From: nowhere@nevernet.at   
      
   On 23/03/2022 18:50, James Harris wrote:   
   [agreed..]   
   > For Intel and probably AMD it looks as though one can get the CPU to   
   > report the Limit with an LSL instruction and the Attributes with LAR but   
   > I don't know a way to get the base.   
      
   get_base:        ;selector in eax assume DS=flat   
      MOV esi,anybuffer   
      SGDT [ds:esi]   ;now you know where the GDT resides   
      AND eax,FFF8    ;just in case   
    SHL eax,3       ;mul by 8   
    ADD esi,eax   
      LEA esi,[eax*8+esi]   ;same as the two lines above but faster/shorter   
      MOV ecx,[esi+2]       ;low 24 bits of base   
      AND ecx,00FFFFFF   
      MOV bl,[esi+7]   
      SHL ebx,24            ;decimal yet!   
      OR ecx,ebx            ;ecx hold 32 bit base of selector eax yet   
      
   it works on both code and data descriptors.   
      
   > On Cyrix there's SVDC to write the entire Descriptor to ten bytes of   
   > memory.   
      
   I never used and wont recommend any exotic CPU to rely on.   
   ...   
   >> Seems an old wiki note were burned into my brain:   
   >> "the transition from RM to PM occur only on the final far jump"   
      
   > I've heard similar. Perhaps whoever wrote that didn't know about PM16 -   
   > which I also didn't until a few weeks ago.   
      
   me too learned something new even it wont affect any of my code :)   
   __   
   wolfgang   
      
   --- SoupGate-Win32 v1.05   
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