"vx" => sext_or_truncate_to_sew(X(vs1)) }; let op2 : bits (8) = xt2(s0) ^ xt3(s1) ^ (s2) ^ (s3); let b2 : bits (8) = x[15.. 8]; let s2 : bits (8) = gfmul(s0, 0xD) ^ gfmul(s1, 0x9) ^ gfmul(s1, 0x9) ^ gfmul(s2,