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???
09/20/07 05:37
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 		 #144807 - Good idea, bad example
Responding to: ???'s previous message
Richard said:
Now, consider that you have seven inputs, hypothetically, of course, and they're left-justifed on P1. You have a table, called JTBL, containing 128 addresses, each corresponding to a value that can occur on P1. Many of these input "states" might require the same action. Nonetheless, a specific response is provided in this table, for each possible input state.

STP1: Load DPTR with JTBL.
Now load A with P1,
then LJMP @A+DPTR

Hi Richard,

The technique you describe is valid and useful. However, the implementation you have suggested is flawed in multiple ways and very likely to confuse a novice. For the benefit of those who might take what you have given here at face value, could you find the time to implement an example that demonstrates the technique, debug it, and post a complete program that will actually work?

-- Russ


List of 62 messages in thread
TopicAuthorDate
weekend survey            01/01/70 00:00      
   1. programming through the whole night            01/01/70 00:00      
   two things at once            01/01/70 00:00      
      not entirely correct            01/01/70 00:00      
   I'm afraid, but...            01/01/70 00:00      
      stealing codes?            01/01/70 00:00      
         A lesson learned by many            01/01/70 00:00      
         They are way faster...            01/01/70 00:00      
            sounds like a bitter experience            01/01/70 00:00      
   3)Math            01/01/70 00:00      
      0) Math            01/01/70 00:00      
   I have to agree with Erik            01/01/70 00:00      
   For hardware design(VHDL)            01/01/70 00:00      
      then, throw out the crap            01/01/70 00:00      
   Math, experience, tools and code libraries            01/01/70 00:00      
   Why?            01/01/70 00:00      
      tradeoffs            01/01/70 00:00      
         Well said, but not what I asked            01/01/70 00:00      
            different question            01/01/70 00:00      
               technique v tool            01/01/70 00:00      
      two reasons            01/01/70 00:00      
         valuation            01/01/70 00:00      
            that's a given, but            01/01/70 00:00      
            Lookup tables are good for lots of stuff            01/01/70 00:00      
   Good topic!            01/01/70 00:00      
      common tool, but            01/01/70 00:00      
         Function Pointers on the 8051            01/01/70 00:00      
            table-driven whatever and function pointers            01/01/70 00:00      
               reduce a task to its basic elements            01/01/70 00:00      
                  Good idea, bad example            01/01/70 00:00      
                     I didn't really want to use 805x instructions            01/01/70 00:00      
                        I can\'t find my old, (t)rusty 65C02 cheatsheet...            01/01/70 00:00      
                           Only the Rockwell version had it            01/01/70 00:00      
                              Oh, mea culpa...            01/01/70 00:00      
                        A very simple example would be helpful            01/01/70 00:00      
                           let\\\'s start at your end            01/01/70 00:00      
                              Here's what's confusing            01/01/70 00:00      
                                 FAQ?            01/01/70 00:00      
                                 Yes, you're quite right ... ... Mea culpa            01/01/70 00:00      
                  inconsistent instruction set            01/01/70 00:00      
                     I ask you, seriously, to inform us            01/01/70 00:00      
                        a few things            01/01/70 00:00      
                           so much \'fun\' with ajmp            01/01/70 00:00      
                              I give up            01/01/70 00:00      
                                 the answer            01/01/70 00:00      
                           My intuition            01/01/70 00:00      
                              mhm            01/01/70 00:00      
      to russ            01/01/70 00:00      
         to erik            01/01/70 00:00      
            to Russ            01/01/70 00:00      
               to Erik            01/01/70 00:00      
               To Erik            01/01/70 00:00      
                  WOW, a companion CD            01/01/70 00:00      
   the bad ideas            01/01/70 00:00      
      Anachronism?            01/01/70 00:00      
         he's certainly not a HW guy...            01/01/70 00:00      
      Hardware protection slated            01/01/70 00:00      
         this is an academic view...            01/01/70 00:00      
            Proving correctness            01/01/70 00:00      
   Why state machine / lookup tables?            01/01/70 00:00      
      Not to disagree ... but ...            01/01/70 00:00      
         A good reference            01/01/70 00:00      

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