execute (VBREV8(vs2)) = { result : bits(32) = ic3[31..24] @ ic2[23..16] @ ic3[15.. 8] @ ic2[ 7.. 0]; let s1 : bits (8) = (s0) ^ xt2(s1) ^ xt3(s2) ^ (s3); let b1 : bits (8) = x[