Compute the sum of absolute differences (SADs) of quadruplets of unsigned 8-bit integers
in a compared to those in b, and store the 16-bit results in dst.
Eight SADs are performed using one quadruplet from b and eight quadruplets from a.
One quadruplet is selected from b starting at on the offset specified in imm8[1:0].
Eight quadruplets are formed from sequential 8-bit integers selected from a starting
at the offset specified in imm8[2].
Compute the sum of absolute differences (SADs) of quadruplets of unsigned 8-bit integers in a compared to those in b, and store the 16-bit results in dst. Eight SADs are performed using one quadruplet from b and eight quadruplets from a. One quadruplet is selected from b starting at on the offset specified in imm8[1:0]. Eight quadruplets are formed from sequential 8-bit integers selected from a starting at the offset specified in imm8[2].