> > If 64-bit arithmetics cannot be avoided, the do_div64() macro defined in
> > include/asm/div64.h comes in handy.
> > mod = do_div((unsigned long) x, (long) y)
> > will set x to the quotient x/y and mod to the remainder x%y .
>
> I have looked at this header file and I do not understand the asm
> syntax.
>
> In particular the only x86 div instruction I know only returns a 32 bit
> div result. Because I don't understand the div64 header I cannot
> see how a 64 bit result is calculated.
>
Sorry, there are (platform-dependent) restrictions that I forgot to
mention. I think do_div(x,y) should work for all platforms if
y < 2^16 and x/y < 2^32, but I may stand corrected.
Actually, Momchil Velikov just pointed out that some archs only do 32 bit
divs in do_div64, where at least the C code from asm-parisc/div64.h
should be used.
Tim
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This archive was generated by hypermail 2b29 : Thu Jan 31 2002 - 21:00:50 EST