home bbs files messages ]

Forums before death by AOL, social media and spammers... "We can't have nice things"

   comp.lang.asm.x86      Ahh, the lost art of x86 assembly      4,675 messages   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]

   Message 3,689 of 4,675   
   R.Wieser to All   
   Re: Interpreting (the data following) a    
   05 Dec 18 10:16:21   
   
   From: address@nospicedham.not.available   
      
   Rick,   
      
   > I apologize, Rudy.  I completely misunderstood what you were posting   
   > here.  My mistake.   
      
   Don't worry about it.   And thank you for telling me (quite a number of   
   people would have either denied or ignored it, or have simply disappeared).   
      
   > Is it possible 0x8afa or 0xfa8a is a memory pointer to the   
   > instruction to emulate, or an offset in the current data segment?   
      
   I don't think so.  Ralf Browns interrup list mentions that the INT 0x35   
   translates to the 0xD9 opcode.   The bytes following the INT seem to be part   
   of that FPU command (a bit, but not much, of guesswork here).   
      
   In this case (confirmed by disassembling a 0xD9 0x7E 0xFA sequence) the   
   result is an FPU instruction, with the 0x7E representing the ModRegR/M byte   
   and the 0xFA byte a relative offset over BP.   
      
   In short, I was confused to what the "/6" (in my first quote) was referring   
   to in that ModRegR/M byte, and from it did not notice the ModR/M part was to   
   be used as normally.   
      
   In other words: Now I know that the "/6" should match the "Reg" bits the   
   rest simply fell into its place.   
      
   Thanks for the help.   
      
   Regards,   
   Rudy Wieser   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]


(c) 1994,  bbs@darkrealms.ca