- rex2.w is used as a opcode extension (JMPABS), not rex2.x1 as an
earlier version of the spec had.
- Segment prefixes used as Jcc hints are valid in 64-bit mode.
- Avoid duplicate warning messages for ignored/invalid prefixes.
* emit_prefixes() is called twice during code generation.
- Add the UDB #UD opcode in 64-bit mode; SALC is 16/32-bit only.
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
