Addressing Mode

Addressing modes specify how the data/arguments for an instruction are retrieved/stored.

Addressing modes may include:

• Implicit - Any arguments are implied by the instruction (e.g., a return-from-subroutine instruction, which pop a value off the stack and place it in the program counter).
• Register - Data is read from (or written to) a register.
• Absolute - An exact memory address is specified.
• Indirect - A memory address is specified, which contains the address of the memory for reading/writing. Effectively, the argument in this addressing mode is the address of a pointer to the actual data.
• Base plus offset - An absolute or indirect memory address is specified as a base address along with a register that contains an offset value. The base and offset values are added together, and the resulting address is used to read/write data.
• Relative - A signed or unsigned offset is added to the current program counter to obtain a new address. This is most often used for jumps but is also used for some kinds of data access.
• Stack - Values are pushed to or popped from the stack.