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

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
Erik Malund
01/04/08 11:16
Read: 1029 times
Mt Airy, Nc
USA


 
#149056 - there are no cache misses in 'linear code'
Responding to: Jan Waclawek's previous message
I don't see the point. I believe the jump-caching processor such as the fast silabs-s and upsd3xxx-s cache the "jmp @a+dptr"-s, too, so you have the same degree of uncertainty in using this method as in a djnz loop.

If you use the JMP@ you will get 2 cache misses (the call to the routine and the jmp@, but THAT is a constant) there are NO cache misses in 'linear code' i.e. the setup and the string of NOPs.

If you use the djnz you do not have the foggiest idea how many cache misses you get. Of course, you COULD use the cache lock.

Erik



List of 27 messages in thread
TopicAuthorDate
Number of CPU cycle for 8051 function call      Jae-yong Kim      01/04/08 01:03      
   Do it in assembler      Andy Neil      01/04/08 03:00      
   Delay functions      Andy Neil      01/04/08 03:07      
   A related trick        Russ Cooper      01/04/08 05:56      
      Offset      Andy Neil      01/04/08 07:03      
         Offset      Russ Cooper      01/04/08 07:23      
            Sure      Andy Neil      01/04/08 07:40      
               Over Drive?      Neil Kurzman      01/04/08 10:20      
      a refinement      Erik Malund      01/04/08 07:58      
      NOPs are so bad waste of space...      Jan Waclawek      01/04/08 08:51      
         waste of space... waste of time      Erik Malund      01/04/08 09:24      
            fixed delay      Jan Waclawek      01/04/08 09:54      
               Variable delay      Russ Cooper      01/04/08 11:04      
                  determinism of the cache      Jan Waclawek      01/04/08 11:36      
               there are no cache misses in 'linear code'      Erik Malund      01/04/08 11:16      
                  I got only ONE cache miss...      Jan Waclawek      01/04/08 11:39      
      Old Keil Thread      Jon Ward      01/06/08 18:29      
   What about a Delay like this.      Jerry Black      01/07/08 05:31      
      No, it won't.        Christoph Franck      01/07/08 05:55      
         Ok.      Jerry Black      01/07/08 07:08      
         also      Erik Malund      01/08/08 06:47      
      Also ...      Christoph Franck      01/08/08 07:01      
         Actually...      Brett Wallace      01/08/08 08:02      
            will.      Jerry Black      01/08/08 08:21      
               ANSI C      Maarten Brock      01/10/08 05:58      
                  Keil option: Disable ANSI casts      Andy Neil      01/10/08 07:08      
         typo.      Jerry Black      01/08/08 08:24      

Back to Subject List