On Thu, Feb 23, 2017 at 07:32:07AM -0800, h...@zytor.com wrote: > Well, once you are using invalid instructions, it depends not on > what the CPU decodes but what your own handler expects. Consider > Microsoft's use of C4 C4 /ib as a meta-instruction (called BOP, "BIOS > operation")... that format has nothing to do with the CPU, but if you > want to disassemble the resulting code you need to know about how they > encode BOP.
How do they use that? They rely on the fact that C4 C4 is going to #UD as it is an invalid VEX insn? The second C4 selecting the 100b map which is reserved? Or? -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.