Detailed reference for the SETF instruction in PIC18 ISA.
The SETF instruction sets the specified file register to logical 1.
d = 0 → the result (logic 1) is stored in WREG.d = 1 → the result is written back to the file register f.a (access/banked) operand; addressing is performed using the normal file register syntax.; d=0 → result in WREG
SETF 0x20, 0 ; W = 1; d=0 → result in WREG
SETF 0x20, 0 ; W = 1; d=1 → result back to file register
SETF 0x20, 1 ; 0x20 = 1; d=1 → result back to file register
SETF 0x20, 1 ; 0x20 = 1