Analog Devices ADSP-BF53x Blackfin Reference page 652

Instruction Overview
r3 = byteop3p (r1:0, r3:2) (lo, r) ;
r3 = byteop3p (r1:0, r3:2) (hi, r) ;
Also See
BYTEOP16P (Quad 8-Bit Add)
Special Applications
This instruction is primarily intended for video motion compensation
algorithms. The instruction supports the addition of the residual to a
video pixel value, followed by unsigned byte saturation.
18-12 ADSP-BF53x/BF56x Blackfin Processor Programming Reference