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11/12/08 22:10
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 		 #159996 - I think Erik has it?
Responding to: ???'s previous message
Richard Erlacher said:
What's the "best", or at least generally accepted, way to describe all these various forms of read/write memory unambiguously?

I think the way Erik said is the most widespread?

viz:

  • DATA is directly-addressable by MOV; Address range 0-7F;
  • SFRs are directly-addressable by MOV; Address range 80-FF;
  • IDATA is indirectly-addressable by MOV @Rn; Address range 0-FF;
  • PDATA is indirectly-addressable by MOVX @Rn; Address range 0-FF;
  • XDATA is indirectly-addressable by MOVX @DPTR; Address range 0-FFFF;
  • CODE is read-only, accessed by instruction fetch, also indirectly-addressable by MOVC @DPTR; Address range 0-FFFF.

    Note that DATA overlays the first 128 bytes of IDATA, and PDATA overlays 256 bytes of XDATA.

    The terms "internal" and "external" are essentially meaningless these days (or, at best, their meanings are purely historical).

    • List of 34 messages in thread
    TopicAuthorDate
    a simple SETB question            01/01/70 00:00      
       SETB from 20h to 2FH            01/01/70 00:00      
          assembler missed this one            01/01/70 00:00      
             I know of none that can't            01/01/70 00:00      
       what about this?            01/01/70 00:00      
          try ORL to set any bit in internal RAM            01/01/70 00:00      
             wrong, nonstandard and why            01/01/70 00:00      
                ORL, Set any bit (more informative)            01/01/70 00:00      
                   iram            01/01/70 00:00      
                      Where is that defined?            01/01/70 00:00      
                         my word was not 'defined' but            01/01/70 00:00      
                            a rose, by any other name ...            01/01/70 00:00      
                               I think Erik has it?            01/01/70 00:00      
                                  aliased/overlayed            01/01/70 00:00      
                                     Fair enough            01/01/70 00:00      
                                  pDATA?            01/01/70 00:00      
                                     Why do you think 64TB would be enough?            01/01/70 00:00      
                                        It would not be            01/01/70 00:00      
                                           Tools are important for size            01/01/70 00:00      
                                              That's why there's ASM to use instead            01/01/70 00:00      
                                           this flies against some previous posts of yours            01/01/70 00:00      
                                              It's like herding cats            01/01/70 00:00      
                                                 Flame bait?            01/01/70 00:00      
                                                    No ... not really            01/01/70 00:00      
                                                       yes            01/01/70 00:00      
                                     PDATA & XDATA            01/01/70 00:00      
                                        I won't argue that ... but ...            01/01/70 00:00      
                                           Agreed, but...            01/01/70 00:00      
                                              It is seldom that simple ...            01/01/70 00:00      
                                                 That's the point!            01/01/70 00:00      
                                                 since you are really interested            01/01/70 00:00      
                                                    Thanks!            01/01/70 00:00      
          Yes, that is the way I normally do it            01/01/70 00:00      
          WHY TO DISTURB ACC ?            01/01/70 00:00      

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