Synopsis

unsigned __usad8(uint8x4 val1,
                 uint8x4 val2);

Description

__usad8 inserts a USAD8 instruction. __usad8 returns the 8-bit unsigned equivalent of

• res = abs(val1[0] - val2[0]) + abs(val1[1] - val2[1]) + (val1[2] - val2[2]) + (val1[3] - val2[3])
  
  where [0] is the lower 8 bits and [3] is the upper 8 bits.