Instructions Affected by Indexed Literal Offset Mode

Any of the core PIC18 instructions that can use Direct Addressing are potentially affected by the Indexed Literal Offset Addressing mode. This includes all byte-oriented and bit-oriented instructions, or almost one-half of the standard PIC18 instruction set. Instructions that only use Inherent or Literal Addressing modes are unaffected.

Additionally, byte-oriented and bit-oriented instructions are not affected if they do not use the Access Bank (Access RAM bit is ‘1’), or include a file address of 60h or above. Instructions meeting these criteria will continue to execute as before. A comparison of the different possible Addressing modes when the extended instruction set is enabled is shown in the following figure.

Those who desire to use byte-oriented or bit-oriented instructions in the Indexed Literal Offset mode need to note the changes to assembler syntax for this mode. This is described in more detail in the “Extended Instruction Syntax” section.

Figure 1. Comparing Addressing Options for Bit-Oriented and Byte-Oriented Instructions (Extended Instruction Set Enabled)