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 Post subject: Extra protected memory
PostPosted: Sun Apr 18, 2010 1:22 am 
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Joined: Mon Dec 27, 2004 11:40 pm
Posts: 318
If you set an invalid memory area then have an instruction with an address register indirect with predecrement effective address as the destination that is in this area only before the address register is decremented the access will cause a bus error at the decremented address.

E.g. ..
Code:
      MEMORY      invalid     $008000,$FFFFFF

      ORG   $1000

start
      MOVEA.l     #$8000,a0
      MOVE.b      #$00,-(a0)

      NOP

      END   start

.. causes a Bus Error: Instruction at 1006 accessing address 7fff

Lee.


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PostPosted: Sat Apr 24, 2010 12:38 pm 
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Joined: Thu Dec 16, 2004 6:42 pm
Posts: 1036
Corrected in v5.4.0

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Prof. Kelly


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