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posted by  jbaili on 11/5/2009 2:25:52 AM  |  status: Closed  |  Earned Karma: 25

assembly6

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N/A N/A N/A N/A 11/5/2009 at 8:00:00 PM
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Write a 68000 assembly program to clear the contents of memory

locations in the range $5000 to $6000

?
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posted by rachel 's on 11/5/2009 3:10:05 AM  |  status: Live
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Dear,
               MOVE.W          #$1000, D0           ;     Load length of data into D0
               MOVEA.L         #$00005000, A0   ;     Load starting address into A0
REPEAT:CLR.W             (A0)+                      ;    Clear a location pointed to  by A0 and increment A0 by 2
                SUBQ.W         #1, D0                     ;    Decrement D0 by 1
                BNE.B             REPEAT                 ;    Branch to repeat if Z=0, otherwise it go to next instruction.
 
    CLR.W  (A1): IF A1.L = $00005000, then after execution of CLR.W[A1], the 16-bit content memory location $005000 will be cleared zero.
  clear 100016 words starting at memory locations 00500016.
  Note that # symbol used by motorola assembler to indicate immediate mode.                                  
         
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