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

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   Message 3,622 of 4,675   
   R.Wieser to All   
   Re: Indirect INT calling   
   28 Oct 18 13:08:42   
   
   From: address@nospicedham.not.available   
      
   Terje,   
      
   > Selfmodifying code, i.e. fixing the 60h constant to whichever INT value is   
   > being used, is by far the simplest to implement in asm.   
      
   Agreed.   
      
   But as that INT 0x60 is present at several different locations thruout the   
   program all those locations need to be stored, and walked thru on init.   
   Forget one, and the program will fail ... somewhere.   Hence my "call a   
   procedure" preference (only one spot to change).   
      
   > Then when you need to call the driver you can do this:   
   >   
   >   pushf   
   >   CLI   
   >   call far [local_int]   
      
   Don't forget the CS: prefix - DS can be, depending on the API function, be   
   pointing somewhere rather different than where the "local_int" is stored.   
   :-)   
      
   One question though: The specs mention three flags being cleared by the INT   
   instruction, and you only clear the interrupt flag.  Experience or something   
   else ?   
      
   Regards,   
   Rudy Wieser   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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