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???
04/13/08 14:15
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Msg Score: +1
 +1 Good Answer/Helpful		 #153195 - 3 top bits of 11-bit address
Responding to: ???'s previous message
The destination address field of the instruction is 11 bits, so you take your 8AH and work out what the top 3 bits are.

In your case the address only occupies 8 bits so the top 3 are 000.

8AH is 1000 1010 but written in 11 bits it's
000 1000 1010


So your first instruction byte is
Save This Code
00010001


and the whole two bytes are: 11H, 8AH.

As Juergen says though, this instruction is only good for calls within the same 2K block of memory. An assembler would tell you if your destination was too far away.




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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