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???
04/13/08 13:44
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Msg Score: +1
 +1 Good Answer/Helpful		 #153191 - Not possible, use LCALL
Responding to: ???'s previous message
Hello

The ACALL if executed from address 2000H as in your example, can only reach addresses in the 2K area from 2000H to 27FFH.

So, if the target address is 8AH, which actually is 008AH, the ACALL is not possible. For this, the LCALL exists, which can be used to access the whole 64K range.

You should use a data sheet of an 8051, even an old Intel manual explains good, how it works.

Best regards
Juergen




List of 42 messages in thread
TopicAuthorDate
Problem with ACALL instruction            01/01/70 00:00      
   It is an absolute paged call...            01/01/70 00:00      
      my question is different            01/01/70 00:00      
         The Opcode is Selected...            01/01/70 00:00      
   not using an assembler?            01/01/70 00:00      
      still confused...            01/01/70 00:00      
         Not possible, use LCALL            01/01/70 00:00      
            Why should anyone WANT to know the hex            01/01/70 00:00      
               he'd want to know it because ...            01/01/70 00:00      
                  Unnecessary complication            01/01/70 00:00      
         compiler results error            01/01/70 00:00      
            There is no compiler involved. Just an assembler.            01/01/70 00:00      
         3 top bits of 11-bit address            01/01/70 00:00      
            only good for calls within the same 2K block            01/01/70 00:00      
            one more question...            01/01/70 00:00      
               Read your instruction set            01/01/70 00:00      
                  i am making an assembler.            01/01/70 00:00      
                     Now I understand. Far more interesting.            01/01/70 00:00      
                        Absolute Assembler            01/01/70 00:00      
                           what is an absolute assembler            01/01/70 00:00      
                              Which do you love.            01/01/70 00:00      
                                 actually I didn't            01/01/70 00:00      
                                    Linking assemblers are more complicated            01/01/70 00:00      
                     why not?            01/01/70 00:00      
               ajmp            01/01/70 00:00      
                  Reconsider Robert....            01/01/70 00:00      
                     positive offset...            01/01/70 00:00      
                        No !!!            01/01/70 00:00      
                           let's try this way            01/01/70 00:00      
                              abc?            01/01/70 00:00      
                                 I do not know how micro            01/01/70 00:00      
                                    can any1 tell abc??            01/01/70 00:00      
                                       As easy as 'abc'            01/01/70 00:00      
                                       How to get ABC            01/01/70 00:00      
                           whats the operand here?            01/01/70 00:00      
                              neither!!!!            01/01/70 00:00      
                                 is that an error?            01/01/70 00:00      
                                    error, not necessarily, but ..            01/01/70 00:00      
                                    it is not an error, but it is poor practice            01/01/70 00:00      
                        Not offset            01/01/70 00:00      
                           Oops, I was wrong earlier            01/01/70 00:00      
   Problem solved            01/01/70 00:00      

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