Generic Addressing Modes

03/21/96


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.