Detailed reference for the ADDWFC instruction in PIC18 ISA.
Add the contents of WREG and the carry bit to file register f.
d = 0 → result is stored in WREG.d = 1 → result is stored back into register f.a = 0 → Access‑bank addressing.a = 1 → Banked addressing.; d=0, a=0 → result in WREG, Access bank
ADDWFC 0x20, 0, 0 ; W = W + 0x20 + C; d=0, a=0 → result in WREG, Access bank
ADDWFC 0x20, 0, 0 ; W = W + 0x20 + C; d=0, a=1 → result in WREG, Banked address
ADDWFC 0x20, 0, 1 ; W = W + 0x20 + C; d=0, a=1 → result in WREG, Banked address
ADDWFC 0x20, 0, 1 ; W = W + 0x20 + C; d=1, a=0 → result back to file register, Access bank
ADDWFC 0x20, 1, 0 ; 0x20 = 0x20 + W + C; d=1, a=0 → result back to file register, Access bank
ADDWFC 0x20, 1, 0 ; 0x20 = 0x20 + W + C; d=1, a=1 → result back to file register, Banked address
ADDWFC 0x20, 1, 1 ; 0x20 = 0x20 + W + C; d=1, a=1 → result back to file register, Banked address
ADDWFC 0x20, 1, 1 ; 0x20 = 0x20 + W + C; Load literal into WREG then add, result in WREG (Access bank)
MOVLW 0x10
ADDWFC 0x20, 0, 0 ; W = W + 0x20 + C; Load literal into WREG then add, result in WREG (Access bank)
MOVLW 0x10
ADDWFC 0x20, 0, 0 ; W = W + 0x20 + C