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???
08/11/07 06:56
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 		 #143088 - I need a hint
Responding to: ???'s previous message
Hi Jan,

Well, well. Today I had some spare time so I thought I would see if I could improve on your CRC code by adding some comments and then trying to make it faster.

Ha! I couldn't even figure out how it works! I understand the concept of the CRC calculation, and I almost understand how the published table-driven implementations work. (The paper at http://www.ross.net/crc/crcpaper.html seems to be pretty good.) But I couldn't even begin to see how your 22-cycle, no-table version works.

Can you provide a hint or two without completely explaining it? I would still like to figure it out for myself if my brain is smart enough to do so.

-- Russ



List of 32 messages in thread
TopicAuthorDate
CRC16 CCITT - What a challenge!            01/01/70 00:00      
   Have you seen this?            01/01/70 00:00      
      Of course!            01/01/70 00:00      
         Balance            01/01/70 00:00      
            I know, Russ,            01/01/70 00:00      
         Code? What code?            01/01/70 00:00      
            in the code library - look to the left column            01/01/70 00:00      
               Thanks! I missed that note in the first post.            01/01/70 00:00      
   I need a hint            01/01/70 00:00      
      write down the bits            01/01/70 00:00      
         Thanks for the hint            01/01/70 00:00      
            Your observations plus a comparison in C            01/01/70 00:00      
               The rest of the story ...            01/01/70 00:00      
                  Compilers, but Keil C51 8.09 for the stated 28~            01/01/70 00:00      
                  and this processes only a nibble, isn't it...            01/01/70 00:00      
                     No, it process the entire byte.            01/01/70 00:00      
                        now it\'s my pencil time...            01/01/70 00:00      
                           FYFI            01/01/70 00:00      
                              Clarification re: 8-bit optimized term            01/01/70 00:00      
                              on optimisation            01/01/70 00:00      
                                 Jan's optimization            01/01/70 00:00      
                                    Re: on optimization            01/01/70 00:00      
                                       Can you please be more specific?            01/01/70 00:00      
                                          More specifically ...            01/01/70 00:00      
            and what            01/01/70 00:00      
               More on checksums            01/01/70 00:00      
   No reason to hide the excreted code            01/01/70 00:00      
      Excreted code needs context like any other code            01/01/70 00:00      
   One More Comment            01/01/70 00:00      
      ... and a marginal remark ...            01/01/70 00:00      
         Init all ones frequently specified            01/01/70 00:00      
   18 cycles            01/01/70 00:00      

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