From: nowhere@never.at   
      
   Rod Pemberton wrote:   
      
   >> PLease let me know if you find any undefined opcode that doesn't   
   >> raise an exeption or act as NOP. I'd like to check in detail what   
   >> they may do.   
      
   > I'm not able to run the code even though I have Linux.   
   > The project requires some software or upgrades I don't have.   
      
   Flying Bucket's code doesn't work anyway...   
      
   To create a list of unknown instruction  may just need a decent disassembler   
   which reports either undefined or illegal or not available in certain CPU   
   modes (mine is still not fully up to date).   
      
   And we can assume all single byte opcodes are well defined (SALC,LAHF,SAHF   
   may or not work in LM depending on CPU revision), so there could be some   
   undocumented in the not fully used opcode groups like x87, 3Dnow and   
   in the 3-byte opcode maps.   
      
   My tools allow me to enter any unknown opcode into a free memory area,   
   pad it with NOPs, set all registers to known values, select RM,PM,CM   
   16 or 32 or LM, and then hit the single step key. So I see either an   
   exception or upgraded registers including EIP, flags, FPU/XMM, MMX and stack.   
   But I have to manually view it and cannot automate the analyse.   
      
   If no exception occured I can check if any memory locations pointed to   
   by 0x9090.., or by my initial register settings, were altered.   
   I once used this in a loop to detect all present MSRs. Of course a check   
   on SIMD/XOP/VEX/AVX/FMA instructions must be preceded by enabling it.   
   __   
   wolfgang   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)