On: Faster remainders when the divisor is a constant: ...

[nitrogen]

This is called reciprocal multiplication. You can trade off accuracy for number of bits required, etc. I used this to do meaningful processing of Kinect data on a CPU without an FPU at near full frame rate.

Just curious, did you try making x an 8-bit integer to see if the compiler chose a different multiplier?

[mark-r → nitrogen]

No, I didn't try casting to char although I thought about it.