Detailed reference for the TBLRD* instruction in PIC18 ISA.
Read the contents of the table location pointed to by the 21‑bit table pointer (TBLPTR) into WREG. The address is formed by combining the 8‑bit TBLPAG page register with the TBLPTR register. The TBLRD instruction is a single‑word instruction that has no operands or options; it always writes the retrieved byte into WREG.
TBLPAG: 8‑bit register that selects the current table page.TBLPTR: 16‑bit register that holds the low and high byte of the table address.TBLPAG << 8 | TBLPTR) and places it in WREG.; TBLPAG=0, TBLPTR=0x0005 (address 5), read into WREG
TBLRD ; WREG = table[5]; TBLPAG=0, TBLPTR=0x0005 (address 5), read into WREG
TBLRD ; WREG = table[5]; TBLPAG=1, TBLPTR=0x0100 (address 256 within page 1), read into WREG
TBLRD ; WREG = table[0x100]; TBLPAG=1, TBLPTR=0x0100 (address 256 within page 1), read into WREG
TBLRD ; WREG = table[0x100]; TBLPAG=2, TBLPTR=0x0200 (address 512), read into WREG
TBLRD ; WREG = table[0x200]; TBLPAG=2, TBLPTR=0x0200 (address 512), read into WREG
TBLRD ; WREG = table[0x200]; TBLPAG=0, TBLPTR=0x00FF (address 255), read into WREG
TBLRD ; WREG = table[0xFF]; TBLPAG=0, TBLPTR=0x00FF (address 255), read into WREG
TBLRD ; WREG = table[0xFF]