PX4/Flow — pull request #4 by bn999 (2013-08-20 20:59:59+00:00)
Title: Replace SAD function with assembly version ~ 25% faster

This may be of some interest. The original compute_sad_8x8() function's use of compiler intrinsics ended up with 4 instructions per 4 pixels when compiled with GCC. This hand coded assembly version brings that down to 3 instructions per 4 pixels.

Tested and found that identical results are being generated with reduced clock cycles.