XED2 and 8F opcode halting problem

XED2 and 8F opcode halting problem

Hi all,

I set up a binary decoder using XED2 library and run it under debian. When it reaches 8F opcode, halts and returns a "can't decode this instruction" error? but shoud 8F indicate "pop a value from the stack", shouldn't it?is there any workaround ? 

Thanks,Regards,

Marco

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Portrait de Mark Charney (Intel)

Hi, XED can decode 0x8F but it needs at least one more byte. In the base architecture, 0x8F is part of a 2 byte opcode. The second byte must have bits 5:3 as 0: xx000xxx.  

% kits/current/xed -d 8f 00

8F00
ICLASS: POP CATEGORY: POP EXTENSION: BASE IFORM: POP_MEMv ISA_SET: I86
SHORT: pop dword ptr [eax]

Please note the 8F opcode also serves as the prefix for the AMD XOP instructions.

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