Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
07/06/05 17:11
Read: times


 		 #96706 - Micro-Optimisations - real-life example
Responding to: ???'s previous message
Erik Malund said:
The discussion is not about 'micro optimisations' which, in the best case, will save a cycle or two, but about habits that will save "save a cycle or two" in hundereds of places.

Real example:

I had to port some supposedly-portable "reference code" to an 8051.

I got it all to compiler and run. Then I noticed that one particular variable was referencesd very frequently all over the place; moving that one variable (probably just a char, but might've been an int - I don't remember now) from XDATA to DATA resulted in saving several K on the overall code size!

"Micro optimisation?" maybe - but repeated so often to cause a macroscopic benefit!



List of 54 messages in thread
TopicAuthorDate
code optimization            01/01/70 00:00      
   erm...            01/01/70 00:00      
   guidelines            01/01/70 00:00      
   Duh !!!!            01/01/70 00:00      
      yes its a link to learn optimization            01/01/70 00:00      
         the links provided            01/01/70 00:00      
            Really Wicked Optimisations!            01/01/70 00:00      
            counters in loops?            01/01/70 00:00      
               DJNZ            01/01/70 00:00      
                  ahh            01/01/70 00:00      
                  DOES it ?            01/01/70 00:00      
                     on Keil forum            01/01/70 00:00      
                     Yes!            01/01/70 00:00      
                     Of course it does...            01/01/70 00:00      
                        But...            01/01/70 00:00      
                           asking too much            01/01/70 00:00      
                              Not at all            01/01/70 00:00      
                           Maybe it does...            01/01/70 00:00      
                              Not when I tried it.            01/01/70 00:00      
                                 Lopp Rtation            01/01/70 00:00      
                        While you're there, Jon...            01/01/70 00:00      
                           how like a salt block?            01/01/70 00:00      
                              oh -- got it            01/01/70 00:00      
                           Overlaying and Scope            01/01/70 00:00      
                              Does it matter?            01/01/70 00:00      
                                 debugging            01/01/70 00:00      
   Previously on 8052.com            01/01/70 00:00      
      yes its in the board            01/01/70 00:00      
      IAR Article - Getting the Least            01/01/70 00:00      
   To be taken with a pinch of salt            01/01/70 00:00      
      more like a salt block            01/01/70 00:00      
      Re            01/01/70 00:00      
         switch            01/01/70 00:00      
            Switch/Case Optimization            01/01/70 00:00      
               Re: Switch/Case Optimization            01/01/70 00:00      
                  Look Why            01/01/70 00:00      
               Jon, I may have made a mistake            01/01/70 00:00      
         Big switches            01/01/70 00:00      
         Was?            01/01/70 00:00      
            Link to newer version            01/01/70 00:00      
               Hitex; Chris Hills            01/01/70 00:00      
                  Draft!            01/01/70 00:00      
   intermediate values in lookup tables            01/01/70 00:00      
      Generating lookup tables            01/01/70 00:00      
   a general statement on code optimization            01/01/70 00:00      
      Craft            01/01/70 00:00      
      Corrections            01/01/70 00:00      
         urban legends            01/01/70 00:00      
            Been there.            01/01/70 00:00      
               I think this is closer to the truth            01/01/70 00:00      
                  I just realize that the above            01/01/70 00:00      
               EE/CS            01/01/70 00:00      
            Micro-Optimisations - real-life example            01/01/70 00:00      
               manual optimization            01/01/70 00:00      

Back to Subject List