We were ignoring REX_B while special-casing NOP, i.e. xchg eax,eax.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
break;
case 0x91 ... 0x97: /* xchg R, EAX */
+ do_xchg_reg_eax:
ot = dflag + OT_WORD;
reg = (b & 7) | REX_B(s);
rm = R_EAX;
/************************/
/* misc */
case 0x90: /* nop */
- /* XXX: xchg + rex handling */
/* XXX: correct lock test for all insn */
- if (prefixes & PREFIX_LOCK)
+ if (prefixes & PREFIX_LOCK) {
goto illegal_op;
+ }
+ /* If REX_B is set, then this is xchg eax, r8d, not a nop. */
+ if (REX_B(s)) {
+ goto do_xchg_reg_eax;
+ }
if (prefixes & PREFIX_REPZ) {
gen_svm_check_intercept(s, pc_start, SVM_EXIT_PAUSE);
}