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???
10/24/06 23:58
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 		 #126962 - SFRs forever...
Responding to: ???'s previous message
Maarten Brock said:
...to have indirect and indexed access. Stuff like:

movx a, @dptr+0xNN
movx @dptr+0xNN, a

mov a, @ri+0xNN
mov @ri+0xNN, a


Something similar can be made via a SFR (OK, not the most straighforward approach)
mov OFFSET_SFR,#NN
movx @dptr,a ;implicitly added OFFSET

If the reset default value of OFFSET_SFR would be zero, it's fuly backward compatible.
Of course it can be extended also to 16-bit offset.

Maarten Brock said:

lcall dptr
ljmp dptr

There is a jmp @a+dptr which is essentially ljmp dptr; lcall dptr is constructed simply by calling a jmp @a+dptr...

OK these all are multi-instruction constructions but you can't expect >256 single-byte single-cycle instructions from an 8-bitter... :-)))

Jan Waclawek

List of 29 messages in thread
TopicAuthorDate
Just One More...            01/01/70 00:00      
   DEC DPTR            01/01/70 00:00      
      or how about DDEC            01/01/70 00:00      
      what about            01/01/70 00:00      
         ???            01/01/70 00:00      
            who told you it is for data            01/01/70 00:00      
   Begin self destruct sequence,BSDS            01/01/70 00:00      
   DWIM            01/01/70 00:00      
   HCF ... HALT and CATCH FIRE            01/01/70 00:00      
      Synonym for BSDS?            01/01/70 00:00      
         instruction            01/01/70 00:00      
   The Missing Bit            01/01/70 00:00      
      Bit addressable            01/01/70 00:00      
         I Stand Corrected            01/01/70 00:00      
      ANL, ORL, XRL ?            01/01/70 00:00      
      The Question was            01/01/70 00:00      
         compilers like...            01/01/70 00:00      
            SFRs forever...            01/01/70 00:00      
               SFRs rule!            01/01/70 00:00      
      The Question was            01/01/70 00:00      
   There\'s always SUB (without the borrow)            01/01/70 00:00      
   XRL C,bit and XRL bit,C            01/01/70 00:00      
   in a dual dptr derivative            01/01/70 00:00      
      you mean both MOVC and MOVX, don't you            01/01/70 00:00      
         naah, just movx, mov was an oversight            01/01/70 00:00      
            some of 'em do that already, e.g. Dallas            01/01/70 00:00      
      mem to mem, not just autoincrement            01/01/70 00:00      
         mem to mem through acc            01/01/70 00:00      
         the Dallas parts do that            01/01/70 00:00      

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