Datasheet

PIC16(L)F722A/723A
DS41417B-page 26  2010-2012 Microchip Technology Inc.
2.5 Indirect Addressing, INDF and
FSR Registers
The INDF register is not a physical register. Addressing
the INDF register will cause indirect addressing.
Indirect addressing is possible by using the INDF
register. Any instruction using the INDF register
actually accesses data pointed to by the File Select
Register (FSR). Reading INDF itself indirectly will
produce 00h. Writing to the INDF register indirectly
results in a no operation (although Status bits may be
affected). An effective 9-bit address is obtained by
concatenating the 8-bit FSR register and the IRP bit of
the STATUS register, as shown in Figure 2-6.
A simple program to clear RAM location 020h-02Fh
using indirect addressing is shown in Example 2-2.
EXAMPLE 2-2: INDIRECT ADDRESSING
FIGURE 2-6: DIRECT/INDIRECT ADDRESSING
MOVLW020h ;initialize pointer
MOVWFFSR ;to RAM
BANKISEL020h
NEXTCLRFINDF ;clear INDF register
INCFFSR ;inc pointer
BTFSSFSR,4 ;all done?
GOTONEXT ;no clear next
CONTINUE ;yes continue
Note: For memory map detail, refer to Figures 2-3 and 2-4.
Data
Memory
Indirect AddressingDirect Addressing
Bank Select Location Select
RP1 RP0 6
0
From Opcode
IRP File Select Register
7
0
Bank Select
Location Select
00 01 10 11
180h
1FFh
00h
7Fh
Bank 0 Bank 1 Bank 2 Bank 3