4 - Addressing Modes

• Absolute Memory - The t register contains a memory address, which is used to refer to an absolute memory address. An example would be 'mov8 (t),r0'.
• Immediate - Data is encoded in the instruction byte or the bytes following, and the CPU decodes or extracts it. This mode is exclusive to the ldt instruction.
• Register - The data affects a specific register, like the t register, and so needs no addressing. However, the 't' still needs to be specified in code, such as for example 'dec t' for decrementing the t register.
• Register Immediate - The instruction has a value embedded in it, which is a register index referring to the register used in the instruction. In assembly code it is referred to by a register number, such as 'mov t,r4', to move the t register's contents to register 4.
• Register Indirect - Using the RPTR index, the instruction acts on that register. It is coded with the 'rp' entry; for example 'inc rp' would increment the appropriate register's value.