MC81F4x16
Example : Addressing accesses the address 0135H regardless of G-flag.
:
;When G = 0
INC !0135h ;increase ROM[135h]
:
:
;op code is 98h
Indexed Addressing
X indexed direct page (no offset) → {X}
In this mode, an address is specified by the X register.
ADC, AND, CMP, EOR, LDA, OR, SBC, STA, XMA
Example :
:
;When G = 1, X = 15h
;A = ROM[(RPR<<8) + X]
;op code is 0D4h
LDA {X}
:
:
X indexed direct page, auto increment→ {X}+
In this mode, a address is specified within direct page by the X register and the content of X is
increased by 1.
LDA, STA
October 19, 2009 Ver.1.35
67