On Friday, 19 de August de 2011 20:46:32 [email protected] wrote: > In general, we have discussed dropping the concept of qreal and sticking to > the native C++ types. It is a pain to develop something on desktop and have > the sizeof(qreal) change behind the scenes or to have an algorithm you > developed suddenly become numerically unstable when ported to device. We've > been thinking it is better to be explicit.
Every time I meet someone from Canonical, they also ask me to drop the
distinction.
The following code usually works fine on the desktop:
qMax(1.0, someQRealFunction());
but on embedded platforms with qreal==float, it breaks. Sure, we can fix it for
qMin, qMax, qBound, but there are plenty more template functions to be fixed.
Unfortunately, the argument to the contrary is that double-precision floating
point on the ARM Cortex-A8 is still much worse than single-precision -- it's
even worse than on ARM11. Only on the A9 is the performance acceptable.
--
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
Software Architect - Intel Open Source Technology Center
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