ABOV SEMICONDUCTOR MC81F4204 User Manual page 58

MC81F4204
Direct Page Addressing -> dp
In this mode, an address is specified within direct page. Current accessed page is selected by
RPR(RAM Page select Register). And dp( Direct Page ) is an one byte data which indicates the
target address in the current accessed page.
Example :
: ;When G = 0
LDA 35h ;A = [35h]
: ;op code is 0C5h
:
Absolute Addressing
Absolute addressing sets corresponding memory data to Data, i.e. second byte (Operand I) of
command becomes lower level address and third byte (Operand II) becomes upper level address.
With 3 bytes command, it is possible to access to whole memory area.
ADC, AND, CMP, CMPX, CMPY, EOR, LDA, LDX,LDY, OR, SBC, STA, STX, STY
The operation within data memory (RAM) : ASL, BIT, DEC, INC, LSR, ROL, ROR
Example :
: ;When G = 0
ADC !0F035h ;A = A + C + ROM[0F035h]
: ;op code is 07h
:
58 April 24, 2012 Ver.1.41