7. Summary of memory modes

Memory modes
Type Comment
Immediate Apply a constant to the accumulator. No need to access main memory
Direct or Absolute addressing This is a very simple way of addressing memory - the code refers directly to a location in memory. Disadvantage is that it makes relocatable code more difficult.
Indirect Addressing Looks to another location in memory for an address and then fetches the data that is located at that address. Very handy of accessing in-memory libraries whose starting address is not known before being loaded into memory
Indexed Addressing Takes a base address and applies an offset to it and fetches the data at that address. Excellent for handling data arrays
Relative Addressing Tells the CPU to jump to an instruction that is a relative number of locations away from the current one. Very efficient way of handling program jumps and branching.

 

 

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