MC68HC705P9 Datasheet, PDF (50/160 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Central Processor Unit (CPU)
4.7.1 Addressing Modes
The CPU uses eight addressing modes for flexibility in accessing data.
The addressing modes provide eight different ways for the CPU to find
the data required to execute an instruction. The eight addressing modes
are:
• Inherent
• Immediate
• Direct
• Extended
• Indexed, no offset
• Indexed, 8-bit offset
• Indexed, 16-bit offset
• Relative
4.7.1.1 Inherent
Inherent instructions are those that have no operand, such as return
from interrupt (RTI) and stop (STOP). Some of the inherent instructions
act on data in the CPU registers, such as set carry flag (SEC) and
increment accumulator (INCA). Inherent instructions require no operand
address and are one byte long.
4.7.1.2 Immediate
Immediate instructions are those that contain a value to be used in an
operation with the value in the accumulator or index register. Immediate
instructions require no operand address and are two bytes long. The
opcode is the first byte, and the immediate data value is the second byte.
4.7.1.3 Direct
Technical Data
50
Direct instructions can access any of the first 256 memory locations with
two bytes. The first byte is the opcode, and the second is the low byte of
the operand address. In direct addressing, the CPU automatically uses
$00 as the high byte of the operand address.
Central Processor Unit (CPU)
For More Information On This Product,
Go to: www.freescale.com
MC68HC705P9 — Rev. 4.0
MOTOROLA