32->64 divide.
It ends up doing a full 64/64 divide thing.
Linus
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This archive was generated by hypermail 2b29 : Mon Jul 07 2003 - 22:00:15 EST