Jon Masters wrote:
On 4/27/06, Ming Zhang <mingz@xxxxxxxxxxx> wrote:
kernel does not allow float point computation. google about why.
However, if the original poster just wanted higher precision on 32-bit
then there is limited support in-kernel for 64-bit arthimetic.
Functions like do_div can help, if you're stuck.
Jon.
--
Related question -
In-kernel code must do shift then int-multiply to get approximation of
floating point mult.
Is it possible use floating point math at compile-time (ie reduced by
gcc to constants)
to compute the shift and multiply terms ?
In a sense, it could be done by macros which extract the mantissa &
exponent from a
floating point number ( except that this implies the availability of
that floating-point register)
The use-case Im thinking of is the new Generic-Timekeeping-System code
now in 17-rcX-mmY
(X >=1) iirc. Computing the .shift, .mult values at compile-time in
macros that hide
the complexities would be nice. There are runtime helper-funcs that use
do_div().
-jimc
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