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???
03/02/05 17:31
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Msg Score: +1
 +1 Good Answer/Helpful		 #88897 - Ridiculous MOVC addressing modes...
Responding to: ???'s previous message
The DPTR addressing modes are horrible.
For MOVX they make a bit of sense yet. A,@DPTR, @DPTR,A is fine, A,@Ri makes little sense but it doesn't hurt.
But MOVC? MOVC A,@A+DPTR and MOVC A,@A+PC.
Try to read 4 bytes in a row in a reasonable number of instructions with these. Why couldn't that be MOVC A,@B+DPTR or something? What sense does using A here make if it gets overwritten? You need to reset it every time you want to read the next byte. CLR A, INC DPTR...
Whoever designed that should be fired.

List of 43 messages in thread
TopicAuthorDate
Kitchen Drain .. Unwanted Features            01/01/70 00:00      
   13-bit Mode for Timers            01/01/70 00:00      
   Dumb A5 Opcode            01/01/70 00:00      
      0xA5 opcode            01/01/70 00:00      
         Finally room for XOR C,bit :)            01/01/70 00:00      
            MOV bit,bit            01/01/70 00:00      
      CY flag            01/01/70 00:00      
         My A5 source information....            01/01/70 00:00      
            More A5 opcode info            01/01/70 00:00      
            0xA5 is derivative-depend            01/01/70 00:00      
      Oh no it doesn't            01/01/70 00:00      
   Inverted wishlist            01/01/70 00:00      
      Inverted wishlist            01/01/70 00:00      
         wishlist II.            01/01/70 00:00      
            Loadsa XRAM!            01/01/70 00:00      
               Don't believe all you see...            01/01/70 00:00      
                  because of the taste of vanilla            01/01/70 00:00      
                     chocolate chips            01/01/70 00:00      
                  Unbelievable!            01/01/70 00:00      
            Ridiculous MOVC addressing modes...            01/01/70 00:00      
               MOVC            01/01/70 00:00      
               MOVC Designer.....Your Fired !!            01/01/70 00:00      
      Errr then it's not an 8051 then!            01/01/70 00:00      
         Is it then 8051            01/01/70 00:00      
         AVR???            01/01/70 00:00      
      wishlist continued            01/01/70 00:00      
         low power at slow clock            01/01/70 00:00      
            low power            01/01/70 00:00      
               i am confused!            01/01/70 00:00      
                  But I thought they ARE CMOS!            01/01/70 00:00      
                     quiescent            01/01/70 00:00      
   what I definitely do not want            01/01/70 00:00      
      Right architecture            01/01/70 00:00      
         some of us do bits a bit fast            01/01/70 00:00      
            I know but...            01/01/70 00:00      
               all things to all people            01/01/70 00:00      
                  erics last post            01/01/70 00:00      
         RIght Achitecture???            01/01/70 00:00      
      So what do you think about...            01/01/70 00:00      
         ADC/DAC will live forever!            01/01/70 00:00      
            That guy?            01/01/70 00:00      
               Stick            01/01/70 00:00      
   Ability of changing return from interupt            01/01/70 00:00      

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