x86/APX: make .insn extended-EVEX capable

So far tricks had to be played to use .insn to encode extended-EVEX
insns; the X4 bit couldn't be controlled at all. Extend the syntax just
enough to cover all features, taking care to reject invalid feature
combinations (albeit aiming at being as lax there as possible, to offer
users as much flexibility as we can - we don't, after all, know what
future will bring).

In a pre-existing testcase replace all but one .byte; the one that needs
to remain wants to have EVEX.U clear in a way that's neither
controllable via AVX10/256 embedded rounding (would otherwise also set
EVEX.ND), nor via the index register (EVEX.X4), as there's no memory
operand. For one of the converted instances ModR/M.mod needs correcting:
An 8-bit displacement requires that to be 1, not 2. Also adjust source
comments to better represent what the bad insns mimic.

0 files changed, 0 insertions, 0 deletions