+++ Paul Brook [2010-07-15 22:29 +0100]: > > > Do the math, there are 6 more vmov instructions (all between rX and sX > > > registers) in the softfp versions. Ok, if one gives a stall of 20 cycles, > > > how many cycles do we lose in sinf() alone? > > > > Depends how the function is called. Worst case we loose 17 cycles, best > > case we should be ~10 cycles faster. > > A simple benchmark confirms this hypothesis. > softfp is actually faster in many cases. > > // uncomment one of these. > //x[i] = sinf(y[i]); // hard 15% slower > //x[i] = sinf(y[i]) + 1.0; // hard 5% slower > //x[i] = sinf(y[i] + 1.0); // hard 0.5% slower > //x[i] = sinf(y[i] + 1.0) + 1.0; // softfp 2.5% slower
Hmm, interesting. What hardware/CPU/emulator did you test this on? I guess the answers will vary to some degree depending what it is run on. Wookey -- Principal hats: Linaro, Emdebian, Wookware, Balloonboard, ARM http://wookware.org/ -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/[email protected]
