On Tue, 2019-01-29 at 10:10 +0100, Erik Faye-Lund wrote: > On Mon, 2019-01-28 at 09:31 -0800, Matt Turner wrote: > > Use the trick of adding and then subtracting 2**52 (52 is the number > > of > > explicit mantissa bits a double-precision floating-point value has) > > to > > implement round-to-even. > > > > Cuts the number of instructions on SKL of the piglit test > > fs-roundEven-double.shader_test from 109 to 21. > > Won't this approach only work for "small" values, that is values equal > to or smaller than DBL_MAX - 2**52? Once you add 2**52, you'll get > infinity, and you can't subtract 2**52 away again without being stuck > with infinity, no...
2**52 is such a small value compared to anything close to DBL_MAX, it will just be absorbed. regards Philipp _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
