This instruction is effectively dead since Linux reserves the lower
16bits for itself, but in the case that someone manages to encode it
then we will at least attempt to access the correct RIP.
In an edge cases of pushing with a 32bit immediate sign extended to
64bit then there could have been a conflict.
Rearrange the ordering a bit to ensure it is correct
These instructions treat the immediate encoding differently depending on
the operating size of the instruction
For 16bit and 32bit operation they treat the immediate as an
appropriately sized immediate.
For 64bit operand size the immediate is sign extended to handle the new
operating width.
CMP was previously set to SEXT for this which would have its own set of
problems handling it like that.
Ryan Houdek