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Addressing Modes

  The term addressing mode refers to the way the processor specifies addresses of data items (or operands) being processed. The 68000 has a powerful range of addressing modes.

Clements, Section 2.3, describes addressing modes with many examples.

The Motorola 68000 Programmer's Reference Manual, Chapter 2, describes in some detail the available addressing modes.

The following table summarises the basic addressing modes.

type effective address example
immediate    
  none MOVE.L #$1A4E,D4
direct    
register EA=Rn MOVE.L D0,D3
absolute EA=<address> MOVE.L D0,$1234
indirect    
address register EA=(An) MOVE.L (A0),D3
displacement EA=(An) + <displacement> MOVE.L 12(A0),D3
index EA=(An) + (Dn) + <displacement> MOVE.L 9(A1,D0.W),D3
predecrement An = An - k, EA=(An) MOVE.L -(A0),D3
postincrement EA=(An), An = An + k MOVE.L (A0)+,D3
PC relative with displacement    
  EA=(PC) + <displacement> MOVE.L LABEL(PC),D5



 
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