SECTION VI-16: Instruction Size of the PIC18 MOVFF Instruction Formation

The MOVFF is a 4 byte (32 bit) instruction. Of the 32 bits, the first 16 bits are set aside for the opcode and the address of the source fileReg and the other 16 bits are used for the opcode and the address of the destination. This is shown below:


PIC18 MOVFF Instruction Formation


Notice that for both the source and destination parts of the instruction, 12 bits are used for the file register address of the PIC18. The 12 bits cover the entire range of the addresses 000 - FFFH for the file register, which has 4096 bytes (4K) of data RAM space. That means that MOVFF can move the contents of any location in the file register to any other location directly. This is done without going through the WREG register.


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