The following instructions have simple encodings: - bitcast.f32.i32 - bitcast.i32.f32 - bitcast.f64.i64 - bitcast.i64.f64 - fpromote.f64.f32 - fdemote.f32.f64 Also add helper functions enc_flt() and enc_i32_i64 to intel.encodings.py for generating the common set of encodings for an instruction: I32, I64 w/REX, I64 w/o REX.