98 Chapter 5 is needed as before to identify the data source register. Bit 7 (d) controls the data destination. This bit must be 0 to direct the data into W, the usual operation. For example, to move an 8-bit data word from file register 0C to W requires the syntax MOVF 0C,W. 5.2.3. Data Processing The arithmetic and logic unit (ALU) can add, subtract or carry out logical operations on single data bytes or pairs of numbers (see Chapter 2). These operations are carried out in conjunction with the data multiplexer and working register. The multiplexer allows new data to be fed from the instruction (a literal) or a register. This may be combined with data from W, or register data manipulated in a single register operation. W is used in register pair operations as a temporary data source or store, but the final result must usually be copied back into a file register, since W may be needed for the next operation. 5.2.4. Jump Instructions If a GOTO instruction is executed, the program counter will be loaded with the program memory address of the jump destination given as the instruction operand. The program label used in the source code will have been replaced by the destination address by the