AN1218 datasheet(21/56 Pages) FREESCALE

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Application Note

Data Movement

AN1218 Rev. 2

New MOVE

Instruction, Detail

The new CPU08 Move instruction is detailed below. Examples for this

instruction and all four of its addressing modes are given in

Appendix E — New CPU08 MOV Instruction Examples

. The

examples in Appendix E — New CPU08 MOV Instruction Examples

also compare the CPU05 and the CPU08 bus cycles and memory

requirements for the algorithm to execute the movement of data.

MOV

Move

Operation:

(M)destination ← (M)source

Description: Moves a byte of data from a source address

to a destination address. Data is examined

as it is moved, and condition codes are set.

Source data is not changed. Internal

registers (other than CCR) are not affected.

There are four addressing modes for the

MOV instruction. A discussion of these

modes was given in an earlier section.

Software

Techniques

The MOV command will cut cycle time and code space when moving

data. The most obvious advantage of the MOV instruction is when the

configuration registers are being initialized along with other RAM

variables at the start of the program.

Code Example

A user wants to start his application one of two different ways. The user

initializes the application on the MCU based on the logic level of port D

bit 4. Once the part is out of reset, it reads port D and moves data from

ROM into the RAM configuration registers according to the logic level of

bit 4. Refer to Appendix F — CPU05 and CPU08 Data Movement

Code

for code comparing the CPU05 and the CPU08.

Freescale Semiconductor, Inc.

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