On Tue, Nov 06, 2012 at 09:23:01PM +0100, Søren Sandmann wrote:
> Peter Hutterer <[email protected]> writes:
>
> > The double_to_f1616() functions do the same thing, and they're tested.
> >
> > Signed-off-by: Peter Hutterer <[email protected]>
> > ---
> > Turns out we already have these functions and the macro was just a leftover
> > from earlier, happier times.
>
> Is there any reason to not just use the pixman_double_to_fixed() macro:
>
> #define pixman_double_to_fixed(d) ((pixman_fixed_t) ((d) * 65536.0))
Jeremy, do you remember any specific reason why we didn't end up using the
pixman macro for this?
Cheers,
Peter
>
> The double_to_fp1616() function looks rather complicated and slow:
>
> FP1616
> double_to_fp1616(double in)
> {
> FP1616 ret;
> int32_t integral;
> double tmp;
> uint32_t frac_d;
>
> tmp = floor(in);
> integral = (int32_t) tmp;
>
> tmp = (in - integral) * (1UL << 16); /* Optimized: ldexp(in -
> integral, 16) */
> frac_d = (uint16_t) tmp;
>
> ret = integral << 16;
> ret |= frac_d & 0xffff;
> return ret;
> }
>
>
> Søren
>
>
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