Generic Addressing Modes

03/21/1996

Absolute:

To a specific address location. (sometimes referred to as General Addressing)

Immediate:

The method of loading the specific value(s) following the Op-Code.

Relative:

A location that is forward or backward, relative to, or from, the current location.

Indirect:

To a specific address location, that is identified as an address value, contained within another address location (as an Indirect Location)

Register:

To a specific address location, specified by the contents of a register.

Indexed:

A specific form of Register Addressing, with provision for an additive "Offset" of the specified address, allowing variable "Indexing" from the "Base Address" within the Index-Register.

Pre-Indexed:

A combination addressing method, incorporating Indexed Addressing prior to the use of Indirect Addressing.

Post-Indexed:

A combination addressing method, incorporating Indexed Addressing after the use of Indirect Addressing.

Page:

A form of addressing related to specific "Pages", or "Blocks" of memory.

Base Page:

Page Addressing restricted to specifically the "Base-Page" of memory.

Extended:

A form of memory addressing that allows for an extension beyond the normal range of addressing.

Internal:

Any form of activity that is only within the CPU, and does not affect outside devices or memory.

I/O:

Address Lines are used for "Device Address" in all cases.

Port Mapped:

I/O Device Addressing in conjunction with "IOREQ" type of signals.

Memory Mapped:

I/O Device Addressing in conjunction with conventional "MREQ" type of signals.