Review Board 2.0.15


ARM/O3: store the result of the predicate evaluation in DynInst or Threadstate.

Review Request #177 - Created Aug. 13, 2010 and submitted

Information
Ali Saidi
gem5
Reviewers
Default
Min 
ARM/O3: store the result of the predicate evaluation in DynInst or Threadstate.
THis allows the CPU to handle predicated-false instructions accordingly.
This particular patch makes loads that are predicated-false to be sent
straight to the commit stage directly, not waiting for return of the data
that was never requested since it was predicated-false.

   

  


 


 

  

  









  
 


  

 
















 



 

  


 


  



   

   
Gabe Black

   
Posted  (Aug. 13, 2010, 5:08 p.m.)


  


  


  

   



  

   

   
    
    
   


  




   







    

     
     

      

       
        

         
          src/cpu/thread_context.hh
          

           (Diff revision 1)

          
         
        

       
       
        
 


        
 


       
      

     

    

    


     
This isn't really a property of a thread, it's the property of a single instruction. I don't think this is being done in the right place. I think we should have a discussion on m5-dev to determine the best way to handle this. There was a little code added to the simple CPU that does what this is supposed to do if a memory instruction didn't actually read or write memory, and I think this is a better way to handle this. We should have a discussion about this on m5-dev, especially since it touches lots of low level bits like *contexts, instruction behavior, CPUs, etc. These sorts of changes need to be made carefully.